JPH04356570A - Water-base recording ink - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous recording ink used in an inkjet printer that performs recording using liquid ink.

0002

[Prior Art] Conventional inkjet recording inks have mainly been made by dissolving dyes as colorants in water, organic solvents, wax, etc.; It had poor water resistance. In order to solve this problem, inks using pigments such as carbon black and aniline black as colorants were devised.
-31881 etc. In addition, examples containing water-soluble polymers are JP-A-55-80477 and JP-A-58-13.
675, JP-A-62-124167, JP-A-62-22
5577 etc. Furthermore, examples including colloidal solutions of rubber and resin are described in JP-A-55-18412 and the like.

Although aqueous dispersion inks have improved printing density, light resistance, water resistance, etc. compared to dye-based inks, they do not clog the fine ejection nozzles and have problems with the abrasion resistance of printed materials. It is required to have excellent touchability to the touch, no agglomeration of coloring material particles, no ink physical properties or precipitation of solid content during storage, and no loss of dispersion stability and storage stability even if a solvent is added later. However, the ink obtained by the above-mentioned prior art does not completely satisfy all of these problems.

0004

[Problems to be Solved by the Invention] Therefore, the present invention solves these problems, and aims to improve clogging resistance, scratch resistance of printed materials, and finger scratch resistance without impairing print density, light resistance, and water resistance. Water-based recording ink with excellent tactility, no agglomeration of colorant particles, no change in ink physical properties, no precipitation of solids during storage, and storage stability that does not impair dispersion stability and storage stability even when a solvent is added later. Our goal is to provide the following.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the aqueous recording ink of the present invention comprises water, a pigment dispersed in the water, and a water-soluble pigment having a solubility in water of 15% or more (at 20°C). Substances with solubility in water of less than 15% (20°C
) resin or wax.

Preferably, the content of the pigment is 1 to 20 wt% based on the entire ink, and the water-soluble substance is polyvinylpyrrolidone and/or polyvinyl alcohol, and the solubility in water is less than 15% (at 20°C). )
The resin or wax is a water-insoluble or poorly water-soluble resin emulsion and/or wax emulsion, and is characterized by containing 1 to 40 wt% of a water-miscible organic solvent.

[0007]

EXAMPLES Examples of the present invention will be described in detail below. Conventionally, water has been mainly used as a solvent for ink because of its low viscosity, excellent safety, ease of handling, low cost, and lack of odor. In addition, for this main solvent, ethanol, propanol, isopropanol,
Alcohols such as butanol, hexanol, heptanol, and octanol, polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, and glycerin, or their monoethers, diethers, and esters, such as ethylene Glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, etc., and other N-methyl 2-pyrrolidone, 1
．． A water-soluble organic solvent such as a nitrogen-containing organic solvent such as 3-dimethylimidazolidinone can be added.

The pigment used as the coloring material is not particularly limited and can be used as long as it has good affinity with water, which is the main solvent. For example, for monochrome use, furnace black, lamp black, acetylene black are used. , carbon blacks such as channel black, or copper, iron,
Examples include metals such as titanium oxide and organic pigments such as altonitroaniline black. Furthermore, for color use, Toluidine Red, Permanent Carmine FB, Fast Yellow AAA, Disazo Orange PMP, Lake Red C, Brilliant Carmine 6B, Phthalocyanine Blue, Quinacridone Red, Dioxane Violet, Pictoria Pure Blue, Alkaline Blue Toner, Fast Yellow 10G , Disazo Yellow AAMX, Disazo Yellow AAOT, Disazo Yellow AAOA, Yellow Iron Oxide, Disazo Yellow HR, Orthonitroaniline Orange, Dinitroaniline Orange, Vulcan Orange, Toluidine Red, Chlorinated Para Red, Brilliant First Scarlet, Naphthol Red 23, Pyrazolone Red, Barium Red 2B , Calcium Red 2B,
Strontium Red 2B, Manganese Red 2B, Barium Lysome Red, Pigment Scarlet 3B Lake, Lake Bordeaux 10B, Ansosine 3B Lake, Ansosine 5B Lake, Rhodamine 6G Lake, Eosin Lake, Japanese Garla, Faftol Red FGR, Rhodamine B Lake, Methyl Violet Lake, Dioxazine Violet, Basic Blue 5B Lake, Basic Blue 6G Lake, Fast Sky Blue, Alkaline Blue R Toner, Peacock Blue Lake, Deep Blue, Ultramarine, Reflex Blue 2G, Reflex Blue R,
Brilliant green lake, diamond green thioflavin lake, phthalocyanine green G, green gold, phthalocyanine green Y, iron oxide powder, rust, zinc white, titanium oxide, calcium carbonate, clay,
Barium sulfate, alumina white, aluminum powder, bronze powder, daylight fluorescent pigment, pearl pigment, naphthol carmine FB, naphthol red M, permanent carmine FB, Fastero G, Disazo Yellow AAA, Disazo Orange PMP, Lake Red C, Dioxane Bio Red, alkali blue G toner, and other processed pigments such as grafted carbon whose surface is treated with a resin or the like can be used. The amount added is preferably 1 to 30% by polymerization, more preferably 3 to 12% by polymerization. Grain size is 25μ
Pigments with particles of 0.1 μm or less are used, and it is more preferable to use pigments with particles of 0.1 μm or less.

Solubility in water used in the present invention: 15
% or more of water-soluble substances include polyvinyl alcohol,
Water-soluble polymers that are generally called polymeric dispersants such as polyvinylpyrrolidone and have an average molecular weight of 10,000 to 300,000, or waxes that have hydrophilic groups such as hydroxyl groups, carboxyl groups, ethylene oxide groups, and amine groups. These can be used alone or in a mixture of two or more. The amount added is preferably 10% by weight or more, more preferably 100% by weight or more, based on the amount of coloring material added. However, as the amount added increases, the viscosity of the ink also increases, so it is preferable to limit the amount added to about 20% by weight based on the total ink.

The solubility in water used in the present invention is 1
Less than 5% resins or waxes include glue, gelatin, casein, albumin, gum arabic, alginic acid, methylcellulose, carboxymethylcellulose,
polyethylene oxide, hydroxyethyl cellulose,
Slightly soluble or soluble resins such as polyacrylic acid and polyvinyl ether, as well as polymer products such as polyvinyl alcohol and polyvinylpyrrolidone, carnauba wax, paraffin wax, polyethylene wax, oxidized polyethylene wax, microcrystalline wax, alpha olefin and maleic anhydride, etc. Waxes such as polymers, montan wax, candelilla wax, etc. can be used alone or in combination.

The solubility in water used in the present invention is 1
Emulsions that can be used as less than 5% resin include dispersions in which water-insoluble or poorly soluble polymers are dispersed in a water-based medium, such as acrylic ester, methacrylic ester, and styrene-based emulsions. , styrene-acrylic copolymer, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polybutadiene, vinyl acetate, polyvinyl chloride, polyvinylidene chloride, ethylene-vinyl acetate copolymer, polyethylene, as well as olefinic and amino group, amide Homopolymerized or copolymerized resin emulsions such as monomers having hydrophilic functional groups such as hydroxyl groups, carboxyl groups, and hydroxyl groups, microemulsions, resin emulsions such as internally three-dimensionally crosslinked organic fine particles, and paraffin wax, polyethylene wax, and carnauba wax. , natural and synthetic wax emulsions such as α-olefin/maleic anhydride copolymers, and other latexes, colloidal solutions, and suspensions.

Furthermore, in order to improve the wettability, dispersibility, etc. of the coloring material in water, ordinary water-soluble ionic, amphoteric, or nonionic surfactants, or fluorine-based, silicone-based, or polymer-based surfactants are used. Surfactants can be added. For example, anionic surfactants include higher fatty acid salts, higher alkyl dicarboxylate salts, higher alcohol sulfate salts, higher alkyl sulfonate salts, condensates of higher fatty acids and amino acids, sulfosuccinate salts, naphthenates, etc.
Examples of cationic surfactants include aliphatic amine salts, quaternary ammonium salts, sulfonium salts, phosphonium salts, etc.
As the amphoteric surfactant, betaine type and the like can be used, and as the nonionic surfactant, fatty acid ester type of polyoxyethylene compound, polyethylene oxide condensation type, etc. can be used. However, the addition of a hydrocarbon surfactant also improves the wettability between the ink and the paper surface and promotes the penetration of the ink into the paper, so the addition of a fluorine surfactant, which has less of this effect, is also useful. .

[0013] Other pH adjusters such as potassium dihydrogen phosphate and disodium hydrogen phosphate, fungicides,
Benzoic acid, dichlorophene, hexachlorophene, sorbic acid, p-hydroxybenzoic acid ester, ethylenediaminetetraacetic acid (EDTA), etc. can be included for the purpose of preserving and preventing rust. Further, for the purpose of preventing nozzle drying, urea, thiourea, ethylene urea, etc. can be added. Further, for the purpose of preventing nozzle drying, urea, thiourea, ethylene urea, etc. can be added.

Examples 1 to 9 of the present invention and Comparative Examples 1 to 9
The composition of ink No. 3 is shown below. All figures below are in percent by weight.

(Example 1) Ingredients
Composition ratio CB(M
A-100) 5
Dispersant (nonionic surfactant)
0.1 Polyvinylpyrrolidone
1 (solubility 1
5% or more) Acrylic-styrenic emulsion 3 (Solubility less than 15%)
glycerin
2 Ethanol
5
water
83.9 The MA-100 used here is carbon black manufactured by Mitsubishi Chemical Industries, Ltd., and PVP (K-30) used as a water-soluble resin.
is polyvinylpyrrolidone with an average molecular weight of about 40,000 manufactured by Tokyo Kasei Co., Ltd., and the acrylic-styrene emulsion used as the poorly soluble component is manufactured by Gifu Shellac Co., Ltd. (SG-40).
)Met.

The ink was manufactured according to the following procedure, but the procedure is not limited thereto. First, carbon black and dispersant were stirred and mixed in water using a paint shaker for 30 minutes or more, and it was confirmed by microscopic observation that the particle size was approximately 1 μm or less. Polyvinylpyrrolidone was added thereto and further 30 minutes. Mix and stir until completely dissolved. The acrylic styrene emulsion was gradually added to the dispersion while stirring, and the mixture was stirred and mixed in a paint shaker for more than 5 minutes, followed by vacuum filtration using an 8 μm membrane filter to remove dust and coarse particles. After that, add glycerin and ethanol, stir for 5 minutes, and reduce the average particle size to 0.0.
An aqueous recording ink having a diameter of 6 μm and a pH of 7 was obtained. Performing the filtration operation one last time is effective in preventing contamination of impurities.

The following examples were prepared in substantially the same manner as above.

(Example 2) Ingredients
Composition ratio CB(M
A-11)
5 Polyvinylpyrrolidone
2 (Solubility 15% or more)
carnauba wax emulsion
3 (Solubility less than 15%) Glycerin
18 Ethanol
8
water
64 MA used here
-11 is carbon black made by Mitsubishi Chemical Industries, Ltd. PVP (K-30) used as a water-soluble resin is polyvinylpyrrolidone made by Tokyo Kasei Co., Ltd. with an average molecular weight of about 40,000, and carnauba wax used as a slightly soluble component The emulsion was a wax emulsion manufactured by Nikko Fine Products.

(Example 3) Ingredients
Composition ratio CB(R
AVEN150) 6
Polyvinyl alcohol (B03)
6 (Solubility 15% or more) Polystyrene emulsion 1.5
(Solubility less than 15%) Glycerin
8
1-propanol
5.5 Water

73 RAVEN150 used here is carbon black manufactured by Columbia Carbon Co., Ltd., and polyvinyl alcohol (B03) used as a water-soluble resin is a water-soluble resin manufactured by Denki Kagaku Kogyo Co., Ltd. The polystyrene emulsion used as the poorly soluble component was a styrene emulsion manufactured by Gifu Shellac. Example 4
Ingredients
Composition ratio CB (Vu
lcan sc) 5
PVP (K-60)
6 (Solubility 15% or more)
Methylcellulose (Metrose) 3
(Solubility less than 15%) Glycerin
8 2-butanol
6 water

72 Vulcan s used here
c is carbon black manufactured by Cabot Corporation, and PVP (K-60) used as the water-soluble resin is polyvinylpyrrolidone manufactured by Tokyo Kasei Corporation with an average molecular weight of about 160,000. Moreover, Metrose used as a poorly soluble component was a water-soluble resin manufactured by Shin-Etsu Chemical Co., Ltd. (Example 4) Ingredients
Composition ratio CB(R
AVEN150) 6
Polyvinyl alcohol (B03)
6 (Solubility 15% or more) Paraffin wax emulsion 3.5 (
solubility less than 15%) glycerin
8
1-propanol
6 water
72
RAVEN150 used here is carbon black manufactured by Columbia Carbon Co., Ltd., and polyvinyl alcohol (B03) used as a water-soluble resin is a water-soluble resin manufactured by Denki Kagaku Kogyo Co., Ltd. The wax emulsion used as the poorly soluble component was a wax emulsion manufactured by Johnson Polymer Company.

(Example 5) Ingredients
Composition ratio CB(M
A-100) 5
Dispersant (acrylic polymer surfactant) 0
．． 1 Polyvinylpyrrolidone (K-30)
2 (Solubility 15% or more) Polyvinylpyrrolidone (K-90) 2
(Solubility less than 15%) Glycerin

2 Ethanol
5 Water

83.9 MA-100 used here is carbon black manufactured by Mitsubishi Chemical Industries, Ltd., and PVP (K-30) used as a water-soluble resin is polyvinylpyrrolidone manufactured by Tokyo Kasei Corp. with an average molecular weight of about 40,000, or The PVP (K-90) used as the poorly soluble component was polyvinylpyrrolidone manufactured by Tokyo Kasei Co., Ltd. and having an average molecular weight of about 400,000.

(Example 6) Ingredients
Composition ratio Pigment (K
ETRed309) 5
Dispersant (nonionic surfactant)
0.1 Polyvinylpyrrolidone
1 (Solubility 15% or more) Acrylic-styrene emulsion
3 (Solubility less than 15%) Glycerin
2 Ethanol
5
water
83.9 The pigment used here is an organic pigment for color toner manufactured by Dainippon Ink and Chemicals.

The following is the same as in Example 1.

(Example 7) Ingredients
Composition ratio Pigment (K
ETYELLOW403) 5 Dispersant (nonionic surfactant) 0.1
Polyvinylpyrrolidone
1 (Solubility 15% or more)
Acrylic-styrenic emulsion
3 (Solubility less than 15%) Glycerin
2 Ethanol
5 Water

83.9 The pigment used here is an organic pigment for color toner manufactured by Dainippon Ink and Chemicals.

The following is the same as in Example 1.

(Example 8) Ingredients
Composition ratio Pigment (K
ETBLUEEx-1) 5 Dispersant (nonionic surfactant) 0.
1 Polyvinylpyrrolidone
1 (Solubility 15% or more)
Acrylic-styrenic emulsion
3 (Solubility less than 15%) Glycerin
2 Ethanol
5 Water

83.9 The pigment used here is an organic pigment for color toner manufactured by Dainippon Ink and Chemicals.

The following is the same as in Example 1.

Other ingredients include TrilonBS
A small amount of EDTA (manufactured by BASF) can be added as a preservative to water-soluble ink.

(Comparative Example 1) Ingredients
Composition ratio CB(M
A-100) 5
Dispersant (nonionic surfactant)
0.1 Acrylic-styrene emulsion 4 (Solubility less than 15%)
glycerin
2 Ethanol
5
water
83.9 Comparative Example 1 is a composition example that does not contain any component having a solubility in water of 15% or more.

The following is the same as in Example 1.

(Comparative Example 2) Ingredients
Composition ratio CB(M
A-100) 5
Dispersant (nonionic surfactant)
0.1 Polyvinylpyrrolidone
10 (solubility 15
% or more) Glycerin
2 Ethanol
5 Water
77.9
Comparative Example 2 is a composition example that does not contain any component having a solubility in water of less than 15%.

The following is the same as in Example 1.

(Comparative Example 3) Ingredients
Composition ratio CB(M
A-100) 5
Dispersant (nonionic surfactant)
0.1 Polyvinylpyrrolidone
4 (solubility 1
5% or more) Acrylic styrene emulsion 4 Water
86
．． 9 Comparative Example 3 is a composition example that does not contain any component having a solubility in water of less than 15%.

The following is the same as in Example 1.

Examples 1 to 9 and Comparative Example 1 thus obtained
Regarding the ink samples of ~3, viscosity measurement at 20°C with a B-type viscometer No. 1 rotor (manufactured by Tokyo Keiki Co., Ltd.) and HVL
- Surface tension was measured at 25°C using an ST type surface tension meter (manufactured by Kyowa Interface Science Co., Ltd.), and the discharge nozzle diameter was 50 μm.
, each water-based ink was printed using a prototype 9-nozzle evaluation machine with a piezoelectric element drive voltage of 100 V, a drive frequency of 6 kHz, and a resolution of 300 dots/inch, and the printing quality was evaluated by microscopic observation of the printed sample at 200 times magnification. After solid printing, recording was performed. Drying time evaluation by aligning the paper with the printing surface and examining the time until ink transfer disappears; fixation evaluation by rubbing strongly with your finger after leaving it for 2 hours after solid printing; appearance of missing dots in printing after being left at 40°C for 2 days A discharge stability evaluation was conducted to investigate the

[0035] Storage stability evaluation was also carried out by observing and examining the degree of aggregation of pigment particles in the ink after freezing the ink in a sealed glass sample bottle at an ambient temperature of -30°C for 7 days and then thawing it at room temperature. Ta. The above results are shown in Table 1.

[0036]

[Table 1]

Note that Xerox PPC paper was used as the recording paper. In addition, the unit of viscosity in Table 2 is mPa・s (20℃
), the unit of surface tension is dyn/cm (20°C).

[0038] Also, the symbols in the table are ○ based on each evaluation result.
: Excellent, no problems, △: Some problems, ×: Poor.
This shows the results of a three-level subjective evaluation: There is clearly a problem.

[0039] The aqueous recording ink of the present invention had high print quality without bleeding in all evaluations conducted this time, had sufficient fixing properties, and had good ejection stability and storage stability (freezing stability). We obtained excellent results and were able to satisfy all of these characteristics. Also, it takes about 15 to 30 seconds for the ink on the paper to stop setting off onto the layered paper (previously it took about 30 seconds).
The time could be shortened to 1 second to 1 minute). On the other hand, the inks of Comparative Examples 1 to 3 had poor printing quality, ejection stability, and storage stability (freezing stability).
However, it was not possible to achieve both fixing performance (preventing stains and loss of density when the recorded material is rubbed) on the market.

The above results are due to the effect of mixing materials with high and low solubility in water and impregnating them with an appropriate amount of a hydrophilic organic solvent.

Conventionally, when a volatile solvent such as ethanol was used to improve the drying performance, the solvent content evaporated in the vicinity of the nozzle in ordinary dispersion inks, and the pigments precipitated and fixed, causing the eyes of the ink to dry. It was difficult to use because it was prone to clogging. However, with the ink of the present invention, it takes a long time for the ink to stick inside the head and on the front surface of the head, and it is possible to give the pigment redispersibility, so that the precipitated and fixed pigment can be quickly redispersed and restored, making it easier to see. It achieves both high print quality and fixation (quick drying) without clogging.

Regarding the fixability after printing, due to the appropriate permeability of the ink of the present invention, even if it is given redispersibility like the aqueous recording ink of the present invention, it will not be easily touched by touch. A sufficient level was obtained without staining, density reduction, bleeding, etc.

Furthermore, when the print quality was evaluated using the aqueous recording ink of the present invention on recycled paper, such as New CK paper manufactured by Xerox Corporation, R paper, and Yamayuri paper manufactured by Honshu Paper Industries, it was found that
Even on seed recycled paper, good print quality with little bleeding etc. could be obtained.

Although the embodiments of the present invention have been described in detail above, the aqueous recording ink of the present invention is not limited to these configurations, materials, and manufacturing methods.

[0045]

Effects of the Invention As explained above, the aqueous recording ink of the present invention does not impair print density, light fastness, and water resistance, and improves clogging resistance, abrasion resistance, and finger touch of printed matter. It is excellent in that there is no agglomeration of coloring material particles, no change in ink physical properties, and no precipitation of solid content during storage, and storage stability is obtained that does not impair dispersion stability even if a solvent is added later.

Claims (5)

[Claims] Claim 1: Water, a pigment dispersed in the water, a water-soluble substance having a solubility in water of 15% or more (at 20°C), and a resin or wax having a solubility in water of less than 15% (at 20°C). An aqueous recording ink characterized by containing. 2. The aqueous recording ink according to claim 1, wherein the content of the pigment is 1 to 20 wt% based on the entire ink. 3. The aqueous recording ink according to claim 1, wherein the water-soluble substance is polyvinylpyrrolidone and/or polyvinyl alcohol. 4. The resin or wax according to claim 1,
An aqueous recording ink characterized by being a water-insoluble or poorly water-soluble resin emulsion and/or wax emulsion. 5. Further comprising 1 to 3 organic solvents which are compatible with water.
The aqueous recording ink according to claim 1, characterized in that it contains 40 wt%.