JPH10298467A - Water-base ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-base ink which can give prints excellent in water resistance and improved in printing density, printing quality, especially color tone, saturation and lightness by using a suspension of a polymer containing an adsorbed mixed colorant comprising a non-fluorescent water-insoluble or difficultly water-soluble colorant and a fluorescent water-insoluble or a difficultly water-soluble colorant in a specified ratio. SOLUTION: This ink comprises a suspension of a polymer containing an adsorbed mixed colorant comprising a non-fluorescent water-insoluble or difficultly water-soluble colorant (e.g. C.I. Solvent Red 18) and a fluorescent water-insoluble or difficultly water-soluble colorant (e.g. C.I. solvent Red 49) in a ratio of 5/1 to 1/10. The ink desirably contains an acid value of 3-100 KOHmg/g, and more desirably, it contains a suspension of a polymer being of a type of urethane, (meth)acrylic, epoxy, polyester, polyester amide or polyamide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based ink having excellent water resistance of printed matter, improved print density and print quality, and especially improved color tone and chroma, and particularly useful as an ink for ink jet recording. It relates to water-based ink.

[0002]

2. Description of the Related Art Water-based inks are often used for printing and writing implements because of their ease of production and handling. For example, printer devices have become widespread due to the recent development and spread of computers, and water-based inks have been actively used in such printer devices.

[0003] Ink used in an ink jet printer, which is one of the typical printer devices, usually uses a water-soluble dye that dissolves in water in order to prevent nozzles from being clogged with ink. The use of the water-soluble dye makes it difficult for the nozzles to be clogged, but has a problem in that the printed matter has poor water resistance. Therefore, in order to improve the water resistance of the printed matter, the composition of the ink is important.

In order to improve the water resistance of the ink for ink jet recording, a pigment is used as the ink (A) (JP-A-4-28776, JP-A-4-189876, JP-A-4-3599071, and JP-A-4-359907). -359072
Or (B) using a non-aqueous liquid medium (Japanese Unexamined Patent Publication No.
JP-A-261478), (C) using a dye having excellent water resistance (U.S. Pat. No. 4,963,189), and (D) using emulsion-polymerized or dispersed-polymerized particles dyed with a dye (Japanese Patent Laid-Open No. 250069/1991). Publication No. 6-340
835, 7-150098) and the like.

However, when a pigment is used as the ink (A), there is a possibility that the saturation of a printed matter may be reduced and a problem such as clogging in a nozzle may occur. In addition, the pigment has poor dispersion stability and may settle. Therefore, there was a problem in storage stability when the ink was used. In the case of using (D) dyed polymer particles, it is difficult to dye at a high concentration. It was bad. In addition, even in the proposals of (B) and (C), an ink which sufficiently satisfies all required characteristics such as water resistance and print density of a printed matter has not yet been obtained.

Accordingly, it is an object of the present invention to provide a water-based ink which is excellent in water resistance of printed matter, has improved print density and print quality, and particularly has improved color tone, chroma and lightness.

Another object of the present invention is to provide a water-based ink which is particularly useful as an ink for ink-jet recording.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and have found that a mixed color material in which a color material having no fluorescence and a color material having fluorescence are blended in a specific quantitative ratio. It has been found that an ink containing a water-based suspension in which is adsorbed on a polymer improves the water resistance of the printed matter, and also improves the print density and print quality, particularly the color tone and saturation.

The present invention has been made based on the above findings, and is a mixture comprising a water-insoluble or sparingly water-soluble coloring material having no fluorescence and a water-insoluble or sparingly water-soluble coloring material having fluorescence (B). The color material (A) contains a suspension of a polymer to which a color material is adsorbed, and is contained in an ink.
And the weight ratio (A) / (B) of the color material (B) is 5/1 to 1
The above object has been attained by providing a water-based ink characterized in that the ratio is / 10.

The present invention also provides an ink jet recording ink characterized by using the above-mentioned aqueous ink.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the water-based ink of the present invention, a water-insoluble or sparingly water-soluble coloring material (A) having no fluorescence and a water-insoluble or sparingly water-soluble coloring material (B) having fluorescence will be described later. A mixed color material blended at a specific quantitative ratio, and containing a polymer aqueous suspension to which the mixed color material is adsorbed. That is,
In the water-based ink of the present invention, at least a part of the mixed colorant is adsorbed by micelles (particles) formed by the polymer, or is enclosed in the micelle. That is, in the present specification, "the coloring material is adsorbed" means that at least a part of the coloring material is adsorbed by the micelle formed by the polymer or is enclosed in the micelle. The aqueous ink of the present invention is obtained by mixing micelles (particles) of the polymer adsorbed with the mixed colorant in water as a suspension, and further mixing various additives as necessary in the suspension. It is.

The above polymer preferably has an acid value based on JIS K 0070 of 3 to 100 KOH mg / g. If the acid value is less than 3 KOH mg / g, a suspension in which the mixed color material is stably adsorbed may not be obtained. If the acid value exceeds 100 KOH mg / g, the water resistance of the ink may be poor. It is preferable to be within the range. The acid value is preferably 3 to 70 KOHm from the viewpoint of improving suspension formability and stability.
g / g, more preferably 10 to 60 KOH mg / g.
g, more preferably 20 to 50 KOH mg / g, and still more preferably 25 to 50 KOH mg / g.

The above-mentioned polymer has a Tg (glass transition point) measured by DSC (differential scanning calorimetry) of 20 ° C. or higher when the ink jet method uses a piezoelectric element, and the ink jet method uses heat energy. Is preferably 30 ° C. or higher, more preferably 40 ° C. or higher and 150 ° C. or lower, and further preferably 50 to 15 ° C., irrespective of both the piezoelectric and thermal energy types.
0 ° C. When Tg is within the above range, when the water-based ink of the present invention is used in an ink jet printer, for example, when the polymer is solidified in the nozzle of the printer, the nozzle is clogged, or when the printed paper is overlaid. Does not cause any inconvenience such as the reflection of the ink on paper.

The above polymer has a number average molecular weight (converted to polystyrene by gel permeation chromatography) of 500 to 100,000, especially 1000.
A value of from 10,000 to 10000 is desirable from the viewpoints of water resistance and fixing property of the ink after printing and formability of the suspension, and in particular, in the case of using the water-based ink of the present invention in an ink jet printer to prevent scorching on a printer head.

The polymer used in the aqueous ink of the present invention is not particularly limited as long as it can adsorb the mixed colorant. In particular, from the viewpoint of the adsorbing property of the mixed colorant, the urethane-based polymer, the polymer or copolymer of (meth) acrylic acid or its derivative, or the like, which has high suspension-forming properties, and the fixability to paper are good. Any one or more of a suitable epoxy polymer, polyester polymer such as polyester, polyester polyamide polymer or polyamide polymer is preferably used.

The above polymer preferably contains a unit derived from a diol component represented by the following formula (1) in the polymer chain from the viewpoint of controlling the thermal properties of the polymer.

[0017]

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In particular, from the viewpoint of fixability to paper, it is preferable to use a polyester polymer containing a bisphenol derivative in a polymer chain as the polymer. Hereinafter, such a polyester-based polymer will be described.

The polyester-based polymer is not particularly limited. For example, a diol component represented by the above formula (1) (hereinafter referred to as component (a)) and a polyvalent carboxylic acid derivative [hereinafter referred to as component (b) [Polyester (A)] is preferably used.
In the present specification, the “polyvalent carboxylic acid derivative”
It refers to a polycarboxylic acid, an acid anhydride thereof or a lower alkyl ester thereof.

The diol component represented by the above formula (1), which is the component (a), will be described. The diol component is not particularly limited, but an alkylene oxide adduct of bisphenol A, preferably bisphenol A Of ethylene oxide or propylene oxide, specifically, polyoxypropylene (2.2)-
2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis ( 4-hydroxyphenyl)
Propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6)-
2,2-bis (4-hydroxyphenyl) propane and the like can be preferably used.

Further, in obtaining the polyester by co-condensation polymerization, the diol component represented by the above formula (1) and other alcohol components can be used in combination.
In this case, the proportion of the diol component represented by the above formula (1) is preferably 40 to 10 in all the alcohols used.
0 mol%. Other alcohol components include, for example, aliphatic diols and trivalent or higher alcohols. In this case, the proportion of the aliphatic diol is preferably less than 20 mol% in the total alcohol used, and the proportion of the trihydric or higher alcohol is preferably less than 60 mol% in the total alcohol used. is there. Examples of the aliphatic diol include ethylene glycol,
Diethylene glycol, triethylene glycol, 1,
2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedi Examples include methanol, dipropylene glycol, polyethylene glycol, polypropylene glycol and polytetramethylene glycol. Examples of the above trihydric or higher alcohols include sorbitol, 1,2,2
3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol,
1,2,5-pentanetriol, glycerol, 2-
Methylpropanetriol, 2-methyl-1,2,4-
Butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like.

Next, the polycarboxylic acid derivative as the component (b) is not particularly limited, and may be at least one selected from the group consisting of polycarboxylic acids, acid anhydrides and lower alkyl esters thereof. Is used.

As the polyvalent carboxylic acid, divalent carboxylic acids and trivalent or higher carboxylic acids are used. The divalent carboxylic acid is not particularly limited, but includes, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacin Acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n-octenyl succinic acid, n-octyl succinic acid, isooctenyl succinic acid, dimer acid, isomeric Octyl succinic acid and the like are preferably used. On the other hand, the trivalent or higher carboxylic acid is not particularly limited, and for example, 1,2,4-benzenetricarboxylic acid, 2,2
5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-
Dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,2
7,8-octanetetracarboxylic acid, pyromellitic acid,
Trimellitic anhydride, embolic trimer acid and the like are preferably used. As the lower alkyl ester of these polyvalent carboxylic acids, an alkyl ester having 1 to 4 carbon atoms is preferably used. In particular, as the polyvalent carboxylic acid, a divalent carboxylic acid such as maleic acid, fumaric acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, dimer acid, or 1,2,4-benzenetricarboxylic acid It is preferable to use an acid or trimellitic anhydride.

The molar ratio of the component (a) to the component (b) in the polyester (A) depends on the acid value, number average molecular weight, Tg and the like of the polyester (A). The acid number based on 0070 is preferably 3
The above components may be freely combined and selected within a range of １００100 KOH mg / g. As an example of the component ratio,
The component (b) is added in an amount of 0.1 to 1 mol of the component (a).
It is preferably from 0.1 to 1.4 mol, and from 0.1 to 1.
More preferably, it is 2 mol.

In addition, as the polyester-based polymer, a diol component represented by the above formula (1) (that is, the component (a)), a dimer acid (hereinafter, referred to as a (b) ′ component), and other than the dimer acid It is also preferable to use a product obtained by co-condensation polymerization of a polycarboxylic acid derivative [hereinafter, referred to as "component (b)"] [this polyester-based polymer is hereinafter referred to as polyester (B)].

The component (a) used in the polyester (B) includes the same components as those used in the polyester (A). In the description of the dimer acid as the component (b) ′, “dimer acid” in this specification refers to a substance synthesized by a polymerization reaction of two molecules of unsaturated fatty acids. Examples of the dimer acid include acyclic dimer acids represented by the following formulas (I) and (II), and the following formula (III)
), (IV) and (V) monocyclic dimer acids,
In addition, bicyclic dimer acids represented by the following formulas (VI) and (VII) can be used. By using the dimer acid as the copolycondensation component in the polyester, the formability and stability of the suspension are improved, and the adsorbed amount of the mixed colorant is improved. The dimer acids may be used alone or in combination of two or more. As the dimer acid, commercially available products can also be used. Such commercial products generally include acyclic dimer acids represented by the following formulas (I) and (II), and monocyclic dimer acids represented by the following formulas (III), (IV) and (V): Dimer acid, and the following formulas (VI) and (VI
I) It is composed of a complex mixture of bicyclic dimer acids represented by (I), for example, Unidim 22 (trade name, acyclic rich type) manufactured by Union Cap or Haridima 250K (trade name, monocyclic. Bicyclic rich type).

[0027]

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[0028]

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[0029]

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Of the above-mentioned dimer acids, it is preferable to use an acyclic dimer acid as a main component from the viewpoint of improvement in suspension formability and stability, and particularly to use a dimer acid represented by the formula (I). preferable.

The component (b) "used in the polyester (B) is the same as the component (b) used in the polyester (A) except for dimer acid. be able to.

In the polyester (B), the molar ratio of the component (a), the component (b) ′, and the component (b) ″ is determined by the acid value, the number average molecular weight and the Tg of the polyester (B). The above components may be freely combined and selected within a range where Tg is 20 ° C. or higher, although the value of the component (b) ′ is particularly preferable.
It is preferably from 0.001 to 0.7 mol, more preferably from 0.01 to 0.5 mol, per 1 mol of the component (a). On the other hand, the component (b) ″ is preferably 0.3 to 1.2 mol, more preferably 0.5 to 1.1 mol, per 1 mol of the component (a).

Further, as the polyester-based polymer, a diol component represented by the above formula (1) (that is, the component (a)), a dimer acid (that is, the component (b) ′), and trimellitic anhydride Acid [hereinafter, referred to as (b) ^* component] and a polyvalent carboxylic acid derivative other than these acids [(b) ′ and (b) ^* component] [hereinafter, referred to as (b) ^** component]
It is also preferable to use those obtained by co-condensation polymerization of the following [hereinafter, this polyester-based polymer is referred to as polyester (C)].

The component (a) used in the polyester (C) includes the same components as those used in the polyester (A). Examples of the component (b) ′ include the same components as those used in the polyester (B). Further, by using trimellitic anhydride as the component (b) ^* as the copolycondensation component in the polyester, the formability and stability of the suspension are improved, and the adsorbed amount of the mixed colorant is improved.

The component (b) ^** used in the polyester (C) includes dimer acid and trimellitic anhydride from those exemplified as the component (b) used in the polyester (A). Can be used.

In the polyester (C), the molar ratio of the component (a), the component (b) ′, the component (b) ^{* and the} component (b) ^** is the same as that of the polyester (C). The above components may be freely combined and selected within a range where Tg is preferably 20 ° C. or higher, although it depends on the values such as the acid value, number average molecular weight, and Tg. As a particularly preferable example of the component ratio, the component (b) ′ is preferably 0.001 to 0.7 mol, more preferably 0.01 to 0.5 mol, per 1 mol of the component (a). Is more preferable.
The component (b) ^* is preferably present in an amount of 0.05 to 0.7 mol based on 1 mol of the component (a).
More preferably, it is 0.1 to 0.5 mol. Also,
The component (b) ^** is used per mole of the component (a).
0.3 to 1.2 mol, preferably 0.5 to
More preferably, it is 1.1 mol.

In the above-mentioned polyester, for example, each co-condensation polymerization component at the time of co-condensation polymerization [the above-mentioned component (a),
(B), (b) ', (b) ", (b) ^* and (b) ^** ]
The acid value, Tg, number average molecular weight, and the like can be adjusted by changing the addition ratio of carboxylic acid, using a carboxylic acid ester, or blocking the acid with a monohydric alcohol. The method of the copolycondensation is not particularly limited, and a known method is used.

In the water-based ink of the present invention, the polymer is preferably incorporated in the ink in an amount of 1 to 50% by weight, more preferably 2 to 30% by weight. If the amount of the polymer is less than 1% by weight, the print density is insufficient. If the amount is more than 50% by weight, the storage stability of the suspension as ink deteriorates. The printer head may be clogged due to thickening of the ink and aggregation of the suspension due to the evaporation of the ink at the leading end portion.

Next, the mixed color material adsorbed by the polymer micelles (particles) will be described. The mixed coloring material comprises a water-insoluble or poorly water-soluble coloring material having no fluorescent light (A) and a water-insoluble or poorly water-soluble coloring material having fluorescent light (B). In the present specification, "a water-insoluble or poorly water-soluble colorant having no fluorescence" is a water-insoluble or poorly water-soluble colorant which is generally used as a colorant for ordinary inks and has no fluorescence. It means the whole, and includes all coloring materials other than the coloring material having fluorescence among the water-insoluble or hardly water-soluble coloring materials. The weight ratio (A) / (B) of the color material (A) to the color material (B) in the aqueous ink of the invention is from 5/1 to 1/10, preferably from 4/1 to 1/1. 9, more preferably 2/1 to 1 /
9, more preferably 1/2 to 1/6. By blending the color material (A) and the color material (B) in the ink at the above weight ratio, the brightness of the ink is improved,
The color tone is improved, resulting in improved print density and print quality.

The coloring material (A) and the coloring material (B) are water-insoluble or hardly water-soluble coloring materials, each having no fluorescence or having fluorescence and capable of adsorbing to the polymer. If it is, it can be used without particular limitation, and examples thereof include dyes and pigments such as oil-soluble dyes and disperse dyes. In particular, it is preferable to use an oil-soluble dye or a disperse dye from the viewpoint of good adsorption.

The disperse dye used as the colorant (A) is not limited to the following, but a preferred specific example is C.I. I. Disperse Yellow 5,
42, 54, 64, 79, 83, 93, 99, 100,
119, 122, 126, 160, 184: 1, 18
6, 198, 199, 201, 204, 224 and 23
7; I. Disperse Orange 13, 29, 3
1: 1, 33, 49, 54, 55, 66, 73, 11
8, 119 and 163; I. Disperse Red 54, 72, 73, 86, 88, 91, 92, 93, 1
11, 126, 127, 134, 135, 143, 14
5, 152, 153, 154, 159, 164, 16
7: 1, 177, 181, 204, 206, 207, 2
21, 239, 240, 258, 277, 278, 28
3, 311, 323, 343, 348, 356 and 36
2; I. Dispers Violet 31, 33;
C. I. Disperse Blue 36, 56, 60, 7
3, 87, 113, 128, 143, 148, 154,
158, 165, 165: 1, 165: 2, 176, 1
83, 185, 197, 198, 201, 214, 22
4, 225, 257, 266, 267, 287, 35
4, 358, 365 and 368; and C.I. I. Disperse Green 6: 1 and 9; Also,
The disperse dye used as the color material (B) is not limited to the following, but a preferred specific example is C.I. I. Disperse Yellow 82, 124,
C. I. Disperse Red 60 and the like.

On the other hand, the oil-soluble dye used as the coloring material (A) is not limited to the following,
Preferred specific examples include C.I. I. Solvent Black 3, 7, 27, 29 and 34; C.I. I. Solvent
Yellow 14, 16, 19, 21, 25, 29, 30,
56, 82, 93 and 162; I. Solvent Red 1, 3, 8, 18, 19, 24, 27, 51, 7
2, 73, 83, 109, 112, 117, 122, 1,
32, 138 and 218; I. Solvent Violet 3; C.I. I. Solvent Blue 2, 11, 2
5, 35, 38, 63, 67, 70, 95 and 117;
C. I. Solvent Green 3 and 7; and C.I.
I. Solvent Orange 2 and the like. The oil-soluble dye used as the coloring material (B) is not limited to the following, but preferable specific examples include C.I. I. Solvent Yellow 44, 82, 11
6, C.I. I. Solvent Red 43, 44, 45, 4
9, 60 and the like.

The dyes used as the coloring material (A) and the coloring material (B) may be dissolved in a solvent from the viewpoint of being efficiently adsorbed on the polymer, especially the polyester-based polymer, etc. by phase inversion emulsification described below. For example, it is preferable to dissolve 20 g / l or more in a ketone-based solvent, more preferably 40 g / l or more, even more preferably 50 g / l or more.
The dissolution is more preferably 0 g / l or more, and even more preferably 100 to 600 g / l.

On the other hand, as the pigment used as the coloring material (A), any conventionally known organic and inorganic pigments having no fluorescence can be used as long as they can be adsorbed by the polymer. For example, azo pigments such as azo lakes, insoluble azo pigments, condensation azo pigments, chelate azo pigments,
Polycyclic pigments such as phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthaloni pigments, and dye lakes such as basic dye lakes and acid dye lakes; Organic pigments such as nitro pigment, nitroso pigment, aniline black, and daylight fluorescent pigment; and inorganic pigments such as titanium oxide, iron oxide, and carbon black. In addition, any pigment that is not described in the color index can be used as long as it can be dispersed in the aqueous phase. Further, those obtained by subjecting the above pigment to a surface treatment with a surfactant, a polymer dispersant or the like, or graft carbon, etc., can of course be used. Among the above pigments, it is particularly preferable to use azo pigments, phthalocyanine pigments, anthraquinone pigments, and carbon black pigments.

In the present invention, two or more of the above color materials (A) and (B) may be used in combination. In the color material (A) and the color material (B), the same type of dye may be used (for example, disperse dyes in both the color materials (A) and (B)), or different types of dyes may be used. [For example, one of the coloring materials (A) and (B) is a disperse dye and the other is an oil-soluble dye]. Further, a dye may be used for one of the coloring material (A) and the coloring material (B), and a pigment may be used for the other. Further, a dye and a pigment may be used in combination as the color material (A) and the color material (B). When a dye and a pigment are used in combination, the mixing ratio (weight) of the dye and the pigment is the former: the latter = 10: 90 to 90: 1.
It can be freely selected within the range of 0. In the present specification, "dispersed dye" is insoluble or poorly soluble in water,
A dye that is dissolved in an aqueous dispersion close to a colloid,
“Oil-soluble dye” refers to a dye that is not water-soluble and is soluble in mineral oil, fats and oils, and “pigment” refers to a dye that is insoluble or hardly soluble in water and organic solvents (Chemical Dictionary, Kyoritsu Publishing Co.). Further, in the present invention, as the color material (A) and the color material (B), together with the preferred color material described above,
Direct dyes, acid dyes and basic dyes can be used as long as the effects of the present invention are not impaired.

In the water-based ink of the present invention, the compounding amount of the mixed colorant (that is, the sum of the compounding amounts of the colorant (A) and the colorant (B)) is determined by the colorant (A) and the colorant (B). Provided that the weight ratio (A) / (B) to (B) is within the above range, it is preferably 1 to 30% by weight, and 1.5 to 2% by weight.
More preferably, it is 5% by weight. If the amount of the mixed colorant is less than 1% by weight, the print density is insufficient,
Even if it is used in an amount exceeding 30% by weight, the print density cannot be significantly improved, and the stability of suspension particle diameter over time decreases, and the average particle diameter tends to increase. Is preferred.

The average particle diameter of the suspension of the polymer to which the mixed colorant is adsorbed is preferably 0.5 to 500 nm. If the average particle diameter is less than 0.5 nm, bleeding of the ink may occur. If the average particle diameter exceeds 500 nm, the dispersion stability of the suspension itself may be reduced. The average particle size is preferably from 0.5 to 300 nm, more preferably from 1 to 200 nm, and still more preferably from 10 to 300 nm, from the viewpoint of suspension formability and stability.
100 nm. The average particle diameter can be adjusted, for example, by changing the conditions of phase inversion emulsification described below. The average particle size of the polymer suspension can be determined by measurement using COULTER Model N4SD (trade name) or observation by an electron microscope (TEM, SEM).

The aqueous ink of the present invention preferably contains a benzenecarboxylic acid ester compound represented by the following formula (a) from the viewpoint of further improving the print density and print quality. Although the reason for this is not clear, the benzene carboxylate compound is compatible with the mixed color material, so that the benzene carboxylate compound is compatible with the mixed color material adsorbed on the polymer suspension to thereby form the mixed color material. Of the mixed color material is improved, and the amount of adsorption of the mixed color material is improved. As a result, the print density and print quality are further improved.

[0049]

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In the above formula (a), Ra has 6 to 6 carbon atoms.
15, preferably a hydrocarbon group having 8 to 13 carbon atoms,
n is a number from 2 to 4. Examples of the hydrocarbon group represented by Ra include 2-ethylhexyl, isononyl,
Examples include, but are not limited to, alkyl groups such as normal octyl, normal decyl, isodecyl, normal undecyl, normal dodecyl, and tridecyl. Here, as the benzenecarboxylic acid ester compound, when n = 2, dialkyl benzenedicarboxylate is preferably used, and when n = 3,
Trialkyl benzenetricarboxylate and the like are preferably used. When n = 4, tetraalkyl benzenetetracarboxylate and the like are preferably used.

The dialkyl benzenedicarboxylate (n
= 2) include, for example, dialkyl phthalate, dialkyl isophthalate, and dialkyl terephthalate, with dialkyl phthalate being particularly preferred. When using the above dialkyl benzenedicarboxylate, one or more of these compounds can be used. Further, as the dialkyl benzenedicarboxylate, a compound in which two Ras in the above formula (a) are both 2-ethylhexyl groups, particularly from the viewpoint of compatibility with the mixed colorant, that is, benzenedicarboxylic acid-di- 2-Ethylhexyl, especially di-2-ethylhexyl phthalate, is preferred. As the dialkyl benzenedicarboxylate, commercially available products can also be used. For example, a vinylizer 80, a vinylizer 90, a vinylizer 85, a vinylizer 105, and a vinylizer 12 manufactured by Kao Corporation.
4, the vinylizer 20 (trade name) and the like.

Examples of the trialkyl benzenetricarboxylate (n = 3) include, for example, trialkyl trimellitate, trialkyl hemimellitate, and trialkyl trimesate. The trialkyl trimellitate represented is preferred.

[0053]

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R ¹ , R ² and R ³ in the trialkyl trimellitate represented by the above formula (a) ′ are the same or different and represent a hydrocarbon group having 6 to 15, preferably 8 to 13 carbon atoms. Specific examples thereof include the same as the examples of Ra in the above formula (a). When using the above trialkyl benzenetricarboxylate, one or more of these compounds can be used. In addition, the trialkyl benzenetricarboxylate is a compound in which all three Ras in the above formula (a) are 2-ethylhexyl groups, that is, benzenetricarboxylic acid-trialkyl, particularly in view of compatibility with the mixed colorant. −
2-ethylhexyl, especially trimellitic acid-tri-
2-Ethylhexyl is preferred. Commercial products can also be used as the trialkyl benzenetricarboxylate, for example, T-08 and T-0 manufactured by Kao Corporation.
9, T-10, N-08, NSK (trade name) and the like.

The tetraalkyl benzenetetracarboxylate (n = 4) includes, for example, tetraalkyl pyromellitate, tetraalkyl prenitate, and tetraalkyl melophanate, with tetraalkyl pyromellitate being particularly preferred. . When using the above-mentioned tetraalkyl benzenetetracarboxylate, one or more of these compounds can be used. Further, as the tetraalkyl benzenetetracarboxylate,
Particularly from the standpoint of the compatibility with the colorant, the formula (1) any four R _a in even a 2-ethylhexyl group or a n-octyl group compounds, namely benzene tetracarboxylic acid - tetra-2-ethylhexyl or benzene Tetracarboxylic acid-tetra-normal octyl, especially pyromellitic acid-tetra-2-ethylhexyl or pyromellitic acid-tetra-normal octyl, is preferred. Further, as the tetraalkyl benzenetetracarboxylate,
Commercial products can also be used, and examples thereof include P-08 and PN-08 (trade name) manufactured by Kao Corporation.

The benzene carboxylate compound can be used alone or in combination of two or three of n = 2, n = 3 and n = 4. Can also be used. When two or three kinds are used in combination, their use ratio is appropriately adjusted within a range in which the compatibility with the above-mentioned coloring material is optimized.

In the water-based ink of the present invention, the benzenecarboxylic acid ester compound is contained in the ink at a concentration of 0.0
It is preferable to mix 5 to 20% by weight,
More preferably, it is added at 0% by weight. If the amount of the benzene carboxylate compound is less than 0.05% by weight, the mixed colorant may not be stably adsorbed at a high concentration. If the amount exceeds 20% by weight, the stability of the suspension may be reduced. In some cases, the particle size of the suspension may increase, and the particle size of the suspension may be increased.

The aqueous ink of the present invention comprises a polymer suspension in which water (preferably ion-exchanged water) is used as a medium and the mixed colorant is adsorbed. If necessary, various conventionally known additives, For example, wetting agents such as polyhydric alcohols, dispersants, antifoaming agents such as silicones, surface tension regulators such as various surfactants of cation, anion or nonionic, fungicides such as chloromethylphenol and Chelating agents such as EDTA, oxygen absorbers such as sulfites, ultraviolet absorbers such as benzotriazole, benzophenone, hydroxybenzoate, salicylate and cyanoacrylate, and light stabilizers such as hindered phenol and hindered amine. May be blended.

The wetting agent is not particularly limited, but may be, for example, glycols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol and polyethylene glycol; glycerin; diethylene glycol diethyl ether. , Diethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methyl carbitol, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, diethyl carbitol, triethylene glycol monomethyl ether, triethylene Glycol monoethyl ether and propylene glycol monomethyl Ethers of polyhydric alcohols such as ether, acetates; thiodiglycol; N- methyl -
2-pyrrolidone; 1,3-dimethylimidazolidinone;
Triethanolamine; formamide; nitrogen-containing compounds such as dimethylformamide, amino acids such as glycine, methylglycine, leucine, proline, ε-amino-n-caproic acid, alanine and phenylalanine, and one or more of dimethylsulfoxide. Can be used. There is no particular limitation on the amount of these wetting agents,
0.1 to 50% by weight in the aqueous ink of the present invention
It can be blended, more preferably 0.1 to 30% by weight.

The dispersing agent is not particularly limited. Examples of the anionic surfactant include higher fatty acid salts, higher alkyl dicarboxylates, higher alcohol sulfates, higher alkyl sulfonates, and the like. As a cationic surfactant such as a condensate salt of a higher fatty acid and an amino acid, a sulfosuccinate ester salt, a naphthenate salt, an amphoteric surfactant such as an aliphatic amine salt, a quaternary ammonium salt, a sulfonium salt, and a phosphonium salt,
Examples of the nonionic surfactant such as a betaine compound include a fatty acid ester type of a polyoxyethylene compound and a polyethylene oxide condensed type. When used, one or more of these may be used. Also,
As a polymer dispersant, gelatin, proteins such as casein, natural gums such as gum arabic, glucoxides such as saponin, methyl cellulose, carboxymethyl cellulose, cellulose derivatives such as hydroxymethyl cellulose, lignin sulfonate, natural polymers such as shellac,
Polyacrylate, styrene-acrylic acid copolymer salt,
Vinyl naphthalene-acrylic acid copolymer salt, styrene-
Maleic acid copolymer salt, vinyl naphthalene-maleic acid copolymer salt, naphthalene sulfonic acid formalin condensate salt, special aromatic sulfonic acid formalin condensate salt, anionic polymer such as polyphosphoric acid, polyvinyl alcohol, polyvinyl pyrrolidone And non-ionic polymers such as polyethylene glycol. When used, one or more of these can be used. Above all, it is particularly preferable to contain a β-naphthalenesulfonic acid formalin condensate represented by the following formula (2), since the average particle diameter of the suspension can be reduced and the dispersion stability of the suspension can be improved.

[0061]

Embedded image

In the above formula (2), a hydrogen atom or a methyl group is preferably used as R ′. M is preferably an ion of an alkali metal such as sodium or potassium. Also, l is preferably 100 to 8
00. The compound represented by the above formula (2) has its H
It is preferable that the LB value is 5 to 15 because the effect as a dispersant is exhibited and the average particle diameter of the suspension is suppressed from increasing.

As the compound represented by the above formula (2), commercially available products can also be used. As such a commercially available product, for example, a dispersant Demol SNB, M manufactured by Kao Corporation
S, N, SSL, ST, P, and C (product names).

The amount of the dispersant is not particularly limited,
In the aqueous ink of the invention, it is usually incorporated in an amount of 0.01 to 10% by weight. If the amount of the dispersant is less than 0.01% by weight, it is difficult to reduce the particle size of the suspension, and if it exceeds 10% by weight, the average particle size of the suspension increases or the suspension stability decreases, Therefore, it is preferable that the content is within the above range. Preferably, the compounding amount of the dispersant in the aqueous ink of the present invention,
It is 0.05 to 5% by weight, further 0.1 to 1% by weight.

The defoaming agent is not particularly limited, but a compound represented by the following formula (3), particularly, a compound represented by the following formula (4) may be used. It is particularly preferable in terms of suppressing generation and adjusting the surface tension of the ink.

[0066]

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[0067]

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In the above formula (3), R ₁ , R ₂ , R ₃ and R ₄ are preferably the same or different C 1 -C 5 lower alkyl groups or phenyl groups, and m and n are preferably 10-100 of an integer, R ₅ and R ₆ is preferably a lower alkyl group or a phenyl group of the same or different C1 -C5.

As the compound represented by the above formula (3) or (4), commercially available products can also be used. Examples of such commercially available products include KF96 manufactured by Shin-Etsu Silicone Co., Ltd.
66, 69, KS68, 604, 607A, 602, 6
03, KM73, 73A, 73E, 72, 72A, 72
C, 72F, 82F, 70, 71, 75, 80, 83
A, 85, 89, 90, 68-1F, 68-2F (trade name) and the like.

The amount of the compound represented by the above formula (3) or (4) is not particularly limited, but is preferably 0.001 to 2% by weight in the aqueous ink of the present invention.
If the compounding amount of the compound is less than 0.001% by weight, bubbles are easily generated at the time of preparing the ink, and it is difficult to remove small bubbles in the ink. If it exceeds 2% by weight, the generation of bubbles is suppressed. During printing, repelling may occur in the ink and the print quality may be degraded. More preferably, the above formula (3) or (4)
The compounding amount of the compound represented by is 0.005 to 0.5% by weight in the aqueous ink of the present invention.

As the surface tension adjusting agent, the above-mentioned silicone-based antifoaming agents and various cationic, anionic or nonionic surfactants can be used. Particularly, a silicone-based antifoaming agent represented by the above formula (3) or (4), an ethylene oxide compound of an alkyl phenol represented by the following formula (5), and an ethylene of an acetylene glycol represented by the following formula (6) The use of an oxide adduct is preferable in terms of suppression of bubble generation, ease of adjusting the surface tension of the ink, ink dischargeability, less bleeding, and non-uniform print density.

[0072]

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[0073]

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When using the surface tension modifier, one or more of these compounds can be used.
It is desirable to add 0.005 to 15% by weight in the water-based ink of the present invention. If the amount is less than 0.005%, the above properties may not be exhibited,
If the content is more than 15% by weight, on the contrary, bleeding or uneven printing density may occur to lower the printing quality or lower the liquid stability of the ink.

Surface tension of water-based ink of the present invention (20 ° C.)
Is preferably in the range of 25 to 50 dyne / cm. If the surface tension is less than 25 dyne / cm, bleeding of ink and deterioration of printing quality may occur, and ink leakage may occur from a print head nozzle of an ink jet printer. Is too slow, the ink mixes on the paper after printing, the printhead becomes dirty, and the ink supply to the printhead nozzles fails, which results in poor ink ejection and poor print quality. May occur. The surface tension is more preferably 28 to 43 dyne / cm. Further, when the color tone is magenta, cyan, or yellow, preferably 28 to
40 dyne / cm, more preferably 28 to 36 dyn
e / cm, 28 to 40 dyn when the color tone is black
e / cm is more preferred. In order to make the surface tension of the aqueous ink of the present invention within the above range, for example, adjusting the concentration of the mixed colorant, adjusting the concentration or molecular weight of the polymer, or a surface tension adjusting agent such as various surfactants The surface tension of the ink is 2 among the wetting agents used.
Means such as selecting one within a range of 5 to 50 dyne / cm may be used. The measurement of the surface tension is as follows.
Automatic surface tensiometer (CBVP-Z) manufactured by Kyowa Interface Science Co., Ltd.
Type).

The viscosity of the water-based ink of the present invention is 20
It is preferably 0.5 to 8 cps at C, more preferably 1 to 5 cps, and still more preferably 1 to 3 cp.
s. That is, if the viscosity is less than 0.5 cps, the bleeding of the ink becomes remarkable, and the ink leaks from the print head nozzles of the ink jet printer. Also, if it exceeds 8 cps,
The viscosity of the ink for inkjet is too high,
Since ink is not supplied to the print head, ejection failure occurs, and problems such as blurring and poor print quality occur.
It is preferable to be within the above range. In order to make the viscosity of the water-based ink of the present invention within the above range, for example, adjusting the concentration of the mixed colorant, adjusting the concentration and molecular weight of the polymer, various surfactants and the like, and a surface tension adjusting agent Or the like may be added, or a wetting agent to be used may be selected from those having a viscosity of the ink of 0.5 to 8 cps, and the amount used may be adjusted. The viscosity was measured using an E-type viscometer (VISC manufactured by Tokyo Keiki Co., Ltd.).
(ONIC ELD) or a rotary vibration type viscometer (Viscomate VM-100) manufactured by Nikkato Tokyo Branch.

Next, a preferred method for producing the water-based ink of the present invention will be described with reference to an example in which the polyester (A) is used as the polymer. The aqueous ink of the present invention is preferably produced by so-called phase inversion emulsification described below.

In the phase inversion emulsification, the diol component represented by the above formula (1) (ie, the component (a)) and the polyvalent carboxylic acid derivative (ie, the component (b)) are used together. Polyester (A) obtained by condensation polymerization (acid value: 3 to 100K)
OH mg / g) to the solvent together with the mixed color material,
After adding a neutralizing agent to ionize the carboxyl groups in the polyester (A), and then adding water, the solvent is distilled off and the phase is changed to an aqueous phase.

First, the polyester (A) is added to a solvent together with the mixed color material. In this case, it is preferable to add 5 to 50 parts by weight of the polyester (A) to 100 parts by weight of the solvent from the viewpoint of forming a suspension. Examples of the solvent include, but are not particularly limited to, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, methyl isobutyl ketone, ketone solvents such as methyl isopropyl ketone, and ether solvents such as tetrahydrofuran. Of these, methyl ethyl ketone and tetrahydrofuran are preferably used.

Next, a neutralizing agent is added to a mixture of the polyester (A), the mixed color material, and the solvent. This ionizes the carboxyl groups in the polyester (A). As the neutralizing agent, the polyester (A)
Any substance can be used without particular limitation as long as it can ionize a carboxyl group in the substance. Examples of such a neutralizing agent include aqueous solutions of monovalent inorganic salts such as aqueous ammonia, lithium hydroxide, sodium hydroxide and potassium hydroxide, allylamine, isopropylamine, diisopropylamine, ethylamine, diethylamine, triethylamine, and the like. -Ethylhexylamine, 3-ethoxypropylamine, diisobutylamine, 3-diethylaminopropylamine, tri-n-octylamine, t-
Butylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, n-propanolamine, butanolamine, 2-amino-4-pentanol, 2-amino-3-
Hexanol, 5-amino-4-octanol, 3-amino-3-methyl-2-butanol, monoethanolamine, diethanolamine, dimethylethanolamine, triethanolamine, isopropanolamine,
Neopentanolamine, diglycolamine, ethylenediamine, 1,3-diaminopropane, 1,2-diaminopropane, 1,6-diaminohexane, 1,9-diaminononane, 1,12-diaminododecane, dimer fatty acid diamine 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, hexamethylenediamine, N-aminoethylpiperazine, N-aminopropylpiperazine, N-aminopropyldipiperidipropane, piperazine and the like Amines and the like. In particular, it is preferable to use sodium hydroxide, potassium hydroxide, triethylamine and dimethylethanolamine as the neutralizing agent, because the resulting suspension has a smaller particle size and the suspension stability is further improved. In particular, it is more preferable to use sodium hydroxide and potassium hydroxide as the neutralizing agent because the heat resistance of the obtained suspension is improved. The amount of the neutralizing agent used may be an amount capable of ionizing at least the carboxyl group in the polyester (A). A particularly preferable range of the amount of the neutralizing agent to be used is 0.8 × F (g) to 1.5 × F (g), where F (g) is a value calculated by the following formula (i). Is a range that satisfies.

[0081]

(Equation 1)

After the addition of the neutralizing agent, water is added to the mixture to cause phase inversion. As a result, a suspension of the polyester (A) is formed in the aqueous phase. The amount of water to be added is 100 to 300 parts by weight per 100 parts by weight of the mixture.
It is preferably in parts by weight. In this case, it is preferable to add a compound obtained by adding the compound represented by the formula (2) to water to the mixed solution because the average particle diameter of the suspension can be reduced. Further, when a mixture of water and a compound represented by the above formula (3), (4), (5) or (6) is added to the mixture, the generation of bubbles can be suppressed. Is preferable because the surface tension can be adjusted. As described above, the amount of the compound represented by the formula (2) is 0.1 to 0.1 in the ink finally obtained.
It is preferable that the amount is from 0.01 to 10% by weight. On the other hand, the amount of the compound represented by the formula (3) or (4) is set to 0.1 in the ink finally obtained as described above.
The amount is preferably 001 to 2% by weight.

After the phase inversion is completed, the solvent is removed from the mixture by heating the system under reduced pressure, and a predetermined amount of water is removed. The aqueous ink of the present invention containing the suspension of the polyester (A) having the coloring material adsorbed thereon is obtained.

In preparing the water-based ink of the present invention, it is preferable to remove coarse particles. For example, the ink obtained as described above is filtered under pressure by a filter or processed by a centrifugal separator, and preferably 2,000 n
By removing particles of m or more, more preferably of 1000 nm or more, and more preferably of 500 nm or more, an ink without clogging can be obtained.

As described above, the preferred method for producing the aqueous ink of the present invention has been described using the case where the above-mentioned polyester (A) is used.
Instead of using the other polymer, an aqueous ink comprising a suspension of the polymer having the mixed colorant adsorbed thereon can be obtained. For example, by using the polyester (B) or (C) in place of the polyester (A), an aqueous ink containing a suspension of the polyester (B) or (C) to which the mixed colorant is adsorbed can be obtained. Can be Further, the pH of these suspensions and the final water-based ink is preferably pH = 5 to 12, preferably 5.5 to ensure the stability of the suspension.
It is preferable to adjust so as to be 10.

The water-based ink of the present invention is particularly useful as an ink for ink-jet recording. In this case, the water-based ink can be used for any of a piezoelectric type and a thermal jet type ink jet printer, and the water-based ink may be used as it is, or various types of the water-based ink may be used as needed. You may use what added the additive. Further, the water-based ink of the present invention can be used as other inks, for example, as ink for writing implements such as general fountain pens, ball-point pens, and felt-tip pens.

[0087]

EXAMPLES Next, the effectiveness of the water-based ink of the present invention will be illustrated by examples. However, it goes without saying that the present invention is not limited to such an embodiment.

Example 1 Polyoxypropylene (2.
2) containing 1000 g of 2,2-bis (4-hydroxyphenyl) propane, 20% by weight of the dimer acid compound represented by the above formula (I) and 20% by weight of the dimer acid compound represented by the above formula (II) 100 g of dimer acid mixture, 280 g of fumaric acid, 140 g of trimellitic anhydride, and 1.5 g of hydroquinone are placed in a glass 2-liter four-necked flask. Attached to. The reaction was carried out while stirring at 210 ° C. under a nitrogen stream in a mantle heater. The degree of polymerization was monitored from the softening point according to ASTM E28-67, and the reaction was terminated when the softening point reached 110 ° C. The obtained polyester (hereinafter, this polyester is referred to as “polyester”) was a pale yellow solid, and had a Tg of 65 ° C. by DSC. Also,
The acid value of the polyester based on JIS K 0070 was 40 KOH mg / g, and the number average molecular weight (in terms of polystyrene by gel permeation chromatography) was 5,100. Next, the polyester 150
g, 35 g of C.I. I. Solvent Red 18 and 45g
C. I. Solvent Red 49, a mixed color material, trimellitic acid-tri-2-ethylhexyl [8-g, T-08 (trade name) manufactured by Kao Corporation], and 500 g of tetrahydrofuran are put into a separable flask, and the flask is filled with N. After the _2- substitution, the mixture was stirred to completely dissolve the polyester, the mixed colorant, and tri-2-ethylhexyl trimellitate in tetrahydrofuran. Subsequently, 10.49 g of dimethylethanolamine and 0.86 g of sodium hydroxide were added to ionize the carboxyl groups in the polyester. Furthermore, Kao Corporation's Demol N
(Dispersant; HLB 8.51) 960 g of an aqueous solution prepared by dissolving 3 g of ion-exchanged water in drops was stirred, and then heated to 40 ° C. under reduced pressure to remove tetrahydrofuran. A suspension-based ink containing trimellitic acid-tri-2-ethylhexyl was obtained. The average particle size and concentration of the polyester adsorbed with the mixed colorant in the aqueous ink were 22
nm and 20% by weight, trimellitic acid-tri-2
The concentration of -ethylhexyl was 0.66% by weight.

Example 2 Instead of the mixed colorant used in Example 1, 40 g of C.I. I. Solvent Yellow 29
And 40 g of C.I. I. A mixed colorant comprising Disperse Yellow 82 and trimellitic acid-tri-2-
Instead of ethylhexyl, di-2-ethylhexyl phthalate [Vinicizer 80 (trade name) manufactured by Kao Corporation]
The same procedure as in Example 1 was repeated, except that the polyester adsorbed with the mixed colorant and phthalic acid-di-2-
An aqueous ink of a suspension containing ethylhexyl was obtained. The average particle diameter and concentration of the polyester adsorbed with the mixed colorant in the aqueous ink were 33 nm and 20% by weight, respectively, and the concentration of di-2-ethylhexyl phthalate was 0.66% by weight.

Example 3 Using the aqueous ink obtained in Example 1, the respective components were mixed according to the following formulation, and the obtained dispersion was filtered through a 1000 nm filter to remove dust and coarse particles. An ink for inkjet recording was obtained. Using this ink, printing was performed with a commercially available color bubble jet printer manufactured by Canon (model number BJC-420J), and the color tone, the amount of the mixed colorant introduced, the print density, and the liquid stability were evaluated by the following methods. Table 1 shows the results. Furthermore, when the water resistance, fixability and scratch resistance were evaluated by the following methods, it was found that all were good. [Formulation] 60 g of the water-based ink obtained in Example 1 10 g of diethylene glycol 2 g of glycerin 1 g of acetylenol EH 27 g of ion-exchanged water

<Color Tone> The solid color was printed using PPC recycled paper [manufactured by Nippon Kaishi Paper Co., Ltd.]
After naturally drying for 4 hours, the color tone was visually evaluated. <Amount of mixed colorant introduced> 10 g of the suspension adsorbing the mixed colorant was dissolved by adding 40 g of toluene, the absorbance of the solution was measured, the amount of the mixed colorant adsorbed on the suspension was determined, and the values were mixed. The coloring material introduction amount was used. It should be noted that the mixed color material introduction amount can also be calculated from the color material / polymer amount at the time of producing the suspension. <Print Density> Printing was carried out using solid paper using recycled paper for PPC [manufactured by Nippon Kaishi Paper Co., Ltd.], allowed to dry naturally in a room for 24 hours, and then measured its optical density using a Macbeth densitometer R.
D918 (manufactured by Macbeth). <Liquid Stability> The evaluation ink was placed in a constant temperature room at 50 ° C. for one month, and the particle diameter distribution before and after that was measured by a Coulter counter to evaluate the liquid stability. ：: No change in particle diameter distribution at all, average particle diameter of 100 nm or less in monodispersed system ○: Fine change in particle diameter distribution, but average particle diameter of 100 nm or less in monodispersed system △: Particle size distribution A polydisperse system having a distribution of two peaks or more and having an average particle diameter of 200 nm or less. ×: Coagulated precipitate formed at the liquid bottom.
After solid printing, and left for 1 hour or more, it was dipped vertically in still water for 10 seconds and pulled up vertically. After air drying naturally in the room, the optical character density of the white portion where no printing was performed was measured with a Macbeth densitometer RD918 (manufactured by Macbeth) to evaluate the water resistance. <Fixing property> Recycled paper for PPC [manufactured by Nippon Kaishi Paper Co., Ltd.]
And OHP sheet for inkjet only (MJOHPSI
NE Epson) and eraser (width 18.
5mm) is fixed at an inclination of 45 °, and a load of 1 kg is placed on it.
Was placed and rubbed 5 times back and forth on the solid printing surface, and the state of the printing surface at that time was visually observed to evaluate the fixability. <Scratch resistance> When a printed image is printed on a boehmite-containing OHP sheet (boehmite-based OHP sheet) which is widely used in plain paper and commercial OHP sheets, and the obtained printed image is rubbed with a nail, the printed image is missing and printed. The smear around the image was examined and the scratch resistance was evaluated.

Example 4 An ink for ink-jet recording was obtained in the same manner as in Example 3, except that the aqueous ink obtained in Example 1 was replaced with the aqueous ink obtained in Example 2. Using this ink, in the same manner as in Example 3, the amount of coloring material introduced, print density, and liquid stability were evaluated. Table 1 shows the results.
Shown in The water resistance, fixability and scratch resistance were also evaluated by the above methods, and all were found to be good.

Comparative Example 1 Polyester synthesized by the following method was used in place of the polyester used in Example 1, and 70 g of C.I. I. Solvent Red 18 and the trimellitic acid-tri-2- used in Example 1
Ethylhexyl [T-08 (trade name) manufactured by Kao Corporation]
The same operation as in Example 1 was performed, except that was not used. However, most of the coloring materials (oil-soluble dyes) used in the preparation were precipitated and settled together with some of the polyester. Therefore, filtration was performed to remove sediment, and a suspension of polyester (average particle size: 40
nm) An aqueous ink containing 10% by weight was obtained. Using this water-based ink, an ink for inkjet recording was obtained in the same manner as in Example 3, and the color tone, the introduced amount of the coloring material, the print density, and the liquid stability were evaluated. Table 1 shows the results. <Synthesis of polyester> In an autoclave equipped with a thermometer and a stirrer, 130 parts by weight of dimethyl terephthalate, 56 parts by weight of dimethyl isophthalate, 6 parts by weight of dimethyl sodium sulfoisophthalate, 159 parts by weight of ethylene glycol, and tricyclodecanediene 30 parts by weight of methanol and 0.1 of tetrabutoxytitanate
A part by weight was added, and the mixture was heated at a temperature of 180 to 230 ° C. for 120 minutes to perform a transesterification reaction. Thereafter, the temperature of the reaction solution is increased to 240 ° C., and the pressure applied to the reaction solution is reduced to 1
When the softening point reached 100 ° C. at 〜１０10 mmHg, the reaction was terminated, and a polyester was synthesized. The obtained polyester was a pale yellow-white solid and had a Tg of 50 ° C.

[0094]

[Table 1]

As is evident from the results shown in Table 1, the inks of Examples 3 and 4 obtained using the polymer suspension to which the mixed colorant was adsorbed were compared with the inks of the conventional formulation (Comparative Example 1). It can be seen that the print density and print quality of the printed matter, particularly the color tone and lightness, are improved. Table 1
Although the results are not shown, the inks of Examples 3 and 4 also showed good results in the evaluation of water resistance, fixability and abrasion resistance as described above. Further, there was no problem with the inks of Examples 3 and 4 regarding the bleeding. Thus, according to the inks of Examples 3 and 4, it can be seen that printed matter excellent in all of the water resistance, fixability, color tone print density and print quality of the printed matter can be obtained.

[0096]

According to the water-based ink of the present invention, the printed matter is excellent in water resistance, the print density and print quality are improved, and especially the color tone and lightness are improved. Further, by adsorbing the mixed color material by phase inversion emulsification, the mixed color material can be easily and efficiently adsorbed, the bleeding of the ink is further prevented, and the water resistance and the fixing property are improved. Further improve. The water-based ink is particularly useful as an inkjet recording ink,
It can also be used as ink for writing implements such as general fountain pens, ballpoint pens, and felt-tip pens.

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Kuniyasu Kawabe 1334 Minato, Wakayama-shi, Wakayama

Claims (6)

[Claims] 1. A polymer suspension having adsorbed a mixed colorant comprising a water-insoluble or poorly water-soluble colorant having no fluorescence (A) and a water-insoluble or sparingly water-soluble colorant having a fluorescence (B). And the weight ratio (A) / (B) between the color material (A) and the color material (B) in the ink is 5 /
A water-based ink characterized by being 1 to 1/10. 2. The aqueous ink according to claim 1, wherein the polymer has an acid value based on JIS K 0070 of 3 to 100 KOH mg / g. 3. The polymer according to claim 1, wherein the polymer is a urethane-based polymer,
The water-based ink according to claim 1, wherein the water-based ink is at least one of an acrylic, epoxy, polyester, polyester polyamide, or polyamide polymer. 4. The aqueous ink according to claim 1, wherein the polymer contains a unit derived from a diol component represented by the following formula (1) in the polymer chain. Embedded image 5. The above-mentioned polymer is a polyester polymer, which is obtained by copolycondensation of a diol component represented by the above formula (1) and a polycarboxylic acid derivative. The water-based ink according to claim 4, which is provided. 6. An ink for inkjet recording, comprising the water-based ink according to claim 1.