JP2005248009A - Inkjet ink and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet ink which is not influenced by oxygen or moisture and capable of stably forming a cured film in various environments, and an inkjet recording method. <P>SOLUTION: The inkjet ink contains less than 1 mass% of a thiol compound having a molecular weight of less than 150 and contains a thiol compound bearing at least two thiol groups in the molecule. Otherwise, the inkjet ink contains less than 1 mass% of a thiol compound having a boiling point at 2,000 Pa of lower than 150°C and contains a thiol compound bearing at least two thiol groups in the molecule. The inkjet recording method comprises using these inkjet inks. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink-jet ink and an ink-jet recording method, and more specifically, an ink-jet ink (also simply referred to as ink) and an ink-jet recording method capable of obtaining good curability for various recording materials even in various environments. About.

  In recent years, the inkjet recording method can be easily and inexpensively produced images, and thus has been applied to various printing fields such as photographs, various printing, marking, and special printing such as color filters. In particular, a recording device that emits and controls fine dots, ink that has improved color reproduction gamut, durability, and emission suitability, and ink absorbability, coloring material color development, surface gloss, etc. have been dramatically improved. It is also possible to obtain image quality comparable to silver halide photography using special paper. The image quality improvement of today's ink jet recording system is achieved only when all of the recording apparatus, ink, and special paper are available.

  However, in an inkjet system that requires dedicated paper, the recording medium is limited, and the cost of the recording medium increases. Therefore, many attempts have been made to record on a transfer medium different from dedicated paper by an ink jet method. Specifically, a phase change ink jet method using a wax ink solid at room temperature, a solvent ink jet method using an ink mainly composed of a fast-drying organic solvent, a UV ink jet method in which crosslinking is performed by ultraviolet (UV) light after recording, etc. It is.

  Among these, the UV inkjet method has been attracting attention in recent years because it has a relatively low odor compared to the solvent-based inkjet method, and can be recorded on a recording medium having no quick drying and no ink absorption. It is disclosed (for example, see Patent Documents 1 and 2).

  However, even if these inks are used, the dot diameter after landing greatly changes depending on the type of recording material and the working environment, and it is not possible to form high-definition images on various recording materials. Is possible. In particular, in the curable ink using the radical polymerizable compound as described above, the film strength is often insufficient due to reaction inhibition by oxygen.

On the other hand, ultraviolet curable ink-jet inks using cationically polymerizable compounds (see, for example, Patent Documents 3 to 5) are not affected by oxygen inhibition but are easily affected by moisture (humidity) at the molecular level. There's a problem.
JP-A-6-200204 Special Table 2000-504778 JP 2001-220526 A (Claims, Examples) JP 2002-188025 A (Claims, Examples) JP 2002-317139 A (Claims, Examples)

  The present invention has been made in view of the above problems, and an object thereof is to provide an inkjet ink and an inkjet recording method capable of forming a cured film stably under various environments without being affected by oxygen and moisture. There is to do.

  The above object of the present invention can be achieved by the following configuration.

(Claim 1)
An ink-jet ink comprising a thiol compound having a molecular weight of less than 150 and a thiol compound having two or more thiol groups in the molecule.

(Claim 2)
An ink-jet ink comprising a thiol compound having a boiling point of less than 150 ° C. at 2000 Pa of less than 1% by mass and having two or more thiol groups in the molecule.

(Claim 3)
The inkjet ink according to claim 1 or 2, wherein the content of the thiol compound having two or more thiol groups in the molecule is 30% by mass or more.

(Claim 4)
The inkjet ink according to claim 1 or 2, wherein the content of the compound having two or more thiol groups in the molecule is 50% by mass or more.

(Claim 5)
An ink jet recording method comprising the step of mixing the ink jet ink according to any one of claims 1 to 4 and a compound having two or more polymerizable unsaturated bonds in a molecule and curing the mixture.

(Claim 6)
The inkjet ink according to any one of claims 1 to 4 and an ink containing a compound having two or more polymerizable unsaturated bonds in a molecule are each ejected by an inkjet head and mixed on a recording medium. 6. An ink jet recording method according to claim 5, further comprising a step of curing.

(Claim 7)
6. The liquid volume ratio is adjusted so that the ratio of the total number of thiol groups and polymerizable unsaturated bonds is 1: 0.5 to 1: 2, and the mixture is mixed on the recording medium. 6. The inkjet recording method according to 6.

(Claim 8)
The liquid volume ratio is adjusted so that the ratio of the total number of thiol groups and polymerizable unsaturated bonds is 1: 0.8 to 1: 1.2, and mixing is performed on a recording medium. The inkjet recording method according to 5 or 6.

(Claim 9)
The ink jet recording method according to any one of claims 5 to 8, further comprising a step of irradiating and curing an energy ray after mixing a thiol compound and a compound having a polymerizable unsaturated bond.

  According to the present invention, it is possible to provide an ink jet ink and an ink jet recording method capable of forming a cured film stably under various environments without being affected by oxygen and moisture.

  The present invention will be described in more detail. The ink of the present invention contains a polythiol compound having two or more thiol groups in the molecule. The polythiol compound preferably has three or more thiol groups in the same molecule, and the content in the ink is preferably 30% by mass or more, more preferably 50% by mass or more. Furthermore, it is more preferable not to contain an organic solvent other than the thiol compound for the purpose of improving the curability of the film and preventing the volatile compound from remaining.

  The ink containing the thiol compound of the present invention has a thiol compound content of less than 150 molecular weight of less than 1% by mass, or a thiol compound having a boiling point of less than 150 ° C. at 2000 Pa is less than 1% by mass. Features. The inventors have found that if the thiol compound having a molecular weight of less than 150 or a boiling point of less than 150 ° C. at 2000 Pa is contained in the ink in an amount of 1% by mass or more, the ejection characteristics at the time of ink ejection are deteriorated, and also for the formed image. It has been found that adverse effects such as a decrease in film strength and a characteristic odor remain. Examples of thiol compounds having a molecular weight of less than 150 include 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,5-pentanedithiol, 2-mercaptoethyl ether, mercaptoacetic acid, 3-mercapto Examples include propionic acid. Examples of thiol compounds having a boiling point of less than 150 ° C. at 2000 Pa include 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 2- Examples include mercaptoethyl ether, mercaptoacetic acid, 3-mercaptopropionic acid. Among these, acid compounds having a thiol group such as mercaptoacetic acid and 3-mercaptopropionic acid are sometimes used as raw materials for the synthesis of polythiol compounds, and are removed by purification when using the corresponding polythiol compounds. It is important to keep it.

  Examples of the polythiol compound having two or more thiol groups in the molecule include 3,6-dioxa-1,8-octanedithiol, triglycol dimercaptan, α, ω-dimercaptopolyethylene oxide, trimethylolpropane. Tris (3-mercaptopropionate), trimethylolpropane tris (2-mercaptoacetate), pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptoacetate), 1,2,6-hexane Examples include triol trithioglycolate. Two or more of these compounds may be used in combination in order to adjust ink viscosity, film physical properties, etc., and a monofunctional thiol compound having a molecular weight of 150 or more and a boiling point of 150 ° C. or more at 2000 Pa is used in combination. Also good.

  The ink of the present invention contains various known dyes and / or pigments together with the above-mentioned polythiol compound, but preferably contains a pigment. When the ink containing a compound having a polymerizable unsaturated bond described later is used in combination, the colorant is either an ink containing the polythiol compound of the present invention or an ink containing a compound having a polymerizable unsaturated bond, or both. Can be included.

The pigments that can be preferably used in the present invention are listed below.
C. I Pigment Yellow-1, 3, 12, 13, 14, 17, 42, 74, 81, 83, 87, 95, 109, 128, 138
C. I Pigment Orange-16, 36, 38,
C. I Pigment Red-5, 22, 38, 48: 1, 48: 2, 48: 4, 49: 1, 53: 1, 57: 1, 63: 1, 122, 144, 146, 185, 101,
C. I Pigment Violet-19, 23,
C. I Pigment Blue-15: 1, 15: 3, 15: 4, 18, 60, 27, 29,
C. I Pigment Green-7, 36,
C. I Pigment White-6, 18, 21,
C. I Pigment Black-7.

  In the present invention, it is preferable to use white ink in order to improve the color concealment property on a transparent substrate such as a plastic film. In particular, in soft packaging printing and label printing, it is preferable to use white ink. However, since the discharge amount increases, the use amount is naturally limited from the viewpoint of discharge stability.

  For the dispersion of the pigment, for example, a ball mill, sand mill, attritor, roll mill, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, paint shaker, or the like can be used. Further, a dispersing agent can be added when dispersing the pigment. As the dispersant, a polymer dispersant is preferably used, and examples of the polymer dispersant include Avecia's Solsperse series and Ajinomoto Fine-Techno's PB series. Moreover, it is also possible to use synergists according to various pigments as a dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment. The dispersion medium is used using a solvent or a polymerizable compound, but the ink used in the present invention is preferably solvent-free because it reacts and cures immediately after ink landing. If the solvent remains in the cured image, the solvent resistance deteriorates and the VOC of the remaining solvent arises. Therefore, it is preferable in view of dispersibility that the dispersion medium is not a solvent but a polythiol compound or a compound having a polymerizable unsaturated bond, and among them, a monomer having the lowest viscosity is selected.

  The pigment is preferably dispersed so that the average particle diameter of the pigment particles is 0.08 to 0.5 μm, and the maximum particle diameter is 0.3 to 10 μm, preferably 0.3 to 3 μm. The selection of the dispersion medium, the dispersion conditions, and the filtration conditions are appropriately set. By controlling the particle size, clogging of the head nozzle can be suppressed, and ink storage stability, ink transparency, and curing sensitivity can be maintained.

  In the ink according to the present invention, the color material concentration is preferably 1% by mass or more and less than 10% by mass of the entire ink.

  Various additives other than those described above can be used in the ink of the present invention. For example, surfactants, leveling additives, matting agents, polyester resins for adjusting film properties, polyurethane resins, vinyl resins, acrylic resins, rubber resins, and waxes can be added.

  Moreover, when irradiating actinic rays such as ultraviolet rays as a curing means, it is desirable to add a polymerization initiator such as a photo radical generator to the ink. The polymerization initiator can be added to both the ink containing the polythiol compound and the ink containing the polyene compound, but is not added to the ink containing the polyene compound from the viewpoint of ink storage stability. It is preferable to add. Examples of photo radical generators include benzophenone, methyl orthobenzoylbenzoate, benzophenone derivatives such as 4-benzoyl-4'-methyldiphenyl sulfide, thioxanthone derivatives such as isopropylthioxanthone and diethylthioxanthone, benzyldimethyl ketal, α-hydroxyalkylphenone, Conventionally known photo radical generators such as arylalkyl ketone derivatives such as α-aminoalkylphenone, maleimides such as N-ethylmaleimide and N-butylmaleimide, acylphosphine oxides, titanocene compounds, benzyl and quinone derivatives, and ketocoumarins Can be used.

  The viscosity of the ink of the present invention is preferably 3 to 100 mPa · s at 25 ° C. Furthermore, it is also preferable from the viewpoint of stable emission and droplet formation to heat the ink and adjust the viscosity so that the ink viscosity at the time of ink emission is 3 to 20 mPa · s.

  Next, the recording method of the present invention will be described. In the ink jet recording method of the present invention, the ink described above is ejected by an ink jet recording method, a polythiol compound and a compound having a polymerizable unsaturated bond are mixed on a recording medium, and then energy rays such as actinic rays and radiation are emitted. A method of curing the ink by irradiation is preferable. As a method of mixing a polythiol compound and a compound having a polymerizable unsaturated bond, a liquid containing a compound having a polymerizable unsaturated bond is applied in advance to a recording medium, and an ink containing a polythiol compound is ejected by an inkjet head. And a method of mixing the ink containing a polythiol compound and a compound having a polymerizable unsaturated bond by an ink jet head and mixing them on a recording medium. The latter method is more preferable because it is easy to adjust the mixing ratio of the polythiol compound and the compound having a polymerizable unsaturated bond.

  An ink containing a compound having a polymerizable unsaturated bond used in combination with a polythiol compound will be described. This ink contains a compound having two or more polymerizable unsaturated bonds in the molecule, and the amount in the ink is preferably 30% by mass or more, more preferably 50% by mass or more. The polymerizable unsaturated bond refers to an unsaturated bond capable of reacting with an active species such as a radical, cation or anion to be polymerized. It is more preferable that the compound having a polymerizable unsaturated bond used in the present invention has three or more polymerizable unsaturated bonds in the same molecule. Further, for the purpose of improving the curability of the film and preventing the volatile compounds from remaining, it is preferable not to contain an organic solvent other than the compound having a polymerizable unsaturated bond.

  Examples of the compound having a bifunctional polymerizable unsaturated bond include triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, and 1,4-butanediol diacrylate. 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, dimethylol-tricyclodecane diacrylate, trimethylolpropane benzoate diacrylate, EO adduct diacrylate of bisphenol A, bisphenol PO adduct diacrylate of A, neopentyl glycol diacrylate of hydroxypivalate, polytetramethylene glycol Acrylates such as diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, methacrylates such as 1,3-butylene glycol dimethacrylate, triethylene glycol divinyl ether, trimethylolpropane divinyl ether, etc. Vinyl ethers, allyl ethers such as trimethylolpropane diallyl ether, diallyl carbonate, diallyl phthalate, diallyl pyrocarbonate, diallyl succinate, (+)-N, N'-diallylterterdiamide, diallyl such as 1,3-diallyl urea Compounds and the like.

  Examples of compounds having a trifunctional or higher polymerizable unsaturated bond include trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol propoxylate triacrylate, dipentaerythritol penta Acrylates such as acrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, glycerin propoxytriacrylate, caprolactone-modified trimethylolpropane triacrylate, pentaerythritol ethoxytetraacrylate, caprolactam-modified dipentaerythritol hexaacrylate, trimethylolpropane trimethacrylate Etc. Tacrylates, vinyl ethers such as trimethylolpropane trivinyl ether, allyl ethers such as pentaerythritol triallyl ether, triallylamine, 1,3,5-benzenetricarboxylate, triallyl trimellitate, triallyl cyanurate, triallyl Examples include polyallyl compounds such as allyl isocyanurate.

  Further, in order to adjust the viscosity and film physical properties of the ink, two or more of these compounds may be used in combination, or a compound having a monofunctional polymerizable unsaturated bond may be used in combination. Monofunctional compounds include isoamyl acrylate, stearyl acrylate, lauryl acrylate, octyl acrylate, decyl acrylate, isomyristyl acrylate, isostearyl acrylate, 2-ethylhexyl-diglycol acrylate, 2-hydroxybutyl acrylate, 2-acryloyloxy Ethyl hexahydrophthalic acid, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2- Hydroxypropyl Chryrate, 2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid, lactone modified flexibility Conventionally known monomers such as acrylate and t-butylcyclohexyl acrylate can be used.

  When both the ink containing a polythiol compound and the ink containing a compound having a polymerizable unsaturated bond are ejected by an inkjet head and mixed on a recording medium, the difference in landing timing of both inks is preferably as small as possible. It is less than 1.0 second, further less than 0.5 second, and more preferably less than 0.1 second.

  Regarding the mixing ratio of the polythiol compound and the compound having a polymerizable unsaturated bond, since the thiol group and the polymerizable unsaturated bond basically react at 1: 1, the total number of thiol groups and polymerizable unsaturated bonds is It is desirable to mix so as to be 1: 0.5 to 1: 2, preferably 1: 0.8 to 1: 1.2. When both compounds are converted into ink and mixed, the mixing ratio can be adjusted by the content of each compound in the ink and the amount of ink discharged from the head.

  Regarding the irradiation conditions of the energy rays, it is preferable that the energy rays are irradiated for 0.001 to 1.0 seconds after the ink is ejected and the ink is landed on the recording medium, and more preferably, the energy ray is irradiated. 001 seconds to 0.5 seconds. In order to form a high-definition image, it is particularly important that the irradiation timing is as early as possible.

  The light source may be any energy ray capable of initiating polymerization of ink, such as a high pressure mercury lamp, a low pressure mercury lamp, a cold cathode tube, a black light, an ultraviolet LED, an ultraviolet laser, an electron beam, a gamma ray, or flash light.

(Preparation of ink)
A pigment dispersion was prepared with the following composition. In addition, dispersion conditions were appropriately adjusted using a known dispersion device so that the average particle diameter of each pigment particle was in the range of 0.2 to 0.3 μm. Moreover, filter filtration was performed after dispersion | distribution.

(Dispersion A)
Pigment Blue 15: 3 20 parts by mass Polymer dispersant (Solspers 24000: manufactured by Avecia) 5 parts by mass Phenoxyethyl acrylate 75 parts by mass (Dispersion B)
Pigment Blue 15: 3 20 parts by mass Polymer dispersant (Solspers 24000: manufactured by Avecia) 5 parts by mass Isobornyl acrylate 75 parts by mass (Dispersion C)
Pigment Blue 15: 3 20 parts by mass Polymer dispersant (Solspers 24000: manufactured by Avecia) 5 parts by mass OXT211 (Oxetane compound: manufactured by Toagosei Co., Ltd.) 75 parts by mass Each of the prepared dispersions is described below. After mixing according to the above formulation, the mixture was filtered through a 0.8 μm filter to prepare an ink. The molecular weights and boiling points of the thiol compounds used are summarized in Table 1.

(Ink A1)
Trimethylolpropane tris (3-mercaptopropionate) 95 parts by mass Initiator (Irgacure 907: Ciba Geigy) 5 parts by mass Trimethylolpropantotris (3-mercaptopropionate) is sufficiently purified and used as a raw material It was used after confirming that the content of 3-mercaptopropionic acid as a substance was less than 0.1% by mass.

(Ink A2)
Dispersion A 20 parts by mass Trimethylolpropane triacrylate 75 parts by mass Phenoxyethyl acrylate 5 parts by mass (Ink A1 ′)
Trimethylolpropane tris (3-mercaptopropionate) 93.8 parts by weight 3-mercaptopropionic acid 1.2 parts by weight Initiator (Irgacure 907: manufactured by Ciba Geigy) 5 parts by weight (ink B)
Dispersion B 20 parts by weight Isobornyl acrylate 25 parts by weight Trimethylolpropane triacrylate 40 parts by weight Tripropylene glycol diacrylate 10 parts by weight Initiator (Irgacure 907: Ciba Geigy) 5 parts by weight (ink C)
Dispersion C 20 parts by mass Oxetane compound (OXT211: manufactured by Toagosei Co., Ltd.) 60 parts by mass Alicyclic epoxy resin (UVR6105: manufactured by UCC) 15 parts by mass Initiator (UVI 6990: manufactured by UCC) 5 parts by mass

Example 1
Recording on a recording medium was performed by an ink jet recording apparatus using a piezo ink jet ink jet nozzle having a nozzle diameter of 23 μm and 128 nozzles. The ink supply system was composed of an ink tank, a supply pipe, and a front chamber ink tank immediately before the head, and heat insulation and heating were performed from the front chamber ink tank to the head portion. Temperature sensors were provided in the vicinity of the front chamber tank and the nozzle of the piezo head, respectively, and temperature control was performed so that the nozzle portion was always 60 ° C. ± 2 ° C. It was driven at a driving frequency of 10 kHz so that the resolution was 720 × 720 dpi (dpi represents 1 inch, that is, the number of dots per 2.54 cm). As a recording support, a polyethylene terephthalate film having a thickness of 50 μm was placed in a printer so that it could be plasma-treated immediately before printing, and recording was carried out while processing.

  0.05 seconds after the landing of the ink A2, the ink A1 was ejected at the same position as the landing position of the A2. Regarding the discharge amounts of the inks A1 and A2, the discharge amounts were adjusted so that the total number of thiol groups contained in the ink A1 and the total number of polymerizable unsaturated bonds contained in the ink A2 were 1: 0.4.

0.2 seconds after the landing of the ink A1, the ink was cured by light irradiation with a metal halide lamp under the conditions of an exposure surface illumination of 1000 mW / cm ² , an exposure time of 0.2 seconds, and an exposure energy of 200 mJ / cm ² .

  Regarding the influence of the environment at the time of image formation, a normal environment at a temperature of 25 ° C. and a humidity of 40%, an oxygen-excess environment when oxygen gas is blown in an image curing process, an environment with a high temperature of 25 ° C. and a humidity of 90%. Images were created and evaluated in three environments.

Example 2
Also in Example 2, an image was produced in the same manner except that the ratio was changed so that the ratio of the total number of thiol groups and polymerizable unsaturated bonds was 1: 0.9.

Comparative Example 1
Similar to Example 1 except that the combination of inks A1 and A2 in Example 1 was changed to a combination of inks A1 ′ and A2 and the ratio of the total number of thiol groups and polymerizable unsaturated bonds was 1: 1.1. An image was formed by the method.

Comparative Examples 2 and 3
An image was formed by the same method as in Example 1 except that the combination of Inks A1 and A2 in Example 1 was changed to Ink B alone for Comparative Example 2, and changed to Ink C alone for Comparative Example 2.

Evaluation (light emission)
A solid image of 10 cm × 10 cm produced in a standard environment was visually observed to evaluate the light emission.
○: A uniform solid image was obtained, and almost no banding derived from nozzle missing or bent was observed. ×: The solid image was uneven, and banding derived from nozzle missing or bent occurred.

(Odor)
Ten test subjects sniff the smell of a solid image of 5 cm × 5 cm produced in a standard environment, and sensory evaluation of the odor was performed.
○: The number of people who evaluated that “almost does not smell” was 7 or more out of 10 ×: The number of people who evaluated that “almost does not smell” was less than 7 out of 10 people.

(Membrane strength)
About the solid image of 3 cm x 3 cm produced in the standard environment, the oxygen excess environment, and the high-humidity environment, sclerosis | hardenability was evaluated by confirming the film | membrane visually and rubbing the image part 5 times with an eraser.
A: The image part formed a film, and no peeling of the image part was seen even after 5 reciprocations. ○: The image part formed a film, but a part of the image peeled slightly after 5 reciprocations. Δ: The image part formed a film, but a considerable part was peeled off after 5 reciprocations. X: The image part was a mixture of liquid and film, and the film was peeled off after 1 reciprocation.

  From Table 2, it can be seen that the sample of the present invention is not affected by oxygen and moisture, and forms a cured film stably even under various environments.

Claims (9)

An ink-jet ink comprising a thiol compound having a molecular weight of less than 150 and a thiol compound having two or more thiol groups in the molecule. An ink-jet ink comprising a thiol compound having a boiling point of less than 150 ° C. at 2000 Pa of less than 1% by mass and having two or more thiol groups in the molecule. The inkjet ink according to claim 1 or 2, wherein the content of the thiol compound having two or more thiol groups in the molecule is 30% by mass or more. The inkjet ink according to claim 1 or 2, wherein the content of the compound having two or more thiol groups in the molecule is 50% by mass or more. An ink jet recording method comprising the step of mixing the ink jet ink according to any one of claims 1 to 4 and a compound having two or more polymerizable unsaturated bonds in a molecule and curing the mixture. The inkjet ink according to any one of claims 1 to 4 and an ink containing a compound having two or more polymerizable unsaturated bonds in a molecule are each ejected by an inkjet head and mixed on a recording medium. 6. An ink jet recording method according to claim 5, further comprising a step of curing. 6. The liquid volume ratio is adjusted so that the ratio of the total number of thiol groups and polymerizable unsaturated bonds is 1: 0.5 to 1: 2, and the mixture is mixed on the recording medium. 6. The inkjet recording method according to 6. The liquid volume ratio is adjusted so that the ratio of the total number of thiol groups and polymerizable unsaturated bonds is 1: 0.8 to 1: 1.2, and mixing is performed on a recording medium. The inkjet recording method according to 5 or 6. The ink jet recording method according to any one of claims 5 to 8, further comprising a step of irradiating and curing an energy ray after mixing a thiol compound and a compound having a polymerizable unsaturated bond.