JP2002348506A - Water-based ink for ink jet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based ink for ink jet recording, capable of rapidly drying without lowering ejection property and storage stability of ink and lowering vividness of image of printed matter, particularly on plain paper. SOLUTION: This purpose is attained by water-based ink for ink jet recording characterized by comprising at least an alcohol represented by formula (I) [wherein, R1, R2 and R3 are each a 1-4C alkyl group], a nonionic surfactant represented by formula (II) [wherein m+n is 10-30], a coloring agent and water and having a weight ratio of the alcohol represented by formula (I) to the surfactant represented by formula (II) of 1:1 to 1:10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an aqueous ink for ink-jet recording. More specifically, the present invention relates to a water-based ink for ink-jet recording which dries quickly without lowering the dischargeability and storage stability of the ink, and in particular, without lowering the sharpness of a printed image on plain paper. .

[0002]

2. Description of the Related Art The ink jet recording system has a feature that high-resolution and high-quality images can be printed by a relatively inexpensive apparatus. Usually, as ink used in the ink jet recording method, aqueous ink occupies the mainstream in terms of odor, safety, etc., and is composed of a mixed solution of a dye or pigment as a colorant, water and a water-soluble organic solvent. Ink is used. The characteristics required for the ink for ink jet recording include print quality, print dryness, print water resistance, storage stability, and the ability not to damage members such as a head. Above all, the printing speed has been remarkably improved due to the recent development of the ink jet recording apparatus, and therefore, quick drying of the ink is strongly required.

[0003] Drying of ink occurs through both evaporation and penetration effects. Since evaporation is determined by the vapor pressure of the solvent, the addition of a high vapor pressure solvent is effective, while penetration is determined by the interfacial energy between the ink and paper and the porosity of the print medium, The use of a penetrant has been studied as a means of increasing the penetration rate of ink.

In general, the addition of a surfactant having a low boiling point and high volatility such as monohydric alcohol, glycol monoether, glycol ether such as diethylene glycol monoether, or a surfactant is effective for improving the drying property of the aqueous ink for ink jet recording. It is a target. Among them, the addition of a monohydric lower alcohol such as ethanol or 2-propanol is useful because it is inexpensive, has high compatibility with water and other organic solvents, and is stable. Since these lower alcohols have a low boiling point of around 100 ° C. and are highly volatile, they promote the evaporation of the ink on the medium and also have the effect of increasing the permeability of the ink into the medium. Often contained.

For example, a pigment ink to which a mixture of 2-propanol and another lower alcohol is added (JP-A-8-209051),
A dye ink containing a polyhydric alcohol and a monohydric alcohol (Japanese Patent Publication No. 7-15074), a combination of a color ink containing acetylene glycol and a dye ink containing a polyhydric alcohol and a monohydric alcohol in a specific ratio (Japanese Unexamined Patent Publication No. -293976)
And the like. However, the lower alcohols described above have insufficient functions as desiccants. In order to increase the drying speed, it is necessary to increase the addition amount to nearly 10% of the whole, but the increase in permeability is accompanied by an uneven ink spread (feathering) along the paper fiber, optical When a pigment is used as a coloring agent, the density is lowered, and the pigment dispersibility is deteriorated. In general, the ink easily spreads. Further, since these alcohols have high volatility, there is a problem in terms of odor and safety, and there is a possibility that clogging due to drying of the nozzle orifice may occur.

In addition, if a wetting agent is added to prevent clogging, the ink will have excellent intermittent ejection properties, but will have poor print drying properties. It is difficult to satisfy all the properties required for ink.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is possible to prevent the print characteristics from being reduced due to feathering or the like, and to reduce the ink discharge performance and stability. An object of the present invention is to provide an ink having excellent quick-drying properties.

[0008]

According to the present invention, there is provided the following formula (I):

[0009]

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Wherein R 1, R 2 and R 3 are an alkyl group having 1 to 4 carbon atoms, represented by the following formula (II):

[0011]

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Wherein m + n is from 10 to 30; and at least a nonionic surfactant, a coloring agent and water, wherein the alcohol of the formula (I) and the surfactant of the formula (II) A water-based ink for inkjet recording characterized in that the weight ratio is 1: 1 to 1:10.

By using the alcohol of the formula (I) and the surfactant of the formula (II) together in a specific weight ratio, a good balance of evaporating and permeating properties can be obtained without deterioration of print quality and dischargeability. This provides an ink having excellent quick drying properties.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the ink of the present invention, in the formula (I) constituting alcohol, the substituents R1, R2 and R3 each have 1 carbon atom.
Selected from the group consisting of 44 alkyl groups, ie, methyl, ethyl, propyl, butyl. Where R1, R2
And R3 may be the same or different from each other. Alcohols of formula (I) having these substituents are specifically neopentyl alcohol, 2,2-dimethyl-1-butanol, 2-methyl-2-ethyl-1-butanol,
Examples include 2,2-diethyl-1-butanol and mixtures thereof. Of these, neopentyl alcohol, 2,2-dimethyl-1-butanol, 2-methyl-2-ethyl-1-butanol and mixtures thereof It is preferred to use.

The alcohol of the formula (I) has a bulky alkyl group steric structure, so that it has high hydrophobicity despite its small molecular weight, and has an interaction with paper fibers and sizing agents by hydrogen bonding. It is small and easily penetrates recording media. As a result, while the alcohols of formula (I) are somewhat smaller than lower alcohols such as ethanol and 2-propanol, they have a relatively high vapor pressure to promote the evaporation of the ink, while having a relatively high vapor pressure. Significantly increases permeability to recording media.

The compound of the formula (I) used in combination with the alcohol of the above formula (I)
In the nonionic surfactant (I), the number of moles of ethylene oxide added, m + n, is 10 to 30, preferably 10 to 20.
It is.

Such a surfactant of the formula (II) has an HLB (hydrophilic lipophilic balance) value of 13 or more, specifically 13 to 40, particularly 1 to 10.
It is preferably in the range of 3 to 18. The greater the number of m + n in the above range and the higher the HLB value, the higher the water solubility of the surfactant of the formula (II) and the higher the solubility stability.

Examples of the surfactant of the formula (II) include commercially available acetylene glycol ethylene oxide adducts, specifically, Surfynol 400 series manufactured by Air Products, and particularly Surfynol 465 is suitably used. .

An ink having an optimum balance between the evaporating property and the permeability and having excellent quick-drying properties can be obtained by mixing the alcohol of the formula (I) and the surfactant of the formula (II) in a weight ratio of 1: 1 to 1:10. It is obtained by using together. When the weight ratio of the formula (II) surfactant to the alcohol of the formula (I) is less than 1, the deterioration of print quality is large, and when the weight ratio of the formula (II) surfactant is more than 10, Ink ejection failure may occur.

The content of the alcohol of the formula (I) is
0.1 to 3% by weight of the total weight of the ink, preferably 0.1 to 1% by weight
Is preferably within the range. By containing alcohol (I) in this ratio, the ink has sufficient drying properties, but does not deteriorate print quality, and minimizes ink bleeding, especially when printing on sized plain paper. .

The nonionic surfactant of the formula (II) is
It increases the permeability of the ink to the recording medium and helps drying of the ink, and has the effects of improving the image quality, improving the ink wettability to the nozzles, and improving the pigment dispersibility. Inevitably, the ink jetting failure (evaporation) and the ink ejection failure due to the remarkable decrease in viscosity and the increase in viscosity are unavoidable. On the other hand, when the added amount is too small, the ink cannot be provided with quick drying property. Therefore, it is preferable that the surfactant of the formula (II) is contained in the range of 0.5 to 5% by weight, particularly 1 to 5% by weight based on the total weight of the ink.

The colorant used in the present invention can be selected from known water-soluble dyes and known water-dispersible pigments, and is not particularly limited. Examples of the dye include direct dyes, acid dyes, basic dyes, reactive dyes, disperse dyes, construction dyes, soluble construction dyes, reaction disperse dyes, and oil dyes, and any of them can be used. These dyes depend on the type of the medium component and the characteristics required for the ink, but generally, 1 to 6% of the total weight of the ink
%.

As the pigments, inorganic pigments and organic pigments can be used. As the inorganic pigments, yellow pigments (such as cadmium yellow, chrome yellow, and strontium yellow), red pigments (such as Komyotan, vermilion, and red iron), and purple Pigment (cobalt violet, etc.), blue pigment (prussian blue, etc.), green pigment (emerald green, cobalt green, etc.), white pigment (titanium oxide, zinc white, lead white, etc.), black pigment (carbon black or oxidize the surface A modified carbon black treated, a self-dispersible carbon black such as a graft carbon having a pigment surface treated with a resin or the like can be used. Further, as the organic pigment, azo, acridine, phthalocyanine, quinacridone, anthraquinone, indanthrene, dioxazine, indigo, thioindigo, perylene, perinone, isoindolenine and the like can be used. .

In general, the pigment may be a pigment dispersion which has been subjected to dispersion treatment with a commercially available or synthesized polymer dispersant of any form, such as a block copolymer, a graft copolymer, and a random copolymer. Well, the particle size is 25μm or less,
It is preferable to use a pigment composed of particles having a particle size of 0.5 μm or less from the viewpoint of print density, storage stability of ink, ejection stability, and the like. Specific types of dispersants include polyvinyl alcohol, polyvinylpyrrolidone, β-naphthalenesulfonic acid formalin condensate, acrylic acid-acrylic acid ester copolymer salt, styrene-acrylic acid copolymer salt, maleic anhydride and the like. And a hydrophobic resin dispersion of an acryl-urethane copolymer. The amount of the pigment added to the total weight of the ink is preferably 1 to 30% by weight, and more preferably 3 to 12% by weight.

The ink of the present invention further comprises, in addition to the above components,
It may contain a water-soluble organic solvent selected from the group consisting of (poly) alkylene glycols, alkylene glycol monoalkyl ethers and mixtures thereof. These solvents have high moisturizing properties and high hygroscopicity, not only prevent nozzle clogging, but also have a high compatibility with the nonionic surfactant of the formula (II) due to having an ethylene oxide skeleton in the molecule. It can assist in dissolving or dispersing the surfactant.

Specific examples of such a water-soluble organic solvent include polyethylene glycol, polypropylene glycol, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monobutyl ether and the like. Polyethylene glycol and tetraglycol monobutyl ether are preferred, and their content is preferably 10 to 30% of the total weight of the ink.

In order to prevent clogging and adjust physical properties,
Other water-soluble organic solvents can be used in the ink of the present invention. Specifically, glycols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, thiodiglycol, glycerins, DMF, amides such as dimethylacetamide, 2
-Pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2
-Nitrogen-containing heterocyclic ketones such as -imidazolidinone; dimethylsulfoxide, sulfolane; and lower alcohols such as 2-propanol, but are not limited thereto. Preferred solvents include polyethylene glycol, diethylene glycol, triethylene glycol, glycerin, triethylene glycol monomethyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone and 2-
And propanol. Of these, diethylene glycol, N-methyl-2-pyrrolidone and 2-propanol are preferred.

In addition, if necessary, inorganic salts such as potassium hydrogen phosphate and sodium hydrogen phosphate as pH adjusters, benzoic acid, dichlorophen, hexachlorophen, sorbic acid for the purpose of fungicidal, antiseptic, rustproofing, etc. , P-hydroxybenzoic acid ester, ethylenediaminetetraacetic acid (EDTA) and the like. In addition, urea,
Thiourea, ethylene urea and the like can also be added.

Various nonionic, anionic, cationic and amphoteric surfactants and dispersants may be added to the total weight of the ink for the purpose of adjusting the surface tension, improving the fixability, and improving the dispersibility of the pigment. It can be added in an amount of 0.01 to 10% by weight. Preferred surfactants include non-ionic surfactants such as alkylphenyl ether ethylene oxide adducts, polyethylene oxide-polypropylene oxide copolymers, and acetylene glycol ethylene oxide adducts, and sulfate and sulfonate type anionic surfactants. ,
Examples include quaternary amine salt type cationic surfactants, betaine type and amino acid type amphoteric surfactants.

In the present invention, an alcohol of the formula (I)
The surfactant, colorant and water of (II) are mixed with an ordinary stirrer to form a mixed solution.If necessary, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, a high-speed disperser, an emulsifier, etc. Can be used as an ink. It is preferable that the mixed ink is sufficiently filtered before or after dilution by centrifugal filtration with a centrifuge and a membrane filter having a pore size of 5 μm or less.

As a recording apparatus suitable for performing recording using the ink of the present invention, an on-demand type or a continuous type ink jet apparatus which prints on a recording medium by ejecting ink is exemplified. As a method of ink ejection, thermal energy corresponding to a recording signal is applied to ink in the recording head chamber, and a droplet is generated and ejected by the energy, or a thermal jet method in which ink in the recording head chamber corresponds to the recording signal. Any of a piezoelectric element type in which a piezoelectric element pressurizes and ejects the liquid may be used.

The recording medium to which the ink of the present invention is adhered is not particularly limited, and examples thereof include papers exclusively for inkjet printing, PPC paper, and plain paper known in the art.

[0033]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Surfactant A: Surfynol 465 (manufactured by Air Products) (ethoxylated tetramethyldecinediol) HLB = 13 m + n = 10 B: Surfinol 440 (same as above) HLB = 8 m + n = 3.5 C: Emulmin 200 (Sanyo Chemical Co., Ltd.) (Higher alcohol ethylene oxide adduct) HLB = 15.5 Colorant A (black): 5% by weight of Cabojet 300 (CB manufactured by Cabot) B (yellow): CI Acid Yellow 17 2% by weight C (magenta): CI Acid Red 52 2.5% by weight D (cyan): CI Direct Blue 199 2.5% by weight

[0034]

[Table 1]

Comparative Example 1 is an ink containing no alcohol of the formula (I). Comparative Example 2 is an ink containing no surfactant of the formula (II). Comparative Example 3 shows that the ratio of the compound of the formula (I) to the compound of the formula (II) is 1:
0.25, wherein the alcohol of formula (I) is 4% by weight based on the total weight of the ink composition. Comparative Example 4 is an ink containing no surfactant of the formula (II). Comparative Example 5 uses the formula (I) and the formula
Ink wherein the ratio of the compound of formula (II) is 1:51 and the surfactant of formula (II) is 5.1% by weight relative to the total weight of the ink composition.

After sufficiently stirring the compositions of Examples and Comparative Examples shown in Table 1, pressure filtration was carried out with a membrane filter having a pore size of 0.8 μm to obtain an ink of the present invention. Using a commercially available ink jet recording printer BJ F300 (manufactured by Canon Inc.), this ink is used for PPC paper (registered trademark PPC manufactured by Xerox Corporation).
Paper), recycled paper (Honshu Paper registered trademark Yamayuri), bond paper
(Milte's registered trademark Gilbert Bond 25% cotton paper)
Print the English letters and lines on each of the following items (1)
-(4) was evaluated.

(1) Evaluation of print quality Observation with a microscope at 100 × and visual observation. …: Bleeding, feathering not observed with the naked eye ○: Bleeding, feathering was slightly observed △: Bleeding, feathering was large but characters could be recognized ×: Bleeding, feathering was large and characters could not be recognized (2) Print Drying Evaluation After printing, rub the printed part with a finger and measure the time until the finger or paper is no longer soiled. (3) Ejection stability evaluation Continuous printing was performed, and the time during which stable printing was possible was measured. ◎: 24 hours or more ○: 10 hours to less than 24 hours ×: less than 10 hours (4) Evaluation of storage stability Leave the sample in a high-temperature bath at 60 ° C for 1 month and measure the number of cleanings until printing is completely recovered. ◎… Complete recovery after cleaning less than 3 times ○… Complete recovery after cleaning more than 3 times and less than 5 times △… Complete recovery after cleaning more than 5 times and less than 10 times ×… No recovery after more than 10 times cleaning Are shown in Table 2.

[0038]

[Table 2]

[0039]

According to the present invention, an alcohol represented by the formula (I), a nonionic surfactant represented by the formula (II) wherein m + n is 10 to 30, a colorant, A water-based ink for ink-jet recording comprising at least water and having a weight ratio of the alcohol of the formula (I) to the surfactant of the formula (II) of from 1: 1 to 1:10 is provided.

In this ink, neopentyl alcohol, 2,2-dimethyl-1-butanol, 2-methyl-2-ethyl-1-butanol, 2,2-diethyl-ethanol are defined as alcohols defined by the formula (I). By selecting 1-butanol or a mixture thereof, quick drying can be imparted to the ink.

The alcohol of the formula (I) is added to the total weight of the ink.
By using the surfactant of the formula (II) in the range of 0.1 to 3% by weight and 0.5 to 5% by weight of the total weight of the ink,
In addition to imparting sufficient drying properties and print quality to the ink, it is possible to impart ejection stability and the like.

The ink of the present invention contains a water-soluble organic solvent selected from the group consisting of (poly) alkylene glycols, alkylene glycol monoalkyl ethers and mixtures thereof in addition to the above-mentioned components, so that the ink has a moisturizing property. In addition, it is possible to obtain an aqueous ink jet recording ink having a high hygroscopicity and an effect of preventing nozzle clogging.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroaki Nakaya 22-22, Nagaikecho, Abeno-ku, Osaka City, Osaka Inside (72) Inventor Ichiro Fujii 22-22, Nagaikecho, Abeno-ku, Osaka City, Osaka Inside Sharp Corporation (72) Inventor Hiromi Nakatsu 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Prefecture Inside Sharp Corporation (72) Inventor Masaru Nakamura 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Sharp Corporation F-term (reference) 2C056 FC01 2H086 BA01 BA53 BA59 BA62 4J039 AE07 BA04 BA12 BA13 BA35 BC07 BC09 BC13 BE01 BE02 BE03 BE04 BE05 BE07 BE08 BE22 CA03 CA06 EA10 GA24

Claims (6)

[Claims] (1) The following formula (I): [Wherein R1, R2 and R3 are alkyl groups having 1 to 4 carbon atoms]
(B) an alcohol represented by the following formula (II): [Wherein, m + n is 10 to 30], a nonionic surfactant represented by the formula (c), a coloring agent, and (d) at least water, wherein the alcohol of the formula (I) and the alcohol of the formula (II) A water-based ink for ink-jet recording, wherein the weight ratio of the surfactant is 1: 1 to 1:10. 2. The method according to claim 1, wherein the alcohol of the formula (I) is neopentyl alcohol, 2,2-dimethyl-1-butanol, 2-methyl-2-ethyl-1-butanol, 2,2-diethyl-1-butanol and the like. The ink of claim 1, wherein the ink is selected from the group consisting of: 3. The method according to claim 1, wherein the alcohol of the formula (I) is
3. The ink according to claim 1, which is in the range of 0.1 to 3% by weight. 4. The method according to claim 1, wherein the surfactant of the formula (II) is based on the total weight of the ink.
The ink composition according to any one of claims 1 to 3, which is 0.5 to 5% by weight. 5. The ink according to claim 1, further comprising a water-soluble organic solvent selected from the group consisting of (poly) alkylene glycols, alkylene glycol monoalkyl ethers, and mixtures thereof. . 6. The ink according to claim 1, which is used in an ink ejecting apparatus that ejects the ink to perform printing on a recording medium.