Ink-jet ink composition and recording method

Abstract

To solve such problems that: a conventional ink which is mainly used for an edible ink not requested in high color development, and printing on tablets has a low color material concentration of a plant charcoal powder coloring matter, and is inferior in color development when being applied to usage excluding printing, and on the other hand, the ink is not excellent in reliability such as redispersion and clog recoverability when a color material concentration of the plant charcoal powder coloring matter is raised in order to enhance color development of the ink; when a grain size of the color material of the plant charcoal powder coloring matter is reduced, thickening or gelatinization is generated caused by volatilization of water and a solvent, and viscosity change occurs; and when the color material is used without reducing the grain size, clog of a nozzle is generated when the ink is discharged.SOLUTION: An inkjet ink composition contains water, a plant-derived carbonized color material, and a lignin resin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an ink-jet ink composition and a recording method. [Background technology]

[0002] The inkjet recording method is capable of recording high-definition images using a relatively simple device, and has been rapidly developed in various fields. In the meantime, various studies have been conducted on how to obtain more stable, high-quality recorded matter.

[0003] For example, Patent Document 1 discloses an inkjet ink for FC tablets, which is an aqueous ink that has good drying properties and excellent ink fixation to tablets. This inkjet ink contains a plant carbon powder colorant, a polyglycerol fatty acid ester, and water, the polyglycerol fatty acid ester being a monoester of a fatty acid having 8 to 12 carbon atoms, and the content of the water-soluble organic solvent relative to the total amount of the ink is 5% by weight or less. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-85474 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the inkjet ink described in Patent Document 1 is specifically intended for use mainly in printing on edible inks and tablets that do not require high color development, and has a low coloring material concentration of the vegetable charcoal pigment, which results in poor color development when used for purposes other than printing (see Examples). On the other hand, when the coloring material concentration of the vegetable charcoal pigment is increased to improve the color development of this ink, there is a problem that the ink is not excellent in terms of reliability, such as redispersibility and clogging recovery. In addition, when the coloring material of the vegetable charcoal pigment is made small in particle size, there is a problem that thickening and gelation occur due to the volatilization of water and solvent, resulting in a change in viscosity. Furthermore, when the coloring material is used without being made small in particle size, there is a problem that the nozzle becomes clogged when the ink is ejected. [Means for solving the problem]

[0006] Means for Solving the Problems The present inventors conducted intensive research to solve the above problems, and as a result, found that the change in viscosity can be suppressed by using an inkjet ink composition containing water, a plant-derived carbonized colorant, and a lignin resin, and thus completed the present invention.

[0007] That is, the present invention provides an ink-jet ink composition comprising water, a plant-derived carbonized colorant, and a lignin resin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The following embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out with appropriate modifications within the scope of its gist.

[0009] Inkjet ink composition The inkjet ink composition of the present embodiment (hereinafter, also simply referred to as "ink composition") contains water, a carbonized coloring material derived from plants, and a lignin resin. The ink composition of the present embodiment is considered to suppress the viscosity change due to the following factors. However, the factors are not limited to these factors. That is, when the coloring material concentration is increased to enhance color development, a conventional ink composition containing a carbonized coloring material derived from plants does not have excellent reliability such as redispersibility and clogging recovery. In addition, when the coloring material of the plant carbon powder pigment is made small in particle size, thickening and gelation occur due to the volatilization of water and solvent, and a viscosity change occurs. Furthermore, when the coloring material is used without being made small in particle size, clogging of the nozzle occurs when the ink is discharged. On the other hand, the ink composition of the present embodiment contains both a carbonized coloring material derived from plants and a lignin resin, and therefore, even when the coloring material is used with a particle size of a predetermined value or less, the lignin resin inhibits the aggregation of the carbonized coloring materials, suppresses thickening and gelation, and suppresses the viscosity change. Since the carbonized color material derived from plants contains components derived from plants, it is presumed that the stability is improved by the simultaneous presence of the carbonized color material and lignin resin, which is one of the components of plants. Even if the carbonized color material contains a content of the carbonized color material of a predetermined value or more, the lignin resin inhibits the aggregation of the carbonized color materials, so that the carbonized color material has excellent reliability such as redispersibility and discharge stability.

[0010] In this specification, the term "inkjet ink composition" refers to an ink composition for recording (printing) on ​​a recording medium using an inkjet method, and the term "recorded matter" refers to an image formed by recording the ink composition on a recording medium.

[0011] Carbonized color material The ink composition of the present embodiment contains a carbonized colorant derived from a plant (hereinafter, also simply referred to as a "carbonized colorant"). In this specification, the term "carbonized colorant derived from a plant" refers to a colorant obtained by treating a plant under high-temperature conditions and carbonizing the plant. Here, the "high-temperature conditions" are not particularly limited as long as the conditions are capable of carbonizing the plant. For example, a high-temperature condition of 250°C or higher known as "charcoal burning" that can turn bamboo or wood into ash, a high-temperature condition of 350°C or higher that is believed to cause the disappearance of uncarbonized components, or a high-temperature condition of 700°C or higher using a charcoal kiln or the like can be adopted. The ink composition of the present embodiment has excellent color development properties, contains a carbonized colorant that can be prepared from a plant, and suppresses viscosity changes.

[0012] The carbonized coloring material is not particularly limited, but examples thereof include Japanese-made carbonized coloring materials such as white charcoal, binchotan charcoal, black charcoal, shaped charcoal, bamboo charcoal, plum charcoal, activated charcoal, mangrove charcoal, and coconut shell charcoal. Among these, binchotan charcoal and bamboo charcoal are preferred, and binchotan charcoal is more preferred.

[0013] The carbonized colorant may be used alone or in combination of two or more. The content of the carbonized colorant is preferably 1.0 to 15 mass %, more preferably 3.0 to 10 mass %, and even more preferably 5.0 to 8.0 mass %, based on the total amount of the ink composition. When the content of the carbonized colorant is within the above range, viscosity change is further suppressed, and redispersibility and ejection stability tend to be improved.

[0014] Lignin Resin The ink composition of the present embodiment contains a lignin resin. In this specification, the term "lignin resin" refers to a resin obtained by polymerizing lignin monomers such as p-coumaryl alcohol (p-hydroxycinnamyl alcohol), coniferyl alcohol, and sinapyl alcohol. When the ink composition contains the lignin resin, the viscosity change is suppressed.

[0015] The lignin resin is not particularly limited, but examples thereof include lignin resins having functional groups such as sulfonic groups, carboxyl groups, and phenolic hydroxyl groups, and lignin sulfonic acids having sulfonic groups are preferred. Examples of lignin sulfonic acids include those having free sulfonic groups and lignin sulfonates which form salts with magnesium, sodium, calcium, or the like and the sulfonic groups, and lignin sulfonates are more preferred.

[0016] The lignin resin may be used alone or in combination of two or more. The content of the lignin resin is preferably 1.0 to 30 mass%, more preferably 3.0 to 15 mass%, and even more preferably 5.0 to 10 mass%, based on the total amount of the ink composition. When the content of the lignin resin is within the above range, viscosity change is further suppressed, and redispersibility and ejection stability tend to be improved.

[0017] The mass ratio of the carbonized colorant to the lignin resin (carbonized colorant:lignin resin) is preferably 1.0:0.1 to 1.0:5.0, more preferably 1.0:0.5 to 1.0:2.0, and even more preferably 1.0:0.7 to 1.0:1.3. When the mass ratio is within the above range, viscosity change is further suppressed, and redispersibility and ejection stability tend to be improved.

[0018] Color material The ink composition of the present embodiment contains at least a carbonized coloring material and a lignin resin as coloring materials. The ink composition of the present embodiment may further contain a known coloring material other than the carbonized coloring material and the lignin resin. Examples of known coloring materials include inorganic pigments and organic pigments.

[0019] The inorganic pigment is not particularly limited, but examples thereof include carbon blacks (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, iron oxide, and titanium oxide.

[0020] Examples of organic pigments include, but are not limited to, azo pigments such as insoluble azo pigments, condensed azo pigments, azo lakes, and chelate azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments; dye chelates (e.g., basic dye chelates, acid dye chelates, etc.); dye lakes (basic dye lakes, acid dye lakes), nitro pigments, nitroso pigments, aniline black, and daylight fluorescent pigments.

[0021] From the viewpoint of redispersibility and ejection stability of the ink composition, the average particle size (D50) of the colorant is preferably from 50 to 500 nm, more preferably from 100 to 400 nm, and even more preferably from 200 to 300 nm.

[0022] In this specification, the term "average particle size" refers to the average particle size based on volume unless otherwise specified. The average particle size can be measured by a particle size distribution measuring device that uses the laser diffraction scattering method as the measurement principle. For example, the "Microtrack Series" (manufactured by Microtrack Bell Co., Ltd.) can be used as a laser diffraction type particle size distribution measuring device.

[0023] Water-soluble organic solvent The ink composition of this embodiment preferably contains a water-soluble organic solvent. In this specification, the term "water-soluble" refers to a property that can be used together with water and that at least a part of the ink is dissolved in water.

[0024] The type of water-soluble organic solvent is not particularly limited, but may be, for example, monoalcohol, alkyl polyol, glycol ether, cyclic nitrogen compound, and aprotic polar solvent. The organic solvent of the present embodiment may be selected from these organic solvents and used.

[0025] The water-soluble organic solvent preferably contains an alkyl polyol. By containing an alkyl polyol in the ink composition, the ink composition tends to have better redispersibility and ejection stability due to the alkyl polyol penetrating between the lignin resin molecules through hydrogen bonding.

[0026] Examples of monoalcohols include, but are not limited to, methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, 2-butanol, tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol.

[0027] The alkyl polyol is not particularly limited, but may be, for example, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol (1,2-propanediol), dipropylene glycol, 1,3-propylene glycol (1,3-propanediol), isobutylene glycol (2-methyl-1,2-propanediol), 1,2-butanediol, 1,3-butylene glycol (1,3-butanediol), 1,4-butanediol, 2-butene-1,4-diol, 1,2-pentanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 1,7-heptanediol, and 1,8-octanediol. Among these, glycerin, propylene glycol, and 1,3-butylene glycol are preferred.

[0028] The glycol ether is not particularly limited, but examples thereof include diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monobutyl ether, diethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol mono-n-propyl ether, and dipropylene glycol mono-iso-propyl ether.

[0029] The aprotic polar solvent is not particularly limited, but examples thereof include cyclic ketone compounds, chain ketone compounds, and chain nitrogen compounds. In addition, typical examples of the cyclic nitrogen compounds and the aprotic polar solvent include pyrrolidones, imidazolidinones, sulfoxides, lactones, amide ethers, and imidazoles. The pyrrolidones are not particularly limited as long as they have a pyrrolidone skeleton, but examples thereof include 2-pyrrolidone, N-alkyl-2-pyrrolidone, and 1-alkyl-2-pyrrolidone. The imidazolidinones include, for example, 1,3-dimethyl-2-imidazolidinones, sulfoxides include, for example, dimethyl sulfoxide, lactones include, for example, γ-butyrolactone, and imidazoles include, for example, imidazole, 1-methylimidazole, 2-methylimidazole, and 1,2-dimethylimidazole.

[0030] The water-soluble organic solvent may be used alone or in combination of two or more. The content of the water-soluble organic solvent is preferably 1.0 to 70 mass %, more preferably 5.0 to 50 mass %, and further preferably 10 to 30 mass %, based on the total amount of the ink composition. When the content of the water-soluble organic solvent is within the above range, redispersibility and ejection stability tend to be better.

[0031] Surfactants The ink composition preferably contains a surfactant. In this specification, the term "surfactant" refers to a substance that promotes the dissolution of a water-soluble organic solvent in the ink composition, particularly in water.

[0032] The surfactant is not particularly limited, but examples thereof include acetylene glycol surfactants, alkyl ether surfactants, fluorine-based surfactants, and silicone-based surfactants.

[0033] The acetylene glycol surfactant is not particularly limited, but is preferably one or more selected from 2,4,7,9-tetramethyl-5-decyne-4,7-diol, alkylene oxide adducts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol, and alkylene oxide adducts of 2,4-dimethyl-5-decyne-4-ol and alkylene oxide adducts of 2,4-dimethyl-5-decyne-4-ol. Commercially available acetylene glycol surfactants include, but are not limited to, Olfin E1010, PD-002W, PD-005, EXP4200, EXP4300, WE-003, and the like (trade names, manufactured by Nissin Chemical Industry Co., Ltd.), Surfynol 104E, 104PG50, 420, 465, 485, 61, 82, DF110D, DF37, DF75, MD-20, and the like (trade names, manufactured by Evonik Industries Co., Ltd.).

[0034] The alkyl ether surfactant is not particularly limited, but preferably at least one selected from polyoxyethylene 2-ethylhexyl ether, polyoxyethylene oleyl ether, polyoxyethylene tridecyl ether, polyoxyethylene castor oil ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene alkyl ether, and polyoxyalkylene tridecyl ether. The commercially available alkyl ether surfactant is not particularly limited, but for example, Newcol 1006, 1008, 1020 (trade name of Nippon Nyukazai Co., Ltd.), Noigen DL-0415, ET-116B, ET-106A, DH-0300, YX-400, EA-160 (trade name of Daiichi Kogyo Seiyaku Co., Ltd.), Emulgen 430, 1108 (trade name of Kao Corporation).

[0035] The fluorine-based surfactant is not particularly limited, but for example, perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl phosphate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl betaine, and perfluoroalkyl amine oxide compound can be mentioned. The commercially available fluorine-based surfactant is not particularly limited, but for example, S-144, S-145 (trade names, manufactured by Asahi Glass Co., Ltd.); FC-170C, FC-430, Fluorad-FC4430 (trade names, manufactured by Sumitomo 3M Co., Ltd.); FSO, FSO-100, FSN, FSN-100, FS-300 (trade names, manufactured by Dupont Co., Ltd.); FT-250, 251 (trade names, manufactured by Neos Co., Ltd.).

[0036] The silicone surfactant is not particularly limited, but examples thereof include polysiloxane compounds and polyether-modified organosiloxanes. Examples of commercially available silicone surfactants include, but are not limited to, SAG503A (trade name, manufactured by Nissin Chemical Industry Co., Ltd.), BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-347, BYK-348, and BYK-349 (all trade names, manufactured by BYK-Chemie), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, and KF-6017 (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0037] Among the surfactants mentioned above, acetylene glycol surfactants are preferred.

[0038] The surfactant may be used alone or in combination of two or more. The content of the surfactant is preferably 0.05 to 2.5% by mass, more preferably 0.1 to 1.5% by mass, and even more preferably 0.3 to 1.0% by mass, based on the total amount of the ink composition. When the content of the surfactant is within the above range, redispersibility and ejection stability tend to be improved.

[0039] water The ink composition of the present embodiment contains water. Examples of water include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, as well as ultrapure water from which ionic impurities have been removed as much as possible. Furthermore, by using water sterilized by ultraviolet irradiation or the addition of hydrogen peroxide, the generation of mold and bacteria can be prevented when the flocculating liquid is stored for a long period of time. This tends to further improve storage stability.

[0040] The water content is preferably 10 to 95% by mass, more preferably 40 to 90% by mass, and even more preferably 60 to 85% by mass, based on the total amount of the ink composition. When the water content is within the above range, redispersibility and ejection stability tend to be improved.

[0041] The ink composition may also contain various additives as appropriate, in addition to the components described above, such as a dispersant for the colorant (e.g., decamoglyceryl caprylate), resin particles, a dissolution aid, a viscosity adjuster, a pH adjuster such as potassium hydroxide or triethanolamine, an antioxidant, an anti-mold / preservative, an anti-fungal agent, a corrosion inhibitor, and a chelating agent for capturing metal ions that affect dispersion (e.g., sodium ethylenediaminetetraacetate).

[0042] Recording method The recording method of the present embodiment includes a step of adhering the ink composition onto a recording medium (hereinafter referred to as an "adhering step"). More specifically, in the adhering step, the ink composition is discharged onto the recording medium by an inkjet method to obtain a recorded matter. Examples of the recording medium include absorbent recording media and non-absorbent recording media. The recording method of the present embodiment can be widely applied to recording media having various absorption properties, from non-absorbent recording media into which the water-soluble ink composition has difficulty penetrating, to absorbent recording media into which the water-soluble ink composition can easily penetrate, but is preferably applied to absorbent recording media.

[0043] Specific examples of absorbent recording media include plain paper such as electrophotographic paper, which has high ink permeability, and inkjet paper (paper specifically for inkjet printing that has an ink absorbing layer made of silica particles or alumina particles, or an ink absorbing layer made of a hydrophilic polymer such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP)), as well as art paper, coated paper, and cast paper used in general offset printing, which have relatively low ink permeability.

[0044] Specific examples of non-absorbent recording media include films and plates of plastics such as polyvinyl chloride, polyethylene, polypropylene, and polyethylene terephthalate (PET), plates of metals such as iron, silver, copper, and aluminum, as well as metal plates and plastic films produced by vapor deposition of these various metals, and alloy plates such as stainless steel and brass.

[0045] In this embodiment, in order to promote drying of the ink composition, a heating step may be included in which the recording medium is heated before, during, or partly or entirely after recording. The heating means is not particularly limited as long as it is a device capable of controlling temperature, and examples thereof include a method using a radiant heating type sheath heater or infrared heater, a contact heating type sheet heater, electromagnetic waves, or the like. The heating temperature is preferably 40 to 80° C. as the surface temperature of the recording medium. Furthermore, a blowing step using a fan or the like may be further included.

[0046] The recording method of the present embodiment may include known steps included in conventional inkjet recording methods in addition to the above steps. EXAMPLES

[0047] Hereinafter, the present embodiment will be described in more detail with reference to examples and comparative examples. However, the present embodiment is not limited in any way to the following examples and comparative examples as long as the gist of the present embodiment is not exceeded.

[0048] The materials used as colorants in the following Examples and Comparative Examples are as follows. [Carbonized coloring material] Binchotan charcoal (Kiriya Chemical Co., Ltd., fine powdered binchotan charcoal powder (Kishu)) Bamboo charcoal (Kiriya Chemical Co., Ltd., bamboo charcoal powder (domestic)) [Pigments] Carbon black (referred to as "CB" in the table) [Lignin resin] Sanex P252 (sodium lignosulfonate, product name of Nippon Paper Industries Co., Ltd.) Sanex P321 (magnesium lignosulfonate, product name of Nippon Paper Industries Co., Ltd.) Vanilex N (high-purity partially desulfonated sodium lignosulfonate, a trade name manufactured by Nippon Paper Industries Co., Ltd.) [Dispersant] Decamonoglyceryl caprylate (product name "SY Glystar MCA-750" manufactured by Sakamoto Pharmaceutical Co., Ltd.) 〔water〕 pure water

[0049] [Preparation of color materials] The carbonized colorant or pigment was mixed into a solution in which lignin resin or dispersant was dissolved in water, and each material was dispersed for 2 hours using a pin-type horizontal bead mill with 0.3 mm zirconia beads to obtain each colorant, with the composition shown in Table 1 below. Note that the numerical values ​​in Table 1 below indicate the solid content, and the unit is mass%, with the total being 100.0 mass%.

[0050] [Table 1]

[0051] The materials used in the ink compositions in the following examples and comparative examples are as follows. [Coloring materials] Colorants 1 to 10 in Table 1 [Water-soluble organic solvent] Propylene Glycol 1,3-Butylene glycol Glycerin [Surfactant] Olfin E1010 (product name of Nissin Chemical Industry Co., Ltd.) Surfynol 104 (trade name of Evonik Industries) 〔water〕 pure water

[0052] [Preparation of Ink Composition] Each material was mixed in the composition shown in Table 2 below and thoroughly stirred to obtain each ink composition. In Table 2 below, the numerical values ​​indicate the solid content, the unit is mass %, and the total is 100.0 mass %.

[0053] [Redispersibility] 0.5 g of each ink composition was dropped into a beaker and dried for 2 days in an environment of a temperature of 40° C. and a humidity of 20%. After drying, 30 g of pure water was added to the beaker, and the ink composition was allowed to stand for 30 seconds, after which the state of dissolution was observed and the redispersibility was evaluated according to the following evaluation criteria. (Evaluation Criteria) A: Completely dissolved B: More than half has dissolved, but some remains undissolved C: More than half remains dissolved D: Not dissolved at all

[0054] [Viscosity change] Each ink composition was placed in a screw tube, and left with the lid on for 5 days in an environment at a temperature of 60° C. The viscosity was measured before and after leaving it, and compared with the viscosity before leaving it (initial viscosity), and the change in viscosity was evaluated according to the following evaluation criteria. (Evaluation Criteria) A: Viscosity change rate less than 5% B: Viscosity change rate: 5% to less than 10% C: Viscosity change rate: 10% to less than 20% D: Viscosity change rate 20% or more

[0055] [Discharge stability] Using an inkjet recording device ("PX-S840" manufactured by Seiko Epson Corporation), the ink cartridge of the inkjet recording device was filled with each ink composition, and 50 sheets of A4 size plain paper were printed continuously with 100% duty solid printing. After printing, the ejection stability was evaluated based on the number of nozzles that ejected the ink composition and the following evaluation criteria. (Evaluation Criteria) A: Less than 10 missing nozzles B: 10 or more but less than 20 missing nozzles C: 20 or more but less than 50 missing nozzles D: 50 or more nozzles missing

[0056] [Table 2]

Claims

1. Water, Plant-derived carbonized coloring material, Lignin resin, and an alkyl polyol, The content of the alkyl polyol is 1.0 to 30% by mass based on the total amount of the ink-jet ink composition.

2. 2. The ink-jet ink composition according to claim 1, wherein a mass ratio of the carbonized color material to the lignin resin (carbonized color material:lignin resin) is from 1.0:0.5 to 1.0:2.

0.

3. 3. The ink-jet ink composition according to claim 1, wherein the content of the carbonized colorant is 3.0 to 10% by mass based on the total amount of the ink-jet ink composition.

4. The ink-jet ink composition according to any one of claims 1 to 3, wherein the lignin resin comprises a lignin sulfonate.

5. The inkjet ink composition according to claim 1, further comprising an acetylene glycol surfactant.

6. The inkjet ink composition described in any one of claims 1 to 5, wherein the content of the alkyl polyol is 5.0 to 30 mass % relative to the total amount of the inkjet ink composition.

7. A method for producing a recording medium comprising the steps of: depositing the ink-jet ink composition according to any one of claims 1 to 6 on a recording medium; Recording method.

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