JP2003049097A - Ink-jet ink and ink set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a recording liquid for ink-jet excellent in discharge stability from a nozzle. SOLUTION: In an ink-jet ink obtained by dispersing a coloring agent in an aqueous liquid, the coloring agent comprises colored particles obtained by physically bonding a pigment on the surfaces of silica particles having 10-100 nm average particle size by a mechanochemical method.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an inkjet ink having excellent water resistance and a set thereof.

[0002]

2. Description of the Related Art Conventionally, as an ink jet recording liquid, a water soluble dye such as an acid dye, a direct dye or a basic dye dissolved in a glycol solvent and water has been used (Japanese Patent Laid-Open No. 53-1412). , JP-A-54-9811, JP-A-55-5269, etc.). As the water-soluble dye, those having high solubility in water are generally used in order to obtain stability of the recording liquid. Therefore, the ink jet recorded matter generally has poor water resistance, and there is a problem that spillage of water easily causes bleeding of the dye in the recorded portion.

In order to improve such poor water resistance,
Attempts have been made to change the structure of the dye and to prepare a recording liquid having a strong basicity (JP-A-56-57862). Further, it has been attempted to improve the water resistance by making good use of the reaction between a recording paper and a recording liquid (Japanese Patent Laid-Open No. 4900 / 50-4900).
4, JP-A-57-36692, and JP-A-59-2069.
6, JP-A-59-146889). Although these methods have a remarkable effect on a certain kind of recording paper, various recording papers are used in the recording by the ink jet method, and therefore the recording liquid containing a water-soluble dye does not have sufficient water resistance of the recorded matter. Is often not obtained.

Recording liquids having good water resistance include those in which an oil-soluble dye is dispersed or dissolved in a high boiling point solvent, and those in which an oil-soluble dye is dissolved in a volatile solvent. May be environmentally disliked by the emission of
The necessity of solvent recovery may be a problem when recording a large amount of data or depending on the installation location of the device. Therefore, in order to improve the water resistance of a recorded matter, a recording liquid in which a pigment is dispersed in an aqueous medium has been developed. However, unlike a dye, a pigment does not dissolve in a recording medium, and thus it is very difficult to disperse it as fine particles and to keep its dispersed state stable. While exhibiting excellent water resistance and light resistance, it is possible to adjust recording liquid ejection conditions, stability for long-term storage, fixing to non-recording media such as paper, image color, and bleeding quality. At present, further improvement is required in order to obtain properties equal to or better than dyes.

Further, in the recording liquid for ink jet, the diameter of the nozzle has become thinner as the resolution of the printer has become higher, and accordingly, the particle diameter of the coloring agent has to be made fine. In addition, the ink in which the pigment is dispersed is required to have the contradictory characteristics of re-solubility in the recording liquid and water resistance on the paper surface similar to the dye. However, it was difficult to obtain sufficient properties in terms of water resistance on paper.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an ink jet recording liquid which solves the above problems of the conventional method and has good ejection stability at the nozzle.

[0007]

SUMMARY OF THE INVENTION The present invention provides an inkjet ink prepared by dispersing a colorant in an aqueous liquid, wherein the colorant is an average of the particles physically bound to the silica particles by a mechanochemical method. The present invention relates to an inkjet ink, which is colored particles having a particle size of 10 to 100 nm.

Further, the present invention relates to the above-mentioned ink-jet ink, wherein the mechanochemical method is compaction pulverization treatment. Furthermore, in the present invention, the consolidation crushing treatment is performed by line weighting of 10 to 70 kg / cm
And the above inkjet ink. The present invention further relates to the above inkjet ink, wherein the mechanochemical method is carried out using silica particles treated with a silane coupling agent or in the presence of a silane coupling agent.
Furthermore, the present invention relates to the above inkjet ink, wherein the mechanochemical method is carried out in the presence of a pigment derivative.

The present invention further relates to the above ink jet ink further containing a dispersant. Further, the present invention relates to the above inkjet ink further containing a binder resin. Furthermore, the present invention relates to the inkjet ink, wherein the binder resin is an emulsion resin.

Furthermore, the present invention provides Pigment Red 122,
Pigment Violet 19 and the like, the inkjet ink containing at least one magenta pigment selected from quinacridone red, carmine 6B and naphthol red, and at least one yellow pigment selected from disazo yellow, quinophthalone, isoindoline, isoindolinone and condensed azo yellow. The present invention relates to an ink set including the inkjet ink containing the above and the inkjet ink containing a cyan pigment made of phthalocyanine blue. Furthermore, the present invention further relates to the ink set including the inkjet ink including the black pigment made of carbon black.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The colored particles of the present invention have a particle constitution in which the surface of silica particles is coated with a pigment, and the pigment is physically bonded to the silica particles by a known mechanochemical method. The silica used here has an average particle size of 5
It is a powder of silica oxide having a particle size of up to 100 nm, and can be either hydrophobic or hydrophilic. Colored particles are SEM
The average particle size measured by is 10 to 100 nm.

As the pigment, one selected from carbon black and organic pigments can be appropriately used depending on the purpose, but from the viewpoint of efficiency of mechanochemical treatment, a finely divided pigment is preferable. Such finely divided pigments include SEM
The average particle size measured in 1. is 10 to 80 nm.

The ratio of silica particles to pigment is silica particles.
The pigment is 10 to 200 parts by weight with respect to 100 parts by weight. However, considering the concentration as an ink, silica 100
70 to 130 parts by weight relative to parts by weight.

The mechanochemical method is a compaction crushing treatment, and is preferably carried out under the condition that the line weight is 10 to 70 kg / cm. The treatment time is 10 to 300 minutes and is adjusted depending on the characteristics of the pigment to be treated.

In the mechanochemical method, the use of an additive is also an important factor in the above-mentioned compaction pulverization treatment, and a silane coupling agent is used as such an additive. Silane coupling agent is silica particles 100
It is preferable to use 0.1 to 30 parts by weight with respect to parts by weight. The silane coupling agent may be used for the surface treatment of the silica particles before the mechanochemical treatment of the silica particles and the pigment.

The colored particles of the present invention have a silica surface of 1-10.
A pigment layer having a thickness of about nm is formed, and it has an effect of having a feeling of density and excellent color development as compared with the pigment used. According to the mechanochemical method of the present invention, the colored particles are
Although it depends on the shape of the silica particles, the aspect ratio when viewed as a planar shape is close to a spherical shape with a ratio of within about 1: 1.5.

In the mechanochemical treatment of the silica particles and the pigment, if the pigment derivative is used in an amount of 5 to 50 parts by weight per 100 parts by weight of the pigment, the mechanochemical treatment time is shortened, the particles are made finer, and when ink is formed. Brings improved dispersibility.

The organic pigments include toluidine red, toluidine maroon, Hansa yellow, benzidine yellow,
Insoluble azo pigments such as pyrazolone red, soluble azo pigments such as litol red, heliobordeaux, pigment scarlet, permanent red 2B, derivatives from vat dyes such as alizarin, indanthrone and thioindigo maroon, phthalocyanine blue, phthalocyanine green, etc. Phthalocyanine, quinacridone red,
Quinacridones such as quinacridone magenta, perylenes such as perylene red and perylene scarlet, isoindolinone such as isoindolinone yellow and isoindolinone orange, pyranthrone such as pyranthrone red and pyranthrone orange, thioindigo, condensed azo , Benzimidazolone series, quinophthalone series such as quinophthalone yellow, isoindoline series such as isoindoline yellow, and other pigments such as diketopyrrolopyrrole, flavanthron yellow, acylamide yellow,
Examples thereof include nickel azo yellow, copper azomethine yellow, perinone orange, anthron orange, dianthraquinonyl red, dioxazine violet and the like.

The organic pigments are shown by color index (CI) numbers, CI pigment yellow 12, 13,
14, 17, 20, 24, 74, 83, 86 93, 1
09, 110, 117, 125, 137, 138, 14
7, 148, 153, 154, 166, 168, CI
Pigment Orange 16, 36, 43, 51, 55,
59, 61, CI Pigment Red 9, 48, 49,
52, 53, 57, 97, 122, 123, 149, 1
68, 177, 180, 192, 215, 216, 2
17, 220, 223, 224, 226, 227, 2
28, 238, 240, CI Pigment Violet 1
9, 23, 29, 30, 37, 40, 50, CI Pigment Blue 15, 15: 1, 15: 4, 15: 6, 2
2, 60, 64, CI Pigment Green 7, 36, C.
I. Pigment Brown 23, 25, 26 etc.

It is preferable that these pigments have a particle size of several tens nm to 300 nm in terms of efficiency of mechanochemical treatment.
Alternatively, it is preferable to perform various fine particle treatments (for example, acid pasting) to adjust the particle size to be suitable for use.

In the mechanochemical method of the present invention, silica particles may be coated with a pigment derivative together with a pigment. The pigment derivative is one in which a basic group or an acidic group is introduced into the pigment or a skeleton similar to the pigment, and examples thereof include those represented by the following general formula (1).

P- [XYZN (R ¹ ) R ² ] n (1) (In the formula, P is an organic dye or its similar structure compound residue, and X is —SO ₂ —, − _{CO -, - CH 2 -,} - CH
_{2 S -, - CH 2 O} -, - O -, - COO -, - NH-,
-CH ₂ NHCOCH- or a divalent linking group selected from a combination thereof, Y is a direct bond, -NR- (wherein R is H or an alkyl group having 1 to 18 carbon atoms), -O.
A divalent linking group selected from-, Z is an alkylene group having 1 to 6 carbon atoms, R ^{1 and} R ² are each independently an optionally substituted alkyl group having 1 to 18 carbon atoms (R ¹ and A heterocycle may be formed with R ² and the heterocycle may have a substituent.), And n is an integer of 1 to 3. )

Examples of the organic dye residue represented by P in the formula (1) include the residues of the organic pigments exemplified above, and examples of the pigment-similar structure compound include anthraquinone and acridone.

Specific examples of the pigment derivative represented by the formula (1) include the following a to g. Pigment derivative a organic pigment residue substituent CI Pigment Blue _{15 -SO 2 NH (CH 2)} 2 N
(C ₂ H ₅ ) ₂ Pigment derivative b Organic dye residue Substituent CI Pigment Yellow 24-SO ₂ NH (CH ₂ ) ₂ N
(C ₃ H ₇ ) ₂ Pigment derivative c Organic dye residue Substituent CI Pigment Violet 19 --SO ₂ NH (CH ₂ ) ₃
N (C ₄ H ₉ ) ₂

Pigment derivative d Organic dye residue Substituent CI Pigment Blue 15 --CH ₂ S--CH ₂ N (C ₃
H ₇ ) ₂ Pigment derivative e Organic dye residue Substituent CI Pigment Yellow 150 --SO ₂ NH (CH ₂ ) ₃ N
(C ₂ H ₅ ) ₂

Pigment derivative f Organic dye residue Substituent CI Pigment Yellow 108 --CH ₂ O--CH ₂ N (C ₂
H ₅ ) ₂ Pigment derivative g Organic dye residue Substituent CI Pigment Violet 19 -CH ₂ S-CH ₂ N
(C ₄ H ₉ ) ₂

In the mechanochemical method, the use of additives is also an important factor in the above-mentioned compaction pulverization treatment, and a silane coupling agent is used as such an additive. Silane coupling agent is silica particles 100
It is preferable to use 0.1 to 30 parts by weight with respect to parts by weight. The silane coupling agent may be used for the surface treatment of the silica particles before the mechanochemical treatment of the silica particles and the pigment.

As the silane coupling agent, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-
Aminoethyl) aminopropylmethyldimethoxysilane, aminosilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-ureidopropyltriethoxysilane Etc.

In the ink-jet ink of the present invention, a water-soluble resin, a water-soluble low molecular compound, a surfactant, a pigment derivative or the like can be used as a dispersant for a colorant. Specific examples of the dispersant include acrylic acid ester resin, styrene-acrylic resin, styrene-maleic acid resin, maleic acid resin, fumaric acid resin, urethane resin, acrylic urethane resin, polyester resin, phenol resin, hydroxyl group-containing carboxylic acid ester. , Long chain polyaminoamide and high molecular weight acid ester salt, high molecular weight polycarboxylic acid salt,
Long-chain polyaminoamide and acid ester salt, high molecular weight unsaturated acid ester, polyether ester type anionic activator, naphthalenesulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate salt, polyoxyethylene alkyl phosphate ester , Polyoxyethylene nonylphenyl ether, stearylamine acetate, etc., 12
There are polycondensates of hydroxystearic acid and polyethyleneimine.

The pigment derivative that can be used as the dispersant is one in which a basic group or an acidic group is introduced into the pigment or a similar skeleton thereof, and examples thereof include the compound represented by the above general formula (1).

The binder resin of the present invention is a water-soluble or water-dispersible resin, and in the case of a water-soluble resin, it may also serve as a dispersant for the colorant. Examples of such resins include acrylic ester resins, urethane resins, polyester resins, and styrene-maleic acid resins. It is preferably an emulsion resin, and more preferably styrene-
It is an acrylic resin emulsion. A styrene-acrylic resin emulsion is a copolymer containing a styrene-based monomer, (meth) acrylic acid, and optionally a (meth) acrylic acid alkyl ester, and has an acid value of, for example, acrylic acid, styrene, or α-methylstyrene. Is 90 ~
There are 120 terpolymers. The terpolymer preferably has a molecular weight of 2000 to 5000 from the viewpoint of dispersibility of the colorant and ejection stability of the ink. Also, this 3
The original copolymer is sodium, potassium hydroxide, an aliphatic amine, in order to be stably dissolved in an aqueous liquid.
Alcohol amines such as ethanolamine, propanolamine and methylethanolamine, morpholine, N-methylmorpholine, dimethylaminoethanol, diethylaminoethanol and the like can be used as the neutralizing agent. The use of these neutralizing agents in an equimolar amount to a few% of the terpolymer and an excess amount of several% makes the solubility, water resistance and re-solubility maintain good.

The colorant of the present invention is dispersed with a binder resin in an aqueous medium, or is dispersed with a binder resin in advance and diluted with an aqueous medium to give an ink jet ink.

The particle size of the colorant after dispersion is preferably 1.0 μm or less, more preferably 0.2 μm or less in terms of average particle size by laser scattering method. With such a particle size, ink ejection is stable during recording,
The filtration operation in the production of the ink is easy and the sedimentation of the ink over time is reduced. The colorant of the present invention is used in an amount of 0.5 to 5% by weight in the ink, and if it is less than the above range, image density and color reproduction will be insufficient. On the other hand, if the amount is larger than this, the ejection stability is significantly reduced,
Frequent clogging at the nozzles makes it difficult to adjust the viscosity of the ink liquid.

Water, a humectant, and an aqueous solvent may be included in the aqueous liquid component of the present invention. The humectant and the water-based solvent prevent the ink from drying at the nozzle portion and prevent the ink from solidifying, and enable stable ink ejection. Such humectants and aqueous solvents include ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol,
Polyethylene glycol, glycerin, tetraethylene glycol, dipropylene glycol, ketone alcohol, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether ethylene glycol monoethyl ether, 1,2-hexanediol, N-methyl-2-pyrrolidone, substituted pyrrolidone, 2, 4,6-
Hexanetriol, tetrafurfuryl alcohol, 4
Examples thereof include -methoxy-4 methylpentanone.

For the purpose of accelerating the drying of the recording liquid on paper, alcohols such as methanol, ethanol and isopropyl alcohol can be used. These aqueous solvents are used alone or in a mixture in the range of 1 to 50% by weight in the ink. As the water that is the medium of the ink, ion-exchanged water or distilled water from which metal ions have been removed is used.

When the material to be printed is paper, a penetrant can be added in order to stop the penetration of the recording liquid into the paper and accelerate the apparent drying property. As the penetrant, glycol ether such as diethylene glycol monobutyl ether described as an aqueous solvent, alkylene glycol, polyethylene glycol monolauryl ether, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium oleate, sodium dioctylsulfosuccinate, etc. may be used. it can. These have a sufficient effect when used in an amount of 5% by weight or less in the ink, and when the amount is more than this amount, bleeding of printing and paper drop (print through) occur, which is not preferable.

The mildew-proofing agent prevents the generation of mildew on the ink, and is sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, zincpyridinethione-1-oxide, 1,2-. Benzisothiazolin-3-one, 1-benzisothiazolin-
An amine salt of 3-one or the like is used. These are used in the ink in an amount of about 0.05 to 1.0% by weight.

The chelating agent blocks the metal ions in the ink and prevents the deposition of metal at the nozzle portion and the insoluble matter in the recording liquid. Ethylenediaminetetraacetic acid, ethylenediaminetetraacid 0.005-0.5% by weight of sodium salt of acetic acid, diammonium salt of ethylenediaminetetraacetic acid, tetraammonium salt of ethylenediaminetetraacetic acid, etc. is used in the ink.

Further, in order to adjust the pH of the recording liquid to a desired pH and to stabilize the ink and the stability with the piping in the recording apparatus, an adjusting agent such as amine, inorganic salt and ammonia,
A buffer solution such as phosphoric acid can also be used. Further, an antifoaming agent may be added to prevent the circulation or movement of the ink or the generation of bubbles during the production of the recording liquid. The ink of the present invention may contain the following surfactants for the purpose of dispersing the colorant and improving the image quality. Such surfactants include anionic, nonionic, cationic and zwitterionic surfactants.

Examples of the anionic activator include fatty acid salt, alkyl sulfate ester salt, alkyl aryl sulfonate, alkyl naphthalene sulfonate, dialkyl sulfonate, dialkyl sulfosuccinate, alkyl diaryl ether disulfonate and alkyl phosphate. Salt, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl aryl ether sulfate, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester salt, glycerol borate fatty acid ester, polyoxyethylene glycerol fatty acid ester, etc. It can be illustrated.

As the nonionic activator, polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, polyoxyethylene oxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, Examples thereof include glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine, fluorine-based and silicon-based nonionic activators. Examples of the cationic activator include alkylamine salts, quaternary ammonium salts, alkylpyridinium salts, alkylimidazolium salts and the like. Examples of the zwitterionic activator include alkylbetaine, alkylamine oxide, phosphadylcholine and the like.

The dye can be used in such a form that there is no problem in water resistance and light resistance for the purpose of adjusting the hue of the pigment and imparting the concentration. Depending on the use of the dye, the dispersion stability of the colorant may be deteriorated, so it is necessary to limit the use of the colorant to 40% by weight or less, preferably 25% by weight or less. As dyes, acid dyes, basic dyes, direct dyes,
Reactive dyes, disperse dyes, metal-containing dyes and the like are used. These dyes are preferably purified dyes from which inorganic salts have been removed.

Examples of these dyes include C.I. I. Direct Black 17, 19, 32, 51, 71, 108, 1
46, 154, 166, C.I. I. Add Black 2,
7, 24, 26, 31, 52, 63, 112, 118,
C. I. Basic Black 2, C.I. I. Direct Blue 6, 22, 25, 71, 90, 106, C.I. I. Acid Blue 9, 22, 40, 59, 93, 102, 1
04, 113, 117, 120, 167, 229, 23
4, C.I. I. Basic Blue 1, 3, 5, 7, 9, 2
4, 25, 26, 28, 29, C.I. I. Direct Red 1, 4, 17, 28, 83, C.I. I. Acid Red 1, 6, 32, 37, 51, 52, 80, 85, 87,
92, 94, 115, 180, 256, 315, 31
7. C. I. Basic Red 1, 2, 9, 12, 1
3, 14, 37, C.I. I. Direct Yellow 12, 2
4, 26, 98, C.I. I. Acid Yellow 11, 17,
23, 25, 29, 42, 61, 71, C.I. I. Basic Yellow 11, 28. C. I. Direct orange 3
4, 39, 44, 46, 60, C.I. I. Direct violet 47, 48, C.I. I. Direct brown 10
9, C.I. I. Direct Green 59, C.I. I. Acid Orange 7, 19, C.I. I. Acid Violet 4
9, C.I. I. Basic violet 7, 14, 27, etc. can be illustrated.

Other additives such as urea and dimethylurea may be added. Further, various conventionally known solvents, additives, salts, synthetic and natural resins and the like can be used in combination.

The ink of the present invention is mixed with a colorant, a dispersant, water and an aqueous solvent and dispersed by a known disperser such as a sand mill, a homogenizer, a ball mill, a paint shaker and an ultrasonic disperser, and then a binder resin. Add the solution of and mix. Alternatively, a colorant, a binder resin, a dispersant, water and an aqueous solvent are mixed and dispersed with a disperser. Alternatively, the colorant and the binder resin are well kneaded in advance by a two-roll mill, then further dispersed by the above sand mill or the like, appropriately diluted with water, and other additives are mixed to obtain an ink. The mixing and stirring can be performed by a high-speed dispersing machine, an emulsifying machine or the like, in addition to the stirring with a usual stirrer using blades.

The ink has a pore size of 3 μm before or after dilution.
Thoroughly filter with the following filters. Preferably 1.
It is preferable to filter with a filter of 0 μ or less, more preferably a filter of 0.65 μ or less. Filtration by centrifugation can also be used prior to filtration of the filter, which results in less clogging during filter filtration and less filter replacement.

The ink is prepared as a liquid having a viscosity of 0.8 to 15 cps (25 ° C.), depending on the type of recording apparatus. The surface tension is 21 to 60 dyn / cm. PH
Is not particularly limited, but is in the range of 7 to 12, and preferably 7 to 10 is weakly alkaline. The inkjet ink of the present invention comprises a coloring agent of 0.5 to 5% by weight, a dye of 0 to 1% by weight, a moisturizing agent of 0 to 25% by weight, and an antifungal agent of 0.0.
3 to 0.5% by weight, resin 0.5 to 8% by weight, aqueous solvent 0
.About.25% by weight and 50 to 95% by weight of water.

The ink produced according to the present invention is suitable for use as an ink jet ink because it is water-based but has extremely good water resistance, and is suitable for use as an ink-jet ink for making documents in offices, marking symbols, cardboard markings, numbering, bar codes, etc. Can be used in the field of recorded materials. Further, compared to dye ink, it is possible to form a special image having excellent storage stability of recorded matter.

The present invention will be described below based on examples.
In the examples, "parts" means "parts by weight".

Method for producing colored particles P1: Silica particles (AEROSIL R-200 manufactured by Nippon Elosil Co., Ltd.)
100 parts, 90 parts of copper phthalocyanine pigment (Toyo Ink Mfg. Co., Ltd., Lionol Blue FG-7330), line weighted 50 kg / cm
Then, the powder was crushed for 20 minutes. The colored particles obtained are
It is a blue particle in which copper phthalocyanine is bound to the surface of silica particle by mechanochemical, and the specific surface area is 71 m ² /
The average particle size measured by SEM was 30 nm.

P2: Silica particles (AERO manufactured by Nippon Aerosil Co., Ltd.
SIL R-200) 100 parts, silane coupling agent (γ-methacryloxypropyltrimethoxysilane) 2 parts, copper phthalocyanine pigment (Toyo Ink Mfg. Co., Ltd. Lionol Blue FG-7330) 90 parts at a line weight of 50 kg / cm. A 20-minute compaction crushing process was performed. The obtained colored particles were blue particles in which copper phthalocyanine was bound to the surface of silica particles by mechanochemically, the specific surface area was 77 m ² / g, and the average particle diameter by SEM measurement was 31 nm.

P3: P- [CH ₂ NH (CH ₂ ) ₄
N (CH _{3) 2] 3} was performed (P copper phthalocyanine residue) mechanochemical treatment under the same conditions as P1 by adding 25 parts.
The obtained colored particles had a specific surface area of 78 m ² / g and an average particle diameter by SEM of 32 nm.

P4: Silica particles (Japan Aerosil AERO
SIL R-200) 100 parts, silane coupling agent (γ-methacryloxypropyltrimethoxysilane) 2 parts, copper phthalocyanine pigment (Toyo Ink Mfg. Co., Ltd. Lionol Blue FG-7330) 90 parts, P- [CH ₂ NH (CH ₂ ) ₄ N (C
H ₃ ) ₂ ] ₃ (P is a copper phthalocyanine residue) (25 parts) was added, and mechanochemical treatment was performed under the same conditions as for P1. The obtained colored particles have a specific surface area of 73 m ² / g and an average particle diameter by SEM
It was 30 nm. Hereinafter, colored particles were produced by the same method.

[0054] Colored particles Silica Pigment Silane capping agent Additive compound Line weighting time   P5 R-200 P.R122 60Kg 20 minutes   P6 R-200 P.R122 GP 60Kg 20 minutes   P7 R-200 P.R122 Compound (B) 60Kg 20 minutes   P8 R-200 P.R122 GP Compound (B) 60Kg 20 minutes   P9 R-972 P.R122 60Kg 20 minutes   P10 R-972 P.R122 Compound (B) 50Kg 15 minutes   P11 R-200 P.Y180 60Kg 20 minutes   P12 R-200 P.Y180 MP 60Kg 20 minutes   P13 R-200 P.Y180 Compound (C) 60Kg 20 minutes   P14 R-200 P.Y180 MP Compound (C) 60Kg 20 minutes   P15 R-972 P.Y180 60Kg 20 minutes   P16 R-972 P.Y180 Compound (C) 60Kg 15 minutes   P17 R-200 P.BK7 60Kg 20 minutes   P18 R-200 P.BK7 MP 60Kg 20 minutes   P19 R-200 P.BK7 Compound (A) 60Kg 20 minutes   P20 R-200 P.BK7 MP Compound (A) 50Kg 20 minutes   P21 R-972 P.BK7 60Kg 15 minutes   P22 R-972 P.BK7 Compound (A) 50Kg 10 minutes   P23 (Comparative example) P.BL15: 3 Untreated   P24 (Comparative example) P.R122 Untreated   P25 (Comparative example) P.Y180 Untreated   P26 (Comparative example) P.BK7 Untreated

R-200: AEROSIL R-200 (manufactured by Nippon Aerosil) R-972: AEROSIL R-972 (manufactured by Nippon Aerosil) GP: γ-glycidoxypropyltrimethoxysilane MP: γ-methacryloxypropyltri methoxysilane compound (A): P- _{[CH 2 NH (CH 2) 4} N (CH 3)
₂ ] ₃ (P is a copper phthalocyanine residue) Compound (B): P- [CH ₂ NH (CH ₂ ) ₄ N (CH ₃ ).
_{2] 3} (P is a quinacridone residue) Compound (C): P- _{[CH 2 NH (CH 2) 4} N (CH 3)
₂ ] ₃ (P is a benzimidazolone residue)

Synthesis Example A terpolymer resin (solid content: 30%) having the following monomer composition was synthesized according to the method of synthesizing an acrylic resin.

[0057]             Acrylic acid Styrene α Methylstyrene Acid value Molecular weight   Resin R1 1 1.8 2.0 105 105 3000        R2 1 2.0 2.0 100 100 2000

Example 1 The following raw materials were placed in a sand mill and dispersed for 3 hours to prepare an ink jet ink concentrate. Colored particles (P1) 30 parts Resin (R1) 1.5 parts Dimethylaminoethanol 0.1 parts Dispersant (Emulgen 420 manufactured by Kao) 1 part Purified water 51.5 parts Glycerin 6 parts After dispersion, mix with the following . After mixing, an ink was produced by filtering with a 1 μ membrane filter. Dispersion 13.5 parts Dispersant (Emulgen 420 manufactured by Kao Corporation) 0.2 parts Resin (R1) 2.5 parts Ethylene glycol 10 parts Proxel GXL (manufactured by Zeneca) 0.15 parts Ethylenediaminetetraacetic acid sodium salt 0.02 parts Purified water 63.53 parts When this ink was put in a cartridge of a commercially available piezo printer and recording was carried out, good recorded matter was obtained. I drew water on the recording surface and checked for ink bleeding,
There was no ink bleeding or running out, and it had sufficient water resistance. The recorded matter was rubbed 10 times with a cotton swab soaked with water, but no ink adhered to the cotton swab.

Examples 2 to 22 and Comparative Examples 23 to 26 Ink jet inks were obtained in the same manner as in Example 1 except that the coloring particles, the resin and the dispersion time were changed as shown in the following table.

[0060] Dispersion 2 3 4 5 6 7 8 9 10 Colored particles P2 P3 P4 P5 P6 P7 P8 P9 P10 Resin R1 R1 R1 R1 R1 R2 R2 R2 R2 Dispersion time 3 3 2 3 2 3 3 3 3 2

[0061] Dispersion 11 12 13 14 15 16 16 17 18 19 20 Colored particles P11 P12 P13 P14 P15 P16 P17 P18 P19 P20 Resin R1 R1 R1 R1 R1 R2 R2 R2 R2 R1 Dispersion time 3 2 3 3 3 2 3 2 3 1.5

[0062] Dispersion 21 22 23 24 25 26 Colored particles P21 P22 P23 P24 P25 P26 Resin R1 R1 R1 R1 R1 R2 Dispersion time 2 1.5 6 6 6 6

After dispersion, the following was mixed. After mixing
An ink was produced by filtering with a 1 μ membrane filter. (Ink number corresponding to dispersion) The above dispersion 13.5 parts Dispersant (Emulgen 420 manufactured by Kao) 0.2 parts Resin (R1) 2.5 parts Ethylene glycol 10 parts Proxel GXL (manufactured by Zeneca) 0. 15 parts Ethylenediaminetetraacetic acid sodium salt 0.02 part Purified water 63.53 parts When this ink was put in a cartridge of a commercially available piezo printer and recording was performed, a good recorded matter was obtained. I drew water on the recording surface and checked for ink bleeding,
There was no ink bleeding or running out, and it had sufficient water resistance. The recorded matter was rubbed 10 times with a cotton swab soaked with water, but no ink adhered to the cotton swab.

[0064]               Water resistance Redissolvability Filtration Viscosity Jet characteristics Dispersibility D50               K Art 1.0μ   Ink 1 Good Good Good 1L or more 1.9 Good Good 161nm         2 Good Good Good 1L or more 1.9 Good Good 150nm         3 Good Good Good 1L or more 2.1 Good Good 113nm         4 Good Good Good 1L or more 2.3 Good Good 101nm         5 Good Good Good 1L or more 2.2 Good Good 144nm         6 Good Good Good 1L or more 2.4 Good Good 135nm         7 Good Good Good 1L or more 2.7 Good Good 114nm         8 Good Good Good 1L or more 2.7 Good Good 120nm         9 Good Good Good 1L or more 2.8 Good Good 126nm         10 Good Good Good 1L or more 2.6 Good Good 103nm         11 Good Good Good 1L or more 2.7 Good Good 173nm         12 Good Good Good 1L or more 3.0 Good Good 164nm         13 Good Good Good 1L or more 2.6 Good Good 161nm         14 Good Good Good 1L or more 2.7 Good Good 136nm         15 Good Good Good 1L or more 3.0 Good Good 145nm         16 Good Good Good 1L or more 3.0 Good Good 124nm         17 Good Good Good 1L or more 3.0 Good Good 164nm         18 Good Good Good 1L or more 2.6 Good Good 161nm         19 Good Good Good 1L or more 2.7 Good Good 146nm         20 Good Good Good 1L or more 3.0 Good Good 105nm         21 Good Good Good 1L or more 3.0 Good Good 124nm         22 Good Good Good 1L or more 2.6 Good Good 104nm   Comparative Example 23 Good Good Good 0.3L or less 2.7 Good Bad 177nm   Comparative Example 24 Good Good Good 0.3L or less 3.0 Good Bad 199nm   Comparative Example 25 Good Good Good 0.1L or less 3.0 Good Bad 254nm   Comparative Example 26 Good Good Good 0.5L or less 3.0 Good Bad 171nm

Water resistant plain paper (Xerox K)
After being dried, the printed matter was visually evaluated for bleeding when immersed in water for 1 minute. The change in the printed part when the solid print on the art paper was rubbed three times with a damp cotton swab was visually evaluated. Re-dissolvability After drying the recording liquid on a nickel plate (after 2 days)
The solubility when immersed in the same recording liquid was visually evaluated. Filterability The amount of filtration with a membrane filter having a diameter of 90 mm was compared. Viscosity Vibrating viscometer (25 ° C, Yamaichi Denki Co., Ltd. Viscomate VM-1A) Jetting characteristics The jetting failure of the nozzle during continuous printing was evaluated from the defects of the printed matter. Dispersibility The presence or absence of precipitated particles after storage at 50 ° C for 7 days was evaluated.

EFFECT OF THE INVENTION The ink-jet ink of the present invention can reduce the particle size even if it is a pigment having a large particle size, and the dispersion time can be shortened. In addition,
The formation of colored particles by mechanochemical treatment of silica particles and pigments can suppress the precipitation of pigment particles and stabilize the dispersion. It is possible to reduce the amount of dye component used, and to enable a formulation that reduces the proportion of expensive materials.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09C 1/28 C09C 3/04 3/04 3/08 3/08 3/12 3/12 B41J 3/04 101Y F term (reference) 2C056 EA13 FC01 FC02 2H086 BA55 BA59 BA60 4J037 AA18 CB23 CB28 4J039 AD03 AD10 AD12 AD13 AD14 AD23 AE04 AE06 AE07 AE09 BC17 BC57 BD04 BE01 BE12 BE22 CA06 EA15 EA16 EA38 EA17 EA17 EA17 EA17 EA17 EA17 EA17

Claims (10)

[Claims] 1. An ink-jet ink comprising a colorant dispersed in an aqueous liquid, the colorant having a mean particle size of 10 to 100 nm in which the colorant is physically bound to a silica particle surface by a mechanochemical method. An inkjet ink characterized in that 2. The ink-jet ink according to claim 1, wherein the mechanochemical method is compaction pulverization treatment. 3. Consolidation crushing treatment is line weighted 10-70 Kg / c
The inkjet ink according to claim 2, which is m. 4. The inkjet ink according to claim 1, wherein the mechanochemical method is carried out by using silica particles treated with a silane coupling agent or in the presence of a silane coupling agent. 5. The inkjet ink according to claim 1, wherein the mechanochemical method is carried out in the presence of a pigment derivative. 6. The inkjet ink according to claim 1, further comprising a dispersant. 7. The inkjet ink according to claim 1, further comprising a binder resin. 8. The inkjet ink according to claim 7, wherein the binder resin is an emulsion resin. 9. A quinacridone red such as Pigment Red 122 or Pigment Violet 19 and Carmine 6B.
And at least one magenta pigment selected from naphthol red, and at least one yellow pigment selected from disazo yellow, quinophthalone, isoindoline, isoindolinone, and condensed azo yellow. Item 9. An ink set comprising the inkjet ink according to any one of items 1 to 8 and the inkjet ink according to any one of items 1 to 8 containing a cyan pigment made of phthalocyanine blue. 10. The ink set according to claim 9, further comprising the inkjet ink according to any one of claims 1 to 8, further comprising a black pigment made of carbon black.