JPH09183932A - Water-base ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-base ink which can give a print having a high printing density, improved water resistance and improved fixabiity on a sub strate by adding a suspension containing a specified polymer containing an adsorbed dye or pigment to a water-base ink. SOLUTION: A suspension containing a polyester containing an adsorbed dye or pigment and desirably having an acid value (JIS K0070) of 3-100mgKOH/g is added to a water-based ink. The polyester used is desirably one obtained by copolycondensing a diol component represented by the formula (wherein R is a lower alkyl; A is an alkylene; (x) and (y) are 1 or greater; and x+y=2-7 on the average) with at least one acid component (e.g. fumaric acid) selected from among at least dibasic carboxylic acids, anhydrides thereof and lower alkyl esters thereof and desirably has a number-average molecular weight of 500-100,000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous ink having improved fixability to a printed material and water resistance, and more particularly to an aqueous ink useful as an ink for ink jet recording.

[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.

As ink used in an ink jet printer which is one of typical printer devices, a water-soluble dye which is usually dissolved in water is used in order to prevent the nozzle from being clogged with ink. By using a water-soluble dye, the ink is less likely to be clogged in the nozzle, but on the other hand, the problem of poor water resistance, and especially in the case of the thermal jet type, the dye is oxidized by the excessive heat in the printer head There was a problem that it was easy to burn. Therefore, the composition of the ink is important for improving the water resistance of the ink.

In order to improve the water resistance of the ink for ink jet recording, a pigment is used as the ink (Japanese Patent Application Laid-Open Nos. 4-28776, 4-189876, 4-3599071, 4-35972). Gazette, etc.) or using a non-aqueous liquid medium (JP-A-4-26147)
No. 8) and the use of a dye having excellent water resistance (US Pat. No. 4,963,189) has been proposed.

However, when a pigment is used as an ink, there is a possibility that the saturation of a printed matter is reduced and a problem such as clogging in a nozzle is caused. In addition, fixing to a printing object such as paper or an OHP sheet is performed. The printability was insufficient, and there was a problem in the record preservability as a printed matter. Even with other proposals, an ink which sufficiently satisfies both the water resistance and the fixing property cannot be obtained.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a water-based ink having improved fixability to a printing object such as paper or an OHP sheet and improved water resistance.

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 inventors of the present invention have made extensive studies in order to achieve the above object. As a result, by adsorbing dyes or pigments to the micelles of polyester, the coloring properties of these dyes or pigments are not impaired. It has been found that the fixability of the ink on the printing object and the water resistance are improved.

The present invention has been made based on the above findings, and achieves the above object by providing an aqueous ink containing a polyester suspension having a dye or a pigment adsorbed thereto. is there.

The present invention also provides a water-based ink for ink-jet recording, characterized by using the above-mentioned water-based ink.

Furthermore, the present invention provides a preferred method for producing the above water-based ink from a diol component represented by the following formula (1), a divalent or higher polyvalent carboxylic acid, its acid anhydride and its lower alkyl ester. The acid value obtained by copolycondensation with one or more acid components selected from the group consisting of
KOH mg / g polyester is added to a solvent together with a dye or pigment, a neutralizing agent is added to ionize the carboxyl groups in the polyester, and then water is added, and then the solvent is distilled off to invert the phase to an aqueous system. The present invention provides a method for producing a water-based ink.

[0012]

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[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The water-based ink of the present invention is characterized by containing a polyester suspension having a dye or a pigment adsorbed thereto. That is, the dye or pigment is adsorbed on or encapsulated in the micelle formed of at least polyester. That is, in the present specification, "the dye or the pigment is adsorbed" means that at least a part of the dye or the pigment is adsorbed on the micelle formed by the polyester, or is encapsulated in the micelle. .
The water-based ink of the present invention comprises the above-mentioned polyester micelle having a dye or pigment adsorbed therein as a suspension in water.

The above polyester is preferably one capable of forming a micelle capable of adsorbing a dye or pigment at least in its entirety or in part, but encapsulating the dye or pigment in all or in part therein. Even those capable of forming an effective micelle can be used without particular limitation as long as the effects of the present invention are not impaired. The polyester preferably used in the present invention as the polyester has an acid value of 3 to 100 according to JIS K0070.
A KOH mg / g polyester, which is particularly preferably used, is selected from the group consisting of a diol component represented by the following formula (1), a divalent or higher polyvalent carboxylic acid, an acid anhydride thereof and a lower alkyl ester thereof. An acid value obtained by copolycondensation with one or more selected acid components is 3 to 100K.
OH mg / g polyester.

[0015]

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The above polyester will be described in detail below. As described above, the polyester is JIS K 0
Acid value based on 070 is preferably 3 to 100 KOHmg
/ G, more preferably 3 to 70 KOHmg / g,
More preferably 10 to 60 KOHmg / g, even more preferably 15 to 45 KOHmg / g, particularly preferably 1
5-40 KOHmg / g, particularly preferably 18-3
It is 7 KOHmg / g. The above acid value is 3 KOHmg / g
If it does not meet the requirement, a suspension in which a dye or pigment is stably adsorbed may not be obtained, and 100 KOHmg /
If it exceeds g, the fixability of the ink to the printing object and the water resistance may deteriorate, so it is preferable to set it within the above range. The diol component represented by the above formula (1) will be described. The diol component is an alkylene oxide adduct of a bisphenol A-based compound, preferably an ethylene oxide or propylene oxide adduct of bisphenol A. , 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.

When the polyester is obtained by copolycondensation, the diol component represented by the above formula (1) and other alcohol component can be used in combination. In this case, the proportion of the diol component represented by the above formula (1) is preferably 40 to 100 mol% in all the alcohols used. 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,
Examples include 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Examples of the above trihydric or higher alcohols include sorbitol, 1, 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. Can be

Next, the above-mentioned acid component will be explained. As the acid component, as mentioned above, a polyvalent carboxylic acid having a valence of 2 or more,
One or more selected from the group consisting of the acid anhydride and the lower alkyl ester are used.

As the above-mentioned divalent or higher 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-
Octylsuccinic acid, isooctenylsuccinic acid, dimer acid, isooctylsuccinic acid and the like are preferably used. On the other hand, the trivalent or higher carboxylic acid is not particularly limited, but for example, 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid,
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, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, trimellitic anhydride, trimer acid of embol and the like are preferably used. In addition, as the lower alkyl esters of these divalent or higher polycarboxylic acids, alkyl esters having 1 to 4 carbon atoms are 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 polyester is obtained by copolycondensation of the diol component and the acid component. The method of the copolycondensation is not particularly limited, and a known method is used.

The acid value of the polyester is adjusted by, for example, changing the addition ratio of the diol component and the acid component, using a carboxylic acid ester, or blocking the acid with a monohydric alcohol. You can

The polyester has a number average molecular weight (converted to polystyrene by gel permeation chromatography) of 500 to 100,000, preferably 1.
000 to 50,000, more preferably 1500 to 300
00, more preferably 2000 to 15000, and still more preferably 2000 to 10000, the durability of the ink after printing and the formability of the suspension, and particularly the printer head when the aqueous ink of the present invention is used in an inkjet printer. It is preferable from the viewpoint of preventing the non-sticking.

When the water-based ink of the present invention is used as an ink for ink jet recording, the polyester has a Tg (glass transition point) measured by DSC (Differential Scanning Calorimetry) which is a piezoelectric element. In the conventional inkjet recording method, the temperature is preferably 20 ° C. or higher,
30 in the inkjet recording method using thermal energy
The temperature is preferably ℃ or more, particularly preferably 40 ℃ or more and 150 ℃ or less, more preferably 50 ℃ or more 15
0 ° C. or less. If Tg is below the lower limit of the above condition, the polyester is solidified in the nozzle of the printer,
The nozzle may be clogged. In addition, when the printed papers are placed on top of each other, ink may appear on the paper. The Tg of the polyester can be adjusted, for example, by changing the addition ratio of the diol component and the acid component.

Next, the dye and the pigment will be described. As the dye, any dye can be used without particular limitation as long as it can be adsorbed by the polyester, and examples thereof include an oil dye, a disperse dye, a direct dye, an acid dye, and a basic dye. It is particularly preferable to use an oil dye and a disperse dye from the viewpoint of adsorptivity. The disperse dye is not limited to the following, but a particularly preferred specific example is C.I. I.
Disperse Yellow 5, 42, 54, 64, 79, 8
2, 83, 93, 99, 100, 119, 122, 12
4, 126, 160, 184: 1, 186, 198, 1
99, 201, 204, 224 and 237; C.I. I. Disperse Orange 13, 29, 31: 1, 33, 4
9, 54, 55, 66, 73, 118, 119 and 16
3; I. Disperse Red 54, 60, 72, 7
3, 86, 88, 91, 92, 93, 111, 126,
127, 134, 135, 143, 145, 152, 1
53, 154, 159, 164, 167: 1, 177,
181, 204, 206, 207, 221, 239, 2
40, 258, 277, 278, 283, 311, 32
3, 343, 348, 356 and 362; I. Disperse Violet 31, 33; C.I. I. Disperse Blue 36, 56, 60, 73, 87, 113, 12
8, 143, 148, 154, 158, 165, 16
5: 1, 165: 2, 176, 183, 185, 19
7, 198, 201, 214, 224, 225, 25
7, 266, 267, 287, 354, 358, 365
And 368; and C.I. I. Disperse Green 6:
1 and 9 and the like. The oily dye is not limited to the following, but particularly preferred specific examples include, for example, C.I. I. Solvent Black 3,7,
27, 29 and 34; C.I. I. Solvent Yellow 1
4, 16, 19, 21, 25, 29, 30, 56, 8
2, 93 and 162; C.I. I. Solvent Red 1,
3, 8, 18, 19, 24, 27, 43, 49, 51,
72, 73, 83, 109, 112, 117, 122,
132, 138 and 218; C.I. I. Solvent Violet 3; C.I. I. Solvent Blue 2, 11, 2
5, 35, 38, 63, 67, 70, 75 and 117;
C. I. Solvent Green 3 and 7; and C.I.
I. Solvent Orange 2 and the like. The direct dye is not limited to the following, but particularly preferable specific examples thereof include C.I. I. Direct Black 19 and the like. The acidic dye is not limited to the following, but particularly preferred specific examples include, for example, C.I. I. Acid black 2
And 52; C.I. I. Acid Yellow 23; C.I. I.
Acid Red 51, 87 and 92; and C.I. I.
Acid Blue 1, 9 and 74 and the like. The basic dye is not limited to the following, but particularly preferable specific examples thereof include C.I. I. Basic Yellow 2 and 11; C.I. I. basic·
Red 1 and 13; C.I. I. Basic Violet 1, 3, 7 and 10; and C.I. I. Basic Blue 5, 7, 9 and 26 and the like.

The dye used in the present invention is preferably dissolved in a solvent, particularly a ketone solvent, in an amount of 20 g / l or more, from the viewpoint of being efficiently adsorbed to the polyester by the phase inversion emulsification described later, and preferably 100 to 600 g / l. More preferably, it dissolves.

On the other hand, the type of the above-mentioned pigment is not particularly limited, and conventionally known organic and inorganic pigments can all be used. For example, azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, chelated azo pigments, and phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthaloni pigments, and the like. Cyclic pigments, dye lakes such as basic dye lakes and acid dye lakes, organic pigments such as nitro pigments, nitroso pigments, aniline black, daylight fluorescent pigments, titanium oxide,
Inorganic pigments such as iron oxide and carbon black are exemplified. 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. The particle size of the pigment is not particularly limited as long as it is a particle size that can be adsorbed by the polyester micelle.

The above dye or pigment is contained in the ink in an amount of 1 to 3
It is preferably 0% by weight, and more preferably 1.5 to 25% by weight. If the compounding amount of the above dye or pigment is less than 1% by weight, the print density is insufficient, and if it exceeds 30% by weight, the stability of suspension particle size over time decreases and the particle size tends to increase. It is preferably within the range.

In the present invention, the above dyes and pigments may be used alone or in combination. When both are used in combination, the mixing ratio (weight) of the dye and the pigment is the former: the latter = 10: 9
It may be freely selected in the range of 0 to 90:10. In the present specification, "pigment" refers to fine particles of solid insoluble in water, solvent, oil, etc., whereas "dye" is dyed in a state dissolved in water or solvent. [Chemical Encyclopedia of Color Chemistry, March 1988, 1st printing, edited by CMC Co., Ltd., Synthetic Organic Chemistry Association, p. 45].

The average particle size of the polyester suspension to which the above dye or pigment is adsorbed is 0.005 to 0.
Preferably it is 5 μm. The average particle diameter is 0.0
If it is less than 05 μm, ink bleeding may occur, and if it exceeds 0.5 μm, the dispersion stability of the suspension itself may be reduced. Further, the average particle size is preferably 0.005 to 0.3 μm from the viewpoint of suspension formability and stability, and more preferably 0.005 to 0.3 μm.
0.2 μm, more preferably 0.01 to 0.1 μm
m. The average particle diameter can be adjusted, for example, by changing the conditions of phase inversion emulsification described below.

In the water-based ink of the present invention, the above polyester is preferably contained in the ink in an amount of 1 to 50% by weight, more preferably 2 to 30% by weight. If the amount of the polyester 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.

The water-based ink of the present invention contains water (desirably,
(Ion-exchanged water) as a medium, in addition to containing a polyester suspension having the above dye or pigment adsorbed thereto, various conventionally known additives such as wetting agents such as polyhydric alcohols, dispersants, and silicone-based agents. Defoaming agents such as cations, anions or surface active agents such as nonionic surfactants, antifungal agents such as chloromethylphenol and / or chelating agents such as EDTA, and oxygen absorption such as sulfite. You may contain an agent etc.

The humectant is not particularly limited, but 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;
Nitrogen-containing compounds such as triethanolamine; formamide; dimethylformamide; and one or more of dimethyl sulfoxide can be used. The amount of these wetting agents is not particularly limited, but may be preferably 0.1 to 50% by weight in the aqueous ink of the present invention.
More preferably, 0.1 to 30% by weight can be added.

The dispersant is not particularly limited, but examples of the anionic surfactant include alkyl sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkanes or olefin sulfonates. , A group consisting of an alkyl sulfate ester salt, a polyoxyethylene alkyl or alkyl aryl ether sulfate ester salt, an alkyl phosphate salt, an alkyl diphenyl ether disulfonate salt, an ether carboxylate, an alkyl sulfosuccinate salt, an α-sulfo fatty acid ester, and a fatty acid salt. A surfactant selected from the above, a condensate of a higher fatty acid and an amino acid, a naphthenate, or the like can be used. Anionic surfactants preferably used include alkylbenzene sulfonates (particularly linear alkyl), alkanes or olefin sulfonates (particularly secondary alkane sulfonates, α-olefin sulfonates), alkyl sulfates Polyoxyethylene alkyl or alkyl aryl ether sulfates (especially polyoxyethylene alkyl ether sulfates), alkyl phosphates (especially monoalkyl), ether carboxylates,
A surfactant selected from the group consisting of alkyl sulfosuccinates, α-sulfo fatty acid esters, and fatty acid salts, particularly preferably alkyl sulfonates, alkyl benzene sulfonates (particularly linear alkyl ones), polyoxy Ethylene alkyl or alkylaryl ether sulfate ester salts (particularly polyoxyethylene alkyl ether sulfate ester salts), and alkyl sulfate ester salts. These can be used alone or in combination of two or more. Further, as a cationic surfactant, an aliphatic amine salt, a quaternary ammonium salt,
A sulfonium salt, a phosphonium salt, or the like can be used. These can be used alone or in combination of two or more. Further, as the nonionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester,
A surfactant or the like selected from the group consisting of glycerin fatty acid ester, polyoxyethylene fatty acid ester and alkyl (poly) glycoxide can be used. Nonionic surfactants preferably used are surfactants selected from polyoxyethylene alkyl ethers and polyoxyethylene alkyl aryl ethers. These can be used alone or in combination of two or more. In addition, as the amphoteric surfactant, an amino acid type or betaine type compound or the like can be used.

As the polymer dispersant, proteins such as gelatin and casein, natural rubber such as gum arabic, glucooxide such as saponin, cellulose derivatives such as alkyl cellulose, carboxyalkyl cellulose and hydroxyalkyl cellulose, lignin sulfonate, Natural polymers such as shellac, polyacrylic acid salts, styrene-acrylic acid copolymer salts, vinylnaphthalene-acrylic acid copolymer salts, styrene-maleic acid copolymer salts, vinylnaphthalene-maleic acid copolymer salts, β-naphthalenesulfonic acid formalin condensate salt, anionic polymers such as polyphosphoric acid, polyvinyl alcohol, polyvinylpyrrolidone, nonionic polymers such as polyalkylene glycol, and the like. Can use more than one seed That.

Especially, it is particularly preferable to use the compound represented by the following formula (2) from the viewpoint that the average particle diameter of the suspension can be reduced.

[0036]

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In the above formula (2), R'is a hydrogen atom,
It represents a hydrocarbon group or a hydroxyl group having 1 to 10 carbon atoms, and preferably a hydrogen atom is used. Also, R "is a carbon number of 1 to
5 is shown, and a methylene group is preferably used. Further, M represents a monovalent cation, and preferably an alkali metal ion such as sodium or potassium is used. In addition, l represents an integer of 1 to 1000,
It is preferably 100 to 800. In addition, the above equation (2)
The HLB value of the compound represented by is preferably 5 to 15 from the viewpoint of exhibiting the effect as a dispersant and suppressing the increase in the average particle diameter of the suspension.

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

The compounding amount of the compound represented by the above formula (2) is not particularly limited, but 0.01% in the water-based ink of the present invention.
Preferably, it is blended at 10 to 10% by weight. If the compounding amount of the compound is less than 0.01% by weight, it is difficult to reduce the particle size of the suspension. If it exceeds 10% by weight, the average particle size of the suspension increases, the suspension stability decreases, and gelation occurs. Therefore, it is preferable to be within the above range. More preferably, the compounding amount of the compound represented by the above formula (2) is in the aqueous ink of the present invention.
It is 0.1 to 1% by weight.

The defoaming agent is not particularly limited, but it is preferable to use a compound represented by the following formula (3), especially a compound represented by the following formula (4) at the time of ink preparation. It is particularly preferable from the viewpoint of suppressing the generation of bubbles and controlling the surface tension of the ink.

[0041]

[Chemical 6]

[0042]

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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 to} C ₅ lower alkyl groups or phenyl groups, and m and n are preferably 10 Is an integer from 1 to 100, and R ₅ and R ₆ are preferably the same or different C _{1 to} C ₅ lower alkyl groups or phenyl groups.

Commercially available products can be used as the compound represented by the above formula (3) or (4). 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 compounding amount of the compound represented by the above formula (3) or (4) is not particularly limited, but it is preferably 0.001 to 2% by weight in the water-based 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 type defoaming agent 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.

[0047]

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[0048]

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In using the above surface tension adjusting agent, one or more of these compounds can be used,
It is desirable to add 0.005 to 15% by weight to 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.

The water-based ink of the present invention preferably has a viscosity at 20 ° C. of 0.5 to 8 cps, more preferably 1 to 20 from the viewpoint of ejection stability when used in an ink jet printer. It is 5 cps, more preferably 1 to 3 cps. That is, the viscosity is 0.
If it is less than 5 cps, ink bleeding becomes remarkable, and ink may leak from the nozzle of the printer head when used in an inkjet printer. If the viscosity exceeds 8 cps, the viscosity of the inkjet ink becomes too high, ink is not supplied to the printer head, ejection failure occurs, and problems such as blurring and deterioration of print quality occur. It is preferable to set the inside. In order to bring the viscosity of the water-based ink of the present invention into the above range, for example, the concentration of the dye or the pigment is adjusted, the concentration or the molecular weight of the polyester is adjusted, and the additives such as the surface tension adjusting agent are added. Or a wetting agent having a low viscosity is selected from among the wetting agents to be used, and the usage amount thereof is adjusted.

The water-based ink of the present invention has a temperature of 20 ° C.
The surface tension at is preferably in the range of 25 to 50 dyn / cm. The surface tension is 25 dyn / c
If it is less than m, ink bleeding and print quality deterioration may occur, and ink may leak from the nozzle of the printer head when used in an inkjet printer.
If it exceeds 0 dyn / cm, the ink drying speed becomes too slow, the printer head becomes dirty, or the ink supply failure to the nozzles of the print head occurs, thereby causing the ink ejection failure and deteriorating the print quality. The surface tension is
It is preferably 28 to 43 dyn / cm. Further, when the color tone is magenta, cyan or yellow, it is preferably 28 to 40 dyn / cm, more preferably 2
8 to 36 dyn / cm, more preferably 28 to 3
It is 3 dyn / cm. On the other hand, when the color tone is black, it is preferably 28 to 40 dyn / cm. In order to bring the surface tension of the water-based ink of the present invention into the above range, for example, the concentration of the dye or pigment is adjusted, the concentration or molecular weight of the polyester is adjusted, and the surface tension adjusting agent or the like is added. The agent may be added, or a wetting agent used may have a low surface tension.

The water-based ink of the present invention is particularly useful as a water-based ink for ink jet recording. In this case, the water-based ink can be used in both piezoelectric and thermal jet inkjet printers, but as is apparent from the examples described below, a thermal jet inkjet recording printer is particularly used. In that case, the excellent effect of further improving the fixability is exhibited. In particular, the water-based ink of the present invention exerts a particularly remarkable effect as heat energy of a heat jet type in the case of ink jet recording using a heater of a heating resistance element.

Next, a preferred method for producing the water-based ink of the present invention will be described. The water-based ink of the present invention is preferably produced by so-called phase inversion emulsification described below.

Here, in the phase inversion emulsification, the above polyester is added to a solvent together with the above dye or pigment, and a neutralizing agent is added to ionize the carboxyl groups in the polyester,
Then, after adding water, the solvent is distilled off and the phase is converted to an aqueous system.

First, the polyester is added to a solvent together with the dye or pigment. In this case, it is preferable from the viewpoint of suspension formation that the polyester and the dye or pigment are dissolved in 5 to 50 parts by weight and 0.1 to 50 parts by weight, respectively, with respect to 100 parts by weight of the solvent.
The solvent is not particularly limited, for example, acetone, methyl ethyl ketone, diethyl ketone,
Examples thereof include ketone solvents such as dipropyl ketone, methyl isobutyl ketone, and methyl isopropyl ketone, and of these, methyl ethyl ketone is preferably used.

Next, a neutralizing agent is added to the mixed liquid of the polyester, the dye or pigment, and the solvent. Thereby, the carboxyl groups in the polyester are ionized. The neutralizing agent can be used without any particular limitation as long as it can ionize a carboxyl group in the polyester. Such neutralizing agents include, for example, aqueous ammonia, aqueous alkaline solutions of monovalent inorganic salts such as lithium hydroxide, sodium hydroxide and potassium hydroxide, allylamine, isopropylamine, diisopropylamine,
Ethylamine, diethylamine, triethylamine, 2
-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-trimethylhexamethylene diamine ,
2,4,4-trimethylhexamethylenediamine, hexamethylenediamine, N-aminoethylpiperazine, N
And amines such as -aminopropylpiperazine, N-aminopropyldipiperidipropane, and piperazine. 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 that can at least ionize the carboxyl groups in the polyester.

After the addition of the neutralizing agent, water is added to the mixture to cause phase inversion. This results in a polyester suspension with the dye or pigment adsorbed in the aqueous phase. The amount of water to be added is preferably 100 to 300 parts by weight based on 100 parts by weight of the mixed solution. 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, by adding water to which the compound represented by the above formula (3) or (4) is added to the above mixed solution, generation of bubbles can be suppressed, and further, the surface tension can be adjusted. It is preferable because it is possible. The addition amount of the compound represented by the above formula (2) is 0.01 to 10% by weight in the finally obtained ink.
The amount is preferably such that On the other hand, the amount of the compound represented by the above formula (3) or (4) is preferably such that it becomes 0.001 to 2% by weight in the finally obtained ink.

After completion of the phase inversion, the system is heated under reduced pressure to remove the solvent in the mixed solution and a predetermined amount of water to remove the solvent of the present invention having a desired concentration. A water-based ink is obtained. The pH of the water-based ink thus obtained is preferably adjusted to pH = 5 to 12 in order to ensure the stability of the suspension. In preparing the aqueous ink of the present invention, it is preferable to remove coarse particles. For example, the ink obtained as described above may be filtered under pressure with a filter or treated with a centrifuge to give preferably 2 μm.
By removing particles of m or larger, more preferably 1 μm or larger, and even more preferably 0.5 μm or larger, an ink without clogging can be obtained.

The water-based ink of the present invention is particularly useful as an ink-jet recording water-based ink as described above, but can also be used as other inks, for example, inks for writing instruments such as general fountain pens, ballpoint pens and felt-tip pens. is there.

[0060]

EXAMPLES Next, the water-based ink of the present invention will be described in more detail with reference to examples. However, it goes without saying that the present invention is not limited to such an embodiment.

Example 1 Polyoxypropylene (2,
2) -2,2-bis (4-hydroxyphenyl) propane (1050 g), fumaric acid (340 g), and hydroquinone (1.5 g) were placed in a glass 2-liter four-necked flask, and a thermometer, a stainless steel stirring rod, a flow-down condenser and A nitrogen inlet tube was attached to this. 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 100 ° C. The obtained polyester is a pale yellow solid,
The Tg by DSC was 57.3 ° C. Also, JIS
The acid value of the polyester based on K 0070 is 32.
It was 0 KOHmg / g, and the number average molecular weight (in terms of polystyrene by gel permeation chromatography) was 3,200. Next, the polyester 150
g, oil dye (Orient Chemical, OIL BLACK
860) 40 g and methyl ethyl ketone 500 g were put in a separable flask, and after the inside of the flask was replaced with N ₂ ,
The polyester and the oil dye were completely dissolved in methyl ethyl ketone with stirring. Subsequently, 9.15 g of dimethylethanolamine was added to ionize the carboxyl groups in the polyester. Furthermore, ion-exchanged water 960
2 g of polyester suspension (average particle size; 0.04 μm) having a dye adsorbed thereon was removed by heating to 40 ° C. under reduced pressure to remove methyl ethyl ketone.
A 0% by weight aqueous ink was obtained.

Example 2 In place of fumaric acid in Example 1, terephthalic acid and trimellitic anhydride were mixed in a ratio of 2:
A polyester was obtained by the same operation as in Example 1 except that 1 mixture was used [acid value: 33.0 KOHmg / g, T
g: 55.8 ° C., number average molecular weight: 3,400]. Using this polyester, as a neutralizing amine, 12.50 g of triethylamine instead of dimethylethanolamine
Dye (manufactured by Orient Chemical Co., VALIFAST BLUE 260
A 20% by weight aqueous ink of a polyester suspension (average particle size: 0.09 μm) having 6) adsorbed thereon was obtained.

Example 3 Ion-exchanged water 9 containing 3 g of Demol N (dispersant, HLB value 8.51) manufactured by Kao Corporation in place of 960 g of ion-exchanged water in Example 1
A polyester suspension having a dye (OIL PINK 312, manufactured by Orient Chemical Industry Co., Ltd.) adsorbed by the same operation as in Example 1 except that 60 g was used (average particle size;
0.01 μm) of a 20% by weight aqueous ink was obtained.

Example 4 Polyoxypropylene (2.
2) -2,2-bis (4-hydroxyphenyl) propane 1050 g, dimer acid [Unidim 22 (trade name) manufactured by Union Cap] 168 g, fumaric acid 250
g, trimellitic anhydride 115 g, hydroquinone 1.
5 g was placed in a glass 2-liter four-necked flask, and a thermometer, a stainless stir bar, a downflow condenser and a nitrogen inlet tube were attached to this. In the mantle heater,
The reaction was carried out while stirring at 210 ° C. under a nitrogen stream.
The degree of polymerization was traced from the softening point according to ASTM E2867, and the reaction was terminated when the softening point reached 101 ° C. The obtained polyester is a pale yellow solid and has a DS
The Tg according to C was 58.1 ° C. Also, JIS K
The acid value of the polyester based on 0070 is 38.5K
OH mg / g, number average molecular weight (polystyrene conversion by gel permeation chromatography) 3,3
It was 00. Next, 150 g of the above polyester and an oily dye (OIL YELLOW 12 manufactured by Orient Chemical Co., Ltd.
9) 40 g and 500 g of methyl ethyl ketone were placed in a separable flask, the inside of the flask was replaced with N ₂ , and the mixture was stirred to completely dissolve the above polyester and oil dye in methyl ethyl ketone. Then, sodium hydroxide 4.5
3 g was added to ionize the carboxyl groups in the polyester. Further, 960 g of ion-exchanged water containing 3 g of Demol N (dispersant, HLB value: 8.51) manufactured by Kao Corporation was added dropwise and stirred, and then heated to 40 ° C. under reduced pressure to remove methyl ethyl ketone, Dye-adsorbed polyester suspension (average particle size: 0.01μ
A 20% by weight aqueous ink of m) was obtained.

Example 5 Ion-exchanged water 9 containing 3 g of Demol N (dispersant, HLB value 8.51) manufactured by Kao Corporation in place of 960 g of ion-exchanged water in Example 1
A suspension of polyester (average particle size; 0.05 μm) in which a pigment (Carbon Black MA-100, manufactured by Mitsubishi Kasei) was adsorbed by the same operation as in Example 1 using 60 g.
A 20% by weight aqueous ink of m) was obtained.

Example 6 Aqueous ink of the polyester suspension obtained in Example 1 85 g Ethanolamine 2 g Diethylene glycol 10 g Glycerin 2.5 g Acetylenol EL 0.5 g Obtained by mixing the above components. The dispersion was filtered through a 5 micron filter to remove dust and coarse particles, and an inkjet ink was obtained. Using this ink, printing was performed with a commercially available Canon Micro Bubble Jet Printer (model number BJ-10VL), and the ink discharge amount, print density, bleeding, fixability, water resistance and clogging prevention property were evaluated by the following methods. Table 1 shows the results.

<Ink ejection amount> For printing, solid printing is performed using recycled paper for PPC [manufactured by Nippon Kakoh Paper Co., Ltd.],
Measure the weight of the ink cartridge before and after printing,
The ink ejection amount was calculated from the change amount. <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). <Bleeding> Recycled paper for PPC [manufactured by Nippon Kaishi Paper Co., Ltd.]
After printing an alphanumeric character and leaving it for one hour or more, the sharpness of the character and the degree of mustache-like bleeding generated from the character were evaluated with a microscope and visually. ：: Characters are sharp and have no bleeding blemishes Δ: Characters are not sharp and bleeding occurs a little ×: Characters are not sharp and there are many bleeds <Water-resistant> Recycled paper for PPC [Nippon Kaishi Paper ( Co., Ltd.)
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 solid print portion and the white portion where no print was made was measured with a Macbeth densitometer RD918 (manufactured by Macbeth). <Clogging prevention> After printing alphanumeric characters continuously for 10 minutes with a commercially available Canon micro bubble jet printer (model number BJ-10VL), stop the printer,
It was left for 2 weeks in an environment of 40 ° C. and 25% RH without a cap. After the standing, alphanumeric characters were printed again, and the number of clogging recovery operations required until the same printing as before the standing was obtained was examined. ：: Printing equivalent to the initial state is possible with 0 to 2 recovery operations. Δ: Printing equivalent to the initial period is possible with 3 to 5 recovery operations. ×: Printing equivalent to the initial state is not possible even after 6 or more recovery operations. Possible <Fixing property> OHP sheet for inkjet only (MJOH
PS1N, made by Epson), and the eraser (width 18.5mm) is fixed on the printing surface at an inclination of 45 °.
A load of 1 kg was placed thereon, and rubbed five times on the solid printing surface, and the state of the printing surface at that time was visually observed. ◯: There is no scratch or peeling on the printed surface. Δ: There is scratch on the printed surface. X: There is peeling on the printed surface.

[Examples 7 to 10] Similar to Example 6 except that the polyester emulsion aqueous inks obtained in Example 1 were replaced with the polyester emulsion aqueous inks obtained in Examples 2 to 5, respectively. An ink for inkjet recording was obtained by the operation of. The same evaluation as in Example 6 was performed using the obtained ink. Table 1 shows the results.

[Comparative Example 1] An ink was obtained from the following formulation using a water-soluble dye that is commonly used in ink jet recording inks.・ C. I. Acid Yellow 4 g ・ Ethanolamine 2 g ・ Diethylene glycol 10 g ・ Glycerin 2.5 g ・ Pure water 81 g ・ Acetyleneol EL 0.5 g That is, the above components were mixed for 12 hours using a ball mill, and the obtained dispersion was filtered with a 5 μm filter. To remove dust and coarse particles to obtain an ink. The same evaluation as in Example 6 was performed using the obtained ink. Table 1 shows the results. [Comparative Example 2] A pigment ink was manufactured under the following conditions and evaluated in the same manner as in Example 6. (Preparation of pigment dispersion) -Styrene-acrylic acid copolymer 3 parts by weight-Triethanolamine 7 parts by weight-Ion-exchanged water remaining amount That is, the above components are mixed and heated to about 70 ° C to completely remove the resin component. Dissolved in. To this aqueous solution, 15 parts of pigment (phthalocyanine blue) was added, and dispersion treatment was performed under the following conditions. Disperser: Sand mill (Yasukawa Seisakusho) Grinding media: Glass beads (1.7 mm diameter) Media filling rate: 1.5 times (weight) Dispersion time: 2 hours After dispersion, remove glass beads and coarsen with a 5 μm membrane filter. Particles and dust were removed to obtain a pigment dispersion liquid (average particle diameter: 0.15 μm). (Manufacture of ink)-50 parts by weight of the above dispersion-2.5 parts by weight of glycerin-10 parts by weight of diethylene glycol-2 parts by weight of polyethylene glycol (PEG300)-0.5 part by weight of acetylenol EL-35 parts by weight of ion-exchanged water

[0070]

[Table 1]

As is clear from the results shown in Table 1, the ink jet ink in which the dye or pigment is adsorbed on the polyester suspension (the product of the present invention, Examples 6 to 6).
In 9), it can be seen that the bleeding and the water resistance are further improved while the same printing density as that of the ink of the conventional formulation (Comparative Example 1) is maintained. Further, in the pigment-based inkjet ink (Example 10), the water resistance of the pigment ink of Comparative Example 2 was maintained to the same extent, and the fixability of the OHP meat or the like on the printing object was improved. I understand.

[0072]

According to the water-based ink of the present invention, by adsorbing a dye or a pigment on a polyester suspension, the printing density of the printed matter is increased, and the fixability and water resistance of the printed matter are improved. In particular, when a dye is used, the water resistance of the ink is extremely improved and bleeding is prevented,
When a pigment is used, the fixability of the ink on the printing object such as paper or OHP sheet is significantly improved. Further, by performing the adsorption by phase inversion emulsification, the dye and the pigment can be easily and efficiently adsorbed, and the water resistance and the fixability of the ink are further improved. The above-mentioned water-based ink is particularly useful as a water-based ink for ink-jet recording, and can also be used as ink for writing implements such as general fountain pens, ball-point pens, and felt-tip pens.

Claims (6)

[Claims] 1. An aqueous ink containing a suspension of polyester having a dye or a pigment adsorbed thereto. 2. JIS K007 of the above polyester
The water-based ink according to claim 1, wherein the acid value based on 0 is 3 to 100 KOHmg / g. 3. The polyester according to claim 1, wherein the polyester is a diol component represented by the following formula (1) and at least one acid selected from the group consisting of a divalent or higher polycarboxylic acid, an acid anhydride thereof and a lower alkyl ester thereof. 3. The aqueous ink according to claim 1, which is obtained by co-condensation polymerization of the components. Embedded image 4. The polyester having a number average molecular weight of 50.
The water-based ink according to claim 1, which is 0 to 100,000. 5. A water-based ink for inkjet recording, which uses the water-based ink according to claim 1. 6. A diol component represented by the following formula (1) and one or more acid components selected from the group consisting of divalent or higher polyvalent carboxylic acids, their acid anhydrides and their lower alkyl esters. Acid value obtained by polycondensation is 3 to 100K
OH mg / g polyester is added to a solvent together with a dye or a pigment, a neutralizing agent is added to ionize carboxyl groups in the polyester, and then water is added, and then the solvent is distilled off to invert the phase to an aqueous system. A method for producing an aqueous ink, comprising: Embedded image