JP2023137373A - Aqueous inkjet ink composition, recording method, and recorded matter - Google Patents

Abstract

To provide an inkjet ink composition which enables acquisition of a recorded matter excellent in image quality and blocking resistance.SOLUTION: An aqueous inkjet ink composition is provided, containing coloring material, fixing resin, and an organic solvent, wherein the organic solvent includes a compound represented by formula (1), and in a coating film obtained by adhering the aqueous inkjet ink composition to a recording medium, a hydrogen bond component of surface free energy by Owens-Wendt method is 10.0 or less. In the formula (1), R1 is each independently an alkylene group having 2 or more and 7 or less carbon atoms, R2 is an alkyl group having 1 or more and 2 or less carbon atoms, and n is 1 or more and 2 or less.SELECTED DRAWING: None

Description

The present invention relates to a water-based inkjet ink composition, a recording method, and a recorded matter.

Inkjet recording methods are capable of recording high-definition images with relatively simple equipment, and are rapidly developing in various fields. Among these, various studies have been made regarding blocking resistance, image quality, and the like. For example, Patent Document 1 discloses that an organic solvent is contained in an amount of 1.0% by mass or more and 13.0% by mass or less based on the total amount of ink, and the organic solvent has a standard boiling point of 150.0°C or more and 280°C or more. A water-based ink composition containing an organic solvent having a temperature of .0°C or lower and containing an organic solvent with a standard boiling point exceeding 280.0°C of 3.0% by mass or less based on the total amount of ink is circulated within the recording head. An inkjet recording method has been disclosed in which ink is ejected from a recording head equipped with a circulation flow path to cause ink to be deposited on a low-absorbency recording medium or a non-absorbency recording medium.

Japanese Patent Application Publication No. 2020-121523

Conventionally, when recording on a low-absorbency recording medium such as a film, the recording medium is sometimes wound up into a roll and stored after ink has adhered thereto. In such a case, it is necessary to quickly dry the ink adhering to the recording medium to prevent ink bleeding and blocking. By the way, when a compound with a relatively high standard boiling point is used as an organic solvent for ink, as in Patent Document 1, it is difficult to dry the ink quickly, so it is difficult to improve the image quality and blocking resistance of the resulting recorded material. There's room.

The aqueous inkjet ink composition of the present invention contains a coloring material, a fixing resin, and an organic solvent, the organic solvent containing a compound represented by the following formula (1), and the aqueous inkjet ink composition of the present invention In the coating film obtained by adhering to the recording medium, the hydrogen bond component of the surface free energy according to the Owens-Wendt method is 10.0 or less. Further, in formula (1), R ¹ is each independently an alkylene group having 2 to 7 carbon atoms, R ² is an alkyl group having 1 to 2 carbon atoms, and n is 1 to 2. .

The recording method of the present invention is an inkjet recording method using an inkjet recording device having an inkjet head, and includes a deposition step of ejecting an aqueous inkjet ink composition from the inkjet head and depositing it on a recording medium, and a step of depositing the ink composition. a drying step of drying the attached recording medium to obtain a coating film, the ink composition contains a coloring material, a fixing resin, and an organic solvent, and the organic solvent has the following formula (1). ), and in the coating film, the hydrogen bond component of the surface free energy according to the Owens-Wendt method is 10.0 or less. Further, in formula (1), R ¹ is each independently an alkylene group having 2 to 7 carbon atoms, R ² is an alkyl group having 1 to 2 carbon atoms, and n is 1 to 2. .

1 is a diagram showing an example of a recording device used in the recording method of this embodiment.

Hereinafter, embodiments of the present invention (hereinafter referred to as "this embodiment") will be described in detail with reference to the drawings as necessary, but the present invention is not limited thereto, and the gist thereof Various modifications are possible without departing from the above. In addition, in the drawings, the same elements are given the same reference numerals, and overlapping explanations will be omitted. In addition, the positional relationships such as top, bottom, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios.

1. Water-based inkjet ink composition The water-based inkjet ink composition (hereinafter also simply referred to as "ink composition") according to the present embodiment contains a coloring material, a fixing resin, and an organic solvent, and the organic solvent is , a compound represented by the following formula (1), and in a coating film obtained by adhering the above ink composition to a recording medium, the hydrogen bond component (hereinafter simply "hydrogen bond") of the surface free energy according to the Owens-Wendt method is It is a water-based ink in which the component (also referred to as "component") is 10.0 or less. Further, in formula (1), R ¹ is each independently an alkylene group having 2 to 7 carbon atoms, R ² is an alkyl group having 1 to 2 carbon atoms, and n is 1 to 2. .

When recording on a low-absorbency or non-absorbency recording medium, it is necessary to improve the image quality by drying the ink droplets recorded on the recording medium quickly and preventing ink bleeding (bleed unevenness). Furthermore, recorded matter recorded on low-absorbency or non-absorbency recording media such as film is often wound up into a roll and stored downstream of the recording device, so the recording surface inside the roll is There is a concern that the non-recording surface overlapping the recording surface may come into contact with the non-recording surface and a blocking (sticking) phenomenon may occur.

Further investigation shows that even when ink compositions with the same composition are used, records can be obtained by using a highly polar recording medium such as PET or nylon, which has many polar groups, and a low polar recording medium, such as OPP, which has few polar groups. It has become clear that the degree of blocking objects also differs. Although the reason for this is not particularly limited, it is thought that the components in the ink coating are affected depending on the polarity state of the surface of the recording medium. More specifically, depending on the polarity state of the surface of the recording medium, low polar components or high polar components tend to concentrate on the interface side of the ink coating film with the recording medium, while on the other hand, the surface of the ink coating film That is, at the gas-solid interface, components of opposite polarity to the interface with the recording medium tend to concentrate. It is thought that the degree of blocking is thought to be affected by the contact between the surface of the ink coating formed in such a polar state and the surface of a low-polarity recording medium or a high-polarity recording medium.

For example, in the case of a low-polarity recording medium, the value of the hydrogen bond component of the surface free energy of the ink coating tends to be high, and since the recording medium overlaid on the recording surface is also a low-polarity recording medium, blocking Occurrence may be relatively rare. On the other hand, in the case of highly polar recording media, the value of the hydrogen bond component of the surface free energy of the ink coating tends to be low, and since the media overlaid on the recording surface is a highly polar recording medium, the occurrence of blocking is relatively low. There may be many targets.

On the other hand, it is not appropriate to change the type of ink depending on the polarity of the recording medium, and it is desirable to achieve desired blocking resistance with a specific ink regardless of the type of recording medium.

Therefore, as a result of extensive studies, the present inventors found that the ink composition contains a compound represented by the above formula (1) as an organic solvent, and furthermore, a coating film obtained by adhering the above ink composition to a recording medium. It has been found that by setting the hydrogen bond component of the surface free energy to 10.0 or less, recorded matter can have excellent image quality and blocking properties. The reason for this is, although not particularly limited, because the ink composition contains a coloring material, a fixing resin, and an organic solvent, and the compound represented by formula (1) acts synergistically as the organic solvent. As a result, the hydrogen bond component in the resulting coating film is lowered, which improves the image quality of the recorded material by allowing the ink to dry earlier, and weakens the strength of the adhesion to the non-recording surface that comes into contact with the coating film. It is assumed that.

Hereinafter, in the ink composition according to the present embodiment, components that may be included, physical properties, and manufacturing method, as well as a recording method using the ink composition and recorded matter thereof will be described.

1.1. Coloring material The coloring material contained in the ink composition includes pigments and dyes. From the viewpoint of improving the image quality and blocking resistance of the resulting recorded matter, it is preferable to use a pigment as the coloring material. Moreover, one type of coloring material may be used alone, or two or more types may be used in combination.

The pigment is not particularly limited, and may be either an organic pigment or an inorganic pigment. One type of pigment may be used alone, or two or more types may be used in combination.

Examples of organic pigments include azo pigments such as azo lake pigments, insoluble monoazo pigments, insoluble disazo pigments, condensed azo pigments, and chelate azo pigments; for example, phthalocyanine pigments, quinacridone pigments, perylene pigments, perinone pigments, anthraquinone pigments, dioxazine pigments, and thioindigo pigments. Pigments, polycyclic pigments such as isoindolinone pigments and quinophthalone pigments, dye chelates such as basic dye-type chelates and acidic dye-type chelates, and nitro pigments such as nitroso pigments.

Examples of inorganic pigments include titanium oxide, iron oxide yellow, iron oxide brown, chromium oxide, navy blue, ultramarine blue, molybdenum red, iron oxide black, yellow lead, composite oxide pigments, and carbon black.

Among the above pigments, in consideration of image quality, light resistance, etc., preferable examples include phthalocyanine pigments, quinacridone pigments, insoluble monoazo pigments, and carbon black.

Specific examples of organic pigments include Pigment Yellow 1 (Color Index (hereinafter referred to as C.I.) 11680), Pigment Yellow 3 (C.I. 11710), and Pigment Yellow 14 (C.I. Pigment Yellow 17 (C.I. 21105), Pigment Yellow 42 (C.I. 77492), Pigment Yellow 74 (C.I. 11741), Pigment Yellow 83 (C.I. 21108) , Pigment Yellow 93 (C.I.20710), Pigment Yellow 98 (C.I.11727), Pigment Yellow 109 (C.I.56284), Pigment Yellow 110 (C.I.56280), Pigment・Yellow 128 (C.I.20037), Pigment Yellow 138 (C.I.56300), Pigment Yellow 139 (C.I.56298), Pigment Yellow 147 (C.I.60645), Pigment Yellow 154 (C.I.11781), Pigment Yellow 155 (C.I.-), Pigment Yellow 180 (C.I.21290), Pigment Yellow 185 (C.I.56290), Pigment Orange 5 ( C.I.12075), Pigment Orange 13 (C.I.21110), Pigment Orange 16 (C.I.21160), Pigment Orange 34 (C.I.21160), Pigment Orange 43 (C.I. Pigment Orange 61 (C.I. 11265), Pigment Orange 71 (C.I. 56120), Pigment Red 5 (C.I. 12490), Pigment Red 8 (C.I. Pigment Red 17 (C.I. 12335), Pigment Red 17 (C.I. 12390), Pigment Red 22 (C.I. 12315), Pigment Red 48:2 (C.I. 15865: 2), Pigment Red 112 (C.I. Pigment Red 122 (C.I. 73915), Pigment Red 177 (C.I. 65300), Pigment Red 202 (C.I. 73907), Pigment Red 254 (C.I. 56110), Pigment Violet 19 (C.I. 46500), Pigment Violet 23 (C.I. 51319), Pigment Blue 15:1 (C.I. 74160), Pigment Blue 15:3 (C.I. Pigment Blue 15:4 (C.I.74160), Pigment Blue 15:4 (C.I. I. 74160), Pigment Blue 60 (C.I. 69800), Pigment Green 7 (C.I. 74260), Pigment Green 36 (C.I. 74265), and the like.

Specific examples of inorganic pigments include Pigment Yellow 42 (C.I.77492), Pigment White 6 (C.I.77891), Pigment Blue 27 (C.I.77510), and Pigment Blue 29. (C.I.77007), Pigment Black 7 (C.I.77266), and the like.

Among the specific examples of the pigments mentioned above, from the viewpoint of reliably achieving the effects of the present invention, the coloring materials are Pigment Yellow 74 (C.I. 11741), Pigment Red 122 (C.I. 73915), Pigment Blue 15:3 (C.I. 74160) and Pigment Black 7 (C.I. 77266).

The dye is not particularly limited, and includes acid dyes, direct dyes, reactive dyes, basic dyes, and the like. One type of dye may be used alone, or two or more types may be used in combination.

Specific examples of the dye are not particularly limited, and include, for example, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C. I. Acid Red 52, 80, 82, 249, 254, 289, C. I. Acid Blue 9, 45, 249, C. I. Acid Black 1, 2, 24, 94, C. I. Food black 1, 2, C. I. Direct Yellow 1, 12, 24, 33, 50, C. I. Direct Red 1, 4, 9, 80, 81, 225, 227, C. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, C. I. Direct black 19, 38, 51, 71, 154, C. I. Reactive Red 14, 32, 55, 79, 249, C. I. Examples include Reactive Black 3, 4, and 35.

The content of the coloring material is not particularly limited, but is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, based on the total amount of the ink composition. , more preferably 2% by mass or more and 12% by mass or less, even more preferably 3% by mass or more and 8% by mass or less. When the content of the coloring material is within the above range, the resulting recorded matter tends to have excellent image quality and/or blocking resistance.

The content of the pigment contained in the ink composition is not particularly limited, but is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, based on the total amount of the ink composition. It is not more than 2% by mass and not more than 12% by mass, even more preferably not less than 3% by mass and not more than 8% by mass. When the pigment content is within the above range, the resulting recorded matter tends to have excellent image quality and/or blocking resistance.

1.2. Fixing Resin The ink composition of this embodiment contains a fixing resin. By containing the fixing resin, the adhesion of the ink composition to the recording medium is improved, and the resulting recorded matter has excellent blocking resistance. Note that the fixing resin may be used alone or in combination of two or more.

The fixing resin is not particularly limited and includes, for example, acrylic resin, urethane resin, fluorene resin, polyolefin resin, rosin modified resin, terpene resin, polyester resin, polyamide resin, epoxy resin, and vinyl chloride. and ethylene-vinyl acetate-based resins. From the viewpoint of reliably improving the image quality and/or blocking resistance of the resulting recorded material, the fixing resin preferably contains at least one type of acrylic resin or urethane resin, and preferably contains at least an acrylic resin. More preferred.

The fixing resin of this embodiment preferably contains at least one of an acrylic resin and a urethane resin having a fluorene skeleton. When the fixing resin contains at least one of an acrylic resin and a urethane resin having a fluorene skeleton, the value of the hydrogen bond component of the surface free energy tends to be low. As a result, blocking resistance tends to be further improved.

The content of the fixing resin is not particularly limited, but is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, based on the total amount of the ink composition. , more preferably 2% by mass or more and 12% by mass or less, even more preferably 3% by mass or more and 8% by mass or less. When the content of the fixing resin is within the above range, the resulting recorded matter tends to have excellent image quality and/or blocking resistance.

1.3. Organic Solvent The ink composition of the present embodiment contains an organic solvent, and further contains a compound represented by the following formula (1) (hereinafter also referred to as "compound of formula (1)") as the organic solvent. Further, in formula (1), R ¹ is each independently an alkylene group having 2 to 7 carbon atoms, R ² is an alkyl group having 1 to 2 carbon atoms, and n is 1 to 2. . Note that the organic solvent and the compound of formula (1) may be used alone or in combination of two or more.

By including the compound of the above formula (1) as an organic solvent, the components can be properly oriented during the formation of a coating film, and as a result, the hydrogen bond component of the surface free energy of the resulting coating film is reduced. Therefore, the image quality and blocking resistance of the recorded matter are improved.

In formula (1), the number of carbon atoms in R ¹ is preferably 2 or more and 6 or less, more preferably 2 or more and 5 or less. When the carbon number of R ¹ is within the above range, the resulting coating film has a low hydrogen bond component, and the image quality and blocking resistance of the recorded material tend to improve.

The standard boiling point of the compound of formula (1) contained in the ink composition is preferably 200° C. or lower. Since the standard boiling point of the compound of formula (1) is 200° C. or less, the ink can be dried quickly, and the resulting recorded matter tends to have better image quality and/or blocking resistance. From the same viewpoint, the standard boiling point of the compound of formula (1) is more preferably 190°C or lower, and even more preferably 180°C or lower. Further, the standard boiling point of the compound of formula (1) is preferably 140°C or higher, more preferably 150°C or higher. Moreover, in this specification, the standard boiling point means the boiling point at an atmospheric pressure of 0.101 MPa.

Specific examples of the compound of formula (1) include 3-methoxy-3-methyl-1-butanol, 3-methoxy-1-butanol, 2-methoxy-1-ethanol, 2-ethoxy-1-ethanol, Examples include 2-methoxy-1-propanol, 3-ethoxy-1-propanol, 3-methoxy-2-butanol, 4-methoxy-2-pentanol, and 1-methoxy-2-hexanol.

From the viewpoint of further improving the image quality and blocking resistance of the resulting recorded material, the compound of formula (1) contains at least one of 3-methoxy-3-methyl-1-butanol and 3-methoxy-1-butanol. More preferably, it contains 3-methoxy-3-methyl-1-butanol.

The ink composition may contain an organic solvent other than the compound of formula (1) as an organic solvent. Specific examples of organic solvents other than the compound of formula (1) include 1,2-hexanediol, propylene glycol, glycerin, N-methylpyrrolidone, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, Examples include tripropylene glycol, propanediol, butanediol, pentanediol, hexylene glycol and the like. From the viewpoint of achieving the effects of the present invention more reliably, it is preferable that the organic solvent contains at least one of 1,2-hexanediol and propylene glycol.

Among these, it is preferable to include 1,2-alkanediol having 5 or more carbon atoms. By containing 1,2-alkanediol, the ink dries quickly and tends to further improve the image quality and/or blocking resistance of the resulting recorded matter. From the same viewpoint, it is more preferable to include a 1,2-alkanediol having 6 or more carbon atoms as the organic solvent other than the compound of formula (1).

The content of the organic solvent is preferably 5% by mass or more and 40% by mass or less based on the total amount of the ink composition. When the content of the organic solvent is within the above range, the resulting recorded matter tends to have better image quality and blocking resistance. From the same viewpoint, the content of the organic solvent is more preferably 8% by mass or more and 35% by mass or less, even more preferably 10% by mass or more and 30% by mass or less, and 15% by mass or more and 25% by mass or less. Even more preferably.

The content of the compound of formula (1) is preferably 2% by mass or more and 30% by mass or less based on the total amount of the ink composition. When the content of the compound of formula (1) is within the above range, the resulting recorded matter tends to have better image quality and blocking resistance. From the same viewpoint, the content of the compound of formula (1) is more preferably 2.5% by mass or more and 25% by mass or less, and 3% by mass or more and 20% by mass or less, based on the total amount of the ink composition. It is more preferably 4% by mass or more and 15% by mass or less, even more preferably 5% by mass or more and 10% by mass or less.

The content of the organic solvent other than the compound of formula (1) is not particularly limited, and may be, for example, 5% by mass or more and 30% by mass or less based on the total amount of the ink composition. From the viewpoint of achieving the effects of the present invention more reliably, the content of the organic solvent other than the compound of formula (1) is preferably 7% by mass or more and 25% by mass or less based on the total amount of the ink composition. , more preferably 10% by mass or more and 20% by mass or less.

Further, the content of the compound of formula (1) is 0.05% by mass or more and 0.50% by mass or less based on the total content of organic solvents. From the viewpoint of further improving the image quality and/or blocking resistance of the resulting recorded material, the ratio of the content of the compound of formula (1) to the content of the organic solvent is 0.10% by mass or more and 0.40% by mass. It is preferably at most 0.15% by mass and at most 0.35% by mass.

1.4. Water The ink composition of this embodiment is an aqueous ink composition containing water. A water-based ink composition is an ink composition that contains at least water as the main solvent component of the ink.

The content of water is preferably 40% by mass or more based on the total amount of ink. Further, the water content is preferably 98% by mass or less, more preferably 90% by mass or less, even more preferably 50% by mass or more and 85% by mass or less, even more preferably 60% by mass or more and 80% by mass. % or less. When the water content is above the above range, early evaporation of water becomes easy while dissolving components other than water, and the resulting recorded material tends to have excellent blocking resistance.

1.5. Surfactant Surfactants include, but are not particularly limited to, silicone surfactants, acetylene glycol surfactants, and fluorine surfactants. From the viewpoint of more reliably achieving the effects of the present invention, it is preferable to use a silicone surfactant as the surfactant. Moreover, one type of surfactant may be used alone or two or more types may be used in combination.

The silicone surfactant is not particularly limited, but polysiloxane compounds are preferred. The polysiloxane compound is not particularly limited, but includes, for example, polyether-modified organosiloxane. Commercially available polyether-modified organosiloxanes include, for example, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 (trade name: BYK-Chemie Japan Co., Ltd.). ), 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.). Among these, BYK-348 is preferably used from the viewpoint of reliably achieving the effects of the present invention.

Acetylene glycol surfactants include, but are not limited to, Surfynol 104, 420, 440, 465, 485, SE, SE-F, 504, 61, DF37, CT111, TG, GA, DF110D (all of the above). Product name (manufactured by Air Products & Chemicals), Olfin B, Y, P, A, STG, SPC, E1004, E1010, PD-001, PD-002W, PD-003, PD-004, EXP. 4001, EXP. 4036, EXP. 4051, AF-103, AF-104, AK-02, SK-14, AE-3 (all product names, manufactured by Nissin Chemical Industry Co., Ltd.), acetylenol E00, E00P, E40, E100 (all product names, Kawa (manufactured by Ken Fine Chemical Co., Ltd.).

As the fluorine-based surfactant, it is preferable to use a fluorine-modified polymer, and specific examples include BYK-3440 (manufactured by BYK-Chemie Japan), Surflon S-241, S-242, and S-243 (product names listed above). AGC Seimi Chemical Co., Ltd.), Ftergent 215M (Neos Co., Ltd.), and the like.

The content of the surfactant is preferably 0.1% by mass or more and 2.0% by mass or less, and preferably 0.2% by mass or more and 1.8% by mass or less, based on the total amount of the ink composition. More preferably, it is 0.5% by mass or more and 1.5% by mass or less.

1.6. pH Adjuster The pH adjuster is not particularly limited, and examples thereof include amines, ureas, morpholines, piperazines, and amino alcohols such as triethanolamine. Examples of ureas include urea, ethyleneurea, tetramethylurea, thiourea, 1,3-dimethyl-2-imidazolidinone, etc., and betaines (trimethylglycine, triethylglycine, tripropylglycine, triisopropylglycine, etc.) etc. Furthermore, examples of amines include diethanolamine, triethanolamine, triisopropanolamine, and the like. Among these, triisopropanolamine is preferably used from the viewpoint of reliably achieving the effects of the present invention.

The ink composition of this embodiment may contain components other than those described above. Examples of such components include wetting agents, chelating agents, oxide particles, and the like.
The presence of each component contained in the ink composition can be confirmed by various conventionally known methods. Specific examples include NMR measurement, mass spectrometry such as HPLC-MS, and IR measurement.

1.7. Hydrogen Bond Component of Surface Free Energy In the coating film obtained by applying the ink composition of this embodiment to a recording medium, the hydrogen bond component of surface free energy according to the Owens-Wendt method is 10.0 or less. The hydrogen bond component is a component related to surface polarity, and the higher the hydrogen bond component, the higher the polarity of the surface of the coating film. In this embodiment, it is preferable that the hydrogen bond component of the coating film is low. As the polarity of the coating film becomes lower, the image quality and blocking resistance of the resulting recorded matter tend to improve. From the same viewpoint, the hydrogen bond component of the resulting coating film is preferably 9.5 or less, more preferably 8.0 or less, even more preferably 6.0 or less, and 5.0 or less. It is even more preferable that it is, and it is especially preferable that it is 3.0 or less.

The surface free energy according to the Owens-Wendt method is calculated as the sum of a hydrogen bond component and a dispersion component. The method for measuring the hydrogen bond component is not particularly limited, but for example, after measuring the contact angle using a commercially available contact angle meter, the hydrogen bond component of the surface free energy in the Owens-Wendt theoretical equation is measured using analysis software etc. One example is to calculate. Examples of the contact angle meter include the DMs series, PCA series, and MCA series manufactured by Kyowa Kimen Kagaku Co., Ltd. In this embodiment, the contact angle meter is measured using PCA-11 (manufactured by Kyowa Interface Science Co., Ltd.) from the PCA series. It's okay.

In addition, in the ink composition of the present embodiment, the coating film when measuring the hydrogen bond component of the surface free energy by the Owens-Wendt method has an ink adhesion amount of 5 mg/inch ² on stretched polypropylene (OPP). A coating film obtained by applying ink and drying at 90° C. for 10 minutes may also be used.

The hydrogen bond component of the surface free energy tends to be highly dependent on the composition of the ink. For example, when the ink composition contains at least one of 3-methoxy-3-methyl-1-butanol and 3-methoxy-1-butanol as the compound of formula (1), the resulting coating film has a low hydrogen bond component. This tends to improve the image quality and blocking resistance of recorded matter. From the same viewpoint, it is more preferable that the compound of formula (1) contains at least 3-methoxy-3-methyl-1-butanol.

In addition, when the ink composition contains an acrylic resin or a urethane resin having a fluorene skeleton as a fixing resin, the hydrogen bond component of the resulting coating film tends to be low, thereby improving the image quality and durability of the recorded material. Blocking properties tend to improve.

1.8. Method for manufacturing a water-based inkjet ink composition The method for manufacturing the water-based inkjet ink composition of the present embodiment is not particularly limited, and includes a coloring material, a fixing resin, and an organic solvent, where the organic solvent has the formula (1 ), and in the coating film obtained by adhering the ink composition to a recording medium, the hydrogen bond component of the surface free energy according to the Owens-Wendt method is 10.0 or less. An example of this method is to adjust and mix the mixture so that the Furthermore, R ¹ , R ² , and n may be as defined above.

2. Inkjet Recording Method The recording method of the present invention is an inkjet recording method using an inkjet recording device having an inkjet head, and includes an adhesion step of discharging an aqueous inkjet ink composition from the inkjet head and adhering it to a recording medium; a drying step of drying the recording medium to which the composition is attached to obtain a coating film, the ink composition containing a coloring material, a fixing resin, and an organic solvent, the organic solvent comprising: The coating film contains a compound represented by formula (1) and has a hydrogen bond component of surface free energy of 10.0 or less according to the Owens-Wendt method. Furthermore, R ¹ , R ² , and n may be as defined above.

2.1. Adhering Step The adhering step is a step of ejecting the water-based inkjet ink composition from an inkjet head and making it adhere to a recording medium. More specifically, the pressure generating means is driven to discharge the colored ink composition filled in the pressure generating chamber of the inkjet head from the nozzle. Such a discharge method is also called an inkjet method.

Examples of the inkjet head used in the adhesion process include a line head that performs recording using a line method, and a serial head that performs recording using a serial method.
In the line method using a line head, for example, an inkjet head having a width greater than the recording width of a recording medium is fixed to an inkjet apparatus. Then, the recording medium is moved along the sub-scanning direction (the vertical direction of the recording medium, the transport direction), and in conjunction with this movement, ink droplets are ejected from the nozzles of the inkjet head to record an image on the recording medium. do.

In a serial method using a serial head, for example, an inkjet head is mounted on a carriage that is movable in the width direction of the recording medium. Then, the carriage is moved along the main scanning direction (horizontal direction, width direction of the recording medium), and in conjunction with this movement, ink droplets are ejected from the nozzle openings of the head, thereby recording an image on the recording medium. be able to.

2.2. Drying Process The drying process is a process of drying the ink composition on the recording medium by heating the recording medium. The heating unit for heating the recording medium is not particularly limited, but includes, for example, a platen heater, a warm air heater, an IR heater, etc., which have a heating function.

In the recording method of this embodiment, the number of drying steps is not particularly limited, but is preferably two or more times. By performing the drying process two or more times, the resulting coating film dries quickly, and the image quality and/or blocking resistance of the recorded material tends to be further improved. In addition, in this specification, when performing a drying process two or more times, it describes as a primary drying process, a secondary drying process, etc. in order.

The heating temperature in the drying step is not particularly limited, but is preferably 20°C or higher and 100°C or lower. When the heating temperature in the drying step is within the above range, it is possible to prevent the resulting recorded material from shrinking, and the image quality and/or blocking resistance tends to be further improved. From the same viewpoint, the heating temperature is preferably 25°C or more and 95°C or less.
Further, from the same viewpoint as above, the heating temperature in the primary drying step is preferably 25°C or more and 80°C or less, more preferably 30°C or more and 70°C or less, and even more preferably 40°C or more and 65°C or less. It is.
Furthermore, from the same viewpoint as above, the heating temperature in the secondary drying step is preferably 30°C or more and 100°C or less, more preferably 40°C or more and 95°C or less, and still more preferably 50°C or more and 90°C or less. It is.

The drying time in the drying step is not particularly limited, but can be, for example, 1 minute or more and 20 minutes or less. From the viewpoint of drying quickly and further improving the image quality and/or blocking resistance of the recorded matter, the drying time is preferably 15 minutes or less, more preferably 12 minutes or less.

2.3. Hydrogen Bond Component of Surface Free Energy In the coating film obtained by the recording method of this embodiment, the hydrogen bond component of the surface free energy according to the Owens-Wendt method is 10.0 or less, preferably 9.5 or less. , is more preferably 8.0 or less, even more preferably 6.0 or less, even more preferably 5.0 or less, and particularly preferably 3.0 or less.

The surface free energy according to the Owens-Wendt method is calculated as the sum of a hydrogen bond component and a dispersion component. The method for measuring the hydrogen bond component is not particularly limited, but for example, after measuring the contact angle using a commercially available contact angle meter, the hydrogen bond component of the surface free energy in the Owens-Wendt theoretical equation is measured using analysis software etc. One example is to calculate. Examples of the contact angle meter include the DMs series, PCA series, and MCA series manufactured by Kyowa Kimen Kagaku Co., Ltd. In this embodiment, the contact angle meter is measured using PCA-11 (manufactured by Kyowa Interface Science Co., Ltd.) from the PCA series. It's okay.

Note that the coating film obtained by the recording method of this embodiment can be formed with any type of recording medium, amount of ink applied, drying conditions, etc. That is, the coating film obtained by the recording method of the present embodiment is adjusted to the type of recording medium, the amount of ink deposited, the drying conditions, etc. so that the hydrogen bond component of the surface free energy according to the Owens-Wendt method is 10.0 or less. may be changed. In this respect, the coating film obtained by the recording method of this embodiment and the coating film obtained from the ink composition of this embodiment are different in meaning.

In the ink composition of this embodiment, the hydrogen bond component of the surface free energy has been described as having a tendency to largely depend on the composition of the ink. In addition to this, in the recording method of this embodiment, the hydrogen bond component of the surface free energy can be influenced by the recording conditions.

For example, when the heating temperature is raised in the drying process, the hydrogen bond component of the resulting coating film tends to be lowered, which tends to improve the image quality and/or blocking resistance of the recorded material. Additionally, when the number of drying steps is increased, the drying of the ink composition progresses, and the hydrogen bond component of the resulting coating film tends to decrease, which tends to improve the image quality and/or blocking resistance of the recorded material. It is in.

On the other hand, there is a concern that performing the high-temperature drying process many times may cause deformation of the recorded material, so it is preferable that the recording method of the present embodiment includes the drying process once or twice. , it is more preferable to have two drying steps.

In this embodiment, the recording medium used is preferably a non-absorbent recording medium for the reasons mentioned above. Non-absorbent recording media can be broadly classified into polar recording media and low polarity recording media. A polar recording medium is one in which the material constituting the surface of the recording medium has a relatively high polarity, such as PET, nylon, ABS, polycarbonate, and the like. The low polarity recording medium is one in which the material constituting the surface of the recording medium has relatively little or no polarity, and includes, for example, polyolefin such as OPP and PE.

It can be expected that the hydrogen bond components of the resulting coating film will change depending on the degree of polarity of the recording medium, but when using the ink composition of this embodiment, it is possible to record on both polar and low polarity recording media. It is effective even when used.

3. Recorded Matter The recorded matter of the present invention includes a recording medium and a coating film formed from the inkjet ink composition described above, which is attached to the recording medium, and the ink composition is attached to the recording medium. In the resulting coating film, the hydrogen bond component of the surface free energy determined by the Owens-Wendt method is 10.0 or less.

As the recording medium used for the recorded matter, it is preferable to use a non-absorbent recording medium. When a non-absorbent recording medium is used, the effects of the present invention are more reliably achieved.
Non-absorbent recording media are not particularly limited, and include, for example, plastic films and plates such as polypropylene, polyethylene terephthalate (PET), polyvinyl chloride, polyethylene, polycarbonate, polystyrene, and polyurethane; iron, silver, copper, and aluminum. metal plates such as; metal plates and plastic films manufactured by vapor deposition of these various metals; plates of alloys such as stainless steel and brass; paper base materials such as polyvinyl chloride, polyethylene, polypropylene, and polyethylene terephthalate. Examples include recording media that are coated with plastic films such as (PET), polycarbonate, polystyrene, and polyurethane. Among these, from the viewpoint of reliably achieving the effects of the present invention, at least one of polypropylene and polyethylene terephthalate (PET) is preferable, and at least one of stretched polypropylene (OPP) and polyethylene terephthalate (PET) is preferable. It is more preferable that there be.

3.1. Hydrogen Bond Component of Surface Free Energy In the coating film obtained by applying the ink composition of this embodiment to a recording medium, the hydrogen bond component of surface free energy according to the Owens-Wendt method is 10.0 or less. The hydrogen bond component is a component related to surface polarity, and the higher the hydrogen bond component, the higher the polarity of the surface of the coating film. In this embodiment, it is preferable that the hydrogen bond component of the coating film is low. As the polarity of the coating film becomes lower, the image quality and blocking resistance of the resulting recorded matter tend to improve. From the same viewpoint, the hydrogen bond component of the resulting coating film is preferably 9.5 or less, more preferably 8.0 or less, even more preferably 6.0 or less, and 5.0 or less. It is even more preferable that it is, and it is especially preferable that it is 3.0 or less.

The surface free energy according to the Owens-Wendt method is calculated as the sum of a hydrogen bond component and a dispersion component. The method for measuring the hydrogen bond component is not particularly limited, but for example, after measuring the contact angle using a commercially available contact angle meter, the hydrogen bond component of the surface free energy in the Owens-Wendt theoretical equation is measured using analysis software etc. One example is to calculate. Examples of the contact angle meter include the DMs series, PCA series, and MCA series manufactured by Kyowa Kimen Kagaku Co., Ltd. In this embodiment, the contact angle meter is measured using PCA-11 (manufactured by Kyowa Interface Science Co., Ltd.) from the PCA series. It's okay.

4. Recording Apparatus FIG. 1 shows an example of a recording apparatus used in the recording method of this embodiment. As shown in FIG. 1, the recording apparatus 1 includes a recording medium feeding section 10, a conveying section 20, a recording section 30, a drying section 90, and a discharging section 70.

The feeding section 10 feeds a roll-shaped recording medium F, which is an example of a recording medium, to the transport section 20 . Specifically, it has a roll medium holder 11, and the roll medium holder 11 holds a roll-shaped recording medium F. By rotating the roll-shaped recording medium F, the recording medium F is fed to the conveying section 20 on the downstream side in the feeding direction Y.

The conveying section 20 conveys the recording medium F sent from the feeding section 10 to the recording section 30. Specifically, it has a first feed roller 21 and conveys the fed recording medium F further to the recording section 30 on the downstream side in the feeding direction Y.

The recording section 30 performs recording by ejecting each ink composition onto the recording medium F sent from the conveying section 20 and making it adhere to the recording medium F. The recording unit 30 includes a plurality of inkjet heads, and is also capable of ejecting a plurality of types of ink. Although seven inkjet heads are provided in FIG. 1, one or more inkjet heads may be provided. The platen 35 is a means for supporting the recording medium F from the back side.

The inkjet head shown in FIG. 1 is a line inkjet head having a length equal to or longer than the recording width in the width direction X of the recording medium F. During recording, the inkjet head does not move, and recording is performed by performing one scan while transporting the recording medium F in the Y direction and ejecting the treatment liquid or ink composition from each attachment part to deposit it on the recording medium F. A one-pass recording method (line recording method) is performed.

Note that in the recording apparatus 1, an inkjet type inkjet head discharges an ink composition or a treatment liquid while moving in the front-back direction in FIG. 1, that is, in the width direction X of the recording medium F, and the inkjet heads face each other. It may also be a serial printer that performs scanning (main scanning) to deposit onto the recording medium F.

A second feed roller 43 is provided downstream of the platen 35 in the feed direction Y. The second feed roller 43 sends the recorded recording medium F to the second drying section 50 on the downstream side in the feeding direction Y.

The drying section 90 includes a first drying section 40 and a second drying section 50. The first drying section 40 is a platen heater that primarily dries the ink composition attached to the recording medium F. Examples of the first drying section 40 include an infrared heater and a heat conduction type heating means such as a nichrome wire. The first drying section 40 may also be a device that emits radiation or a device that blows warm air.

The second drying section 50 further dries the recording medium to which the ink has adhered by heating. The second drying section 50 includes, for example, an air blowing mechanism (not shown) that sends air to the recording medium F, a support section that is in contact with the recording medium F and along which the recording medium is conveyed, and heats the support section to remove the recording medium from the support section. A heat transfer mechanism that transfers heat to F, a radiation irradiation mechanism such as an infrared heater that heats the recording medium F by emitting infrared rays to the recording medium F, etc. can be used. A third feed roller 65 is provided near the outlet 64 of the second drying section 50. The third feed roller 65 is disposed so as to be in contact with the back surface of the recording medium F, and feeds the recording medium F to the discharge section 70 on the downstream side in the feeding direction Y.

The discharge section 70 further conveys the recording medium F sent from the second drying section 50 downstream in the feeding direction Y, and discharges it to the outside of the inkjet recording apparatus 1 . Specifically, the discharge section 70 includes a fourth feed roller 71 , a fifth feed roller 72 , a sixth feed roller 73 , a seventh feed roller 74 , and a take-up roller 75 . The fourth feed roller 71 and the fifth feed roller 72 are arranged so as to be in contact with the surface of the recording medium F. The sixth feed roller 73 and the seventh feed roller 74 are arranged to form a roller pair. The recording medium F discharged by the sixth feed roller 73 and the seventh feed roller 74 is wound up by a take-up roller 75.

The inkjet recording apparatus 1 further includes a control section (not shown). The control unit controls the recording medium feeding unit 10, conveyance unit 20, recording unit 30, drying unit 90, discharge unit 70, etc. when the inkjet recording apparatus 1 performs recording.

The upper limit of the surface temperature of the recording medium F in the area facing the inkjet head during recording is preferably 50° C. or lower, more preferably 45° C. or lower. Further, the temperature is preferably 25°C or higher, more preferably 30°C or higher, even more preferably 35°C or higher, and particularly preferably 40°C or higher. As a result, there is little or no radiant heat received from the drying section or drying device, so it is possible to suppress the drying and composition fluctuations of the ink composition in the inkjet head, and the ink can be fixed early by heating, resulting in improved image quality. can be improved.

The above temperature is the highest surface temperature of the portion of the recording medium F facing the inkjet head during recording. When primary drying is performed by the first drying section 40, the temperature is the same as the primary drying temperature. When primary drying is not performed, the temperature is the temperature around the portion of the recording medium facing the inkjet head.

The second drying section 50 is a heater for drying and solidifying the ink attached to the recording medium F, that is, for secondary heating or secondary drying. The second drying section 50 heats the recording medium F on which the image is recorded, so that water contained in the ink evaporates and scatters more quickly, and an ink film is formed by the resin contained in the ink. . In this way, the ink film is firmly fixed or adhered onto the recording medium F, resulting in excellent film-forming properties, and an excellent high-quality image can be obtained in a short time. The upper limit of the surface temperature of the recording medium F by the second drying section 50 is preferably 120°C or less, more preferably 100°C or less, and even more preferably 90°C or less. Further, the lower limit of the surface temperature of the recording medium F is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher. By keeping the temperature within the above range, high quality images can be obtained in a short time. The above temperature is the maximum temperature of the surface of the recording medium F during secondary drying.

Hereinafter, the present invention will be explained in more detail using Examples and Comparative Examples. The present invention is not limited in any way by the following examples.

1. Preparation of Ink Composition Inkjet ink compositions of each example were obtained by putting each component into a mixture tank so as to have the composition shown in Table 1, mixing and stirring, and then filtering with a membrane filter. In addition, the numerical value of each component shown in each example in a table|surface represents mass % unless otherwise stated. Moreover, in the table, the numerical values of the pigment and the pH adjuster represent the mass % of the solid content.

Details of the abbreviations and product components used in Table 1 are as follows.
[Pigment]
・Pigment Blue 15:3 (Pigment Blue 15:3)
・Pigment Red 122 (Pigment Red 122)
・Pigment Black 7
・Pigment Yellow 74
[Fixing resin]
・Silicon acrylic resin (Chaline LC190, manufactured by Nissin Chemical Industry Co., Ltd.)
・Acrylic resin A (JONCRYL1992, manufactured by BASF Japan Co., Ltd.)
・Acrylic resin B (Movinyl 972, manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.)
・Acrylic resin C (JONCRYL530, manufactured by BASF Japan Co., Ltd.)
・Urethane resin A (fluorene skeleton resin, direct synthesis)
・Urethane resin B (W-6061, manufactured by Mitsui Chemicals, Inc.)
・Urethane resin C (WLS-201, manufactured by DIC Corporation)
・Urethane resin D (AP201, manufactured by DIC Corporation)
[Organic solvent]
・3-methoxy-3-methyl-1-butanol ・1,2-hexanediol ・Propylene glycol [surfactant]
・Silicone surfactant (BYK (registered trademark)-348 (product name), manufactured by BYK Chemie Japan Co., Ltd.)
[pH adjuster]
・Triisopropanolamine [Recording medium type]
・OPP film (product name FOS-BT, both sides corona treated, manufactured by Futamura Chemical Co., Ltd.)
・PET film (product name FE2001, one side corona treated, manufactured by Futamura Chemical Co., Ltd.)

[Synthesis method of urethane resin A]
In a four-bottle flask equipped with a stirrer, a Dimroth condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 119.70 g of 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate was added as a polyisocyanate component. As active hydrogen components, 60.90 g of dimethylolpropionic acid, 60.04 g of bisphenoxyethanol fluorene (manufactured by Osaka Gas Chemical Co., Ltd.), 13.37 g of polytetramethylene glycol with a number average molecular weight of 2,000, and 300.00 g of methyl ethyl ketone as a solvent. were added, the temperature was raised to 80°C under a nitrogen atmosphere, and the mixture was stirred for 12 hours.
Next, after confirming the disappearance of the isocyanate absorption band by infrared absorption spectrum, the temperature was lowered to 40°C, and 45.99 g of triethylamine was added to neutralize it. Then, 700.00 g of water was added, and the mixture was heated using a homodisper. and dispersed. Thereafter, methyl ethyl ketone was distilled off at 50°C and under reduced pressure of 6.66 kPa, resulting in substantially no solvent, fluorene skeleton content of 20% by weight, acid value of 85 KOHmg/g, solid content concentration of 30% by weight, and viscosity of 200 mPa. - An aqueous dispersion (urethane resin A) of the aqueous polyurethane resin of s was obtained.

2. Printing and evaluation method 2.1. Printing PX-G930 (manufactured by Seiko Epson Corporation) was used as an inkjet recording device. The paper guide of this device was modified to include a heater that could change the temperature, and printing was performed using each ink composition. Specifically, the ink composition was deposited on a recording medium at a resolution of 1440×1440 dpi, 100% duty, and an amount of the ink composition deposited at 5.0 mg/inch ² to form a solid pattern. Further, after the ink composition was attached, the recording medium was heated and dried for 10 minutes at a predetermined oven temperature (see Table 1), and various evaluations were performed (primary heating).
In addition, in the evaluation of blocking resistance, when performing secondary heating, the above-mentioned heater was further used to heat and dry at a temperature of 90° C. or 60° C. for 10 minutes.

2.2. Hydrogen Bond Component in Surface Free Energy Each ink composition was applied to OPP and PET films through the above-described printing and drying process to create a printed coating film. Using a portable contact angle meter PCA-11 (manufactured by Kyowa Kaimen Kagaku Co., Ltd.), the contact angle of a liquid (pure water, diiodomethane) with a known surface free energy on each coating film was measured. The measured contact angle data was used to calculate the dispersion component and hydrogen bond component of the surface free energy in the Owens-Wendt theoretical equation using the analysis software of the portable contact angle meter PCA-11 (manufactured by Kyowa Kaimen Kagaku Co., Ltd.), and further, The surface free energy, which is the sum of these values, was obtained. Table 1 shows the hydrogen bond component of the surface free energy in each coating film.

2.3. Blocking resistance Prepare two sheets of recorded material recorded as described above, overlap the image area of one film with the non-printed side of the other film, and use a blocking tester (CO-201 Permanent Deformation Tester, Tester Sangyo Co., Ltd.). A load of 5 kgf/cm ² was applied to the sample (manufactured by the company), and the sample was left at 40° C. for 24 hours.
After standing, the blocking resistance was evaluated based on the degree of image transfer when the film was peeled off based on the following evaluation criteria.
<Evaluation criteria>
A: The image is not transferred to the non-printing surface. B: The image is not transferred to the non-printing surface, but there is some tackiness. C: Less than 30% of the image is transferred to the non-printing surface.
D: 30% or more of the image but less than 70% of the total area is transferred to the non-printing surface. E: 70% or more of the image is transferred to the non-printing surface.

2.4. Image Quality The solid pattern of the recorded material recorded as described above was visually observed, and the image quality (bleeding) was evaluated according to the following evaluation criteria.
<Evaluation criteria>
A: No bleed around the pattern B: Some bleed is visible around the pattern C: Significant bleed is visible around the pattern

3. Evaluation Results Table 1 shows the composition of the ink used in each example and the evaluation results. From Table 1, an aqueous inkjet ink composition containing a coloring material, a fixing resin, and an organic solvent, where the organic solvent contains a compound represented by formula (1), is used for recording. In the coating film obtained by adhering to the medium, the hydrogen bond component of the surface free energy according to the Owens-Wendt method is set to 10.0 or less, so that the recorded matter obtained with the ink composition has excellent blocking resistance and It can be seen that both image quality is excellent.

On the other hand, Comparative Example 1, which does not contain the compound represented by formula (1), and Comparative Examples 2 to 4, in which the hydrogen bond component of the surface free energy by the Owens-Wendt method exceeds 10.0, are It can be seen that the material has poor blocking resistance. Furthermore, it can be seen that in Comparative Example 1, which does not contain the compound represented by formula (1), the recorded matter obtained is inferior in image quality.

DESCRIPTION OF SYMBOLS 1... Inkjet recording device, 10... Feeding part, 11... Roll medium holder, 20... Conveyance part, 21... First feed roller, 30... Recording part, 35... Platen, 40... First drying part, 43... Second Feed roller, 50... Second drying section, 70... Discharge section, 71... Fourth feed roller, 72... Fifth feed roller, 73... Sixth feed roller, 74... Seventh feed roller, 75... Winding roller, 90 ...Drying section, F...Recording medium.

Claims (11)

A water-based inkjet ink composition containing a coloring material, a fixing resin, and an organic solvent,
The organic solvent contains a compound represented by the following formula (1),
(In formula (1), R ¹ is each independently an alkylene group having 2 to 7 carbon atoms, R ² is an alkyl group having 1 to 2 carbon atoms, and n is 1 to 2. )
In the coating film obtained by adhering the water-based inkjet ink composition to a recording medium, the hydrogen bond component of the surface free energy according to the Owens-Wendt method is 10.0 or less.
Water-based inkjet ink composition. The content of the compound represented by the formula (1) is 2% by mass or more and 30% by mass or less based on the total amount of the ink composition.
The aqueous inkjet ink composition according to claim 1. The compound represented by the formula (1) contains at least one of 3-methoxy-3-methyl-1-butanol and 3-methoxy-1-butanol,
The aqueous inkjet ink composition according to claim 1 or 2. The standard boiling point of the compound represented by formula (1) is 200°C or less,
The aqueous inkjet ink composition according to any one of claims 1 to 3. The fixing resin includes at least one of an acrylic resin and a urethane resin having a fluorene skeleton.
The aqueous inkjet ink composition according to any one of claims 1 to 4. The content of the organic solvent is 5% by mass or more and 40% by mass or less based on the total amount of the ink composition.
The aqueous inkjet ink composition according to any one of claims 1 to 5. the coloring material includes a pigment;
The aqueous inkjet ink composition according to any one of claims 1 to 6. the recording medium is a non-absorbent recording medium;
The aqueous inkjet ink composition according to any one of claims 1 to 7. The organic solvent contains a 1,2-alkanediol having 5 or more carbon atoms.
The aqueous inkjet ink composition according to any one of claims 1 to 8. An inkjet recording method using an inkjet recording device having an inkjet head, the method comprising:
an adhesion step of ejecting the water-based inkjet ink composition from the inkjet head and adhering it to the recording medium;
a drying step of drying the recording medium to which the ink composition is attached to obtain a coating film,
The ink composition contains a coloring material, a fixing resin, and an organic solvent,
The organic solvent includes a compound represented by the following formula (1),
(In formula (1), R ¹ is each independently an alkylene group having 2 or more and 7 or less carbon atoms, R ² is an alkyl group having 1 or more and 2 or less, and n is 1 or more and 2 or less.)
In the coating film, the hydrogen bond component of the surface free energy according to the Owens-Wendt method is 10.0 or less,
Inkjet recording method. a recording medium;
a coating film formed from the aqueous inkjet ink composition according to any one of claims 1 to 9 attached to the recording medium,
In the coating film, the hydrogen bond component of the surface free energy according to the Owens-Wendt method is 10.0 or less,
Recorded material.