Ink, inkjet printing method, and printing medium

Abstract

To provide an ink that is good in scratch resistance when printing on an ink non-absorbable or ink hardly absorbable printing medium, and excellent in remelting property of a solid matter generated by drying the ink, an inkjet printing method using the ink, and a printing medium with the ink attached.SOLUTION: An ink includes: a water-insoluble coloring agent; a polyethylene oxide wax; a compound expressed by the following formula (1) or formula (2) and having an HLB value of 7.5 to 20.0; and water. In the formula (1), R1 expresses a linear or branched 7C to 40C hydrocarbon group, EO expresses an ethyleneoxy group, and PO expresses a propyleneoxy group. m1 is 1 to 300 as an average value, and n1 is 0 to 10 as an average value. In the formula (2), R2 and R3 each independently represents a linear or branched 7C to 40C hydrocarbon. m2 is 1 to 300 as an average value, and n2 is 0 to 10 as an average value.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an ink, an ink-jet printing method using the ink, and a print medium having the ink deposited thereon. [Background technology]

[0002] Inkjet printing using an inkjet printer is a method of printing by generating small droplets of ink and depositing them on a print medium such as paper.

[0003] In recent years, the inkjet printing method has been increasingly applied to industrial applications. Colorants contained in inkjet inks are broadly classified into water-soluble colorants and water-insoluble colorants. Of these, water-insoluble colorants, such as pigments, generally have superior fastness properties compared to water-soluble colorants. For this reason, inkjet inks for industrial use often contain water-insoluble colorants.

[0004] Printing media used in industrial applications are diversified, including various types of paper, fiber, and film, and many of these printing media are non-ink absorbing or poorly ink absorbing. Non-aqueous solvent inks, curable inks, and the like are known as inks used when printing on such non-ink absorbing or poorly ink absorbing printing media. However, from the viewpoint of safety to the natural environment, living organisms, and the like, there is a strong demand for aqueous inks to replace these inks. In addition to water-insoluble colorants, such aqueous inks often contain water-insoluble polymeric compounds such as polymers and waxes for the purpose of improving abrasion resistance, solvent resistance, and the like. Such aqueous inks are extremely prone to drying due to their high solid content, and are also prone to generating solid matter when dried. When printing on non-ink absorbing or poorly ink absorbing printing media, a coating is formed using this solid matter to improve fixation and abrasion resistance to the printing media. For this reason, it is considered desirable for the coating formed by the solid matter to be as strong as possible.

[0005] On the other hand, drying of ink also occurs during long-term storage, storage in a high-temperature or low-humidity environment, and the like. When the ink filled in an inkjet printer dries, solid matter is generated in the nozzle or ink flow path of the inkjet head, which causes clogging. When clogging occurs in the inkjet head, ink cannot be ejected stably, leading to a problem that the quality of the printed image is significantly reduced. Furthermore, the inkjet head itself may become unusable, which is a major problem. For this reason, even if clogging occurs in the inkjet head due to solid matter, there is a strong demand for the ability to easily re-dissolve the solid matter with a cleaning liquid. However, since the improvement in fixability and abrasion resistance due to the formation of the above-mentioned coating is contradictory to the ability to easily re-dissolve, an ink that satisfies both of these effects has not yet been proposed. For these reasons, a method has been proposed in which a cap member is provided on the nozzle part of an industrial inkjet head to prevent the ink from drying. However, it is still extremely difficult to completely prevent the ink from drying. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2005-263972 A [Patent Document 2] JP 2018-162341 A [Patent Document 3] International Publication No. 2015 / 152291 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention aims to provide an ink that has good abrasion resistance when printed on a non-ink-absorbing or poorly ink-absorbing printing medium and also has excellent re-solubility of solid matter produced when the ink dries, an inkjet printing method that uses the ink, and a printing medium to which the ink is attached. [Means for solving the problem]

[0008] Specific means for solving the above problems include the following embodiments. [1] An ink containing a water-insoluble colorant, an oxidized polyethylene wax, a compound represented by the following formula (1) or formula (2) and having an HLB value of 7.5 to 20.0, and water.

[0009] [ka]

[0010] (In formula (1), R 1 represents a linear or branched C7-C40 hydrocarbon group, EO represents an ethyleneoxy group, and PO represents a propyleneoxy group. m1 is an average value of 1 to 300, n1 is an average value of 0 to 10, and when m1 and n1 are 1 or more, EO and PO may be arranged in any order.

[0011] [ka]

[0012] (In formula (2), R 2 and R 3 each independently represents a linear or branched C7-C40 hydrocarbon group, EO represents an ethyleneoxy group, and PO represents a propyleneoxy group. m2 is an average value of 1 to 300, n2 is an average value of 0 to 10, and when m2 and n2 are 1 or more, EO and PO may be arranged in any order. [2] The ink according to [1], further comprising at least one selected from glycol ethers and C4-C12 alkanediols. [3] The ink according to [1] or [2], further comprising a dispersant. [4] An inkjet printing method comprising ejecting droplets of the ink according to any one of [1] to [3] from an inkjet printer and depositing the droplets on a printing medium, thereby carrying out printing. [5] The inkjet printing method according to [4], wherein the printing medium is a printing medium that does not absorb ink or has low ink absorption. [6] A print medium having the ink according to any one of [1] to [3] adhered thereto. [7] The printing medium according to [6], which is a printing medium that does not absorb ink or has low ink absorption. Effect of the Invention

[0013] According to the present invention, it is possible to provide an ink that has good abrasion resistance when printed on a non-ink-absorbing or poorly ink-absorbing printing medium and also has excellent re-solubility of solid matter produced when the ink dries, an inkjet printing method using the ink, and a printing medium to which the ink is adhered. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In this specification, when a unit is stated for only one of the upper and lower limits of a range, such as "X to Y%", this means that the units for the upper and lower limits of the range are the same, i.e., "X% to Y%".

[0015] <Ink> The ink according to the present embodiment contains a water-insoluble colorant, an oxidized polyethylene wax, a compound represented by formula (1) or formula (2) and having an HLB value of 7.5 to 20.0, and water. The components contained in the ink according to the present embodiment will be described in detail below. Note that, of the components described below, one type may be used alone, or two or more types may be used in combination.

[0016] [Water-insoluble colorants] The water-insoluble colorant means a colorant having a solubility in water at 25° C. of usually 5 g / L or less, preferably 3 g / L or less, more preferably 1 g / L or less, and even more preferably 0.5 g / L or less. The lower limit of the solubility includes 0 g / L.

[0017] Examples of water-insoluble colorants include pigments, disperse dyes, solvent dyes, and water-insoluble resins colored with colorants such as dyes and pigments. In this specification, self-dispersing pigments are included in the water-insoluble colorants. Among these water-insoluble colorants, pigments are preferred.

[0018] Examples of the pigment include inorganic pigments, organic pigments, and extender pigments.

[0019] Examples of inorganic pigments include carbon black, metal oxides, metal hydroxides, metal sulfides, metal ferrocyanides, and metal chlorides.

[0020] The colorant contained in the black ink is preferably carbon black such as thermal black, acetylene black, oil furnace black, gas furnace black, lamp black, gas black, channel black, etc. Commercially available carbon black products include, for example, the Raven series manufactured by Columbia Carbon Co., the Monarch series, Regal series, and Mogul series manufactured by Cabot Corporation, the ColorBlack series, Printex series, SpecIalBlack series, and Nerox series manufactured by Orion Engineered Carbons, and the MA series, MCF series, No. 25, No. 33, No. 40, No. 47, No. 52, No. 900, and No. 2300 manufactured by Mitsubishi Chemical Corporation.

[0021] Examples of organic pigments include various pigments such as azo, diazo, phthalocyanine, quinacridone, isoindolinone, dioxazine, perylene, perinone, thioindigo, anthraquinone, and quinophthalone.

[0022] Examples of organic pigments include yellow pigments such as CI 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, and 213; Red pigments such as 5, 7, 12, 48, 48:1, 57, 88, 112, 122, 123, 146, 149, 150, 166, 168, 177, 178, 179, 184, 185, 202, 206, 207, 254, 255, 257, 260, 264, 272; blue pigments such as CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 25, 60, 66, 80; violet pigments such as CI Pigment Violet 19, 23, 29, 37, 38, 50; orange pigments such as CI Pigment Orange 13, 16, 68, 69, 71, 73; green pigments such as Green 7, 36, and 54; black pigments such as CI Pigment Black 1; and the like.

[0023] Examples of the extender pigment include silica, calcium carbonate, talc, clay, barium sulfate, white carbon, etc. The extender pigment is often used in combination with other colorants.

[0024] The disperse dye may be any known disperse dye, of which dyes selected from CI Dispers are preferred. Specific examples thereof include yellow dyes such as CI 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, and 237; red dyes such as CI Dispers Red 60, 73, 88, 91, 92, 111, 127, 131, 143, 145, 146, 152, 153, 154, 167, 179, 191, 192, 206, 221, 258, and 283; and CI Dispers Orange. Orange dyes such as 9, 25, 29, 30, 31, 32, 37, 38, 42, 44, 45, 53, 54, 55, 56, 61, 71, 73, 76, 80, 96, 97, etc.; violet dyes such as CI Dispers Violet 25, 27, 28, 54, 57, 60, 73, 77, 79, 79:1, etc.; blue dyes such as CI 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, etc.;

[0025] The average particle size of the water-insoluble colorant is usually 50 to 250 nm, and preferably 60 to 200 nm. In this specification, the average particle size refers to the average particle size of particles measured by a laser light scattering method.

[0026] The content of the water-insoluble colorant is usually 1 to 30 mass %, preferably 1 to 10 mass %, and more preferably 2 to 7 mass %, relative to the total mass of the ink according to this embodiment.

[0027] [Dispersant] When the ink according to this embodiment does not contain a self-dispersing pigment as the water-insoluble colorant, the ink according to this embodiment preferably contains a dispersant to disperse the water-insoluble colorant in the ink.

[0028] The dispersant is not particularly limited, and known dispersants such as polymer dispersants can be used. Examples of polymer dispersants include copolymers composed of at least two types of monomers (preferably at least one of which is a hydrophilic monomer) selected from monomers such as styrene and its derivatives; vinyl naphthalene and its derivatives; aliphatic alcohol esters of α,β-ethylenically unsaturated carboxylic acids; (meth)acrylic acid and its derivatives; maleic acid and its derivatives; itaconic acid and its derivatives; faric acid and its derivatives; vinyl acetate, vinyl alcohol, vinyl pyrrolidone, acrylamide, and their derivatives. Examples of such copolymers include styrene-(meth)acrylic copolymers such as styrene-(meth)acrylic acid copolymers and styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymers; (meth)acrylic acid ester-(meth)acrylic acid copolymers; polyethylene glycol (meth)acrylate-(meth)acrylic acid copolymers; styrene-maleic acid copolymers; and the like. Examples of the types of copolymers include block copolymers, random copolymers, graft copolymers, and the like. These copolymers may be in the form of a salt.

[0029] In this specification, the term "(meth)acrylic" is used to mean both "acrylic" and "methacrylic". The same applies to "(meth)acrylate" and the like.

[0030] Dispersants can be synthesized or obtained commercially.

[0031] Examples of dispersants obtained by synthesis include the AB block polymer disclosed in WO 2013 / 115071. The monomer constituting the A block of the AB block polymer disclosed in WO 2013 / 115071 is at least one monomer selected from (meth)acrylic acid and linear or branched C4 alkyl (meth)acrylate, preferably at least one monomer selected from methacrylic acid and n-butyl methacrylate, and more preferably these two monomers are used in combination. The monomer constituting the B block of the AB block polymer disclosed in WO 2013 / 115071 is at least one monomer selected from benzyl methacrylate and benzyl acrylate, preferably benzyl methacrylate. Specific examples of the AB block polymer include the block copolymers disclosed in Synthesis Examples 3 to 8 of WO 2013 / 115071.

[0032] Examples of commercially available dispersants include the Joncryl series, such as Joncryl 62, 67, 68, 678, and 687 (styrene-acrylic copolymers manufactured by BASF).

[0033] When using a styrene-(meth)acrylic copolymer as a dispersant, it is preferable to add a neutralizing agent, dissolve it in a liquid medium containing water, and use it as a resin solution. Examples of the neutralizing agent include ammonia, alkali metal hydroxides, alkaline earth metal hydroxides, aliphatic amine compounds, alkanolamine compounds, etc. Among these, ammonia and alkali metal hydroxides are preferred, and ammonia is more preferred. The amount of the neutralizing agent used is not particularly limited. As a guideline, the neutralization degree is usually 30 to 300%, preferably 50 to 200%, with the neutralization degree being 100% when neutralized with the theoretical equivalent of the acid value of the dispersant.

[0034] The dispersant is preferably at least one selected from the AB block polymer and the styrene-(meth)acrylic copolymer, and more preferably the AB block polymer and the styrene-(meth)acrylic copolymer are used in combination. When the AB block polymer and the styrene-(meth)acrylic copolymer are used in combination, the content ratio of the AB block polymer and the styrene-(meth)acrylic copolymer is usually 3 / 1 to 7 / 1, preferably 4 / 1 to 6 / 1, and more preferably 4.5 / 1 to 5.5 / 1 by mass.

[0035] The acid value of the dispersant is usually from 90 to 200 mgKOH / g, preferably from 100 to 150 mgKOH / g, and more preferably from 100 to 120 mgKOH / g.

[0036] The mass average molecular weight of the dispersant is usually 10,000 to 60,000, preferably 10,000 to 40,000, more preferably 15,000 to 30,000, and even more preferably 20,000 to 25,000. However, when the dispersant is other than the above-mentioned AB block polymer, the lower limit of the mass average molecular weight is usually 6,000, preferably 7,000, more preferably 8,000, and even more preferably 8,500. The PDI (mass average molecular weight / number average molecular weight) of the above-mentioned AB block polymer is about 1.29 to 1.49. By setting it in the above-mentioned range, the dispersibility and storage stability can be improved.

[0037] The dispersant may be used in a state where it is mixed with the water-insoluble colorant, or the surface of the water-insoluble colorant may be partially or entirely coated with the dispersant, or both of these states may be used in combination.

[0038] When the ink according to this embodiment contains a dispersant, the ratio of the total mass of the dispersant to the total mass of the water-insoluble colorant is usually 0.1 to 1.0, preferably 0.1 to 0.6, and more preferably 0.2 to 0.5.

[0039] [Oxidized polyethylene wax] The oxidized polyethylene wax is not particularly limited, and any known wax can be used. By including the oxidized polyethylene wax in the ink according to this embodiment, the scratch resistance of the printed image tends to be improved.

[0040] The average particle size of the oxidized polyethylene wax is preferably from 40 nm to 5 μm, and more preferably from 40 nm to 1 μm, in order to prevent clogging of the inkjet head.

[0041] The oxidized polyethylene wax is available as a commercial product. Commercially available oxidized polyethylene wax emulsions include, for example, AQUACER 515(45) and 1547 manufactured by BYK-Chemie Co., Ltd., and HYTEC E series manufactured by Toho Chemical Industry Co., Ltd., such as E-6500(40), E-9015(45), and E-6314(85). The numerical value in parentheses following each wax indicates the average particle size (unit: nm) of each wax.

[0042] The content of the oxidized polyethylene wax relative to the total mass of the ink according to this embodiment is typically 0.1 to 10 mass%, preferably 0.2 to 8 mass%, more preferably 0.4 to 5 mass%, even more preferably 0.6 to 3 mass%, and particularly preferably 0.8 to 1.2 mass%.

[0043] [Compound represented by formula (1) or formula (2)] In the above formula (1), R 1 R represents a linear or branched C7-C40 hydrocarbon group, and a linear C7-C40 hydrocarbon group is preferred. 1 The range of the carbon number is preferably C7-C30, more preferably C8-C20, further preferably C9-C19, and particularly preferably C11-C17.

[0044] In addition, in the above formula (2), R 2 and R 3 R each independently represents a linear or branched C7-C40 hydrocarbon group. 2 and R 3The range of carbon numbers is preferably C10-C30, more preferably C13-C21, further preferably C15-C19, and particularly preferably C17.

[0045] R 1 ~R 3 The hydrocarbon group in may have an unsaturated bond in its carbon-carbon bond. The type of unsaturated bond is not particularly limited, but is usually a double bond or a triple bond, preferably a double bond. The number of unsaturated bonds is not particularly limited, but as a guideline, it is usually 1 to 20, preferably 1 to 10, more preferably 1 to 5, even more preferably 1 or 2, and particularly preferably 1.

[0046] In the above formula (1) and formula (2), m1 and m2 represent the number of ethyleneoxy groups, and n1 and n2 represent the number of propyleneoxy groups. m1 is, on average, 1 to 300, preferably 3 to 200, more preferably 5 to 175, even more preferably 7 to 160, and particularly preferably 8 to 150. m2 is, on average, usually 1 to 300, preferably 4 to 290, more preferably 8 to 270, even more preferably 10 to 260, and particularly preferably 12 to 250. n1 and n2 are, on average, 0 to 10, preferably 0 to 5, more preferably 0 to 3, even more preferably 0 to 2, and particularly preferably 0.

[0047] The compound represented by the above formula (1) or (2) has an HLB value of usually 7.5 to 20.0, preferably 8.4 to 19.4. By using a compound having such an HLB value, the resolubility of the ink tends to be improved.

[0048] In this specification, the HLB value is the value listed in the catalog of each compound manufacturer, and if the value is listed to the first decimal place, the value is used as is. If the decimal point is not listed, the first decimal place is written as "zero" and used. If the second or more decimal places are listed, the second decimal place is rounded off to the first decimal place, and the value is used. If the HLB value in the catalog of the same compound differs depending on the manufacturer, the manufacturer's name (and product name, etc.) is clearly stated and each HLB value is used independently.

[0049] As can be seen from the fact that m1, n1, m2, and n2 are average values, the compound represented by the above formula (1) or formula (2) is a mixture of multiple compounds. Then, m1, n1, m2, and n2 are expressed as the average values ​​of the mixture.

[0050] In addition, when the HLB value is not listed in the catalog of each manufacturer of the compound, but the HLB value can be calculated using the Griffin method represented by the following formula (3), the calculated value of the following formula (3) is used. The significant figures of the HLB value in this case are the same as above. HLB value = 20 × hydrophilic group formula weight / molecular weight (3)

[0051] In addition, although the catalog lists the HLB value of a compound, some of the structural information in the above formula (1) and formula (2) (e.g., the numerical values ​​of m1 and n1) is not listed, and it is unclear whether the compound is included in the above formula (1) or formula (2). In such cases, when the structural information can be estimated using the above formula (3), it is determined whether the compound is included in the above formula (1) or formula (2) based on the estimated value. In this case, the HLB value is rounded off to one decimal place and listed as an integer.

[0052] Examples of commercially available products of the compound represented by formula (1) or formula (2) include EMANON 1112, 3199VB, 3299VB, 3299RV, 4110, etc. manufactured by Kao Corporation; IONET DO-600, MO-200, etc. manufactured by Sanyo Chemical Industries, Ltd.; NOIGEN ES-149D, etc. manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; and the like.

[0053] The following Table 1 shows an example of the compound represented by the above formula (1) and its HLB value, and the following Table 2 shows an example of the compound represented by the above formula (2) and its HLB value. In the following Tables 1 and 2, "unsaturation number" is R 1 ~R 3 "HLB" means "the number of carbon-carbon unsaturated bonds" possessed by the hydrocarbon group represented by the formula (2). "HLB" means the HLB value. Note that although the structures of IONET DL-200 and IONET DS-300 in Table 2 are within the range of the above formula (2), their HLB values ​​are 6.6 and 7.3, respectively, and therefore they are compounds that do not satisfy the "HLB value of 7.5 to 20.0".

[0054] [Table 1]

[0055] [Table 2]

[0056] The total content of the compounds represented by formula (1) or (2) in the ink according to this embodiment is usually 0.1 to 5 mass %, preferably 0.5 to 2 mass %, and more preferably 0.8 to 1.5 mass %, relative to the total mass of the ink.

[0057] [water] As the water, ion-exchanged water, distilled water, or the like having a low content of impurities (metal ions, etc.) is preferred.

[0058] The water content is usually 40 to 80 mass %, preferably 45 to 70 mass %, and more preferably 47 to 60 mass %, relative to the total mass of the ink according to this embodiment.

[0059] [Glycol ethers and C4-C12 alkanediols] The ink according to the present embodiment preferably contains at least one selected from glycol ethers and C4-C12 alkanediols. By containing at least one selected from glycol ethers and C4-C12 alkanediols, the ink according to the present embodiment tends to wet and spread well on non-ink-absorbent or poorly ink-absorbent printing media, and to dry well, which tends to improve the print image quality.

[0060] The glycol ether is not particularly limited, but is preferably an alkyl ether of di- or tri-C2-C4 alkylene glycol, and more preferably a monoalkyl ether of di- or tri-C2-C4 alkylene glycol. The C2-C4 alkylene glycol moiety includes ethylene glycol, propylene glycol, butylene glycol, etc., and is preferably ethylene glycol and propylene glycol, and more preferably propylene glycol. The carbon number of the alkyl of the alkyl ether moiety is usually C1-C6, preferably C1-C5, more preferably C2-C4, even more preferably C3-C4, and particularly preferably C4.

[0061] Specific examples of glycol ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, and tripropylene glycol monobutyl ether. Of these, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene glycol monopropyl ether, and dipropylene glycol monobutyl ether are preferred, with dipropylene glycol monobutyl ether being more preferred.

[0062] The C4-C12 alkanediol is not particularly limited, but is preferably a 1,2-(C4-C12) alkanediol, and more preferably a 1,2-(C6-C8) alkanediol.

[0063] Among C4-C12 alkanediols, alkanediols of C7 or more are generally considered to be poorly water-soluble. Specific examples thereof include 1,2-heptanediol, 1,2-octanediol, 5-methyl-1,2-hexanediol, 4-methyl-1,2-hexanediol, 4,4-dimethyl-1,2-pentanediol, etc. Among these, 1,2-octanediol is preferred. Among C4-C12 alkanediols, alkanediols of C6 or less are generally considered to be water-soluble. Specific examples thereof include 1,2-hexanediol, 1,2-pentanediol, 1,2-butanediol, 4-methyl-1,2-pentanediol, 3,3-dimethyl-1,2-butanediol, etc. Although any of these can be used, 1,2-hexanediol is preferred because of its low odor.

[0064] The total content of glycol ether and C4-C12 alkanediol relative to the total mass of the ink according to this embodiment is usually 0.1 to 30 mass%, preferably 0.2 to 20 mass%, more preferably 0.5 to 10 mass%, even more preferably 2 to 8 mass%, and particularly preferably 4 to 6 mass%.

[0065] [Ink preparations] The ink according to this embodiment may further contain ink preparation agents in addition to the above-mentioned components, such as organic solvents, surfactants, preservatives, antifungal agents, pH adjusters, chelating agents, rust inhibitors, water-soluble ultraviolet absorbers, and antioxidants.

[0066] When the ink according to this embodiment contains an organic solvent, the content thereof is usually 1 to 70 mass%, preferably 10 to 60 mass%, more preferably 20 to 50 mass%, even more preferably 25 to 45 mass%, and particularly preferably 30 to 40 mass%, based on the total mass of the ink according to this embodiment. The total content of ink preparation agents other than the organic solvent is usually 0 to 30 mass%, preferably 0.1 to 20 mass%, and more preferably 0.5 to 10 mass%, based on the total mass of the ink according to this embodiment.

[0067] (Organic solvent) Examples of organic solvents include C1-C6 alkanols having one hydroxyl group, such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, and tertiary butanol; amides, such as N,N-dimethylformamide and N,N-dimethylacetamide; lactams, such as 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-methylpyrrolidin-2-one; cyclic ureas, such as 1,3-dimethylimidazolidin-2-one and 1,3-dimethylhexahydropyrimid-2-one; ketones or ketoalcohols, such as acetone, 2-methyl-2-hydroxypentan-4-one, and ethylene carbonate; cyclic ethers, such as tetrahydrofuran and dioxane; ethylene glycol, propylene glycol, and the like. Examples of suitable alkanediols include C2-C3 alkanediols such as glycol and 1,3-propanediol; mono-, oligo-, or polyalkylene glycols or thioglycols having C2-C4 (preferably C2-C3) alkylene units, such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol or polypropylene glycol having a molecular weight of 400 or more, thiodiglycol, and dithiodiglycol; polyols (triols) such as glycerin, diglycerin, hexane-1,2,6-triol, and trimethylolpropane; γ-butyrolactone, dimethyl sulfoxide; and compounds having a hydroxyl group and an ester moiety in the molecule, such as texanol. Among these, C2-C3 alkanediols and oligo- or polyalkylene glycols having C2-C4 alkylene units are preferred, C2-C3 alkanediols are more preferred, and 1,2-(C2-C3) alkanediols are even more preferred.

[0068] (Surfactant) The surfactant may be anionic, cationic, amphoteric, silicone-based, or fluorine-based surfactant.

[0069] Examples of anionic surfactants include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether sulfates, N-acylamino acids or salts thereof, N-acylmethyltaurines, alkyl sulfates, polyoxyalkyl ether sulfates, alkyl sulfates, polyoxyethylene alkyl ether phosphates, rosin acid soaps, castor oil sulfates, lauryl alcohol sulfates, alkylphenol phosphates, alkyl phosphates, alkylarylsulfonates, diethylsulfosuccinates, diethylhexylsulfosuccinates, and dioctylsulfosuccinates.

[0070] Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly(4-vinylpyridine) derivatives.

[0071] Examples of amphoteric surfactants include lauryl dimethylaminoacetate betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, coconut oil fatty acid amidopropyl dimethylaminoacetate betaine, polyoctyl polyaminoethyl glycine, and imidazoline derivatives.

[0072] Examples of silicone surfactants include polyether-modified siloxanes and polyether-modified polydimethylsiloxanes. Examples of such surfactants include Dynol 960 and 980 manufactured by Air Products Co., Ltd.; Silface SAG001, SAG002, SAG003, SAG005, SAG503A, SAG008, SAG009, and SAG010 manufactured by Nissin Chemical Co., Ltd.; BYK-345, 347, 348, 349, 3455, LP-X23288, LP-X23289, and LP-X23347 manufactured by BYK Additives & Instruments Co., Ltd.; and TEGO Twin 4000, TEGO Wet KL245, 250, 260, 265, 270, and 280 manufactured by Evonic Tego Chemie Co., Ltd.

[0073] Examples of fluorine-based surfactants include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups on the side chains.

[0074] (Preservatives) Examples of preservatives include compounds such as organic sulfur compounds, organic nitrogen sulfur compounds, organic halogen compounds, haloarylsulfone compounds, iodopropargyl compounds, haloalkylthio compounds, nitrile compounds, pyridine compounds, 8-oxyquinolines, benzothiazole compounds, isothiazolin compounds, dithiols, pyridine oxide compounds, nitropropane compounds, organic tin compounds, phenol compounds, quaternary ammonium salt compounds, triazine compounds, thiazine compounds, anilides, adamantane compounds, dithiocarbamates, brominated indanone compounds, benzyl bromoacetate compounds, and inorganic salt compounds. Specific examples of commercially available preservatives include Proxel GXL(S) and XL-2(S) manufactured by Arch Chemicals.

[0075] (Anti-mold agent) Examples of antifungal agents include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and salts thereof.

[0076] (pH adjuster) Any substance can be used as the pH adjuster as long as it does not adversely affect the prepared ink and can adjust the pH to 5 to 11. 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); alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium hydrogen carbonate, and potassium carbonate; alkali metal salts of organic acids such as sodium silicate and potassium acetate; and inorganic bases such as disodium phosphate.

[0077] (chelating agent) Examples of the chelating agent include disodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uracildiacetate.

[0078] (rust inhibitor) Examples of the rust inhibitor include acid sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

[0079] (Water-soluble UV absorber) Examples of the water-soluble ultraviolet absorber include sulfonated benzophenone compounds, benzotriazole compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

[0080] (Antioxidants) As the antioxidant, various organic and metal complex-based discoloration inhibitors can be used. Examples of organic discoloration inhibitors include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles.

[0081] [Ink properties, etc.] The pH of the ink according to this embodiment at 25°C is usually 7 to 11, and preferably 8 to 10. The surface tension of the ink according to this embodiment at 25°C is usually 10 to 50 mN / m, and preferably 20 to 40 mN / m. The viscosity of the ink according to this embodiment at 25°C is usually 2 to 30 mPa s, and preferably 3 to 20 mPa s. The pH, surface tension, and viscosity of the ink according to this embodiment can be appropriately adjusted with a pH adjuster, a surfactant, an organic solvent, etc.

[0082] The ink according to the present embodiment can be used in various printing methods, etc. For example, the ink according to the present embodiment is suitable for writing instruments, various information printing, textile printing, etc., and is preferably used in inkjet printing.

[0083] <Inkjet printing method and printing media> The inkjet printing method according to this embodiment performs printing by ejecting droplets of the above-mentioned ink from an inkjet printer and depositing them on a print medium. When performing inkjet printing, a container filled with the above-mentioned ink is loaded into a predetermined position of the inkjet printer, and printing can be performed as described above. There are no particular limitations on the ink nozzles and inkjet method of the inkjet printer, and these can be selected according to the purpose.

[0084] In the inkjet printing method according to the present embodiment, the inks described above may be used alone or in combination with other inks. For example, in order to obtain a full-color recorded image, the inks described above may be used in combination with inks containing yellow, blue, red, green, violet, and orange colorants.

[0085] In order to increase the printing speed, industrial inkjet printers are preferably configured as line head inkjet printers and perform single pass printing. The inks described above can be used under such printing conditions.

[0086] As the inkjet method, a known method can be used. Specific examples of the inkjet method include, for example, a charge control method, a drop-on-demand (pressure pulse) method, an acoustic inkjet method, and a thermal inkjet method. In addition, the inkjet method includes a method of improving image quality by ejecting a large number of inks with a small content of colorant in a small volume; a method of improving image quality by using multiple inks with substantially the same hue but different concentrations of colorant in the ink; and a method of improving the fixation of colorant by using colorless and transparent ink.

[0087] Print media refers to a material to which ink can adhere. Examples of print media include paper, film, fiber or cloth (cellulose, nylon, wool, etc.), leather, and color filter substrates.

[0088] Print media can be broadly divided into those with and without an ink-receiving layer. Print media with an ink-receiving layer are usually called inkjet paper, inkjet film, glossy paper, etc. Print media without an ink-receiving layer include various papers such as coated paper and art paper used for applications such as gravure printing and offset printing; cast-coated paper used for label printing; etc. The above-mentioned inks can be suitably used for non-ink-absorbing or poorly ink-absorbing print media that do not have an ink-receiving layer.

[0089] When using a printing medium that does not have an ink-receiving layer, it is also preferable to subject the printing medium to a surface modification treatment in order to improve the fixation of the colorant, etc. Examples of surface modification treatments include corona discharge treatment, plasma treatment, and frame treatment.

[0090] For all of the above items, combinations of preferred items are more preferred, and combinations of more preferred items are even more preferred. The same applies to combinations of preferred items and more preferred items, combinations of more preferred items and even more preferred items, etc. EXAMPLES

[0091] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0092] In the examples, unless otherwise specified, "parts" means parts by mass, and "%" means % by mass. In the examples, all operations such as synthesis and preparation were performed under stirring unless otherwise specified. In addition, when it was necessary to measure the solid content of the colorant in the liquid, it was calculated as a converted value of only the colorant by the dry weight method using MS-70 manufactured by A&D Co., Ltd.

[0093] [Preparation Example 1: Preparation of resin solution A] Joncryl 678 (MW: 8500) (25 parts) and triethanolamine (14.3 parts) were dissolved in ion-exchanged water (60.7 parts) and stirred for one hour to obtain a solution, which is designated as "resin solution A."

[0094] [Preparation Example 2: Preparation of Colorant Dispersion DP1] A block copolymer was prepared by re-examining Synthesis Example 3 of WO 2013 / 115071. The obtained block copolymer (5 parts) was dissolved in 2-butanone (20 parts) to obtain a homogeneous liquid. A solution obtained by dissolving sodium hydroxide (0.4 parts) in water (50.6 parts) and resin solution A (4 parts) were added to this liquid and stirred for 1 hour to obtain a liquid. CI Pigment Yellow 74 (20 parts) was added to this liquid and dispersed in a sand grinder for 15 hours under the condition of 1500 rpm to obtain a liquid. Water (100 parts) was dropped into the obtained liquid, and the liquid was filtered to obtain a filtrate. 2-butanone and a part of the water were distilled off under reduced pressure from the obtained filtrate to obtain a colorant dispersion having a colorant content of 11.2%. The obtained colorant dispersion is designated as "DP1".

[0095] [Preparation Example 3: Preparation of ink] The components shown in Tables 3 and 4 below were mixed to obtain a total of 100 parts of each liquid, and the resulting liquid was filtered through a membrane filter with a pore size of 3 μm to obtain the inks of Examples 1 to 13 and Comparative Examples 1 to 13. The content of the colorant in the total mass of the ink was adjusted to 4% for each ink. Note that the ink components of the inks of Comparative Examples 4 to 7 were separated to such an extent that they could be clearly confirmed by visual inspection. For this reason, it was determined that the ink stability of the inks of Comparative Examples 4 to 7 was problematic, and the evaluation test described below was not performed.

[0096] [Preparation Example 4: Preparation of cleaning solution] A cleaning liquid was prepared in the same manner as in Example 1, except that water was added instead of the three components DP1, AQ515, and Emanon 1112 from the ink components of Example 1 in Table 3 below.

[0097] The abbreviations in Tables 3 and 4 below have the following meanings. DP1: Colorant dispersion obtained in Preparation Example 2 PG: Propylene glycol 12HD: 1,2-Hexanediol DPnB: Dipropylene glycol monobutyl ether TEA: Triethanolamine TEX: Texanol BYK349: BYK Additives & Instruments, a silicone surfactant, BYK-349 AQ515: AQUACER 515, an oxidized polyethylene wax manufactured by BYK EN1112: Emanon 1112 3199VB: Emanone 3199VB MO-200: IONET MO-200 ES149D: Noigen ES-149D EN4110: Emanone 4110 3299VB: Emanone 3299VB DO-600: IONET DO-600 3299RV: Emanon 3299RV AQ593: Polypropylene wax manufactured by BYK, AQUACER 593 TW-80: Daiichi Kogyo Seiyaku Co., Ltd., polyethylene glycol sorbitan monooleate (HLB value: 15), Solgen TW-80 DL-200: IONET DL-200 (HLB value: 6.6) manufactured by Sanyo Chemical Industries, Ltd. DS-300: IONET DS-300 (HLB value: 7.3) manufactured by Sanyo Chemical Industries, Ltd. NC2303: Newcol 2303 manufactured by Nippon Nyukazai Co., Ltd. (polyoxyethylene alkyl ether, alkyl portion is C12-C13, HLB value: 8.3) NC2320: Newcol 2320 manufactured by Nippon Nyukazai Co., Ltd. (polyoxyethylene alkyl ether, alkyl portion is C12-C13, HLB value: 16.4) ED200: Phosphanol ED-200 manufactured by Toho Chemical Industry Co., Ltd. (polyoxyethylene alkyl ether phosphate ester, alkyl part is branched C8, oxyethylene number is 1, HLB value: 11.4) RS410: Phosphanol RS-410 manufactured by Toho Chemical Industry Co., Ltd. (polyoxyethylene alkyl ether phosphate ester, alkyl portion is branched chain C13, oxyethylene number is 3, HLB value: 9.0)

[0098] [Table 3]

[0099] [Table 4]

[0100] [(A) Evaluation of resolubility] 20 μL of the ink of each Example and Comparative Example was dropped onto a glass petri dish of φ7 cm using a micropipette. The glass petri dish was dried in a thermostatic chamber at 60° C. for 30 minutes to obtain a dried product of each ink as a solid. 10 g of the cleaning solution prepared in Preparation Example 4 was gently poured into the obtained solid and allowed to stand for 1 hour. After standing, the petri dish was gently rocked, and visual observation was made to see whether the solid had redissolved, and the results were evaluated according to the following three-level criteria. The evaluation results are shown in Tables 5 and 6 below. -Evaluation criteria- A: No large solids or adhesions on the dish were observed, and all solids were redissolved. B: No large solid matter was found, but some adhesion was observed on the petri dish. C: Large solids of about 1 mm were confirmed as insoluble matter, and adhesions were observed on the petri dish.

[0101] [(B) Evaluation of abrasion resistance] Using a bar coater No. 3 in an automatic coater (PI-1210, manufactured by Tester Sangyo Co., Ltd.), each ink for evaluation test was applied to the entire surface of "OK Topcoat +" manufactured by Oji Paper Co., Ltd., and then dried in a thermostatic chamber at 70 ° C. for 2 minutes to obtain a test piece. The abrasion resistance of each test piece was evaluated using a No. 428 Gakushin type abrasion tester (friction tester type II) manufactured by Yasuda Seiki Seisakusho Co., Ltd. That is, the coated part was rubbed 20 times with a load of 250 g applied to the test piece, and the degree of dye transfer was evaluated using the following two-stage evaluation criteria using a staining gray scale (JIS L 0805:2005 compliant). The evaluation results are shown in Tables 5 and 6 below. -Evaluation criteria- A: Level 3 or above C: Less than 3rd grade

[0102] [Table 5]

[0103] [Table 6]

[0104] As is clear from the above results, it was confirmed that the inks of the examples have good abrasion resistance and also have excellent resolubility of solid matter generated by drying of the ink, and have two opposing effects in a well-balanced manner. On the other hand, the inks of the comparative examples only had one of the abrasion resistance and resolubility rated as A, but the other was poor rated as C. This confirmed that the two effects are usually opposing each other.

[0105] [(C) Inkjet printing] Using the inks obtained in Examples 1, 4, and 13, inkjet printing was performed on "OK Topcoat+" manufactured by Oji Paper Co., Ltd., using a printer equipped with an inkjet head KJ4B-YH (600 dpi x 600 dpi) manufactured by Kyocera Corporation, under conditions of a droplet size of 12 pL and a speed of 25 m / min. In the inkjet printing, after confirming that there were no nozzles missing in a test drawing, a solid image of 100% duty was printed at 80 cm. Immediately after printing this solid image, a test drawing was performed again to confirm the number of nozzles missing. As a result, there were no nozzles missing when any of the inks were used, and it was confirmed that inkjet printing could be performed well.

Claims

1. An ink containing a water-insoluble colorant, an oxidized polyethylene wax, a compound represented by the following formula (1) or (2) and having an HLB value of 7.5 to 20.0, and water. 【Chemistry 1】 (In formula (1), R １ represents a linear or branched C7-C40 hydrocarbon group, EO represents an ethyleneoxy group, and PO represents a propyleneoxy group. m1 is an average value of 1 to 300, n1 is an average value of 0 to 10, and when m1 and n1 are 1 or more, EO and PO may be arranged in any order. 【Chemistry 2】 (In formula (2), R ２ and R ３ each independently represents a linear or branched C7-C40 hydrocarbon group, EO represents an ethyleneoxy group, and PO represents a propyleneoxy group. m2 is an average value of 1 to 300, n2 is an average value of 0 to 10, and when m2 and n2 are 1 or more, EO and PO may be arranged in any order.

2. 2. The ink of claim 1, further comprising at least one selected from glycol ethers and C4-C12 alkanediols.

3. 3. The ink of claim 1, further comprising a dispersant.

4. 4. An inkjet printing method comprising the steps of: ejecting droplets of the ink according to claim 1 from an inkjet printer and depositing the droplets on a printing medium to perform printing.

5. The inkjet printing method according to claim 4 , wherein the print medium is a print medium that does not absorb ink or that absorbs ink poorly.

6. A print medium having the ink according to any one of claims 1 to 3 attached thereto.

7. The print medium of claim 6 , which is a print medium that does not absorb ink or that absorbs ink poorly.

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