Non-aqueous ink composition, recording method using the same, and method for producing recorded matter

Abstract

The present invention provides a non-aqueous ink composition that can produce recorded materials exhibiting excellent gloss and anti-blocking properties. The non-aqueous ink composition contains an organic solvent and is ejected using an inkjet method. The organic solvent contains an amide solvent (a) and an organic solvent (b) represented by the following formula: R1-(-O-R2-) n -OH···(1) (In formula (1), R1 is an alkyl group having 6 or less carbon atoms, and R2 represents an ethylene group or a propylene group. n represents an integer of 2 or more and 6 or less.) R1-(-O-R2-) n ‑OH···(1)

Description

Technical Field

[0001] The present invention relates to a non-aqueous ink composition, a recording method using the non-aqueous ink composition, and a method for producing a recorded object. Background Art

[0002] As ink compositions, aqueous ink compositions in which a coloring material is dissolved or dispersed in water or a mixture of water and an organic solvent, and non-aqueous ink compositions in which a coloring material is dissolved or dispersed in an organic solvent not containing water are widely used.

[0003] For example, Patent Document 1 describes a technique for a non-aqueous ink composition containing a cyclic ester (lactone-based solvent) and an organic solvent having a predetermined flash point. Patent Document 1 states that by including a cyclic ester (lactone-based solvent) as a solvent in the non-aqueous ink composition, a portion of the recording surface can be dissolved, allowing the ink composition to penetrate into the interior of the recording medium, thereby improving the abrasion resistance of the image.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6256039 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] A lactone-based solvent is a solvent that easily permeates into a resin substrate. A non-aqueous ink composition containing a lactone-based solvent has high permeability into a resin substrate.

[0009] However, the present inventors have found that if the non-aqueous ink composition permeates into the resin substrate and the amount of permeation increases, the glossiness and anti-blocking properties of the recorded surface of the resulting recorded object decrease.

[0010] An object of the present invention is to provide a non-aqueous ink composition that can produce recorded materials exhibiting excellent glossiness and anti-blocking properties.

[0011] Means for solving problems

[0012] The present inventors have conducted intensive research to solve the above-mentioned problems and have found that a non-aqueous ink composition containing a predetermined organic solvent can solve the above-mentioned problems, thereby completing the present invention. Specifically, the present invention provides the following.

[0013] (1) A non-aqueous ink composition containing an organic solvent to be ejected by an inkjet method, wherein the organic solvent contains an amide solvent (a) and an organic solvent (b) represented by the following formula (1).

[0014] [Chemical Formula 1]

[0015] R1-(-O-R2-) n --OH···(1)

[0016] (In formula (1), R1 is an alkyl group having 6 or less carbon atoms, R2 represents an ethylene group or a propylene group, and n represents an integer of 1 or more and 6 or less.)

[0017] (2) The non-aqueous ink composition according to (1), wherein the mass ratio of the content of the above-mentioned amide solvent (a) to the above-mentioned organic solvent (b) (amide solvent (a): organic solvent (b)) is in the range of 95:5 to 3:97.

[0018] (3) The non-aqueous ink composition according to (1) or (2), wherein the amide solvent (a) is represented by the following formula (2).

[0019] [Chemical Formula 2]

[0020]

[0021] (In formula (2), R1 is hydrogen or an alkyl group having 1 to 4 carbon atoms, and R2 and R3 each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms.)

[0022] (4) The non-aqueous ink composition according to (3), wherein the amide solvent (a) contains at least one selected from N,N-diethylformamide, N,N-diethylpropionamide and N,N-diethylacetamide.

[0023] (5) The non-aqueous ink composition according to any one of (1) to (4), wherein the flash point of the organic solvent (b) is 170° C. or lower.

[0024] (6) The non-aqueous ink composition according to any one of (1) to (5), further comprising a resin, wherein the content of the resin having an intrinsic viscosity of 90 mL / g or higher at 25°C is 5% by mass or less of the total amount of the resin.

[0025] (7) The non-aqueous ink composition according to any one of (1) to (6), which is ejected by an inkjet method through an inkjet recording device equipped with a plastic tube.

[0026] (8) The non-aqueous ink composition according to any one of (1) to (7), which is applied to a resin substrate.

[0027] (9) A recording method comprising ejecting the non-aqueous ink composition according to any one of (1) to (8) onto a surface of a substrate using an inkjet method.

[0028] (10) A method for producing a recorded object, comprising ejecting the non-aqueous ink composition according to any one of (1) to (8) onto a surface of a substrate using an inkjet method.

[0029] (11) A recorded object comprising a recording layer of the non-aqueous ink composition according to any one of (1) to (8) formed on a surface of a substrate.

[0030] Effects of the Invention

[0031] The non-aqueous ink composition of the present invention can produce recorded materials exhibiting excellent glossiness and anti-blocking properties. DETAILED DESCRIPTION

[0032] Specific embodiments of the present invention are described in detail below. However, the present invention is not limited to the following embodiments and can be implemented with appropriate modifications within the scope of the present invention. In addition, in this specification, expressions such as "to" mean "above" or "below", and expressions such as "X:Y~A:B" include "X:Y" and "A:B" themselves and refer to the range between "X:Y" and "A:B".

[0033] <1. Non-aqueous ink composition>

[0034] The non-aqueous ink composition of this embodiment is characterized in that it contains an organic solvent and is ejected by an inkjet method, and contains an amide solvent (a) and an organic solvent (b) represented by the following formula as organic solvents.

[0035] [Chemical Formula 3]

[0036] R1-(-O-R2-) n -OH···(1)

[0037] (In formula (1), R1 is an alkyl group having 6 or less carbon atoms, R2 represents an ethylene group or a propylene group, and n represents an integer of 1 or more and 6 or less.)

[0038] Such a non-aqueous ink composition can provide a recorded object exhibiting excellent glossiness and anti-blocking properties.

[0039] Here, the term "non-aqueous ink composition" refers to an ink composition that does not contain water (an oil-based ink composition), as opposed to an aqueous ink composition in which a coloring material is dissolved or dispersed in water or a mixture of water and an organic solvent. It should be noted that, in this specification, the term "does not contain water" does not take into account atmospheric moisture or water that is inevitably present from additives, etc.

[0040] It should be noted that the non-aqueous ink composition of this embodiment can be a colored ink containing a colorant (including both colored and black and white colorants), an ink containing a glitter pigment (scaly metal particles) to impart a metallic feel to the recorded material (printed object), or a transparent ink containing no colorant. In the case of a transparent ink containing no colorant, inks for forming a layer having a desired function can be used. Examples of such inks include overcoat ink compositions for forming an overcoat layer to protect the recorded material (printed object), matte ink compositions for eliminating the gloss of the recorded material (printed object), and inks containing a UV absorber, a light stabilizer, etc., for forming a weather-resistant layer.

[0041] In this specification, the flash point of an organic solvent is defined as the flash point obtained using a Cleveland open cup flash point tester if the flash point obtained using a Tiger closed cup flash point tester is not 80°C or lower; the flash point is defined as the flash point obtained using a Tiger closed cup flash point tester if the flash point is 80°C or lower and the dynamic viscosity of the solvent at that flash point is less than 10 cSt; and the flash point is defined as the flash point obtained using a SETA closed cup flash point tester if the dynamic viscosity of the solvent at that flash point is 10 cSt or higher.

[0042] Hereinafter, each component contained in the non-aqueous ink composition of this embodiment will be described.

[0043] [Organic solvents]

[0044] The organic solvent contains an amide solvent (a) and an organic solvent (b) represented by the following formula.

[0045] [Chemical Formula 4]

[0046] R1-(-O-R2-) n -OH···(1)

[0047] (In formula (1), R1 is an alkyl group having 6 or less carbon atoms, R2 represents an ethylene group or a propylene group, and n represents an integer of 1 or more and 6 or less.)

[0048] (Amide solvent (a))

[0049] The amide-based solvent is a solvent containing a compound having a -C(=O)-N- group (amide bond).

[0050] Amide solvents (a) are solvents that, like lactone solvents, penetrate the substrate to a certain extent. Furthermore, amide solvents (a) dry more easily than lactone solvents, resulting in lower substrate permeability compared to non-aqueous ink compositions containing lactone solvents. This reduces the amount of solvent remaining in the substrate after surface drying, improving anti-blocking properties.

[0051] Furthermore, since the non-aqueous ink composition containing the amide solvent (a) dries before bleeding after it hits the substrate (recording medium), bleeding of the printed text is reduced, resulting in clearer printed text. Furthermore, since the non-aqueous ink composition containing the amide solvent (a) has good wetting and spreading properties on the substrate surface, as described later, the non-aqueous ink composition quickly wets and spreads on the substrate surface after hitting the substrate (recording medium), thereby improving the glossiness of the recorded surface of the resulting recorded object.

[0052] As the amide solvent (a), for example, an organic solvent containing no alkoxy group and consisting only of hydrogen or an alkyl group and a -C(=O)-N- group is preferred. For example, an alkylamide solvent having the following structure can be preferably used.

[0053] [Chemical Formula 5]

[0054]

[0055] (In formula (2), R1 is hydrogen or an alkyl group having 1 to 4 carbon atoms, and R2 and R3 each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms.)

[0056] It should be noted that R2 and R3 in formula (2) are preferably alkyl groups having 1 to 4 carbon atoms, and more preferably alkyl groups having 2 to 4 carbon atoms.

[0057] Specific examples of such alkylamide solvents include N,N-diethylformamide, N,N-diethylacetamide, N,N-dipropylformamide, N,N-dibutylformamide, N,N-diethylpropionamide, N,N-dipropylpropionamide, N-ethylformamide, and N-ethylacetamide. Among these, from the viewpoint of particularly exhibiting the effects of the present invention, it is preferred to contain at least one selected from N,N-diethylformamide, N,N-diethylpropionamide, and N,N-diethylacetamide.

[0058] In addition, examples of amide solvents other than the above-mentioned alkylamide solvents include 3-methyl-2-oxazolidinone, 3-ethyl-2-oxazolidinone, N-vinylmethyloxazolidinone, N-methylcaprolactam, N-ethylcaprolactam, N-propylcaprolactam, N-acetylcaprolactam, ε-caprolactam, N-vinylcaprolactam, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-propyl-2-pyrrolidone.

[0059] The content of the amide solvent (a) is not particularly limited. However, the lower limit of the content of the amide solvent (a) is preferably 1% by mass or greater, more preferably 3% by mass or greater, even more preferably 5% by mass or greater, even more preferably 10% by mass or greater, and even more preferably 15% by mass or greater, based on the total amount of the non-aqueous ink composition. This allows for the advantages of the present invention of achieving a recorded object exhibiting excellent glossiness, while also reducing printed blurring and achieving clearer printed text.

[0060] The upper limit of the content of the amide solvent (a) is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, based on the total amount of the non-aqueous ink composition. This allows for a non-aqueous ink composition capable of producing a recorded object exhibiting even greater gloss.

[0061] (Organic solvent (b))

[0062] The organic solvent (b) is an organic solvent represented by the following formula.

[0063] [Chemical Formula 6]

[0064] R1-(-O-R2-) n -OH···(1)

[0065] (In formula (1), R1 is an alkyl group having 6 or less carbon atoms, R2 represents an ethylene group or a propylene group, and n represents an integer of 1 or more and 6 or less.)

[0066] The organic solvent (b) has -OH groups and exhibits superior wetting and spreading properties on substrates compared to glycol dialkyl ethers. Therefore, by combining it with the amide solvent (a), which exhibits excellent substrate permeability and drying properties, the non-aqueous ink composition rapidly wets and spreads onto the substrate surface after impacting the substrate (recording medium), resulting in less bleeding and clearer printed text. This improves the glossiness of the recorded surface of the resulting recorded object.

[0067] Furthermore, the organic solvent (b) has a higher polarity than a glycol dialkyl ether and has a high solubility for substances that may cause foreign matter, such as metal ions, contained in the ink composition. Therefore, clogging of inkjet head nozzles caused by foreign matter in the ink composition during long-term storage can be suppressed, resulting in a non-aqueous ink composition with excellent storage stability.

[0068] Examples of such organic solvents (b) include dipropylene glycol monomethyl ether (flash point: 76.5°C), tripropylene glycol monomethyl ether (flash point: 123°C), diethylene glycol monohexyl ether (flash point: 141°C), triethylene glycol mono-n-butyl ether (flash point: 156°C), tetraethylene glycol monobutyl ether (flash point: 166°C), and tetraethylene glycol monohexyl ether (flash point: 175°C). Among these, organic solvents having a flash point of 170°C or lower are preferred, more preferably 150°C or lower, and even more preferably 130°C or lower. Including an organic solvent (b) having a flash point of 170°C or lower allows, in addition to the effects of the present invention, such as a non-aqueous ink composition having excellent storage stability, to further reduce bleeding of printed characters and achieve clearer printed characters.

[0069] In addition, the lower limit of the flash point of the organic solvent (b) is not particularly limited, but is preferably 70° C. or higher, for example.

[0070] The content of the organic solvent (b) is not particularly limited, but the lower limit of the content of the organic solvent (b) is preferably 1% by mass or greater, more preferably 3% by mass or greater, and even more preferably 4% by mass or greater, based on the total amount of the non-aqueous ink composition. This allows for a non-aqueous ink composition capable of producing a recorded object exhibiting even greater gloss.

[0071] The upper limit of the content of the organic solvent (b) is preferably 92% by mass or less, more preferably 90% by mass or less, further preferably 85% by mass or less, and even more preferably 80% by mass or less. Thus, in addition to the effects of the present invention, printed text blurring is further reduced, resulting in clearer printed text.

[0072] (Total content of amide solvent (a) and organic solvent (b))

[0073] The total content of the amide solvent (a) and the organic solvent (b) is not particularly limited. For example, the non-aqueous ink composition may contain only the amide solvent (a) and the organic solvent (b), or it may contain a specified amount of another organic solvent described below. When containing a specified amount of another organic solvent, the lower limit of the total content of the amide solvent (a) and the organic solvent (b) is preferably 25% by mass or more, more preferably 30% by mass or more, and even more preferably 35% by mass or more of the total amount of the non-aqueous ink composition. The upper limit of the total content of the amide solvent (a) and the organic solvent (b) is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less of the total amount of the non-aqueous ink composition.

[0074] (Mass ratio of the content of amide solvent (a) to the content of organic solvent (b))

[0075] The mass ratio of the amide solvent (a) to the organic solvent (b) (organic solvent (a): organic solvent (b)) is preferably in the range of 95:5 to 5:95, more preferably in the range of 95:5 to 50:50, and even more preferably in the range of 95:5 to 70:30. By being within this range, in addition to the effects of the present invention, printed text blurring is reduced, and printed text becomes clearer. Furthermore, the mass ratio of the amide solvent (a) to the organic solvent (b) (organic solvent (a): organic solvent (b)) is preferably in the range of 95:5 to 5:95, more preferably in the range of 50:50 to 5:95. By being within this range, a non-aqueous ink composition capable of producing a recorded material exhibiting even superior glossiness can be prepared.

[0076] (Other organic solvents)

[0077] The organic solvent may contain other organic solvents other than the above-mentioned amide solvent (a) and organic solvent (b). Specifically, ethylene glycol dibutyl ether, ethylene glycol dipropyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol dipropyl ether, diethylene glycol propyl methyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, diethylene glycol butyl ethyl ether, diethylene glycol methyl-2-ethylhexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol ethyl methyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol ethyl methyl ether, propylene glycol diethyl ether, propylene glycol ethyl methyl ether, propylene glycol methyl propyl ether, propylene glycol methyl butyl ether, propylene glycol methyl-2-ethylhexyl ether , dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol ethyl methyl ether, dipropylene glycol methyl propyl ether, dipropylene glycol dipropyl ether, dipropylene glycol methyl butyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol ethyl methyl ether and other glycol dialkyl ethers, methanol, ethanol, n-propanol, isopropanol, n-butanol and other alcohols, acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl isopropyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, methyl hexyl ketone, methyl isoamyl ketone, diethyl ketone, ethyl n-propyl ketone, ethyl isopropyl ketone, ethyl n-butyl ketone, ethyl isobutyl ketone, di Ketones such as n-propyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, isophorone, and acetyl ketone; acetates such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, hexyl acetate, and octyl acetate; lactic acid esters such as methyl lactate, ethyl lactate, butyl lactate, propyl lactate, ethylhexyl lactate, amyl lactate, and isoamyl lactate; glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and dipropylene glycol; ethylene glycol monobutyl ether acetate, 2-methylbutyl acetate, 3-methoxybutyl ether acetate, cyclopentyl acetate, Acetic esters such as hexyl acetate; saturated hydrocarbons such as n-hexane, isohexane, n-nonane, isononane, dodecane, and isododecane; unsaturated hydrocarbons such as 1-hexene, 1-heptene, and 1-octene; cyclic saturated hydrocarbons such as cyclohexane, cycloheptane, cyclooctane, cyclodecane, and decalin; cyclic unsaturated hydrocarbons such as cyclohexene, cycloheptene, cyclooctene, 1,1,3,5,7-cyclooctatetraene, and cyclododecene; aromatic hydrocarbons such as benzene, toluene, and xylene; morpholines such as N-methylmorpholine, N-ethylmorpholine, and N-formylmorpholine; terpene-based solvents; and general organic solvents such as ether-based solvents. It is preferred to select a solvent with an appropriate HLB value based on the resin, dispersant, and other factors to be combined.

[0078] [Resin]

[0079] The non-aqueous ink composition of this embodiment may or may not contain a resin. The inclusion of a resin can improve the fixability, water resistance, and stretchability of the recording layer formed using the non-aqueous ink composition. Furthermore, the glossiness of the resulting recorded material can be enhanced.

[0080] The resin is not particularly limited, and for example, acrylic resins, polystyrene resins, polyester resins, vinyl chloride resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, polyethylene resins, polyurethane resins, rosin-modified resins, phenolic resins, terpene resins, polyamide resins, vinyltoluene-α-methylstyrene copolymers, ethylene-vinyl acetate copolymers, cellulose resins, silicone resins, acrylamide resins, epoxy resins, or copolymers thereof, or mixtures thereof, can be used. Among these, acrylic resins, vinyl chloride-vinyl acetate copolymer resins, cellulose resins, polyester resins, or polyurethane resins are preferably included.

[0081] The acrylic resin is not particularly limited as long as it contains a (meth)acrylate monomer as the main component of the monomers. The acrylic resin may be a homopolymer of a single free-radical polymerizable monomer or a copolymer using two or more free-radical polymerizable monomers. The acrylic resin used in the oil-based ink composition of this embodiment is particularly preferably a homopolymer of methyl methacrylate or a copolymer of methyl methacrylate and at least one compound selected from butyl methacrylate, ethoxyethyl methacrylate, and benzyl methacrylate. Commercially available (meth)acrylic resins include, for example, "PARALOID B99N," "PARALOID B60," "PARALOID B66," and "PARALOID B82" from Rohm & Haas.

[0082] A vinyl chloride-vinyl acetate copolymer resin is a polymer of vinyl chloride monomer and vinyl acetate monomer. Examples of vinyl chloride-vinyl acetate copolymer resins include vinyl chloride-vinyl acetate copolymers, vinyl chloride / vinyl acetate / maleic acid copolymers, vinyl chloride / vinyl acetate / vinyl alcohol copolymers, vinyl chloride / vinyl acetate / hydroxyalkyl acrylate copolymers, and mixtures thereof. These vinyl chloride-vinyl acetate copolymer resins are available from Nissin Chemical Industry Co., Ltd. under trade names such as "SOLBIN C, CL, CNL, CLL, CLL2, C5R, TA2, TA3, A, AL, TA5R, and M5," and can be used in the present invention.

[0083] The vinyl chloride-vinyl acetate copolymer resin can be obtained by polymerizing vinyl chloride monomer and vinyl acetate monomer. The polymerization method can be any conventionally known polymerization method. The polymerization method is preferably emulsion polymerization or suspension polymerization, and more preferably suspension polymerization.

[0084] Cellulose resins are resins with a cellulose skeleton obtained by introducing functional groups biologically or chemically into cellulose as a raw material. Examples of cellulose resins include cellulose acetate butyrate resins, cellulose acetate propionate resins, cellulose acetate propionate butyrate resins, and other cellulose acetate alkylated resins, cellulose acetate resins, nitrocellulose resins, and mixtures thereof. These cellulose resins can be obtained and used under trade names such as "CAB551-0.01," "CAB551-0.2," "CAB553-0.4," "CAB531-1," "CAB381-0.1," "CAB381-0.5," "CAB381-2," "CAB381-20," "CAP504," and "CAP482-0.5" from Eastman.

[0085] The so-called polyester resin is a resin containing at least a structural unit obtained by polycondensing an alcohol component and a carboxylic acid component. The polyester resin may include a modified polyester resin. As the above-mentioned polyester resin, "VYLON 226", "VYLON 270", "VYLON 560", "VYLON 600", "VYLON 630", "VYLON 660", "VYLON 885", "VYLONG K250", "VYLONG K810", "VYLON GK890" and the like from Toyobo Co., Ltd. and "elitle UE-3200", "elitle UE-3285", "elitle UE-3320", "elitle UE-9800", "elitle UE-9885" and the like from UNITIKA Co., Ltd. can be obtained and used.

[0086] The so-called polyurethane resin is a resin containing at least a structural unit obtained by copolymerizing an alcohol component and an isocyanate component. The polyurethane resin may include a polyurethane resin modified with polyester, polyether, or caprolactone. As such polyurethane resins, those available under trade names such as "UREARNO KL-424," "UREARNO KL-564," "UREARNO KL-593," and "UREARNO 3262" from Arakawa Chemical Industries, Ltd., and "PANDEX 372E," "PANDEX 390E," "PANDEX 394E," "PANDEX 304," "PANDEX 305E," "PANDEX P-870," "PANDEX P-910," "PANDEX P-895," "PANDEX 4030," and "PANDEX 4110" from DIC Corporation can be used.

[0087] These acrylic resins, vinyl chloride-vinyl acetate copolymer resins, cellulose resins, polyester resins, and polyurethane resins can be used individually, but a mixture of two is preferred, and a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer resin is more preferred. The ratio of the acrylic resin to the vinyl chloride-vinyl acetate copolymer resin can be controlled to meet the color development, drying properties, coating film properties, and printing suitability requirements of non-aqueous inks. When mixing an acrylic resin with a vinyl chloride-vinyl acetate copolymer resin, the mixing ratio is not particularly limited and can be varied appropriately.

[0088] The weight average molecular weight (relative molecular mass) of the resin is not particularly limited, but is preferably 5000 or more, more preferably 15000 or more. The weight average molecular weight (relative molecular mass) is preferably 100000 or less, more preferably 50000 or less. The relative molecular weight of the resin can be measured by conventional GPC (gel permeation chromatography).

[0089] The resin content in the non-aqueous ink composition is preferably 0.05% by mass or greater, more preferably 0.1% by mass or greater, and even more preferably 0.5% by mass or greater, based on the total amount of the non-aqueous ink composition. The resin content in the non-aqueous ink composition is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, and even more preferably 10.0% by mass or less, based on the total amount of the non-aqueous ink composition.

[0090] Furthermore, among the resins contained in the non-aqueous ink composition of this embodiment, it is preferred that the proportion of resins having an intrinsic viscosity of 90 mL / g or higher at 25°C be 5% by mass or less of the total resin amount. This, in addition to the effects of the present invention, reduces the reduction in landing accuracy caused by, for example, flight deflection of ink droplets of the non-aqueous ink composition ejected via an inkjet method, resulting in improved solid coverage. Furthermore, in the non-aqueous ink composition of this embodiment, which exhibits excellent storage stability, by limiting the proportion of resins having an intrinsic viscosity of 90 mL / g or higher to 5% by mass or less of the total resin amount, extremely high inkjet ejection stability can be achieved.

[0091] It should be noted that the intrinsic viscosity in this specification can be determined by dispersing the target resin in a developing solvent and determining the specific viscosity [η] after separating the molecules contained in the resin using a chromatographic column filled with granular gel using GPC (gel permeation chromatography). sP 〕((η-η0) / η0(η0: solvent viscosity, η: solution viscosity)) and concentration C, in the formula Lim(〔η SP〕 / C), the concentration C is determined by extrapolating to 0 (C→0). The developing solvent is not particularly limited, and for example, tetrahydrofuran can be used.

[0092] The content of the resin having an intrinsic viscosity of 90 mL / g or higher at 25°C is preferably 4.0% by mass or less, more preferably 3.5% by mass or less, and even more preferably 2.5% by mass or less, based on the total amount of the resin.

[0093] [color material]

[0094] The non-aqueous ink composition of this embodiment may contain a colorant. The colorant is not particularly limited and may be a dye or pigment. However, from the perspective of achieving good resistance to water and light, etc., of the recorded material, a pigment (pigment-based colorant) is preferably used. The pigments that can be used in the non-aqueous ink composition of this embodiment are not particularly limited, and examples include organic pigments or inorganic pigments used in conventional ink compositions. These pigments may be used alone or in combination of two or more. It should be noted that the non-aqueous ink composition of this embodiment does not need to contain a colorant.

[0095] When a pigment is used in the non-aqueous ink composition of the present embodiment, the dispersion stability of the pigment can be improved by using a dispersant or a dispersing aid (pigment derivative) described below.

[0096] Specific examples of organic pigments include insoluble azo pigments, soluble azo pigments, derivatives derived from dyes, phthalocyanine organic pigments, quinacridone organic pigments, perylene organic pigments, perinone organic pigments, azomethine organic pigments, anthraquinone organic pigments (anthrone organic pigments), xanthene organic pigments, diketopyrrolopyrrole organic pigments, dioxazine organic pigments, nickel azo pigments, isoindolinone organic pigments, pyranthrone organic pigments, thioindigo organic pigments, condensed azo organic pigments, benzimidazolone organic pigments, quinophthalone organic pigments, isoindolinone organic pigments, organic solid solution pigments such as quinacridone solid solution pigments and perylene solid solution pigments, lake pigments as other pigments, and carbon black.

[0097] When organic pigments are listed by color index (CI) number, CI Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 20, 24, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 117, 120, 125, 128, 129, 130, 137, 138, 139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, 185, 213, 214, CI Pigment Red 5, 7, 9, 12, 48, 49, 52, 53, 57, 97, 112, 122, 123, 146, 149, 150, 1 68, 177, 180, 184, 192, 202, 206, 208, 209, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, 254, 255, 269, 291, CI Pigment Orange 16, 36, 43, 51, 55, 59, 61, 64, 71, 73, CI Pigment Violet 19, 23, 29, 30, 37, 40, 50, CI Pigment Blue 15, 15:1, 15:3, 15:4, 15:6, 16, 22, 60, 64, CI Pigment Green 7, 36, 58, 59, 62, 63, CI Pigment Brown 23, 25, 26, CI Pigment Black 7, etc.

[0098] Specific examples of dyes that can be used in the non-aqueous ink composition of this embodiment include azo dyes, benzoquinone dyes, naphthoquinone dyes, anthraquinone dyes, cyanine dyes, squarylium dyes, cretonic acid dyes, merocyanine dyes, stilbene dyes, diarylmethane dyes, triarylmethane dyes, fluoran dyes, spiropyran dyes, phthalocyanine dyes, indigoid dyes such as indigo, fulgide dyes, nickel complex dyes, and azulene dyes.

[0099] Specific examples of inorganic pigments that can be used in the non-aqueous ink composition of this embodiment include titanium oxide, barium sulfate, calcium carbonate, zinc oxide, barium carbonate, silica, talc, clay, synthetic mica, aluminum oxide, zinc oxide, lead sulfate, chrome yellow, zinc yellow, rouge (red iron (III) oxide), cadmium red, ultramarine, Prussian blue, chromium oxide green, cobalt green, amber, titanium black, aluminum, titanium, indium, synthetic iron black, and inorganic solid solution pigments.

[0100] The average dispersed particle size of the pigments that can be included in the non-aqueous ink composition of this embodiment is not particularly limited, as long as it is a particle size that can achieve the desired color development. Although it varies depending on the type of pigment used, from the perspective of good dispersibility and dispersion stability of the pigment and sufficient coloring power, the volume average particle size is preferably in the range of 5 nm or greater, more preferably 20 nm or greater, and even more preferably 30 nm or greater. By setting the volume average particle size above the lower limit, the light resistance of the non-aqueous ink composition can be improved. The volume average particle size is preferably in the range of 300 nm or less, more preferably 200 nm or less, and even more preferably 150 nm or less. By setting the volume average particle size below the upper limit, when the non-aqueous ink composition is a non-aqueous inkjet ink composition that is ejected onto the surface of a substrate by inkjet printing, the ejection stability of the inkjet can be improved. It should be noted that, in the present embodiment, the volume average particle size of the pigment is a volume-based cumulative 50% particle size (D50) measured at 25°C using a particle size distribution measuring device (Microtrac BEL (co., Ltd., particle size analyzer NANOTRACWAVE). It should be noted that, in this specification, the so-called "volume-based cumulative 50% particle size (D50)" refers to the particle size at which the cumulative volume calculated from the smaller diameter side reaches 50%. The "volume-based cumulative 50% particle size (D50)" is sometimes also referred to as the "volume average particle size D50" or the "median particle size."

[0101] Furthermore, in an ink set comprising multiple non-aqueous ink compositions according to this embodiment, the volume average particle sizes of the pigments contained in each non-aqueous ink composition may be the same or different. For example, in an ink set comprising a cyan ink and a magenta ink according to this embodiment, the volume average particle size of the pigment contained in the cyan ink may be the same as or different from the volume average particle size of the pigment contained in the magenta ink.

[0102] The pigment content in the non-aqueous ink composition of this embodiment is not particularly limited, as long as the desired image can be formed, and can be adjusted appropriately. Specifically, while varying depending on the type of pigment, it is preferably 0.05% or greater by mass, and more preferably 0.1% or greater by mass, of the total non-aqueous ink composition. It is preferably 20% or less by mass, and more preferably 10% or less by mass, of the total non-aqueous ink composition. By adjusting the pigment content to 0.05% or greater by mass, or 20% or less by mass, a pigment with an excellent balance between dispersion stability and tinting power can be achieved.

[0103] In addition, the color recorded (printed) by the non-aqueous ink composition of this embodiment is not particularly limited. Color materials can be selected according to the target color, and can also be used in combination. Color materials can be used for various colors such as yellow, magenta, cyan, and black, as well as light magenta, light cyan, light black, orange, green, red, and white. In this case, color materials of the same color can be selected in the ink set including the non-aqueous ink composition of this embodiment.

[0104] [Dispersant]

[0105] A dispersant may be used as needed in the non-aqueous ink composition of this embodiment. Any dispersant used in non-aqueous ink compositions may be used as a dispersant. A polymer dispersant may be used as a dispersant. Such a dispersant includes a main chain containing polyester, polyacrylic acid, polyurethane, polyamine, polycaprolactone, etc., and having polar groups such as amino, carboxyl, sulfonic, and hydroxyl groups as side chains. For polyacrylic acid-based dispersants, for example, Disperbyk-2000, 2001, 2008, 2009, 2010, 2020, 2020N, ​​2022, 2025, 2050, 2070, 2095, 2150, 2151, 2155, 2163, 2164, BYKJET-9130, 9131, 9132, 9133, 9151 (B YK-Chemie Co., Ltd.), Efka PX4310, PX4320, PX4330, PA4401, 4402, PA4403, 4570, 7411, 7477, PX4700, PX4701 (manufactured by BASF), TREPL U S-1200, D-1410, D-1420, MD-1000 (manufactured by Otsuka Chemical Co., Ltd.), FLOWLEN DOPA-15BHFS, 17HF, 22, G-700, 900, NC-500, GW-1500 (manufactured by Kyoeisha Chemical Co., Ltd.), etc. Examples of polycaprolactone dispersants that can be used include Ajisper PB821, PB822, and PB881 (manufactured by Ajinomoto Fine-Techno Co., Ltd.), Hinoact KF-1000, T-6000, T-7000, T-8000, T-8000E, and T-9050 (manufactured by Kawaken Fine Chemicals Co., Ltd.), Solsperse 20000, 24000, 32000, 32500, 32550, 32600, 33000, 33500, 34000, 35200, 36000, 37500, 39000, 71000, 76400, 76500, 86000, 88000, J180, and J200 (manufactured by Lubrizol), and TEGO Dispers 652, 655, 685, 688, 690 (manufactured by Evonik Japan Co., Ltd.), etc.As preferred dispersants, BYKJET-9130, 9131, 9132, 9133, 9151, Efka PX4310, PX4320, PX4330, PX4700, PX4701, Solsperse 20000, 24000, 32000, 33000, 33500, 34000, 35200, 39000, 71000, 76500, 86000, 88000, J180, J200, TEGO Dispers 655, 685, 688, 690, etc. can be used. These can be used alone or in mixtures thereof.

[0106] The dispersant content is not particularly limited, but the lower limit is preferably 0.1% by mass or greater, more preferably 0.5% by mass or greater, and even more preferably 0.8% by mass or greater, based on the total amount of the non-aqueous ink composition. The dispersant content is not particularly limited, but the lower limit is preferably 5.0% by mass or greater, more preferably 4.0% by mass or greater, and even more preferably 3.0% by mass or greater, based on the total amount of the non-aqueous ink composition.

[0107] [Dispersing aid]

[0108] The non-aqueous ink composition of this embodiment may contain a dispersing aid as needed. The dispersing aid adsorbs onto the surface of the colorant (pigment), increasing the affinity of the functional groups for the organic solvent and dispersant in the non-aqueous ink composition, thereby improving dispersion stability. Known pigment derivatives containing functional groups such as acidic groups, basic groups, and neutral groups within the organic pigment residue can be used as dispersing aids.

[0109] [Surfactant]

[0110] The non-aqueous ink composition of this embodiment may contain a surfactant for the purpose of suppressing volatilization of the ink composition in the nozzle portion, pipes, and other equipment, preventing solidification, or preventing redissolution during solidification, or for the purpose of reducing surface tension and improving wettability with the recording medium (substrate). For example, nonionic polyoxyalkylene alkyl ethers include P-208, P-210, P-213, E-202S, E-205S, E-215, K-204, K-220, S-207, S-215, A-10R, A-13P, NC-203, and NC-207 (manufactured by NOF Corporation), Emulgen 106, 108, 707, 709, A-90, and A-60 (manufactured by Kao Corporation), Flowlen G-70, D-90, and TG-740W (manufactured by Kyoeisha Chemical Co., Ltd.), POEM J-0081HV (manufactured by Riken Vitamine Co., Ltd.), and Adekatol. NP-620, NP-650, NP-660, NP-675, NP-683, NP-686, Adekacol CS-141E, TS-230E (manufactured by ADEKA Co., Ltd.), SORGEN 30V, 40, TW-20, TW-80, Noigen CX-100 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), etc. As the fluorine-based surfactant, a fluorine-modified polymer is preferably used, and a specific example thereof is BYK-340 (manufactured by BYK-Chemie Japan Co., Ltd.). As the silicone-based surfactant, polyester-modified silicone and polyether-modified silicone are preferably used, and specific examples thereof are BYK-313, 315N, 322, 326, 331, 347, 348, BYK-UV3500, 3510, 3530, 3570 (all manufactured by BYK-Chemie Japan Co., Ltd.), etc. Japan Co., Ltd.), etc. Specific examples of acetylene glycol surfactants include Surfynol (registered trademark) 82, 104, 465, 485, TG (all manufactured by Air Products Japan Co., Ltd.), OLFINE (registered trademark) STG, E1010 (all manufactured by Nissin Chemical Co., Ltd.), etc.

[0111] The surfactant is not limited to the above examples, and any of anionic, cationic, amphoteric, or nonionic surfactants may be used, and any one may be appropriately selected depending on the purpose of addition.

[0112] [Other ingredients]

[0113] The non-aqueous ink composition of this embodiment may contain, as optional ingredients, known additives such as antioxidants, stabilizers such as UV absorbers, epoxides, polycarboxylic acids, surface conditioners, slip agents, leveling agents (such as acrylic and silicone), defoamers, pH adjusters, bactericides, preservatives, deodorants, charge modifiers, and wetting agents. Specific examples of antioxidants include hindered phenol-based antioxidants, amine-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and hydrazine-based antioxidants. Specifically, BHA (2,3-butyl-4-oxyanisole) and BHT (2,6-di-tert-butyl-p-cresol) may be used. Furthermore, as UV absorbers, benzophenone-based compounds or benzotriazole-based compounds may be used. Specific examples of epoxides include glycidyl esters, epoxy fatty acid monoesters, and epoxy hexahydrophthalate, and more specifically, ADK CIZER O-130P and ADK CIZER O-180A (manufactured by ADEKA Corporation). Specific examples of polycarboxylic acids include citric acid and maleic acid.

[0114] <2. Method for producing ink composition>

[0115] The ink composition of this embodiment can be prepared by mixing an amide solvent (a), an organic solvent having -OH groups (b), and the main components (e.g., resin, colorant, etc.) using a paint shaker. Zirconia beads can be used to disperse the components. The non-aqueous ink composition of this embodiment can be degassed as needed to adjust the dissolved oxygen and dissolved nitrogen contents to desired levels.

[0116] In this case, it is preferable to pre-dry the organic solvent. Pre-drying the organic solvent can reduce the amount of water contained in the non-aqueous ink composition. In particular, organic solvents (b) having -OH groups have high water absorption and absorb moisture from the atmosphere, so pre-drying is particularly preferable. Examples of methods for drying the organic solvent include blowing a dried inert gas (e.g., nitrogen) for a predetermined time under an atmosphere of an inert gas such as nitrogen, purifying the organic solvent by distillation, passing the organic solvent through a semipermeable membrane that selectively permeates water, and selectively absorbing water mixed in the organic solvent using a water-absorbing adsorbent.

[0117] <3. Recording Method Using Ink Composition>

[0118] The recording method of this embodiment is a recording method in which the above-mentioned non-aqueous ink composition is ejected onto the surface of a substrate using an inkjet method. The above-mentioned non-aqueous ink composition can produce a recorded material exhibiting excellent glossiness, and the recording method of this embodiment can also produce a recorded material exhibiting excellent glossiness. Furthermore, the above-mentioned non-aqueous ink composition has excellent storage stability, which can suppress the generation of foreign matter within the non-aqueous ink composition. The recording method in which the above-mentioned non-aqueous ink composition is ejected onto the surface of a substrate using an inkjet method has high inkjet ejection stability. The inkjet ejection method can be a piezoelectric method using a piezoelectric element or a thermal inkjet method using a heating element, without particular limitation.

[0119] <4. Method for producing recorded material>

[0120] The recording method using the above-described ink composition can also be defined as a method for producing a recorded article. The method for producing a recorded article of this embodiment can also produce a recorded article exhibiting excellent gloss. Furthermore, when the above-described non-aqueous ink composition, which exhibits excellent storage stability, is ejected onto a substrate surface using an inkjet method, it also exhibits high ejection stability.

[0121] <5. Records>

[0122] The layers constituting the recorded matter produced by the method for producing a recorded matter according to the above-described embodiment will be described.

[0123] [Medium (recording medium)]

[0124] The substrate (recording medium) that can be used in the recording method of this embodiment is not particularly limited. It can be a resin substrate (including a substrate whose surface mainly contains resin), a non-absorbent substrate such as metal plate glass, an absorptive substrate such as paper, cloth, etc., or a surface-coated substrate such as a substrate with a receiving layer. Various substrates can be used.

[0125] Among them, because above-mentioned non-aqueous ink composition is the non-aqueous ink composition that does not contain water, therefore preferably the substrate that surface mainly comprises resin.Particularly, because above-mentioned non-aqueous ink composition comprises the amide solvent (a) that shows permeability to resin substrate, therefore utilize the printing of the medium (recording medium) that surface comprises resin less oozing, printing becomes clear.As resin, can enumerate polyvinyl chloride polymer, acrylic acid, PET, polycarbonate, PE, PP etc.In addition, also can be used for the resin substrate (so-called resin substrate used for lamination) that is premised on laminating film on the recording surface of record.Particularly preferably the substrate (recording medium) that surface comprises hard or soft polyvinyl chloride polymer.As the substrate (recording medium) that surface comprises polyvinyl chloride polymer, can exemplify polyvinyl chloride substrate (film or sheet) etc.

[0126] [Recording layer]

[0127] The recording layer is formed by the volatilization of the solvent contained in the non-aqueous ink composition, and is a layer on which the desired image is formed. By ejecting the non-aqueous ink composition, a recorded material exhibiting excellent glossiness can be obtained.

[0128] It should be noted that the layer formed by the volatilization of the solvent contained in the above-mentioned non-aqueous ink composition can be composed of multiple layers. For example, a layer of color ink (e.g., yellow, magenta, cyan, black) of the above-mentioned non-aqueous ink composition can be formed on a layer of white ink of the above-mentioned non-aqueous ink composition.

[0129] [Other layers]

[0130] The recorded article of this embodiment may further include a layer with desired functions on the upper surface of the recording layer. For example, to further enhance abrasion resistance and glossiness, an overcoat layer containing at least one of a resin and a wax may be formed. Furthermore, by incorporating fillers or varying the film thickness on a pixel-by-pixel basis, a layer exhibiting a concave-convex surface (a matte surface) may be formed on the surface. Furthermore, to impart weather resistance to the recorded article, a weather-resistant layer containing an ultraviolet absorber, a light stabilizer, or the like, or a glossy layer containing a glossy pigment, etc., may be formed.

[0131] It should be noted that, in the present embodiment, the recorded article is described as including a recording layer formed using the aforementioned non-aqueous ink composition. However, for example, a layer having a desired function can be formed by ejecting the aforementioned non-aqueous ink composition onto a recording layer formed using a conventionally known ink composition. Alternatively, a layer having a desired function can be formed by ejecting the aforementioned non-aqueous ink composition onto a recording layer formed using the aforementioned non-aqueous ink composition.

[0132] <6. Inkjet Recording Device>

[0133] As the inkjet recording apparatus for ejecting the non-aqueous ink composition by the inkjet method, a conventionally known inkjet recording apparatus can be used, for example, an inkjet printer such as VersaArt RE-640 or one manufactured by Roland DG Co., Ltd. can be used.

[0134] As an example of the structure of an inkjet recording device, an inkjet recording device that is a frame-based and serial printer type is described. However, the inkjet recording device that can implement the recording method of this embodiment can also be an off-frame type inkjet recording device in which the ink cartridge is fixed to the outside, or it can be a line printer type inkjet recording device that ejects an ink composition onto a recording medium (substrate) without moving the inkjet head.

[0135] In addition, the inkjet recording device preferably has a heating mechanism and a fixing mechanism for fixing the substrate. By utilizing the heating mechanism provided in the inkjet recording device to control the substrate surface temperature, the non-aqueous ink composition that hits the substrate (recording medium) is dried, and the drying speed of the organic solvent contained in the non-aqueous ink composition can be improved. In addition, the non-aqueous ink composition can be dried under a state in which the substrate (recording medium) is fixed by utilizing the fixing mechanism for fixing the substrate, and the situation in which the application of heat becomes uneven due to the substrate being flexed after being heated can be suppressed. Thus, the non-aqueous ink composition that hits the substrate (recording medium) can be dried efficiently.

[0136] Alternatively, an inkjet recording device may be constructed as follows: that is, a plastic tube connecting a container (ink cartridge, bottle, etc.) storing the non-aqueous ink composition to an inkjet head for discharging the non-aqueous ink composition is provided. The non-aqueous ink composition is supplied to the inkjet head through the plastic tube and discharged using an inkjet method. If the non-aqueous ink composition is present in the plastic tube, a portion of the organic solvent contained in the non-aqueous ink composition may evaporate. This may cause the amount of the organic solvent contained in the non-aqueous ink composition to change during the inkjet discharge process, making it impossible to obtain the desired characteristics.

[0137] In particular, alkylamide solvents exhibit low volatilization rates even within plastic tubes. The volatilization rate of organic solvents within plastic tubes is not necessarily correlated with the solvent's own volatility parameters, such as its boiling point, flash point, and enthalpy of vaporization. This is because the permeability of organic solvents to plastics varies depending on the type of organic solvent. The volatilization rate within sealed low-density polyethylene tubes is more likely to be influenced by the permeability to plastics, specifically, the organic solvent's chemical structure, molecular weight, and compatibility.

[0138] Since alkylamide solvents are solvents with low volatility in plastic tubes, non-aqueous ink compositions containing alkylamide solvents can be ejected by inkjet while maintaining the amount of organic solvent contained in the non-aqueous ink composition.

[0139] The amount of organic solvent volatilized from a plastic tube can be determined by filling a low-density polyethylene tube (a polyethylene hose manufactured by ASONE (Model: 6-608-03, low-density polyethylene (PE-LD) with an inner diameter of 3 mm and an outer diameter of 5 mm) cut into 12 cm pieces) with the organic solvent, sealing the tube, and storing it at 50°C for one week. The amount of volatilization after storage is then measured to determine the amount of organic solvent volatilized. For example, the volatilization amount of diethylene glycol dimethyl ether is 68% by mass, diethylene glycol methyl ethyl ether is 58% by mass, diethylene glycol diethyl ether is 54% by mass, and dipropylene glycol dimethyl ether is 59% by mass, while that of N,N-diethylformamide is 11% by mass, N,N-diethylpropionamide is 12% by mass, and N,N-diethylacetamide is 13% by mass. This indicates that alkylamide solvents have a low volatilization amount from plastic tubes.

[0140] The material of the plastic tube is not particularly limited, and examples thereof include polyolefin resins such as polyethylene resins, ethylene propylene diene rubber, nylon, polyurethane, PTFE, etc. Among them, polyethylene resins and ethylene propylene diene rubber are preferred.

[0141] Furthermore, the inkjet recording apparatus of this embodiment can also be used for various ink colors, such as yellow, magenta, cyan, and black, as well as light magenta, light cyan, light black, orange, green, red, and white, as described above. The order of the printed colors, the position of the nozzles, and the configuration are not particularly limited. Furthermore, the inkjet recording apparatus of this embodiment may or may not include a recording medium (substrate) winding mechanism, a substrate surface drying mechanism, and an ink circulation mechanism.

[0142] The inkjet head for ejecting the non-aqueous ink composition may be a piezoelectric inkjet head using a piezoelectric element or a thermal inkjet head using a heating element, and is not particularly limited.

[0143] Example

[0144] Hereinafter, the present invention will be described in further detail with reference to Examples, but the present invention is not limited to these descriptions.

[0145] 1. Resin production

[0146] (1) Acrylic resin

[0147] To 300 g of diethylene glycol diethyl ether maintained at 100° C., a mixture of 150 g of methyl methacrylate, 50 g of butyl methacrylate, and a specified amount of tert-butyl peroxy-2-ethylhexanoate (polymerization initiator) was added dropwise over 1.5 hours. After completion of the dropwise addition, the mixture was reacted at 100° C. for 2 hours and then cooled to obtain a colorless, transparent methyl methacrylate polymer solution. The solvent was then distilled off from the polymer solution to obtain a methyl methacrylate polymer. The amount of tert-butyl peroxy-2-ethylhexanoate used as the polymerization initiator was varied to control the polymerization average molecular weight of the methyl methacrylate (acrylic resin) to be between 30,000 and 105,000 (the mass of the polymerization initiator used is recorded in Table 1 below. It is indicated as "initiator amount" in Table 1).

[0148] (2) Vinyl chloride-vinyl acetate copolymer resin

[0149] In an autoclave equipped with a stirring device, after nitrogen substitution, 100 parts by mass of deionized water, 40 parts by mass of methanol, 32 parts by mass of vinyl chloride, 5 parts by mass of vinyl acetate, 0.2 parts by mass of glycidyl methacrylate, 3.55 parts by mass of hydroxypropyl acrylate, 0.1 parts by mass of hydroxypropyl methylcellulose (suspending agent), 0.026 parts by mass of di(2-ethylhexyl) peroxydicarbonate (polymerization initiator), and a specified amount of di(3,5,5-trimethylhexanoyl) peroxide (polymerization initiator) were added. The temperature was raised to 63° C. under a nitrogen atmosphere while stirring. Immediately after reaching 63° C., 48 parts by mass of vinyl chloride were continuously pressurized over 6 hours, and a mixture of 0.6 parts by mass of glycidyl methacrylate and 10.65 parts by mass of hydroxypropyl acrylate were continuously pressurized over 5.4 hours to allow copolymerization to proceed. When the pressure inside the autoclave reached 0.3 MPa, the residual pressure was released, and after cooling, the resin slurry was removed, filtered, and dried to obtain a vinyl chloride copolymer resin. The amount of di(3,5,5-trimethylhexanoyl)peroxide used as a polymerization initiator was varied to control the polymerization average molecular weight of the vinyl chloride-vinyl acetate copolymer resin to 40,000 to 75,000 (the mass of the polymerization initiator used is reported in Table 1 below, indicated as "Initiator Amount" in Table 1).

[0150] Table 1 shows the weight average molecular weight (relative molecular mass) of each resin (acrylic resin, vinyl chloride-vinyl acetate copolymer resin), and the proportion of resins with an intrinsic viscosity of 90 mL / g or more at 25°C. It should be noted that the weight average molecular weight (relative molecular mass) is measured using GPC (gel permeation chromatography). In addition, the proportion of resins with an intrinsic viscosity of 90 mL / g or more is determined as follows, that is, a viscosity detector (ViscoStar III manufactured by WYATT Corporation) and a refractive index detector (Optilab T-rEX manufactured by WYATT Corporation) are connected to a SEC (GPC) system of Shimadzu Corporation, tetrahydrofuran is used as a developing solvent, and the sample is first passed through a chromatographic column heated to 40°C in the SEC (GPC) system of Shimadzu Corporation, and then the specific viscosity [η] is determined by using a viscosity detector for the material cooled to 25°C. SP 〕, the concentration C is obtained by using the refractive index detector, and the concentration C is obtained by using the refractive index detector. SP 〕 / C), the intrinsic viscosity is determined by extrapolating the concentration C to 0.

[0151] [Table 1]

[0152]

[0153] 2. Preparation of non-aqueous ink composition

[0154] Non-aqueous ink compositions for Examples and Comparative Examples were prepared using the following ratios of organic solvent, resin, dispersant, and pigment (colorant). Specifically, the non-aqueous ink compositions were prepared by dispersing the components using zirconium oxide beads in a paint shaker. Units are expressed in mass %.

[0155] 3. Evaluation 1

[0156] (Permeability)

[0157] The non-aqueous ink compositions of Examples and Comparative Examples were evaluated for bleeding. Specifically, the non-aqueous ink compositions of Examples and Comparative Examples were printed using an inkjet printer (VersaArt RE-640, manufactured by Roland DG Co., Ltd.) in high-quality printing mode (1440 × 720 dpi) onto a recording medium (adhesive polyvinyl chloride film (IMAGin JT5829R, manufactured by MACtac)) at a substrate surface temperature of 50°C. Images with 6-pt text in a different color than the solid area were printed in the solid area of ​​each color. The resulting printed materials were dried in a 60°C oven for 5 minutes, and the printed materials were then observed for bleeding (indicated as "Bleeding" in the table) both visually and with a magnifying glass (×10).

[0158] Evaluation Benchmarks

[0159] Evaluation 5: No ink bleeding was observed with a magnifying glass.

[0160] Evaluation 4: No ink bleeding was observed visually, and 6-pt text was clear.

[0161] Evaluation 3: Although slight bleeding of the ink was visually observed, the design properties were not impaired.

[0162] Evaluation 2: Although ink bleeding was visually observed, 6-pt characters were recognizable.

[0163] Evaluation 1: Ink bleeding was significantly observed visually, and 6-pt characters were unrecognizable.

[0164] (Glossiness)

[0165] The gloss of the non-aqueous ink compositions of the Examples and Comparative Examples was evaluated. Specifically, as in the aforementioned bleeding evaluation test, solid printing was performed on a recording medium (adhesive polyvinyl chloride film (IMAGin JT5829R, manufactured by MACtac)) in high-quality print mode (1440 x 720 dpi) at a substrate surface temperature of 40°C. After drying in a 60°C oven for 5 minutes, the printed material was measured for 20° gloss. Gloss was measured using a portable gloss meter, the Phopoint IQ-S (manufactured by Konica Minolta) (denoted as "Gloss" in the table).

[0166] Evaluation Benchmarks

[0167] Evaluation 5: 20° gloss is 70 or above

[0168] Evaluation 4: 20° gloss is 65 or more and less than 70

[0169] Evaluation 3: 20° gloss is 55 or more and less than 65

[0170] Evaluation 2: 20° gloss is 50 or more and less than 55

[0171] Evaluation 1: 20° gloss less than 50

[0172] (Anti-blocking properties)

[0173] The non-aqueous ink compositions of Examples and Comparative Examples were evaluated for blocking resistance. Specifically, as in the glossiness evaluation described above, solid printing was performed on a recording medium (adhesive polyvinyl chloride film (IMAGin JT5829R, manufactured by MACtac)) in high-quality print mode (1440 x 720 dpi) at a substrate surface temperature of 40°C. The recorded material was rolled up and left for 24 hours before being unrolled. Smear on the back side of the film (which overlaps with the recorded material surface) and on the recorded material surface were evaluated (indicated as "blocking resistance" in the table).

[0174] Evaluation Benchmarks

[0175] Evaluation 5: There was no smearing to the back surface after winding, and no blurring of the recorded material surface.

[0176] Evaluation 4: There was no smearing to the back surface after winding. However, slight fogging was observed on the surface of the recorded material. However, the design properties were not impaired.

[0177] Evaluation 3: Slight staining was observed toward the back surface after winding, and slight marks were also observed on the surface of the recorded material.

[0178] Evaluation 2: Smudges were clearly observed toward the back surface after winding, and traces were observed on the surface of the recorded material.

[0179] Evaluation 1: Significant ink transfer to the back surface was observed after winding, and the design of the recorded material surface was significantly impaired.

[0180] (Field coverage)

[0181] Solid coverage was evaluated for the non-aqueous ink compositions of Examples and Comparative Examples. Specifically, printing was performed on a recording medium (adhesive polyvinyl chloride film (IMAGin JT5829R, manufactured by MACtac)) in a bidirectional high-speed printing mode (360 x 720 dpi) at a substrate surface temperature of 40°C, similar to the glossiness evaluation described above. The coverage (white spots) of the solid printed areas was determined (indicated as "solid coverage" in the table).

[0182] Evaluation Benchmarks

[0183] Evaluation 5: Can form a uniform solid surface

[0184] Evaluation 4: Although no whitening can be confirmed visually, slight color unevenness can be confirmed, but the design is not damaged.

[0185] Evaluation 3: Although no whitening can be confirmed visually, color unevenness can be confirmed

[0186] Evaluation 2: Whitening can be confirmed

[0187] Evaluation 1: Whitening was remarkably observed, and a decrease in density was observed.

[0188] (Storage stability)

[0189] The storage stability of the non-aqueous ink compositions of the Examples and Comparative Examples was evaluated. Specifically, the non-aqueous ink compositions were stored at 60°C for one month, and changes in viscosity and the pigment's volume-based cumulative 50% particle size (D50) before and after the test were observed. Storage stability was evaluated according to the following criteria. It should be noted that the viscosity of the ink was measured at 20°C using a falling ball viscometer (Anton Paar AMVn), and the pigment's volume-based cumulative 50% particle size (D50) was measured at 25°C using a particle size distribution analyzer (Microtrac BEL Co., Ltd., particle size analyzer NANOTRACWAVE) (indicated as "storage stability" in the table). It should be noted that the evaluation below uses the larger rate of change between "viscosity" and "pigment's volume-based cumulative 50% particle size (D50)" as the evaluation for the non-aqueous ink composition.

[0190] Evaluation Benchmarks

[0191] Evaluation 5: The change rate of the viscosity and the volume-based cumulative 50% particle size (D50) of the pigment is less than 3%.

[0192] Evaluation 4: Either the viscosity or the change rate of the volume-based cumulative 50% particle size (D50) of the pigment is 3% or more and less than 5%.

[0193] Evaluation 3: Either the viscosity or the change rate of the volume-based cumulative 50% particle size (D50) of the pigment is 5% or more and less than 8%.

[0194] Evaluation 2: Either the viscosity or the change rate of the volume-based cumulative 50% particle size (D50) of the pigment is 8% or more and less than 10%.

[0195] Evaluation 1: Either the viscosity or the change rate of the volume-based cumulative 50% particle size (D50) of the pigment is 10% or more.

[0196] [Table 2]

[0197]

[0198] [Table 3]

[0199]

[0200] [Table 4]

[0201]

[0202] [Table 5]

[0203]

[0204] [Table 6]

[0205]

[0206] [Table 7]

[0207]

[0208] [Table 8]

[0209]

[0210] In the table, "MFDG" refers to dipropylene glycol monomethyl ether.

[0211] In the table, "MFTG" refers to tripropylene glycol monomethyl ether.

[0212] In the table, "BTG" refers to triethylene glycol mono-n-butyl ether.

[0213] In the table, "BTeG" refers to tetraethylene glycol monobutyl ether.

[0214] In the table, "HeTeG" refers to tetraethylene glycol monohexyl ether.

[0215] In the table, "DEF" refers to N,N-diethylformamide.

[0216] In the table, "DEPA" refers to N,N-diethylpropionamide.

[0217] In the table, "DEAA" refers to N,N-diethylacetamide.

[0218] In the table, "DMF" refers to N,N-dimethylformamide.

[0219] In the table, "DMDG" refers to diethylene glycol dimethyl ether.

[0220] In the table, "MEDG" refers to diethylene glycol methyl ethyl ether.

[0221] In the table, "DEDG" refers to diethylene glycol diethyl ether.

[0222] In the table, "DMFDG" refers to dipropylene glycol dimethyl ether.

[0223] In the table, "GBL" refers to γ-butyrolactone.

[0224] In the table, "Solsperse 32000" is a polycaprolactone-based dispersant manufactured by Lubrizol.

[0225] In the table, "Solsperse 33000" is a polycaprolactone-based dispersant manufactured by Lubrizol.

[0226] As is clear from Tables 2 to 8, a non-aqueous ink composition containing an amide solvent (a) and an organic solvent (b) can produce a recorded object exhibiting excellent glossiness and anti-blocking properties.

[0227] In particular, in the non-aqueous ink compositions of Examples 1 to 9, in which the mass ratio of the amide solvent (a) to the organic solvent (b) was varied, Examples 2 to 9, in which the mass ratio of the amide solvent (a) to the organic solvent (b) was within the range of 95:5 to 3:97, showed that, in addition to the effects of the present invention, printed information exhibited less blurring than Example 1. Furthermore, Examples 1 to 8 were found to produce recorded materials exhibiting superior gloss compared to Example 9, demonstrating superior storage stability.

[0228] Note that the same trend as that of the non-aqueous ink compositions of Examples 1 to 9 was also observed in the non-aqueous ink compositions of Examples 10 to 14 in which the mass ratio of the content of the amide solvent (a) to the organic solvent (b) was changed and other organic solvents were further contained.

[0229] Furthermore, it can be seen that among Examples 12 and 15 to 18 in which the type of organic solvent (b) was changed, Examples 12 and 15 to 17 containing an organic solvent (b) having a flash point of 170° C. or less exhibited the effects of the present invention, with less bleeding of printed characters and clearer printed characters.

[0230] Furthermore, it was found that the effects of the present invention were particularly exhibited in Examples 12 and 19 to 21 in which the type of the amide solvent (a) was changed.

[0231] In addition, in Examples 22 to 24 in which the types of other organic solvents were changed, the same results as those of Example 12 were obtained.

[0232] Furthermore, in the non-aqueous ink compositions of Examples 34 to 44 in which the content of the resin having an intrinsic viscosity of 90 mL / g or higher at 25°C was varied, the non-aqueous ink compositions of Examples in which the content of the resin having an intrinsic viscosity of 90 mL / g or higher at 25°C was within a range of 5% by mass or less relative to the total amount of resin exhibited improved solid coverage compared to the non-aqueous ink compositions of Examples in which the content of the resin having an intrinsic viscosity of 90 mL / g or higher at 25°C was greater than 5% by mass.

[0233] On the other hand, the non-aqueous ink composition of Comparative Example 1, which did not contain the organic solvent (b), exhibited reduced storage stability and reduced glossiness of the resulting recorded material. Furthermore, the non-aqueous ink composition of Comparative Example 2, which did not contain the amide solvent (a), exhibited printing bleeding.

Claims

1. A non-aqueous ink composition containing an organic solvent and ejected by an inkjet method, The organic solvent contains an amide solvent a and an organic solvent b represented by the following formula (1): In formula (1), R1 is an alkyl group having 6 or less carbon atoms, R2 is an ethylene group or a propylene group, and n is an integer of 1 or more and 6 or less. The amide solvent a is represented by the following formula (2): ・・・（2） In formula (2), R1 is hydrogen or an alkyl group having 1 to 4 carbon atoms, and R2 and R3 each independently represent an alkyl group having 2 to 4 carbon atoms.

2. The non-aqueous ink composition according to claim 1, wherein The mass ratio of the amide solvent a to the organic solvent b, ie, the amide solvent a: the organic solvent b, is in the range of 95:5 to 3:

97.

3. The non-aqueous ink composition according to claim 1 or 2, wherein The amide solvent a contains at least one selected from the group consisting of N,N-diethylformamide, N,N-diethylpropionamide, and N,N-diethylacetamide.

4. The non-aqueous ink composition according to claim 1 or 2, wherein The flash point of the organic solvent b is below 170°C.

5. The non-aqueous ink composition according to claim 1 or 2, further comprising a resin, Among the above resins, the content of the resin having an intrinsic viscosity of 90 mL / g or higher at 25° C. is within a range of 5% by mass or less based on the total amount of the resin. 6 . The non-aqueous ink composition according to claim 1 , wherein the non-aqueous ink composition is ejected through an inkjet method using an inkjet recording apparatus equipped with a plastic tube.

7. The non-aqueous ink composition according to claim 1 or 2, which is used for a resin substrate. 8 . A recording method comprising ejecting the non-aqueous ink composition according to claim 1 onto a surface of a substrate using an inkjet method. 9 . A method for producing a recorded object, comprising ejecting the non-aqueous ink composition according to claim 1 onto a surface of a substrate using an inkjet method. 10 . A recorded object comprising a recording layer comprising the non-aqueous ink composition according to claim 1 formed on a surface of a substrate.

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