JP7376974B2 - Ink set and inkjet recording method - Google Patents

Description

The present invention relates to a set of ink and cleaning liquid, and a method of cleaning a recording apparatus using the set.

Among color printing methods, a printing method using an inkjet printer (inkjet printing method) is one of the representative methods. This method involves generating ink droplets and attaching them to a base material such as paper to perform printing. In recent years, inkjet printing methods have been increasingly applied to industrial applications. Colorants contained in inkjet inks are broadly classified into water-soluble colorants and water-insoluble colorants. Among these, water-insoluble colorants, typified by pigments, are generally superior in various fastness properties compared to water-soluble colorants. For this reason, industrial inkjet inks often contain water-insoluble colorants.

Base materials used for industrial applications are diversifying, including various papers, fibers, and films. Among such base materials, there are many base materials that are non-ink absorbent and base materials that are poorly absorbent in ink (hereinafter referred to as "non-poorly absorbent base materials"). Non-aqueous solvent inks, curable inks, and the like are known as inks used for recording on non- and poorly absorbent substrates. However, from the viewpoint of safety to the natural environment and living organisms, for example, there is a strong demand for water-based inks that can be printed on non-absorbent substrates. Such water-based inks contain water-insoluble colorants and dispersants, and generally also contain polymers, waxes, etc. for the purpose of improving scratch resistance, solvent resistance, and the like. For this reason, such aqueous inks have a high solid content and are extremely easy to dry, and also tend to produce a large amount of solid matter upon drying. Ink tends to dry out during long-term storage, storage in high temperature, low humidity environments, etc. Drying of ink produces solid matter in the nozzles and ink channels of the inkjet head, which causes clogging. When clogging occurs in the inkjet head in this way, ink cannot be ejected stably, resulting in a problem of reduced image density. Furthermore, the inkjet head itself may become unusable, which is a big problem. Generally, industrial inkjet heads are equipped with a cap member on the nozzle portion to prevent ink from drying. However, it is still difficult to completely avoid ink drying.

From the above situation, it is possible to record on non- or poorly absorbent substrates, and in order to improve scratch resistance, even when ink with a high solid content dries to form solids, it can be washed. There is a strong demand for a cleaning solution that can
Patent Documents 1 to 6 disclose cleaning liquids used for cleaning inkjet recording apparatuses. Patent Document 7 discloses an ink composition containing wax. Patent Document 8 discloses an ink composition containing a polymer.
Patent No. 5027444 Patent No. 4649823 Patent No. 4397220 Patent No. 5618250 Patent No. 5819206 Patent No. 5819205 International Publication 2015/147192 Gazette International Publication 2015/152291 Gazette

The present invention provides a water-based ink that can record even on non-hardly absorbent substrates and has good scratch resistance, and a cleaning liquid that can wash away solid matter even when the ink dries to form solid matter. An object of the present invention is to provide an ink and cleaning liquid set having the following.

As a result of extensive research to solve the above-mentioned problems, the present inventors have found at least the following:
An ink containing a colorant, a binder, and water, a surfactant with an HLB value of at least 10.0 to 20.0, a surfactant with an HLB value of 3.0 or more and less than 10.0, and water. The inventors have discovered that the above-mentioned problems can be solved by using an ink set that includes a cleaning liquid, and have completed the present invention.
That is, the present invention relates to the following 1) to 9).

1)
An ink and cleaning solution set comprising an ink containing a colorant, a binder, and water, and a cleaning solution containing at least two types of surfactants and water, wherein one of the surfactants in the cleaning solution is A set of ink and cleaning liquid having an HLB value of 10.0 to 20.0, and the HLB value of the other surfactant being 3.0 or more and less than 10.0.
However, the HLB value of the surfactant is calculated as follows.
[How to calculate HLB value]
A solution is obtained by dissolving 0.5 g of surfactant in 5 mL of ethanol. The obtained solution is stirred at 25°C, and a 2% by mass aqueous phenol solution is added dropwise to this solution, and the end point is defined as the point where the liquid becomes cloudy. When the amount of 2% by mass phenol aqueous solution required to reach the end point is Q (mL), the HLB value is calculated using the following formula (1).

2)
The ink and cleaning liquid set described in 1) above, wherein the surfactant having an HLB value of 10.0 to 20.0 is a surfactant selected from nonionic surfactants.
3)
The ink and cleaning liquid set according to 1) or 2) above, wherein the surfactant having an HLB value of 3.0 or more and less than 10.0 is a surfactant selected from nonionic surfactants.
4)
The ink and cleaning liquid set described in 1) to 3) above, wherein the cleaning liquid contains glycol ether.
5)
The ink and cleaning liquid set described in 1) to 4) above, wherein the binder is one or more types selected from polymers and waxes.
6)
The ink and cleaning liquid set described in 1) to 5) above, wherein the wax is one or more types selected from polyalkylene wax, oxidized polyalkylene wax, and paraffin wax.
7)
The ink and cleaning liquid set described in 1) to 6) above, wherein the wax is one or more types selected from polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax, and paraffin wax.
8)
A method for cleaning a recording device, comprising cleaning a recording device to which the ink according to any one of 1) to 7) has been adhered, with the cleaning liquid according to any one of 1) to 7).
9)
The cleaning method according to item 8) above, wherein the recording device is an inkjet printer.

According to the present invention, a water-based ink that can record even on non-hardly absorbent substrates and has good scratch resistance, and a cleaning liquid that can wash away solid matter even when the ink dries to form solid matter. We were able to provide an ink and cleaning solution set with the following.

In this specification, unless otherwise specified, "%" and "part" are expressed on a mass basis. Furthermore, when "A to B" is written at the beginning of this specification, it means "above A and below B" unless otherwise specified.

[Colorant]
The colorant contained in the ink is not particularly limited, and a colorant selected from water-soluble colorants and water-insoluble colorants can be used. Moreover, these can also be used in combination as necessary.
As used herein, "water-insoluble" means that the solubility of the colorant in water at 25° C. is usually 3 g/liter or less, preferably 2 g/liter or less, more preferably 1 g/liter or less.
Examples of water-insoluble colorants include pigments, disperse dyes, and solvent dyes. Representative examples of these colorants include C.I. I. Pigment, C. I. Disperse and C. I. Colorants selected from Solvents.

Examples of water-soluble colorants include direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, vat dyes, and soluble vat dyes. Typical examples of these dyes include C.I. I. Direct, C. I. Acid, C. I. Food, C. I. Basic, C. I. Reactive,C. I. Vat, C. I. Dyes selected from Solubilised Vat.

As a colorant other than those mentioned above, a resin containing a colorant, which is a transparent, water-insoluble resin containing the colorant described above, can also be mentioned as a water-insoluble colorant.

Examples of the pigment include inorganic pigments, organic pigments, and extender pigments.
Examples of inorganic pigments include carbon black; metal oxides, metal hydroxides, metal sulfides; ferrocyanides; and metal chlorides.

Examples of carbon black include thermal black, acetylene black, oil furnace black, gas furnace black, lamp black, gas black, and channel black. Among these, furnace black, lamp black, acetylene black, channel black, etc. are preferred. Various types of carbon black are readily available from, for example, Columbia Carbon, Cabot, Degussa, and Mitsubishi Chemical Corporation.

Examples of organic pigments include soluble azo pigments, insoluble azo pigments, insoluble diazo pigments, condensed azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, perylene pigments, perinone pigments, thioindigo pigments, anthraquinone pigments, and quinophthalones. Examples include pigments.

Specific examples of organic pigments include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 24, 55, 73, 74, 75, 83, 93, 94, 95, 97, 98, 108, 114, 128, 129, 138, 139, 150, 151, 154, 180, 185, 193, 199, 202; C. I. Pigment Red 5, 7, 12, 48, 48:1, 57, 88, 112, 122, 123, 146, 149, 166, 168, 177, 178, 179, 184, 185, 202, 206, 207, 254, 255, 257, 260, 264, 272; C. I. Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 25, 60, 66, 80; I. Pigment Violet 19, 23, 29, 37, 38, 50; C.I. I. Pigment Orange 13, 16, 68, 69, 71, 73; C.I. I. Pigment Green 7, 36, 54; C.I. I. Pigment Black 1 and the like.

Examples of extender pigments include silica, calcium carbonate, talc, clay, barium sulfate, and white carbon. Although these extender pigments can be used alone, they are usually used in combination with inorganic pigments or organic pigments for the purpose of improving the fluidity of the powder.

Furthermore, it is also possible to use a self-dispersing pigment in which the surface of pigment particles is chemically treated to impart self-dispersing properties.

Examples of disperse dyes include C.I. I. Dispers Yellow 9, 23, 33, 42, 49, 54, 58, 60, 64, 66, 71, 76, 79, 83, 86, 90, 93, 99, 114, 116, 119, 122, 126, 149, 160, 163, 165, 180, 183, 186, 198, 200, 211, 224, 226, 227, 231, 237; C. I. Dispers Red 60, 73, 88, 91, 92, 111, 127, 131, 143, 145, 146, 152, 153, 154, 167, 179, 191, 192, 206, 221, 258, 283; I. Dispers Orange 9, 25, 29, 30, 31, 32, 37, 38, 42, 44, 45, 53, 54, 55, 56, 61, 71, 73, 76, 80, 96, 97; C. I. Dispers Violet 25, 27, 28, 54, 57, 60, 73, 77, 79, 79:1; C. I. Dispers Blue 27, 56, 60, 79:1, 87, 143, 165, 165:1, 165:2, 181, 185, 197, 202, 225, 257, 266, 267, 281, 341, 353, 354, 358, 364, 365, 368 and the like.

The content of the colorant in the total mass of the ink is usually 1 to 30%, preferably 1 to 15%, more preferably 2 to 10%.

When the ink contains a water-insoluble colorant, it is preferable to further contain a dispersant. As dispersants, styrene and its derivatives; vinylnaphthalene and its derivatives; aliphatic alcohol esters of α,β-ethylenically unsaturated carboxylic acids; acrylic acid and its derivatives; maleic acid and its derivatives; itaconic acid and its derivatives ; at least two monomers (preferably, at least one of them is Examples include copolymers composed of hydrophilic monomers).
Examples of the types of copolymers include block copolymers, random copolymers, graft copolymers, and/or salts thereof.
Dispersants can be synthesized or commercially available. Specific examples of commercially available products include styrene-acrylic resins such as Joncryl 62, 67, 68, 678, and 687, all manufactured by Johnson Polymer; Movinyl S-100A (modified vinyl acetate manufactured by Hoechst Synthesis) resin); Jurimer AT-210 (polyacrylic acid ester copolymer manufactured by Nippon Pure Chemical Industries, Ltd.); and the like.
When synthesizing a dispersant, the dispersant disclosed in International Publication No. 2013/115071 Gazette is preferably mentioned.
One type of dispersant can be used or two or more types can be used in combination.

The weight average molecular weight (MW) of the dispersant is not particularly limited, but is usually 3,000 to 50,000, preferably 7,000 to 25,000. Further, the acid value is usually about 50 to 300 KOHmg/g, preferably about 80 to 275 KOHmg/g, and more preferably about 80 to 250 KOHmg/g.

The above-mentioned dispersants can be used in a mixed state with a colorant. Furthermore, the surface of the colorant can be coated with a dispersant and used as a so-called microencapsulated pigment. Moreover, both of these can also be used together.

When the ink contains a water-insoluble colorant, it is preferable to prepare a dispersion containing the colorant and a dispersant and then mix it with other components to prepare the ink. A known method can be used to prepare the dispersion.
As an example, a phase inversion emulsification method can be used when the dispersant is not soluble in water. That is, the first polymer is dissolved in an organic solvent such as 2-butanone, and an aqueous solution of a neutralizing agent is added to prepare an emulsion. A coloring agent is added to the obtained emulsion and a dispersion treatment is performed. By distilling off the organic solvent and a portion of the water under reduced pressure from the liquid thus obtained, the desired colorant dispersion can be obtained.
Examples of the dispersion treatment include a method of dispersing the colorant and the polymer by placing them in a sand mill (bead mill), roll mill, ball mill, paint shaker, ultrasonic disperser, microfluidizer, or the like. For example, when using a sand mill, beads with a particle diameter of about 0.01 mm to 1 mm can be used, and the dispersion process can be performed by appropriately setting the filling rate of the beads.
The dispersion obtained as described above can be subjected to operations such as filtration and/or centrifugation. By this operation, the particle diameters of the particles contained in the dispersion can be made uniform.
If foaming occurs during the preparation of the dispersion, a very small amount of a known antifoaming agent such as silicone or acetylene glycol can be added.
Other methods include acid precipitation method, phase inversion emulsification method, interfacial polymerization method, in-situ polymerization method, in-liquid hardening film method, coacervation (phase separation) method, in-liquid drying method, melt dispersion cooling method, Examples include air suspension coating method and spray drying method. Among these, the phase inversion emulsification method, acid precipitation method, and interfacial polymerization method are preferred.

The average particle size (D50) of the water-insoluble colorant in the dispersion is usually 300 nm or less, preferably 30 to 280 nm, more preferably 40 to 270 nm, even more preferably 50 to 250 nm.
Similarly, D90 is usually 300 nm or less, preferably 280 nm or less, and more preferably 270 nm or less. The lower limit is preferably 100 nm or more.
Similarly, D10 is usually 10 nm or more, preferably 20 nm or more, more preferably 30 nm or more, and the upper limit is 100 nm or less.
Particle size can be measured using laser light scattering.

[binder]
The binder is preferably one or more selected from polymers and waxes. However, the pigment dispersant is not included in the binder.
Examples of the polymer include urethane-based, polyester, acrylic-based, vinyl acetate-based, vinyl chloride-based, styrene-acrylic-based, acrylic-silicone-based, and styrene-butadiene-based polymers, or emulsions containing the same. Among these, preferred are urethane-based, acrylic-based, and styrene-butadiene-based polymers.
The polymer can be synthesized or purchased commercially. When synthesizing a polymer, for example, polymers disclosed in International Publication No. 2015/147192 Gazette and the like are preferred.
Commercially available products include, for example, Superflex 126, 130, 150, 170, 210, 420, 470, 820, 830, 890 (urethane resin emulsion manufactured by Daiichi Kogyo Seiyaku Co., Ltd.); Hydran HW-350, HW- 178, HW-163, HW-171, AP-20, AP-30, WLS-201, WLS-210 (urethane resin emulsion manufactured by DIC Corporation); 0569, 0850Z, 2108 (styrene resin manufactured by JSR Corporation) butadiene resin emulsion); examples include AE980, AE981A, AE982, AE986B, and AE104 (acrylic resin emulsion manufactured by Etech Co., Ltd.).
The content of the polymer based on the total mass of the ink is usually 0.1% to 10%, preferably 0.2% to 8%, more preferably 0.2% to 5%, even more preferably 0.2% to 1%. %. At such a content, scratchability, redispersibility, and dischargeability become good.

The wax is preferably a wax emulsion, more preferably an aqueous wax emulsion. As the wax, natural wax and synthetic wax can be used.
Natural waxes include petroleum-based waxes such as paraffin wax and microcrystalline wax; lignite-based waxes such as montan wax; vegetable-based waxes such as carnauba wax and candelia wax; and animal and plant-based waxes such as beeswax and lanolin. Examples include emulsions in which wax is dispersed in an aqueous medium.

Examples of synthetic waxes include polyalkylene waxes (preferably polyC2-C4 alkylene waxes), oxidized polyalkylene waxes (preferably oxidized polyC2-C4 alkylene waxes), and paraffin waxes. Among the above waxes, one or more waxes selected from polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax, and paraffin wax are preferred.
Further, the average particle size of the wax is preferably 50 nm to 5 μm, more preferably 100 nm to 1 μm, in order to prevent clogging of the inkjet head.

Commercially available wax emulsions include, for example, CERAFLOUR 925, 929, 950, 991; AQUACER 498, 515, 526, 531, 537, 539, 552, 1547; AQUAMAT 208, 263, 272; Mitsui Hiwax NL100, NL200, NL500, 4202E, 1105A, 2203A, NP550, NP055, NP505, etc. manufactured by Mitsui Chemicals; KUE-100, 11, etc. manufactured by Sanyo Chemical.
Among these, AQUACER 515, 531, 537, 539, and 1547 are preferred; AQUACER 515, 531, 537, and 1547 are more preferred.
The content of wax based on the total mass of the ink is usually 0% to 10%, preferably 0% to 8%, more preferably 0% to 5%, and even more preferably 0% to 1%. At such a content, scratchability, redispersibility, and dischargeability become good.

The content ratio of the polymer and wax in the total mass of the polymer and wax contained in the ink is usually 95/5 to 5/95, preferably 90/10 to 10/90, more preferably 80/20 to 20/2. It is 80. By setting such a ratio, a recorded image with a good balance between redispersibility and fixing properties can be obtained.

[Surfactant]
The cleaning liquid contains at least two types of surfactants. The HLB value of one of the surfactants is usually 10.0 to 20.0, preferably 10.5 to 20.0, more preferably 10.5 to 19.5 (hereinafter referred to as "surfactant A"). ). The HLB value of the other surfactant is usually 3.0 or more and less than 10.0, preferably 3.5 or more and less than 10.0, and more preferably 4.0 or more and less than 10.0 (hereinafter referred to as "surfactant B"). ).
The types of surfactants A and B are not particularly limited, and include nonionic, anionic, cationic, amphoteric, silicone, and fluorine surfactants. Among these, surfactants selected from nonionic and anionic surfactants are preferred, and nonionic surfactants are more preferred.
The HLB value of a surfactant is calculated as follows.
[How to calculate HLB value]
A solution is obtained by dissolving 0.5 g of surfactant in 5 mL of ethanol. The obtained solution is stirred at 25°C, and a 2% by mass phenol aqueous solution is added dropwise to the solution, and the end point is defined as the point where the liquid becomes cloudy. When the amount of 2% by mass phenol aqueous solution required to reach the end point is Q (mL), the HLB value is calculated using the following formula (1). The calculated HLB value is rounded off to the second decimal place, and the values up to the first decimal place are used as the calculated value. Surfactants A and B do not include surfactants that do not dissolve in 5 mL of ethanol and surfactants that do not cause turbidity even when a 2% by mass phenol aqueous solution is added dropwise.

[Nonionic surfactant]
Examples of nonionic surfactants include polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, and polyoxyethylene diphenyl ether. Ethers such as styrenated phenyl ethers (e.g. Emulgen A-60, A-90, A-500 manufactured by Kao Corporation); polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan mono Ester systems such as stearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate; 2,4,7,9-tetramethyl-5-decyne-4,7-diol , 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyn-3-ol, and other acetylene glycol (alcohol) systems; polyglycol ether systems, and the like. These commercially available products include, for example, Surfynol 104, 104PG50, 82, 420, 440, 465, 485, Olfin STG, manufactured by Nissin Chemical Co., Ltd.; Emulgen A-60, A-90, A- manufactured by Kao Corporation. 500, MS-110; TEGO Wet 500, 505, 510 manufactured by EVONIC; Softanol 30, 90, EP-9050 manufactured by Nippon Shokubai Co., Ltd.; DKS NL-30 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; Takemoto Yushi Co., Ltd. Examples include Pionin D-1502 and D-1305P manufactured by Manufacturer.

Examples of anionic surfactants include alkyl sulfocarboxylate, α-olefin sulfonate, polyoxyethylene alkyl ether acetate, polyoxyethylene alkyl ether sulfate, N-acylamino acid or its salt, N-acylmethyl taurate, Alkyl sulfate polyoxyalkyl ether sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester salt, lauryl alcohol sulfate ester salt, alkylphenol type phosphate ester, alkyl type phosphate ester, alkylaryl sulfone Examples include acid salts, diethyl sulfosuccinate, diethylhexyl sulfosuccinate, dioctyl sulfosuccinate, and the like.

Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.

Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, imidazoline derivatives, etc. Can be mentioned.

Examples of the silicone surfactant include polyether-modified siloxane, polyether-modified polydimethylsiloxane, and the like. Examples include Dynor 960, 980 manufactured by Air Products; Silface SAG 001, 002, 003, 005, 503A, 008, 009, 010 manufactured by Nissin Chemical Co., Ltd.; and BYK-345 manufactured by BYK Chemie. , 347, 348, 349, 3455, LP-X23288, LP-X23289, LP-X23347; TEGO Twin 4000, TEGO Wet KL 245, 250, 260, 265, 270, 280 manufactured by Evonic Tego Chemie, etc. Can be mentioned.

Examples of fluorosurfactants include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and perfluoroalkyl ether groups in the side chain. Examples include polyoxyalkylene ether polymer compounds having

Table 1 below shows an example of HLB values of surfactants.

The total content of surfactants is usually 0.1% to 10%, preferably 0.2% to 8%, more preferably 0.3% to 8%, based on the total mass of the cleaning liquid. At such a content, redispersibility and cleaning properties become good.

The content ratio of surfactants A and B in the total mass of surfactants A and B contained in the cleaning liquid is usually 8/1 to 1/8, preferably 7/1 to 1/7, more preferably 6 /1 to 1/6. By setting it as such a content ratio, cleaning property becomes favorable.

[Glycol ether]
The cleaning liquid may contain glycol ether. As the glycol ether, monoalkyl ethers of di- or tri-C2-C4 alkylene glycols are preferred.
C2-C4 alkylene glycol moieties include ethylene glycol, propylene glycol, and butylene glycol. Among these, ethylene glycol and propylene glycol are preferred, and ethylene glycol is more preferred.
The range of the carbon number of the alkyl in the monoalkyl ether moiety is usually C1-C6, preferably C1-C5, more preferably C2-C4, still more preferably C3-C4, particularly preferably C4.
Specific examples include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether (butyl diglycol), triethylene glycol monomethyl ether, and triethylene glycol monoethyl ether. , ethylene glycol monoallyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether, propylene glycol monopropyl ether, triethylene glycol monobutyl ether, and the like. Among these, butyl diglycol is preferred.
The total content of glycol ether in the total mass of the cleaning solution is usually 0 to 15%, preferably 0.1 to 15%, more preferably 0.2 to 13%, and even more preferably 0.5 to 10%. .

The ink and cleaning liquid may further contain an ink preparation agent in addition to the above-mentioned components. Examples of ink preparation agents include organic solvents, water-soluble polymer compounds, preservatives, antifungal agents, pH adjusters, chelating reagents, rust preventives, water-soluble ultraviolet absorbers, antioxidants, antifoaming agents, etc. Can be mentioned.
The total content of ink preparation agents other than organic solvents is usually about 0% to 30%, preferably about 0% to 20%, and more preferably about 0% to 10%, based on the total mass of the ink and cleaning liquid.

The cleaning liquid contains substantially no colorant. As used herein, "substantially" means that no coloring agent is intentionally added to the cleaning solution.

[Organic solvent]
Examples of organic solvents include C1-C6 alkanols having one hydroxyl group, such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, and tertiary-butanol; N,N-dimethylformamide, and N,N-dimethylformamide; Amides such as , N-dimethylacetamide; lactams such as 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-methylpyrrolidin-2-one; 1,3-dimethylimidazolidin-2-one, and 1, Cyclic ureas such as 3-dimethylhexahydropyrimid-2-one; ketones or ketoalcohols such as acetone, 2-methyl-2-hydroxypentan-4-one, and ethylene carbonate; cyclic ureas such as tetrahydrofuran and dioxane Ether; ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,6-hexylene glycol, 1,2-hexanediol, 1,2-pentanediol, 4-Methyl-1,2-pentanediol, 3,3-dimethyl-1,2-butanediol, 1,2-octanediol, 5-methyl-1,2-hexanediol, 4-methyl-1,2- Hexanediol, 4,4-dimethyl-1,2-pentanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol or polypropylene glycol with a molecular weight of 400 or more, thiodiglycol or dithiodiglycol, etc. , mono-, oligo- or polyalkylene glycols or thioglycols having C2-C8 alkylene units; polyols (triols) such as glycerin, diglycerin, hexane-1,2,6-triol, trimethylolpropane; γ-butyrolactone, and dimethyl Examples include organic solvents selected from sulfoxides and the like.

[Water-soluble polymer compound]
Examples of the water-soluble polymer compound include anionic and nonionic polymer compounds. Examples of the anionic polymer compound include cellulose derivatives such as carboxymethylcellulose, acrylic acid derivatives such as polyacrylic acid, and polystyrene derivatives such as polystyrene sulfonate. Examples of nonionic polymer compounds include polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, and gelatin.

[Preservative]
Examples of preservatives include organic sulfur-based, organic nitrogen-sulfur-based, organic halogen-based, haloarylsulfone-based, iodopropargyl-based, haloalkylthio-based, nitrile-based, pyridine-based, 8-oxyquinoline-based, and benzothiazole-based. , isothiazoline type, dithiol type, pyridine oxide type, nitropropane type, organotin type, phenol type, quaternary ammonium salt type, triazine type, thiazine type, anilide type, adamantane type, dithiocarbamate type, brominated indanone type, benzyl Examples include bromoacetate-based or inorganic salt-based compounds.
Specific examples of commercially available preservatives include Proxel GXL (S) and XL-2 (S) manufactured by Arch Chemical.

[Mildewproofing agent]
Specific examples of antifungal agents include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and its salts. .

[pH adjuster]
As the pH adjuster, any substance can be used as long as it can adjust the pH of the ink composition to 5 to 11 without adversely affecting the prepared ink composition.
Specific examples include alkanolamines such as diethanolamine, triethanolamine, and N-methyldiethanolamine; alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; ammonium hydroxide (aqueous ammonia); or carbonates of alkali metals such as lithium carbonate, sodium carbonate, sodium bicarbonate, and potassium carbonate; alkali metal salts of organic acids such as sodium silicate and potassium acetate; and inorganic bases such as disodium phosphate.

[Chelating agent]
Specific examples of the chelating reagent include disodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uracil diacetate.

[anti-rust]
Specific examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

[Water-soluble ultraviolet absorber]
Examples of water-soluble ultraviolet absorbers include sulfonated benzophenone compounds, benzotriazole compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

[Antioxidant]
Examples of the antioxidant include various organic and metal complex anti-fading agents. Examples of the organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles. It will be done.

[Defoaming agent]
Examples of antifoaming agents include silicone-based, silica mineral oil-based, olefin-based, acetylene-based, and the like. Examples of commercially available antifoaming agents include Surfynol DF37, DF58, DF110D, DF220, MD-20, and Olfine SK-14, all manufactured by Shin-Etsu Chemical Co., Ltd.
When an antifoaming agent is used, the amount added is usually 0.01 to 5%, preferably 0.03 to 3%, more preferably 0.05 to 1%. When it is 0.01% or more, the effect as an antifoaming agent is obtained, and when it is 5% or less, the dispersion stability becomes good.

The above-mentioned ink and cleaning liquid can contain one selected from all the above-mentioned components. Moreover, two or more types can be selected and contained. For example, the cleaning liquid can select and contain one type of compound from among the compounds represented by formula (1). Moreover, two or more kinds of compounds can be selected and contained. The same applies to other components.

[Ink application process]
When using the above ink as an ink for inkjet recording, it is preferable to use an ink with a low content of inorganic impurities such as metal cation chlorides (e.g., sodium chloride) and sulfates (e.g., sodium sulfate). preferable. The content of the inorganic impurities is approximately 1% or less based on the total mass of the colorant, and the lower limit includes the detection limit of the analytical instrument or less, that is, 0%.
Inorganic impurities are often mixed in colorants. Therefore, inorganic impurities can be removed as necessary. The purification method includes, for example, suspending and refining the solid colorant in a mixed solvent of C1-C4 alcohol such as methanol and water; or, after preparing the ink, inorganic impurities are exchanged and adsorbed with an ion exchange resin. Examples include a method to do so.

The pH of the ink is usually 7 to 11, preferably 8 to 10.
The surface tension of the ink is usually 10 to 50 mN/m, preferably 20 to 40 mN/m.
The viscosity of the ink is usually 2 mPa·s to 30 mPa·s, preferably 3 mPa·s to 20 mPa·s.
The pH and surface tension of the ink can be adjusted as appropriate using a pH adjuster, a surfactant, a water-soluble organic solvent, and the like.

The ink can be used in various types of recording. For example, it is suitable for writing implements, various types of printing, information recording, textile printing, etc., and is particularly preferably used for inkjet recording.

When using the ink for inkjet recording, recording can be performed by ejecting droplets of the ink according to a recording signal and making them adhere to a recording medium. There are no particular restrictions on the ink nozzle, inkjet method, etc. of the inkjet printer, and they can be appropriately selected depending on the purpose.
When performing inkjet recording, recording can be performed as described above by loading a container containing the ink into a predetermined position of an inkjet printer.

As the inkjet method, a known method can be used. Specific examples of the inkjet method include a charge control method, a drop-on-demand (pressure pulse) method, an acoustic inkjet method, a thermal inkjet method, and the like.
Another method is to improve image quality by ejecting a large number of inks with a small content of colorant in a small volume; a method that uses multiple inks with the same or similar hue but different concentrations of colorants in the ink. It also includes a method for improving image quality; and a method for improving the fixability of colorants by using colorless and transparent ink.

The recording medium refers to a material to which the ink can be attached. Examples of recording media include paper, film, etc., fibers and cloth (cellulose, nylon, wool, etc.), leather, base materials for color filters, and the like.
Recording media can be roughly divided into those that have an ink-receiving layer and those that do not.
Recording media having an ink-receiving layer are usually called inkjet paper, inkjet film, glossy paper, and the like. Examples of typical commercially available products include Professional Photo Paper, Super Photo Paper, Glossy Gold, and Matte Photo Paper manufactured by Canon Corporation; Photo Paper Crispier (high gloss) and Photo Paper (Glossy) manufactured by Seiko Epson Corporation. , Photo matte paper; Advanced Photo Paper (glossy) manufactured by Hewlett-Packard Japan Co., Ltd.; Gasai Photo Finish Pro manufactured by Fuji Film Co., Ltd., and the like.

Examples of recording media without an ink-receiving layer include various types of paper such as coated paper and art paper used in gravure printing, offset printing, etc.; cast coated paper used in label printing, and the like.
When using a recording medium that does not have an ink-receiving layer, it is also preferable to subject the recording medium to surface modification treatment in order to improve the fixability of the colorant.

As the surface modification treatment, at least one treatment selected from corona discharge treatment, plasma treatment, and flame treatment is preferably performed. Known methods can be used for these treatments. Furthermore, it is generally known that the effects of these treatments diminish over time. For this reason, when the information transmission sheet is subjected to surface modification treatment, it is preferable to perform inkjet recording continuously without any delay.
The surface modification treatment can be carried out by appropriately adjusting the number of times, time, applied voltage, etc. of the treatment so as to obtain the desired effect.

The cleaning method described above is a method of cleaning the recording device to which the ink has adhered with the cleaning liquid. An example of a cleaning method includes a method in which cleaning liquid is absorbed into a sponge or the like and ink adhering to the recording device is wiped off. The recording device is not particularly limited, but an inkjet printer is preferred.
Further, when the inkjet head is heavily soiled, for example, when ink adheres to the inkjet head and hardens as it dries, the inkjet head may be filled with a cleaning liquid to clean the inkjet head.
When filling an inkjet head with a cleaning liquid for cleaning, it is preferable to perform microfiltration of the cleaning liquid in order to remove impurities from the cleaning liquid.
When carrying out precision filtration, a membrane filter and/or glass filter paper can be used. The pore size of the filter used for precision filtration is usually 0.5 μm to 20 μm, preferably 0.5 μm to 10 μm.

The pH of the cleaning liquid is usually 5 to 11, preferably 7 to 10.5, in order to prevent corrosion of the members of the inkjet printer.
The surface tension of the cleaning liquid is usually 10 mN/m to 50 mN/m, preferably 20 mN/m to 40 mN/m.
The viscosity of the cleaning liquid is usually 30 mPa·s or less, preferably 20 mPa·s or less, and the lower limit is about 0.1 mPa·s.

Regarding all the above-mentioned items, combinations of preferable items are more preferable, and combinations of more preferable items are still more preferable. The same applies to combinations of preferred and more preferred, combinations of more preferred and even more preferred, and the like.
Furthermore, all of the above-mentioned components can be used singly or in combination of two or more.

The cleaning liquid can be used to clean water-based inks containing various colorants. Examples of colorants include water-based dye inks containing water-soluble dyes such as acid dyes, direct dyes, and reactive dyes; water-based inks containing water-insoluble colorants containing disperse dyes and pigments. It will be done.
Since the cleaning liquid has high cleaning power, it can also be used for cleaning water-based inks containing water-insoluble colorants, especially pigments.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to examples, but the present invention is not limited to the following examples. Further, the cleaning liquid and the colored ink were prepared under stirring unless otherwise specified.
Moreover, "water" used in the examples is ion-exchanged water.

[Preparation of cleaning solutions 1 to 5]
Each component listed in Table 2 below was mixed to obtain a total of 100 parts of each solution, and the resulting solution was filtered through a 3 μm membrane filter to obtain cleaning solutions 1 to 5.

[Preparation of comparative solutions 1 to 10]
Comparative cleaning solutions 1 to 10 were obtained in the same manner as cleaning solutions 1 to 5 above, except that the components listed in Table 3 below were used.

Abbreviations in Tables 2 and 3 below have the following meanings. Moreover, the numerical values in Tables 2 and 3 are "parts".
Gly: Glycerin 2Py: 2-pyrrolidone.
BDG: Butyl diglycol.
SN465: Nonionic surfactant, Surfynol 465 manufactured by Nissin Chemical Co., Ltd.
SN485: Nonionic surfactant, Surfynol 485 manufactured by Nissin Chemical Co., Ltd.
LA-16: Hitenol LA-16, an anionic surfactant manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
NL-30: DKS NL-30, a nonionic surfactant manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
A-90: Emulgen A-90, a nonionic surfactant manufactured by Kao Corporation.
MS-110: Emulgen MS-110, a nonionic surfactant manufactured by Kao Corporation.
D-1305P: Pionin D-1305P, a nonionic surfactant manufactured by Takemoto Yushi Co., Ltd.
TW500: TEGO Wet 500, a nonionic surfactant manufactured by EVONIC.
TW505: TEGO Wet 505, a nonionic surfactant manufactured by EVONIC.
TW510: Nonionic surfactant manufactured by EVONIC, TEGO Wet 510.
TEA: Triethanolamine.
GXL(S): Proxel GXL(S).

[Preparation of Polymer A]
25 parts of Joncryl 678 (MW: 8500) and 14.3 parts of triethanolamine were dissolved in 60.7 parts of ion-exchanged water and stirred for one hour to obtain a solution. The obtained solution will be referred to as Polymer A solution. Note that Polymer A is not a dispersant but a binder.

[Preparation of colorant dispersion]
A block copolymer described in Synthesis Example 3 of International Publication No. 2013/115071 was prepared, and the obtained block copolymer (5 parts) was dissolved in 20 parts of 2-butanone to form a homogeneous solution. A solution of sodium hydroxide (0.4 parts) dissolved in water (50.6 parts) was added to this solution, and after adding Polymer A solution (4 parts), the mixture was stirred for 1 hour to obtain an emulsion. . This emulsion contains C. I. Pigment Yellow 74 (20 parts, HANSA YELLOW 5GX01-JP manufactured by Clariant) was added, and dispersion treatment was performed in a sand grinder at 1500 rpm for 15 hours to obtain a liquid. After water (100 parts) was added dropwise to the obtained liquid, this liquid was filtered to obtain a filtrate. From the obtained filtrate, 2-butanone and a portion of water were distilled off under reduced pressure using an evaporator to obtain a colorant dispersion (Dp1) with a pigment content of 12.4%.
The pigment content in the obtained dispersion liquid was determined as a converted value of the pigment content from the total solid content in the liquid by the dry weight method using MS-70 manufactured by A & D Co., Ltd. .

[Preparation of Polymer B]
By repeating Preparation Example 4 of International Publication No. 2015/147192 Gazette, a resin emulsion with an acid value of 6 KOHmg/g, a Tg of 0° C., and a solid content of 25% was prepared. This will be referred to as "Polymer B". Polymer B is a binder.

[Preparation of inks 1 and 2]
After mixing each component listed in Table 4 below to obtain a total of 100 parts of liquid, the resulting liquid was filtered through a 3 μm membrane filter to obtain Inks 1 and 2 used in the evaluation test, respectively.

Abbreviations in Table 4 below have the following meanings. Moreover, the numerical values in Table 4 below are "parts".
Dispersion: Dispersion of Preparation Example 3.
TEG: triethylene glycol.
1,2HD: 1,2-hexanediol.
SN465: Nonionic surfactant, Surfynol 465 manufactured by Nissin Chemical Co., Ltd.
AQ515: Polyethylene wax, AQUACER 515 (solid content 35%) manufactured by Bikkemie.

[Inkjet recording]
Each ink was filled into a cartridge of an inkjet printer PX-205 manufactured by Seiko Epson Corporation, and inkjet recording was performed on Finesse Matt 115 (coated paper) manufactured by UPM Corporation.
Inkjet recording was performed so that a solid image was obtained at 100% duty, and recorded images were obtained using each ink. Using this as a test piece, an abrasion test was conducted.

[Ink abrasion test]
The abrasion resistance of each test piece was measured using Yasuda Seiki Seisakusho No. 428 Gakushin type abrasion tester (friction tester type II) was used for evaluation. That is, with a load of 500 g applied to the test piece, the inkjet recorded area was rubbed together 20 times, and the degree of image deterioration was evaluated using the following three-level evaluation criteria. The results are shown in Tables 5 and 6 below.
Dry abrasion evaluation criteria:
A: Almost no scratches on the recorded image could be observed.
B: Scratches were observed in the recorded image.
C: The recorded image has very large scratches.

[Cleaning liquid stability test]
After each cleaning solution obtained in Preparation Example 1 was allowed to stand at room temperature for 12 hours, the state of the cleaning solution was visually observed to evaluate its stability. The evaluation criteria were the following three levels. The evaluation results are shown in Tables 5 and 6 below.
[Evaluation criteria]
A: There was no change in the condition of the cleaning solution.
B: Separation of the liquid could not be confirmed, but non-uniform areas such as turbidity were observed.
C: Liquid components separated from the cleaning solution were observed floating on the surface of the cleaning solution.

[Cleanability test of cleaning liquid]
20 microliters of the colored ink obtained in Preparation Example 5 was dropped onto a glass petri dish, and the ink was left to stand in a constant temperature bath at 60° C. for 1 hour to dry, thereby obtaining a solid solidified ink.
10 ml of each of the cleaning liquids obtained in Preparation Example 1 was added dropwise to the obtained solids, and whether or not the solids could be washed was visually evaluated. The evaluation criteria were the following four levels. The ink sets and evaluation results of Examples 1 to 5 and Comparative Examples 1 to 10 are shown in Table 5 below.
[Evaluation criteria]
A: A homogeneous liquid was obtained with no solids remaining.
B: A small amount of solid matter remained, but the liquid was mostly homogeneous.
C: The shape of the solid material did not change at all or hardly changed.

In Tables 5 and 6 below, "binder amount" means the total amount of binder contained in each ink, and the unit is "part".
An example of a method for calculating the total amount of binder in Tables 5 and 6 below is shown below.
[Calculation example: Ink No. Total amount of binder in the total amount of 1]
Ink No. The total amount of binder in the total mass of 1 is the sum of "amount of solid content of polymer A in the colorant dispersion", "amount of solid content of AQ515", and "amount of solid content of polymer B" It is. In addition, in calculating these individual quantities, calculations are made up to the third decimal place at the maximum, and when there is a third decimal place, the calculated value is rounded off to the second decimal place. In the calculation of these individual quantities, when the second decimal place is calculated, that value is taken as the calculated value. Furthermore, when calculating these sums, the individual calculated values are used as they are to obtain the sum, the second decimal place is rounded off, and the calculated value is obtained up to the first decimal place.
Solid amount of polymer A in colorant dispersion = Content of colored dispersion in total mass of ink x Content of colorant solids x Content of polymer A relative to colorant solids x Solids in polymer A Content = 32.3 parts x 0.124 x 0.2 x 0.25 = 0.200 parts ≈ 0.20 parts.
Amount of solid content of AQ515 = Content of AQ515 in the total mass of ink x Solid content of AQ515 = 1.4 parts x 0.35 = 0.49 parts.
Amount of solid content of polymer B = content of polymer B in the total mass of ink x solid content of polymer B = 2 parts x 0.25 = 0.50 parts.
From these calculation results, ink No. The total amount of binder in the total mass of No. 1 is 0.20 parts + 0.49 parts + 0.50 parts = 1.19 parts ≈ 1.2 parts.

As is clear from the results in Tables 5 and 6, the cleaning solutions of each example have excellent stability. In addition, regardless of whether the ink's abrasion properties are good or not, it has been confirmed that when ink that can record on recording media that is difficult to absorb ink dries to form solid matter, the solid matter can be sufficiently washed away. It was done. On the other hand, the cleaning liquids used in Comparative Examples 1 to 7 and 12 can be used not only for inks with good abrasion properties, but also for inks with poor abrasion properties that dry and form solids. could not be washed. As is clear from the above results, it was confirmed that the cleaning liquids of Examples were superior in cleaning performance compared to the cleaning liquids used in Comparative Examples 1 to 7 and 12. Further, the cleaning liquids used in Comparative Examples 8 to 11 had a cleaning performance of "A", but were in a non-uniform state so that components separated from the cleaning liquid could be visually confirmed. Therefore, it was questionable whether the cleaning liquids used in Comparative Examples 8 to 11 could exhibit stable cleaning power over a long period of time.

[Washing liquid 6]: Preparation of washing liquid.
Cleaning liquid 6 was obtained in the same manner as cleaning liquids 1 to 5 above, except that each component listed in Table 7 below was used.

[Comparative liquids 11 to 12]: Preparation of comparative cleaning liquids.
Comparative cleaning solutions 11 to 12 were obtained in the same manner as cleaning solutions 1 to 5 above, except that the components listed in Table 7 below were used.

The abbreviations in Table 7 below have the same meanings as the abbreviations listed in Tables 2 and 3 above. Moreover, the numerical values in Table 7 are "parts". Moreover, "amount of binder" in Table 7 has the same meaning as in Tables 5 and 6 above.

Ink sets of Ink 1 and Cleaning Liquid 6, Ink 1 and Comparative Liquid 11, and Ink 1 and Comparative Liquid 12 were prepared as shown in Table 8 below. Using the obtained ink set, the above-mentioned [inkjet recording], [ink abrasion test], [cleaning liquid stability test], and [cleaning liquid cleaning test] were conducted and evaluated using the same evaluation criteria as above. The test results are shown in Table 8 below.

The ink set of the present invention is an ink that can record even on non- or poorly absorbent substrates, has good scratch resistance, and even when the ink dries to form solids, the solids can be washed away. It is extremely useful as an ink and cleaning liquid set for use in various types of recording, especially inkjet printers.

Claims (9)

An ink and cleaning solution set comprising an ink containing a colorant, a binder, and water, and a cleaning solution containing at least two types of surfactants and water, wherein one of the surfactants in the cleaning solution is HLB value is 10.0 to 20.0, the HLB value of the other surfactant is 3.0 or more and less than 10.0, and the cleaning liquid contains HLB value of 10.0 to 20.0. The content ratio of surfactants A and B in the total mass of the surfactant (surfactant A) and the surfactant (surfactant B) with an HLB value of 3.0 or more and less than 10.0 is 6 A set of ink and cleaning liquid ranging from /1 to 1/6 .
However, the HLB value of the surfactant is calculated as follows.
[How to calculate HLB value]
A solution is obtained by dissolving 0.5 g of surfactant in 5 mL of ethanol. The obtained solution is stirred at 25°C, and a 2% by mass aqueous phenol solution is added dropwise to this solution, and the end point is defined as the point where the liquid becomes cloudy. When the amount of 2% by mass phenol aqueous solution required to reach the end point is Q (mL), the HLB value is calculated using the following formula (1).

The ink and cleaning liquid set according to claim 1, wherein the surfactant having an HLB value of 10.0 to 20.0 is a surfactant selected from nonionic surfactants. The ink and cleaning liquid set according to claim 1 or 2, wherein the surfactant having an HLB value of 3.0 or more and less than 10.0 is a surfactant selected from nonionic surfactants. The ink and cleaning liquid set according to claim 1, wherein the cleaning liquid contains glycol ether. The ink and cleaning liquid set according to claim 1, wherein the binder is one or more types selected from polymers and waxes. The ink and cleaning liquid set according to claim 5, wherein the wax is one or more types selected from polyalkylene wax, oxidized polyalkylene wax, and paraffin wax. The ink and cleaning liquid set according to claim 5 or 6, wherein the wax is one or more types selected from polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax, and paraffin wax. A method for cleaning a recording device, comprising cleaning a recording device to which the ink according to any one of claims 1 to 7 has adhered, with the cleaning liquid according to any one of claims 1 to 7. The cleaning method according to claim 8, wherein the recording device is an inkjet printer.