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

Abstract

Provided is a non-aqueous ink composition that has high inkjet ejection stability and can effectively suppress bleeding of printed characters. [Solution] The non-aqueous ink composition contains organic solvents and is ejected by an inkjet method. The organic solvents include an organic solvent (a) having a static surface tension of less than 35 mN / m and a flash point of 80°C or less, and an organic solvent (b) having a static surface tension of 35 mN / m or more and a flash point of 80°C or more.

Description

[Technical Field]

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

[0002] As ink compositions, aqueous ink compositions in which a colorant is dissolved or dispersed in water or a mixture of water and an organic solvent, and non-aqueous ink compositions in which a colorant is dissolved or dispersed in a water-free organic solvent are widely used.

[0003] For example, Patent Document 1 describes a technology related to a non-aqueous ink composition containing multiple organic solvents with predetermined flash points. Patent Document 1 describes that this non-aqueous ink composition contains multiple organic solvents with different flash points, which dissolves part of the recording surface, allowing the ink composition to penetrate into the interior of the recording medium and improving the abrasion resistance of the image. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6256039 Summary of the Invention [Problem to be solved by the invention]

[0005] As described in Patent Document 1, the flash point of an organic solvent affects the drying property of the organic solvent, and the lower the flash point of the organic solvent, the more volatile the solvent. Therefore, in a non-aqueous ink composition containing multiple organic solvents, the organic solvents with lower flash points will volatilize first.

[0006] On the other hand, if such a highly volatile solvent with a low flash point evaporates first, the low-volatile organic solvent with a high flash point will wet and spread over the surface of the substrate. Research by the present inventor has revealed that this wetting and spreading over the surface of the substrate will cause bleeding of the print.

[0007] Furthermore, if an organic solvent with a high static surface tension is added to suppress such bleeding of the print, this can result in poor liquid drainage when the ink is ejected from the nozzle of the inkjet recording device, making stable ejection difficult.

[0008] An object of the present invention is to provide a non-aqueous ink composition that has high inkjet ejection stability and can effectively suppress bleeding of printed images. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result have found that a non-aqueous ink composition containing multiple organic solvents having predetermined static surface tensions can solve the above-mentioned problems, thereby completing the present invention. Specifically, the present invention provides the following.

[0010] (1) A non-aqueous ink composition containing organic solvents and ejected by an inkjet method, the non-aqueous ink composition containing an organic solvent (a) having a static surface tension of less than 35 mN / m and a flash point of 80°C or less, and an organic solvent (b) having a static surface tension of 35 mN / m or more and a flash point of 80°C or more.

[0011] (2) The non-aqueous ink composition according to (1), wherein the mass ratio of the organic solvent (a) to the organic solvent (b) (organic solvent (a):organic solvent (b)) is within the range of 99:1 to 70:30.

[0012] (3) The non-aqueous ink composition according to (1) or (2), wherein the organic solvent (a) contains at least one selected from the group consisting of amide solvents, glycol ether dialkyls, glycol ether monoalkyls, acetates, dibasic acid esters, and lactate esters.

[0013] (4) The non-aqueous ink composition according to (3), wherein the organic solvent (a) contains an alkylamide solvent as the amide solvent.

[0014] (5) The non-aqueous ink composition according to any one of (1) to (4), wherein the organic solvent (b) contains at least one selected from the group consisting of carbonate esters, cyclic esters, amide solvents, and glycol ether monoalkyls.

[0015] (6) The non-aqueous ink composition according to any one of (1) to (5), further comprising a resin, wherein the resin has an intrinsic viscosity of 90 mL / g or more at 25°C in an amount of 5 mass% or less of the total amount of the resin.

[0016] (7) The non-aqueous ink composition according to any one of (1) to (6), which is ejected by an inkjet method using an inkjet recording apparatus equipped with a heating mechanism and a fixing mechanism for fixing a substrate.

[0017] (8) The non-aqueous ink composition according to any one of (1) to (7), which is ejected by an ink jet method through a plastic tube using an ink jet recording apparatus equipped with the plastic tube.

[0018] (9) The non-aqueous ink composition according to any one of (1) to (8), which is used on a resin substrate.

[0019] (10) A recording method comprising ejecting the non-aqueous ink composition according to any one of (1) to (9) onto the surface of a substrate by an inkjet method.

[0020] (11) A method for producing a recorded matter, comprising ejecting the non-aqueous ink composition according to any one of (1) to (9) onto the surface of a substrate by an inkjet method.

[0021] (12) A recorded matter having a recording layer of the non-aqueous ink composition according to any one of (1) to (9) formed on the surface of a substrate. [Effects of the Invention]

[0022] The non-aqueous ink composition of the present invention has high inkjet ejection stability and can effectively prevent bleeding of printed images. DETAILED DESCRIPTION OF THE INVENTION

[0023] Specific embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be practiced with appropriate modifications within the scope of the object of the present invention. Furthermore, in this specification, the notation "to" means "more than or equal to" or "less than or equal to," and the notation "X:Y~A:B" includes "X:Y" and "A:B" themselves and means the range between "X:Y" and "A:B."

[0024] <1. Non-aqueous ink composition> The non-aqueous ink composition according to this embodiment is a non-aqueous ink composition containing organic solvents and ejected by an inkjet method, and is characterized by containing, as the organic solvents, organic solvent (a) having a static surface tension of less than 35 mN / m and a flash point of 80°C or less, and organic solvent (b) having a static surface tension of 35 mN / m or more and a flash point of 80°C or more.

[0025] Such a non-aqueous ink composition has high inkjet ejection stability and can effectively prevent bleeding of printed images.

[0026] Here, "non-aqueous ink composition" means an ink composition that does not contain water (oil-based ink composition), and is different from an aqueous ink composition in which a colorant is dissolved or dispersed in water or a mixture of water and an organic solvent. Note that, in this specification, the term "water-free" does not take into account water that is inevitably contained, such as moisture in the atmosphere or water that originates from additives, etc.

[0027] The non-aqueous ink composition according to this embodiment may be a colored ink containing a colorant (including a colored colorant or a black-and-white colorant), an ink containing a glittering pigment (scale-like metal particles) for giving a metallic finish to a recorded material (substrate), or a clear ink containing no colorant. Clear inks containing no colorant include inks for forming layers with desired functions. Examples of such inks include overcoat ink compositions for forming an overcoat layer that protects a recorded material (substrate), matte ink compositions that eliminate the gloss of a recorded material (substrate), and inks containing UV absorbers, light stabilizers, etc. for forming a weather-resistant layer.

[0028] In this specification, the flash point of an organic solvent refers to the flash point measured by a Cleveland open cup flash point tester if the flash point measured by the Tag closed cup flash point tester is not 80°C or lower; if the flash point measured by the Tag closed cup flash point tester is 80°C or lower and the kinematic viscosity of the solvent at the flash point is less than 10 cSt, the flash point measured by the Tag closed cup flash point tester is used; and if the kinematic viscosity of the solvent at the flash point is 10 cSt or higher, the flash point measured by the Seta closed cup flash point tester is used.

[0029] Each component contained in the non-aqueous ink composition according to this embodiment will be described below.

[0030] [Organic solvents] The organic solvent contains an organic solvent (a) having a static surface tension of less than 35 mN / m and a flash point of 80°C or less, and an organic solvent (b) having a static surface tension of 35 mN / m or more and a flash point of 80°C or more.

[0031] (organic solvent (a)) The organic solvent (a) is an organic solvent having a static surface tension of less than 35 mN / m and a flash point of not more than 80° C. By including such an organic solvent (a), the ejection stability of the non-aqueous ink composition can be improved.

[0032] After the non-aqueous ink composition is inkjet-ejected and lands on a substrate (recording medium), the organic solvent (a) with the lower flash point volatilizes first, and therefore the organic solvent (a) with low static surface tension does not affect the occurrence of bleeding of the print, while the organic solvent (b) described below with a static surface tension of 35 mN / m or more and a flash point of 80°C or more can effectively suppress bleeding of the print.

[0033] The static surface tension of the organic solvent (a) is preferably less than 34 mN / m, more preferably less than 33 mN / m, and even more preferably less than 32 mN / m. The lower limit of the static surface tension of the organic solvent (a) is not particularly limited, but is preferably 20 mN / m or more, more preferably 23 N / m or more, and even more preferably 25 N / m or more.

[0034] In this specification, the static surface tension is a value measured at a measurement temperature of 25°C by the Wilhelmy method (manufactured by Kyowa Interface Science Co., Ltd., Model: DY-300).

[0035] The upper limit of the flash point of the organic solvent (a), although it depends on the type of organic solvent (a), is preferably in the range of 79° C. or lower, more preferably in the range of 78° C. or lower, and even more preferably in the range of 75° C. or lower. The lower limit of the flash point of the organic solvent (a), although it depends on the type of organic solvent (a), is preferably in the range of 40° C. or higher, more preferably in the range of 45° C. or higher, and even more preferably in the range of 50° C. or higher.

[0036] As such organic solvent (a), amide-based solvents, glycol ether dialkyls, glycol ether monoalkyls, acetates, dibasic acid esters, and lactate esters are preferred, and among these, it is particularly preferred to contain an alkylamide-based solvent as the amide-based solvent. The alkylamide-based solvent is a solvent containing an alkyl group (C n H 2n+1-) and a -C(=O)-N- group (amide bond), and is a solvent consisting of a compound composed of hydrogen or an alkyl group and a -C(=O)-N- group.

[0037] Alkylamide solvents dry quickly on the substrate surface. Therefore, by including an alkylamide solvent, it is possible to obtain a recorded material with excellent surface drying properties. Furthermore, the alkylamide solvent (a) penetrates to a certain extent into the substrate (recording medium) whose surface is mainly made of resin. Therefore, by including the alkylamide solvent (a) and the organic solvent (b) described below, it is possible to more effectively suppress bleeding of the print, resulting in clearer prints.

[0038] As the alkylamide solvent, for example, those having the following structure can be preferably used.

[0039] [ka] ···(1) (In formula (1), 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.)

[0040] R2 and R3 in formula (1) are preferably alkyl groups having 1 to 4 carbon atoms, and more preferably alkyl groups having 2 to 4 carbon atoms.

[0041] Specific examples of alkylamide solvents include N,N-dimethylacetamide (32.4 N / m), N,N-diethylformamide (31.7 mN / m), N,N-diethylacetamide (29.1 mN / m), N,N-diethylpropanamide (26.1 mN / m), etc. Among these, from the viewpoint of particularly achieving the effects of the present invention, it is preferable to contain at least one selected from the group consisting of N,N-diethylformamide, N,N-diethylpropanamide, and N,N-diethylacetamide.

[0042] Examples of glycol ether dialkyls include diethylene glycol methyl ethyl ether (27.7 mN / m), diethylene glycol diethyl ether (27.0 mN / m), dipropylene glycol dimethyl ether (21.0 mN / m), ethylene glycol dimethyl ether (23.5 mN / m), ethylene glycol diethyl ether (24.5 mN / m), and diethylene glycol dimethyl ether (25.6 mN / m).

[0043] Examples of glycol ether monoalkyl include dipropylene glycol monomethyl ether (29.0 mN / m), ethylene glycol monomethyl ether (27.7 mN / m), ethylene glycol monoisopropyl ether (27.8 mN / m), and ethylene glycol monobutyl ether (27.7 mN / m).

[0044] Examples of acetates include ethylene glycol monobutyl ether acetate (27.0 mN / m), propylene glycol monomethyl ether acetate (27.0 mN / m), and 3-methoxybutyl acetate (28.0 mN / m).

[0045] Examples of dibasic acid esters include diethyl oxalate (32.2 mN / m).

[0046] Examples of lactate esters include methyl lactate (31.0 mN / m) and ethyl lactate (29.0 mN / m).

[0047] The content of the organic solvent (a) is not particularly limited, but the lower limit of the content of the organic solvent (a) is preferably 30% by mass or more, more preferably 60% by mass or more, and even more preferably 75% by mass or more, of the total amount of the non-aqueous ink composition, and the upper limit of the content of the organic solvent (a) is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 88% by mass or less, of the total amount of the non-aqueous ink composition.

[0048] (organic solvent (b)) The organic solvent (b) is an organic solvent having a static surface tension of 35 mN / m or more and a flash point of 80° C. or more. By including such an organic solvent (b), bleeding of the print due to wetting and spreading on the surface of the substrate can be effectively suppressed.

[0049] The lower limit of the static surface tension of the organic solvent (b) is preferably 37 mN / m or more, more preferably 38 mN / m or more, and even more preferably 40 mN / m or more. The upper limit of the static surface tension of the organic solvent (a) is not particularly limited, but is preferably 60 mN / m or less, more preferably 55 N / m or less, and even more preferably 50 N / m or less.

[0050] The lower limit of the flash point of the organic solvent (b), although it depends on the type of organic solvent (b), is preferably 90° C. or higher, more preferably 95° C. or higher, and even more preferably 100° C. or higher. The upper limit of the flash point of the organic solvent (b), although it depends on the type of organic solvent (b), is preferably 170° C. or lower, more preferably 160° C. or lower, and even more preferably 150° C. or lower.

[0051] As such organic solvent (b), carbonate esters, amide solvents, and glycol ether monoalkyls are preferred, and among these, those containing carbonate esters are particularly preferred.

[0052] Specific examples of carbonate esters include propylene carbonate (41.6 mN / m).

[0053] Specific examples of cyclic esters include γ-butyrolactone (44.1 mN / m) and ε-caprolactone (42.0 mN / m).

[0054] Specific examples of amide solvents include 3-methyl-2-oxazolidinone (46.8 mN / m).

[0055] Examples of glycol ether monoalkyl include tetraethylene glycol monobutyl ether (39.0 mN / m) and diethylene glycol monophenyl ether (44.9 mN / m).

[0056] The content of organic solvent (b) is not particularly limited, but the lower limit of the content of organic solvent (b) is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, of the total amount of the non-aqueous ink composition. The upper limit of the content of organic solvent (b) is preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, of the total amount of the non-aqueous ink composition.

[0057] (Mass ratio of the contents of organic solvent (a) and organic solvent (b)) The mass ratio of the organic solvent (a) to the organic solvent (b) (organic solvent (a):organic solvent (b)) is preferably within a range of 99:1 to 70:30, more preferably within a range of 99:1 to 75:25, and even more preferably within a range of 99:1 to 80:20. By setting the mass ratio within such a range, the effects of the present invention, such as high inkjet ejection stability and effective suppression of print bleeding, can be more effectively achieved.

[0058] (Other organic solvents) The organic solvent may contain organic solvents other than the organic solvents (a) and (b) described above. The flash point and surface tension of these other organic solvents are not particularly limited.

[0059] Specifically, examples of the solvent include alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butyl alcohol; ketones such as acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl isopropyl ketone, methyl-n-butyl ketone, methyl isobutyl ketone, methyl-n-amyl ketone, methyl isoamyl ketone, diethyl ketone, ethyl-n-propyl ketone, ethyl isopropyl ketone, ethyl-n-butyl ketone, ethyl isobutyl ketone, di-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; lactate esters such as butyl lactate, propyl lactate, ethylhexyl lactate, amyl lactate, and isoamyl lactate; ethylene glycol, diethylene glycol, thiazolinone ... Examples of common organic solvents include glycols such as polyethylene glycol, propylene glycol, and dipropylene glycol; acetates such as 2-methylbutyl acetate and cyclohexyl 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; saturated cyclic hydrocarbons such as cyclohexane, cycloheptane, cyclooctane, cyclodecane, and decalin; unsaturated cyclic 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; ether-based solvents such as triethylene glycol mono-n-butyl ether; and amide-based solvents such as N-dimethyl-β-methoxypropanamide. It is preferable to select a solvent with an appropriate HLB value depending on the resin and dispersant to be combined.

[0060] When other organic solvents are contained, the content of the other organic solvents is not particularly limited, but the lower limit of the content of the other organic solvents is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, of the total amount of the non-aqueous ink composition. The upper limit of the content of the other organic solvents is preferably 10% by mass or less, more preferably 9% by mass or less, and even more preferably 8% by mass or less.

[0061] [resin] The non-aqueous ink composition according to this embodiment does not need to contain a resin, but may contain a resin. By containing a resin, the fixability, water resistance, and stretchability of the recording layer formed using the non-aqueous ink composition can be improved. Furthermore, the glossiness of the resulting recorded matter can be improved.

[0062] The resin is not particularly limited, but examples thereof include 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, and copolymer resins or mixtures thereof. Among these, those containing acrylic resins, vinyl chloride-vinyl acetate copolymer resins, cellulose resins, polyester resins, or polyurethane resins are preferred.

[0063] The acrylic resin is not particularly limited as long as it contains a (meth)acrylic acid ester monomer as the main monomer component. The acrylic resin may be a homopolymer of one type of radically polymerizable monomer or a copolymer of two or more selected radically polymerizable monomers. In particular, the acrylic resin preferred for the oil-based ink composition of this embodiment is a homopolymer of methyl methacrylate or a copolymer of methyl methacrylate and at least one compound selected from the group consisting of butyl methacrylate, ethoxyethyl methacrylate, and benzyl methacrylate. Examples of commercially available (meth)acrylic resins include Rohm and Haas's "Paraloid B99N," "Paraloid B60," "Paraloid B66," and "Paraloid B82."

[0064] Vinyl chloride-vinyl acetate copolymer resins are polymers of vinyl chloride and vinyl acetate monomers. 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. Examples of the vinyl chloride-vinyl acetate copolymer resins available from Nissin Chemical Industry Co., Ltd. under the trade names "Solvin C," "Solvin CL," "Solvin CNL," "Solvin CLL," "Solvin CLL2," "Solvin C5R," "Solvin TA2," "Solvin TA3," "Solvin A," "Solvin AL," "Solvin TA5R," and "Solvin M5" can be used in the present invention.

[0065] The vinyl chloride-vinyl acetate copolymer resin can be obtained by polymerizing vinyl chloride monomer and vinyl acetate monomer. The polymerization method may be any conventionally known polymerization method. The polymerization method is preferably emulsion polymerization or suspension polymerization, and more preferably suspension polymerization.

[0066] Cellulose-based resins are resins with a cellulose skeleton obtained by introducing functional groups biologically or chemically into cellulose as a raw material. Examples of cellulose-based resins include cellulose acetate alkylate resins such as cellulose acetate butyrate resin, cellulose acetate propionate resin, and cellulose acetate propionate butyrate resin, cellulose acetate resin, nitrocellulose resin, and mixtures thereof. These cellulose resins are available from Eastman under the trade names "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."

[0067] The polyester resin contains at least a structural unit obtained by polycondensation of an alcohol component and a carboxylic acid component. The polyester resin may contain a modified polyester resin. Examples of the polyester resin include those available from Toyobo Co., Ltd. under the trade names "VYLON226," "VYLON270," "VYLON560," "VYLON600," "VYLON630," "VYLON660," "VYLON885," "VYLONGK250," "VYLONGK810," and "VYLON GK890," and those available from Unitika Ltd. under the trade names "elitleUE-3200," "elitleUE-3285," "elitleUE-3320," "elitleUE-9800," and "elitleUE-9885."

[0068] The polyurethane resin contains 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. Examples of the polyurethane resin include those available from Arakawa Chemical Industries, Ltd. under the trade names "Uriano KL-424," "Uriano KL-564," "Uriano KL-593," and "Uriano 3262," and those from DIC Corporation under the trade names "Pandex 372E," "Pandex 390E," "Pandex 394E," "Pandex 304," "Pandex 305E," "Pandex P-870," "Pandex P-910," "Pandex P-895," "Pandex 4030," and "Pandex 4110."

[0069] Although these acrylic resins, vinyl chloride-vinyl acetate copolymer resins, cellulose resins, polyester resins, and polyurethane resins may be used alone, it is preferable to use a mixture of two of them, and it is even more preferable to use a resin mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer resin. The content ratio of the acrylic resin and the vinyl chloride-vinyl acetate copolymer resin can be controlled to satisfy the requirements for non-aqueous inks, such as color development, drying properties, coating film properties, and printability. When mixing an acrylic resin and a vinyl chloride-vinyl acetate copolymer resin, the mixing ratio is not particularly limited and can be changed as appropriate.

[0070] The weight average molecular weight (relative molecular mass) of the resin is not particularly limited, but is preferably 5,000 or more, and more preferably 15,000 or more. The weight average molecular weight (relative molecular mass) is preferably 100,000 or less, and more preferably 50,000 or less. The relative molecular weight of the resin can be measured by ordinary GPC (gel permeation chromatography).

[0071] The resin contained in the non-aqueous ink composition is preferably contained in a proportion of 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more, based on the total amount of the non-aqueous ink composition. The resin contained in the non-aqueous ink composition is preferably contained in a proportion of 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.

[0072] Furthermore, the resins contained in the non-aqueous ink composition according to this embodiment preferably have an intrinsic viscosity of 90 mL / g or more at 25° C. in an amount of 5% by mass or less of the total amount of resin. The non-aqueous ink composition according to this embodiment has high inkjet ejection stability because it contains multiple organic solvents with predetermined static surface tensions, and further, because the resins having an intrinsic viscosity of 90 mL / g or more are in an amount of 5% by mass or less of the total amount of resin, it is possible to achieve extremely high inkjet ejection stability.

[0073] In this specification, the intrinsic viscosity is the specific viscosity [η SP ]((η-η0) / η0 (η0: solvent viscosity, η: solution viscosity)) and concentration C are calculated using the formula Lim(〔η SP ] / C), the concentration C can be extrapolated to 0 (C→0). The developing solvent is not particularly limited, but tetrahydrofuran, for example, can be used.

[0074] The content of resins having an intrinsic viscosity of 90 mL / g or more at 25°C is preferably 4.0 mass% or less, more preferably 3.5 mass% or less, and even more preferably 2.5 mass% or less, of the total amount of resin.

[0075] [Colorant] The non-aqueous ink composition according to this embodiment may contain a colorant. The colorant is not particularly limited and may be a dye-based or pigment-based colorant. However, it is preferable to use a pigment (pigment-based colorant) from the viewpoint of providing good resistance to water resistance, light resistance, and the like of the recorded matter. The pigment that can be used in the non-aqueous ink composition according to this embodiment is not particularly limited, and examples thereof include organic pigments and inorganic pigments used in conventional ink compositions. These may be used alone or in combination of two or more types. The non-aqueous ink composition according to this embodiment does not have to contain a colorant.

[0076] When a pigment is used in the non-aqueous ink composition according to this embodiment, the dispersion stability of the pigment can be improved by using a dispersant or a dispersion aid (pigment derivative) as described below.

[0077] Specific examples of organic pigments include insoluble azo pigments, soluble azo pigments, dye derivatives, 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, isoindoline organic pigments, quinacridone solid solution pigments, and organic solid solution pigments such as perylene solid solution pigments. Other pigments include lake pigments and carbon black.

[0078] Examples of organic pigments by Color Index (CI) number include 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, and 214; and CI Pigment Red 5, 7, 9, 12, 48, 49, 52, 53, 57:1, 97, 112, 122, 123, 146, 149, 150, 168, 177, 180, and 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.

[0079] Specific examples of dyes that can be used in the non-aqueous ink composition according to this embodiment include azo dyes, benzoquinone dyes, naphthoquinone dyes, anthraquinone dyes, cyanine dyes, squarylium dyes, croconium dyes, merocyanine dyes, stilbene dyes, diarylmethane dyes, triarylmethane dyes, fluoran dyes, spiropyran dyes, phthalocyanine dyes, indigo dyes such as indigoids, fulgide dyes, nickel complex dyes, and azulene dyes.

[0080] Specific examples of inorganic pigments that can be used in the non-aqueous ink composition according to this embodiment include titanium oxide, barium sulfate, calcium carbonate, zinc oxide, barium carbonate, silica, talc, clay, synthetic mica, alumina, zinc white, lead sulfate, yellow lead, zinc yellow, red iron oxide (red iron (III) oxide), cadmium red, ultramarine, Prussian blue, chromium oxide green, cobalt green, umber, titanium black, aluminum, titanium, indium, synthetic iron black, and inorganic solid solution pigments.

[0081] The average dispersed particle size of the pigment that can be contained in the non-aqueous ink composition according to this embodiment is not particularly limited, as long as it can produce the desired color. While this varies depending on the type of pigment used, in order to obtain good pigment dispersibility and dispersion stability and sufficient coloring power, the volume average particle size is preferably 5 nm or more, more preferably 20 nm or more, and even more preferably 30 nm or more. Having a volume average particle size equal to or greater than the above-mentioned lower limit can improve the lightfastness of the non-aqueous ink composition. The volume average particle size is preferably 300 nm or less, more preferably 200 nm or less, and even more preferably 150 nm or less. The non-aqueous ink composition according to this embodiment has high inkjet ejection stability due to the inclusion of multiple organic solvents having a predetermined static surface tension. Furthermore, having a volume average particle size of the pigment equal to or less than the above-mentioned upper limit can achieve extremely high inkjet ejection stability. In this embodiment, the volume average particle diameter of the pigment is the volume average particle diameter (D50) measured at 25° C. using a particle size distribution measuring device (NANOTRACWAVE particle size analyzer manufactured by Microtrackbell Corporation).

[0082] Furthermore, in an ink set including a plurality of non-aqueous ink compositions according to this embodiment, the volume average particle diameters of the pigments included in the respective non-aqueous ink compositions may be the same or may have different relationships. For example, in an ink set including a cyan ink and a magenta ink, which are non-aqueous ink compositions according to this embodiment, the volume average particle diameter of the pigment included in the cyan ink and the volume average particle diameter of the pigment included in the magenta ink may be the same or may be different.

[0083] In the non-aqueous ink composition according to this embodiment, the pigment content is not particularly limited as long as the desired image can be formed, and can be adjusted as appropriate. Specifically, although this varies depending on the type of pigment, it is preferably in the range of 0.05% by mass or more, and more preferably 0.1% by mass or more, of the total amount of the non-aqueous ink composition. It is preferably in the range of 20% by mass or less, and more preferably 10% by mass or less, of the total amount of the non-aqueous ink composition. By having the pigment content in the range of 0.05% by mass or more or 20% by mass or less, an excellent balance between the dispersion stability and coloring power of the pigment can be achieved.

[0084] Furthermore, the non-aqueous ink composition according to this embodiment is not particularly limited in the color to be recorded (printed), and coloring materials may be selected and combined according to the intended color. Colors include inks of 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, coloring materials of the same color may be selected in an ink set containing the non-aqueous ink composition according to this embodiment.

[0085] [Dispersant] A dispersant may be used in the non-aqueous ink composition according to this embodiment, if necessary. Any dispersant used in non-aqueous ink compositions may be used as the dispersant. A polymer dispersant is preferably used as the dispersant. Such dispersants have a main chain made of a polyester, polyacrylic, polyurethane, polyamine, polycaprolactone, or the like, and a polar group such as an amino group, a carboxyl group, a sulfone group, or a hydroxyl group as a side chain. Examples of polyacrylic dispersants include Disperbyk-2000, 2001, 2008, 2009, 2010, 2020, 2020N, ​​2022, 2025, 2050, 2070, 2095, 2150, 2151, 2155, 2163, and 2164, BYKJET-9130, 9131, 9132, 9133, and 9151 (manufactured by BYK-Chemie), Efka PX4310, PX4320, and PX4330, PA4401, 4402, PA4403, 4570, 7411, and 7477, PX4700, and PX4701 (manufactured by BASF), and TREPLUS Examples of compounds that can be used include D-1200, D-1410, D-1420, MD-1000 (manufactured by Otsuka Chemical Co., Ltd.), Florene DOPA-15BHFS, 17HF, 22, G-700, 900, NC-500, and GW-1500 (manufactured by Kyoeisha Chemical Co., Ltd.). Examples of polycaprolactone-based dispersants 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 Corporation), and TEGO Dispers 652, 655, 685, 688, 690 (manufactured by Evonik Japan) and other products are used.Preferred dispersants include 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, and TEGO Dispers 655, 685, 688, and 690. These can be used alone or in combination.

[0086] [Dispersion aid] A dispersing aid may be used as needed in the non-aqueous ink composition according to this embodiment. The dispersing aid adsorbs to the surface of the colorant (pigment), and its functional groups enhance the affinity with the organic solvent and dispersant in the non-aqueous ink composition, thereby improving dispersion stability. Known pigment derivatives having functional groups such as acidic, basic, or neutral groups in the organic pigment residue can be used as the dispersing aid.

[0087] The content of the dispersant is not particularly limited, but the lower limit of the content of the dispersant is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 0.8% by mass or more, based on the total amount of the non-aqueous ink composition. The content of the dispersant is not particularly limited, but the lower limit of the content of the dispersant is preferably 5.0% by mass or more, more preferably 4.0% by mass or more, and even more preferably 3.0% by mass or more, based on the total amount of the non-aqueous ink composition.

[0088] [Surfactants] The non-aqueous ink composition according to this embodiment may contain a surfactant. While the non-aqueous ink composition according to this embodiment does not necessarily contain a surfactant, it contains a plurality of organic solvents having a predetermined static surface tension. The inclusion of a surfactant can further improve ejection stability by suppressing volatilization of the ink composition in devices such as nozzles and tubes, preventing solidification, and enabling resolubilization when solidified. Furthermore, the inclusion of a surfactant can reduce surface tension and appropriately improve wettability with the recording medium (substrate) to a degree that prevents bleeding in the printout.

[0089] Examples of such surfactants include polyoxyalkylene alkyl ethers such as Nonion 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 Nippon Oil & Fats Co., Ltd.), Emulgen 106, 108, 707, 709, A-90, and A-60. (manufactured by Kao Corporation), Floren G-70, D-90, TG-740W (manufactured by Kyoeisha Chemical Co., Ltd.), Poem J-0081HV (manufactured by Riken Vitamin Co., Ltd.), Adekatall NP-620, NP-650, NP-660, NP-675, NP-683, NP-686, Adekacol CS-141E, TS-230E (manufactured by Adeka Corporation), etc., Solgen 30V, 40, TW-20, TW-80, Noigen CX-100 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), etc. As the fluorine-based surfactant, it is preferable to use a fluorine-modified polymer, a specific example of which is BYK-340 (manufactured by BYK Japan), etc. As the silicone-based surfactant, it is preferable to use a polyester-modified silicone or a polyether-modified silicone, specific examples of which include BYK-313, 315N, 322, 326, 331, 347, 348, BYK-UV3500, 3510, 3530, 3570 (all manufactured by BYK Japan), etc. Specific examples of the acetylene glycol-based surfactant include Surfynol (registered trademark) 82, 104, 465, 485, TG (all manufactured by Air Products Japan), Olfine (registered trademark) STG, E1010 (all manufactured by Nissin Chemical Industry Co., Ltd.), etc.

[0090] The surfactant is not limited to the above, and any of anionic, cationic, amphoteric, and nonionic surfactants can be used, and may be selected appropriately depending on the purpose of addition.

[0091] In the non-aqueous ink composition according to this embodiment, the content of the surfactant is not particularly limited, but the lower limit of the surfactant content is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, based on the total amount of the non-aqueous ink composition. Having a surfactant content of 0.01% by mass or more based on the total amount of the non-aqueous ink composition can further improve ejection stability. The lower limit of the surfactant content is preferably 5.0% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less, based on the total amount of the non-aqueous ink composition. Having a surfactant content of 5.0% by mass or less based on the total amount of the non-aqueous ink composition can prevent the non-aqueous ink composition from spreading too much, thereby effectively preventing bleeding.

[0092] [Other ingredients] The non-aqueous ink composition according to this embodiment may optionally contain known additives such as stabilizers, such as antioxidants and UV absorbers, epoxidized compounds, polycarboxylic acids, surface conditioners, slip agents, leveling agents (acrylic or silicone-based), antifoaming agents, pH adjusters, disinfectants, preservatives, deodorizers, charge control agents, 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. Specific examples include BHA (2,3-butyl-4-oxyanisole) and BHT (2,6-di-t-butyl-p-cresol). Benzophenone-based compounds or benzotriazole-based compounds can also be used as UV absorbers. Specific examples of epoxidized products include epoxy glycerides, epoxy fatty acid monoesters, and epoxy hexahydrophthalates, and specific examples include Adeka Cizer O-130P and Adeka Cizer O-180A (manufactured by ADEKA Corporation).Specific examples of polycarboxylic acids include citric acid and maleic acid.

[0093] 2. Method for producing ink composition The ink composition according to this embodiment can be produced by mixing, using a paint shaker, an organic solvent (a) having a static surface tension of less than 35 mN / m and a flash point of 80° C. or less, an organic solvent (b) having a static surface tension of 35 mN / m or more and a flash point of 80° C. or more, and each main component (e.g., resin, colorant, etc.). At this time, each component may be dispersed using zirconia beads.

[0094] The non-aqueous ink composition according to this embodiment may be subjected to a degassing treatment, etc., as needed, to adjust the dissolved oxygen and nitrogen contents to the desired levels. Furthermore, since the non-aqueous ink composition according to this embodiment has a flash point of 60°C or higher, the volatilization of the organic solvent contained in the non-aqueous ink composition can be suppressed.

[0095] It is also preferable to dry the organic solvent in advance. By drying the organic solvent in advance, the amount of water contained in the non-aqueous ink composition can be reduced. Examples of methods for drying the organic solvent include a method of spraying an inert gas (e.g., nitrogen gas) dried under an inert gas atmosphere such as nitrogen for a predetermined period of time, a method of purifying the organic solvent by distillation, a method of passing the organic solvent through a semi-permeable membrane that selectively allows water to pass through, and a method of selectively adsorbing water mixed in the organic solvent onto a water adsorbent that adsorbs water.

[0096] 3. Recording method using ink composition The recording method according to this embodiment is a recording method in which the non-aqueous ink composition described above is ejected onto the surface of a substrate by an inkjet method. The non-aqueous ink composition described above has high inkjet ejection stability and can effectively suppress bleeding of printed characters. The recording method according to this embodiment also has high inkjet ejection stability and can effectively suppress bleeding of printed characters. The method for ejecting ink by the inkjet method is not particularly limited and may be a piezoelectric method using a piezoelectric element or a thermal method using a heating element.

[0097] It is preferable to heat the non-aqueous ink composition that has landed on the substrate (recording medium) using a heating mechanism provided in the inkjet recording device. By heating the non-aqueous ink composition that has landed on the substrate (recording medium), the organic solvent (a) contained in the non-aqueous ink composition can be preferentially volatilized, and the organic solvent (b), which has a high static surface tension and is difficult to spread, can be slowly volatilized later, thereby more effectively suppressing bleeding of the print. The same applies to the method for producing a printed matter described below.

[0098] <4. Manufacturing method of printed matter> The recording method using the ink composition described above can also be defined as a method for producing a printed matter. The method for producing a printed matter according to this embodiment also has high inkjet ejection stability and can effectively suppress bleeding of the printed matter.

[0099] <5. Records> Each layer constituting the recorded matter produced by the method for producing a recorded matter according to the embodiment described above will now be described.

[0100] [Media (recording media)] The substrate (recording medium) that can be used in the recording method according to the present embodiment is not particularly limited, and may be a resin substrate (including those whose surfaces are mainly made of resin), a non-absorbent substrate such as a metal plate glass, an absorbent substrate such as paper or fabric, or a substrate with a surface coating such as a substrate having a receiving layer, and various substrates can be used.

[0101] Among these, the non-aqueous ink composition described above is a water-free non-aqueous ink composition, and therefore one whose surface is primarily made of resin is preferred. In particular, when a non-aqueous ink composition wets and spreads on a non-absorbent substrate, such as a substrate whose surface is primarily made of resin or a metal plate or glass, bleeding of the print may occur. However, the non-aqueous ink composition described above, which contains multiple organic solvents having a predetermined static surface tension, can effectively suppress bleeding of the print even on a non-absorbent substrate such as a resin substrate. Examples of resins constituting such non-absorbent substrates include polyvinyl chloride polymers, acrylic, PET, polycarbonate, PE, and PP. Furthermore, the non-aqueous ink composition may be used for resin substrates intended for laminating a film to the recording surface of a recorded material (so-called resin substrates for lamination). In particular, substrates (recording media) whose surfaces are made of hard or soft polyvinyl chloride polymers are preferred. Examples of substrates (recording media) whose surfaces are made of polyvinyl chloride polymers include polyvinyl chloride substrates (films or sheets).

[0102] [Recording layer] The recording layer is a layer formed by the evaporation of the solvent contained in the non-aqueous ink composition, and is a layer on which a desired image is formed. By ejecting the non-aqueous ink composition, a recorded product can be obtained that has excellent surface drying properties and displays a clear image without bleeding.

[0103] The layer formed by the evaporation of the solvent contained in the non-aqueous ink composition may be formed from multiple layers. For example, a layer of a color ink (e.g., yellow, magenta, cyan, black) of the non-aqueous ink composition may be formed on a layer of a white ink of the non-aqueous ink composition.

[0104] [Other layers] The recorded matter according to this embodiment may further include a layer having a desired function on the upper surface of the recording layer. For example, an overcoat layer containing at least one of resin and wax may be formed to further impart abrasion resistance and gloss to the recorded matter. A layer that expresses a textured surface (matte surface) may also be formed by incorporating a filler or varying the film thickness on a pixel-by-pixel basis. Furthermore, a weather-resistant layer containing an ultraviolet absorber, a light stabilizer, or the like, or a glittering layer containing a glittering pigment may also be formed to impart weather resistance to the recorded matter.

[0105] Although the recorded matter according to the present embodiment includes a recording layer formed from the non-aqueous ink composition, for example, a layer having a desired function may be formed by ejecting the non-aqueous ink composition onto a recording layer formed from a conventionally known ink composition. Also, a layer having a desired function may be formed by ejecting the non-aqueous ink composition onto a recording layer formed from the non-aqueous ink composition.

[0106] <6. Inkjet recording device> The inkjet recording device for ejecting the non-aqueous ink composition by an inkjet method may be a conventionally known inkjet recording device, such as an inkjet printer such as the VersaArt RE-640 manufactured by Roland DG Corporation.

[0107] As an example of the configuration of an inkjet recording device, an on-carriage type, serial printer type inkjet recording device will be described, but an inkjet recording device capable of carrying out the recording method according to this embodiment may also be an off-carriage type inkjet recording device in which the ink cartridge is fixed externally, or a line printer type inkjet recording device in which the inkjet head does not move and ejects the ink composition onto a recording medium (substrate).

[0108] The inkjet recording apparatus preferably includes a heating mechanism and a fixing mechanism for fixing the substrate. The heating mechanism included in the inkjet recording apparatus controls the substrate surface temperature to dry the non-aqueous ink composition that has landed on the substrate (recording medium), which allows the organic solvent (a) contained in the non-aqueous ink composition to volatilize preferentially, and the organic solvent (b), which has a high static surface tension and is difficult to spread, to volatilize later, more slowly, thereby more effectively suppressing bleeding of the print.

[0109] Furthermore, the fixing mechanism for fixing the substrate allows the non-aqueous ink composition to dry while the substrate (recording medium) is fixed, which prevents the substrate from warping due to heating, resulting in uneven heat application. This allows the non-aqueous ink composition that has landed on the substrate (recording medium) to dry effectively, making it possible to more effectively prevent bleeding of the print.

[0110] The heating mechanism provided in the inkjet recording apparatus may be a preheater, a platen heater, an afterheater, or a mechanism for blowing hot air onto the recording material. In addition, a combination of these heating mechanisms may be used.

[0111] The surface temperature of the substrate heated by the heating mechanism is not particularly limited as long as it can volatilize the organic solvent contained in the non-aqueous ink composition, and the lower limit of the surface temperature of the substrate is preferably 20° C. or higher, more preferably 30° C. or higher, and even more preferably 40° C. or higher. The upper limit of the surface temperature of the substrate is preferably 70° C. or lower, more preferably 60° C. or lower, and even more preferably 50° C. or lower.

[0112] The fixing mechanism for fixing the substrate is not particularly limited and may be a fixing mechanism for fixing the substrate with a predetermined jig or a fixing mechanism for sucking and adsorbing the substrate by negative pressure.

[0113] If the non-aqueous ink composition has too high a drying property, the amount of organic solvent contained in the non-aqueous ink composition may change during inkjet ejection, and the desired properties may not be obtained. Therefore, it is preferable that the flash point of the non-aqueous ink composition be 60°C or higher.

[0114] The inkjet head for ejecting the non-aqueous ink composition is not particularly limited and may be a piezoelectric inkjet head using a piezoelectric element or a thermal inkjet head using a heating element.

[0115] The inkjet recording apparatus may also be configured to include a plastic tube connecting a container (such as an ink cartridge or bottle) for storing the non-aqueous ink composition to an inkjet head for ejecting the non-aqueous ink composition, and to supply the non-aqueous ink composition to the inkjet head through the plastic tube and eject the non-aqueous ink composition by an inkjet method. If the non-aqueous ink composition is present in the plastic tube, some of the organic solvent contained in the non-aqueous ink composition may volatilize. This may change the amount of organic solvent contained in the non-aqueous ink composition at the inkjet ejection stage, making it difficult to obtain desired properties.

[0116] In particular, alkylamide solvents, even when present in a plastic tube, are present in relatively small amounts compared to other organic solvents. The amount of volatilization of an organic solvent in a plastic tube does not necessarily correlate with the volatility parameters of the organic solvent itself, such as its boiling point, flash point, or evaporation enthalpy. This is because the permeability of plastics varies depending on the type of organic solvent, and the volatilization rate in a sealed low-density polyethylene tube is rather due to the permeability of plastics, specifically, a parameter resulting from the chemical structure, molecular weight, compatibility, etc. of the organic solvent.

[0117] Alkylamide-based solvents are solvents that volatilize in a relatively small amount inside a plastic tube, and therefore, a non-aqueous ink composition containing an alkylamide-based solvent can be inkjet-ejected while maintaining the amount of organic solvent component contained in the non-aqueous ink composition.

[0118] The organic solvent can be filled into a low-density polyethylene tube (a 12-cm piece of polyethylene tube hose (model number 6-608-03, manufactured by AS ONE Corporation, low-density polyethylene (PE-LD) with an inner diameter of 3 mm and an outer diameter of 5 mm) cut into a 12-cm piece, sealed, and stored at 50°C for one week. The amount of evaporation after storage can be measured. For example, the amount of evaporation for 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 N,N-diethylformamide is 11% by mass, N,N-diethylpropanamide is 12% by mass, and N,N-diethylacetamide is 13% by mass. This shows that alkylamide solvents have a low evaporation rate inside plastic tubes.

[0119] The material of the plastic tube is not particularly limited, but examples thereof include polyethylene resin, ethylene propylene diene rubber, etc., and it is preferable to use polyethylene resin, and among these, it is particularly preferable to use low-density polyethylene resin.

[0120] The material of the plastic tube is not particularly limited, but examples include polyolefin resins such as polyethylene resins, ethylene propylene diene rubber, nylon, polyurethane, PTFE, etc. Among these, polyethylene resins and ethylene propylene diene rubber are preferred.

[0121] Furthermore, the inkjet recording apparatus according to the present embodiment can be used with inks of various colors, such as yellow, magenta, cyan, and black, as described above, or with inks of light magenta, light cyan, light black, orange, green, red, and white, and there are no particular limitations on the order of colors to be printed or the position and configuration of the head. Furthermore, the inkjet recording apparatus according to the present embodiment may or may not be equipped with a winding mechanism for the recording medium (substrate), a drying mechanism for drying the surface of the substrate, and an ink circulation mechanism. [Example]

[0122] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these descriptions in any way.

[0123] 1. Resin Preparation (1) Acrylic resin A mixture of 150 g of methyl methacrylate, 50 g of butyl methacrylate, and a predetermined amount of t-butylperoxy-2-ethylhexanoate (polymerization initiator) was added dropwise to 300 g of diethylene glycol diethyl ether maintained at 100°C over 1.5 hours. After the addition was completed, the mixture was allowed to react 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 t-butylperoxy-2-ethylhexanoate, the polymerization initiator, was varied to control the weight average molecular weight of the methyl methacrylate (acrylic resin) to 30,000 to 105,000 (the mass of the polymerization initiator used is listed in Table 1 below, and is denoted as "initiator amount" in Table 1).

[0124] (2) Vinyl chloride-vinyl acetate copolymer resin An autoclave equipped with a stirrer was charged with 100 parts deionized water, 40 parts methanol, 32 parts vinyl chloride, 5 parts vinyl acetate, 0.2 parts glycidyl methacrylate, 3.55 parts hydroxypropyl acrylate, 0.1 parts hydroxypropyl methylcellulose (suspending agent), 0.026 parts di-2-ethylhexyl peroxydicarbonate (polymerization initiator), and a predetermined amount of di-3,5,5-trimethylhexanol peroxide (polymerization initiator) after nitrogen substitution. The mixture was heated to 63 ° C under a nitrogen gas atmosphere with stirring. Immediately after reaching 63 ° C, 48 parts vinyl chloride was added over 6 hours, and a mixture of 0.6 parts glycidyl methacrylate and 10.65 parts hydroxypropyl acrylate was continuously added over 5.4 hours to carry out the copolymerization reaction. When the internal pressure of the autoclave reached 0.3 MPa, the residual pressure was released, the mixture was cooled, and the resin slurry was removed, filtered, and dried to obtain a vinyl chloride copolymer resin. At this time, the amount of di-3,5,5-trimethylhexanol peroxide, which is a polymerization initiator, was changed to control the weight average molecular weight of the vinyl chloride-vinyl acetate copolymer resin to 40,000 to 75,000 (the mass of the polymerization initiator used at this time is shown in Table 1 below, and is represented as "amount of initiator" in Table 1).

[0125] Table 1 shows the weight-average molecular weight (relative molecular mass) of each resin (acrylic resin, vinyl chloride-vinyl acetate copolymer resin) and the percentage of resins with an intrinsic viscosity of 90 mL / g or more at 25°C. The weight-average molecular weight (relative molecular mass) was measured by GPC (gel permeation chromatography). The percentage of resins with an intrinsic viscosity of 90 mL / g or more was determined by connecting a viscosity detector (WYATT ViscoStar III) and a refractive index detector (WYATT Optilab T-rEX) to a Shimadzu SEC (GPC) system. Using tetrahydrofuran as the developing solvent, the sample was first passed through a column heated to 40°C, and then cooled to 25°C. The passed-through material was measured for specific viscosity [η SP ], and the concentration C is calculated using a refractive index detector. SP ] / C), the intrinsic viscosity was calculated by extrapolating the concentration C to 0.

[0126] [Table 1]

[0127] 2. Preparation of Non-Aqueous Ink Composition Non-aqueous ink compositions of Examples and Comparative Examples were prepared using the organic solvent, resin, dispersant, and pigment (colorant) components in the proportions shown in the table below. Specifically, each component was dispersed with zirconia beads using a paint shaker to prepare the non-aqueous ink compositions. The units are % by mass.

[0128] 3. Rating 1 (bleeding) 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 by inkjet printing on a recording medium (adhesive polyvinyl chloride film (IMAGin JT5829R: manufactured by MACtac)) in high-quality printing mode (1440 x 720 dpi) at a substrate surface temperature of 40°C, with an image of 6-point text of a different color printed within a solid area of ​​each color. The resulting print was dried in an oven at 60°C for 5 minutes, and then the print was visually observed for bleeding using a magnifying glass (x10) (referred to as "Bleeding" in the table). Evaluation criteria Rating 5: No ink bleeding is observed when observed with a magnifying glass. Rating 4: No ink bleeding was observed visually, and 6 pt characters were clear. Rating 3: Slight bleeding of ink was visually observed, but the design was not impaired. Rating 2: Ink bleeding was observed visually, but 6 pt characters were legible. Rating 1: Significant ink bleeding was visually observed, and 6 pt characters were not visible.

[0129] (Surface dryness) The non-aqueous ink compositions of the Examples and Comparative Examples were evaluated for surface drying properties. Specifically, a solid image was printed in high-quality printing mode (1440 x 720 dpi) on a recording medium (adhesive polyvinyl chloride film (IMAGin JT5829R: manufactured by MACtac)) in the same manner as in the bleeding property evaluation described above, and the time until the image dried at 40°C was measured (referred to as "surface drying properties" in the table). Evaluation criteria Rating 5: Dries in less than 2 minutes. Rating 4: Dries in 2 to 4 minutes. Rating 3: Dries in 4 to 6 minutes. Rating 2: Dries in 6 to 8 minutes. Rating 1: Dries in 8 minutes or more.

[0130] (Discharge stability) The non-aqueous ink compositions of the Examples and Comparative Examples were evaluated for ejection stability. Specifically, in the same manner as in the bleeding evaluation described above, solid and thin lines were printed continuously 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, and the presence or absence of missing dots, deflected ink, and ink scattering was visually observed, and the number of occurrences was counted (referred to as "ejection stability" in the table). Rating 5: Missing dots, deflection of ink, or ink scattering occurred less than 10 times during the 24-hour test period. Evaluation 4: Missing dots, deflection of ink droplets, or ink scattering occurred 10 or more times but less than 20 times during the 24-hour test period. Evaluation 3: Missing dots, deflection of ink droplets, or ink scattering occurred 20 or more times but less than 30 times during the 24-hour test period. Evaluation 2: Missing dots, deflection of ink droplets, or ink scattering occurred 30 or more times but less than 40 times during the 24-hour test period. Rating 1: Missing dots, deflected ink, or ink scattering occurred 40 or more times within a 24-hour test period.

[0131] [Table 2]

[0132] [Table 3]

[0133] [Table 4]

[0134] [Table 5]

[0135] [Table 6]

[0136] [Table 7]

[0137] [Table 8]

[0138] [Table 9]

[0139] In the table, "MEDG" stands for diethylene glycol methyl ethyl ether.

[0140] In the table, "DEDG" stands for diethylene glycol diethyl ether.

[0141] In the table, "DMFDG" stands for dipropylene glycol dimethyl ether.

[0142] In the table, "MFDG" stands for dipropylene glycol monomethyl ether.

[0143] In the table, "DEF" stands for N,N-diethylformamide.

[0144] In the table, "DEPA" stands for N,N-diethylpropanamide.

[0145] In the table, "DEAA" stands for N,N-diethylacetamide.

[0146] In the table, "EGMBEA" stands for ethylene glycol monobutyl ether acetate.

[0147] In the table, "PMA" stands for propylene glycol monomethyl ether acetate.

[0148] In the table, "3-MBA" stands for 3-methoxybutyl acetate.

[0149] In the table, "DEOX" stands for diethyl oxalate.

[0150] In the table, "ML" stands for methyl lactate.

[0151] In the table, "EL" stands for ethyl lactate.

[0152] In the table, "PC" stands for propylene carbonate.

[0153] In the table, "GBL" stands for γ-butyrolactone.

[0154] In the table, "ECL" stands for ε-caprolactone.

[0155] In the table, "MOZ" stands for 3-methyl-2-oxazolidinone.

[0156] In the table, "PhDG" stands for diethylene glycol monophenyl ether.

[0157] In the table, "BTeG" stands for tetraethylene glycol mono-n-butyl ether.

[0158] In the table, "BTG" stands for triethylene glycol mono-n-butyl ether.

[0159] In the table, "M100" is N-N-dimethyl-β-methoxypropanamide.

[0160] In the table, "Solsperse 32000" is a polycaprolactone-based dispersant manufactured by Lubrizol Corporation.

[0161] In the table, "Solsperse 33000" is a polycaprolactone-based dispersant manufactured by Lubrizol Corporation.

[0162] As can be seen from Tables 2 to 9, the non-aqueous ink compositions of the examples, which contain an organic solvent (a) having a static surface tension of less than 35 mN / m and a flash point of 80°C or less, and an organic solvent (b) having a static surface tension of 35 mN / m or more and a flash point of 80°C or more, have high inkjet ejection stability and can effectively suppress bleeding of printed images.

[0163] In particular, among the non-aqueous ink compositions of Examples 1 to 5 in which the mass ratio of the organic solvent (a) to the organic solvent (b) was varied, the non-aqueous ink compositions of Examples 1 to 4 in which the mass ratio of the organic solvent (a) to the organic solvent (b) (organic solvent (a):organic solvent (b)) was within the range of 99:1 to 70:30 were able to more effectively suppress bleeding of the print. Furthermore, the non-aqueous ink compositions of Examples 2 to 5 had particularly high inkjet ejection stability.

[0164] Furthermore, in the non-aqueous ink compositions of Examples 3 and 6 to 10, in which the type of organic solvent (b) having a static surface tension of 35 mN / m or more and a flash point of 80°C or more was changed, it was found that the effects of the present invention were achieved even when the carbonate ester of the non-aqueous ink composition of Example 3 was replaced with an amide solvent or a glycol ether monoalkyl.

[0165] Furthermore, the non-aqueous ink compositions of Examples 3 and 11 to 22, in which the type of organic solvent (a) was changed, all achieved the effects of the present invention. Among these, the non-aqueous ink compositions of Examples 14 to 16, which contained an alkylamide solvent as the amide solvent, were particularly effective in suppressing bleeding of prints.

[0166] Furthermore, among the non-aqueous ink compositions of Examples 33 to 44, in which the content of resin with an intrinsic viscosity of 90 mL / g or more at 25°C was varied, the non-aqueous ink compositions of Examples in which the content of resin with an intrinsic viscosity of 90 mL / g or more at 25°C was in the range of 5 mass% or less of the total amount of resin had particularly high inkjet ejection stability, even compared to the non-aqueous ink compositions of Examples in which the content was in the range of more than 5 mass%.

[0167] On the other hand, the non-aqueous ink compositions of Comparative Examples 1 and 2, which do not contain an organic solvent (b) having a static surface tension of 35 mN / m or more and a flash point of 80°C or more, and the non-aqueous ink composition of Comparative Example 3, which does not contain an organic solvent (a) having a static surface tension of less than 35 mN / m and a flash point of 80°C or less, do not exhibit the effects of the present invention.

[0168] 4. Rating 2 The non-aqueous ink composition of Example 14 was ejected by inkjet printing, and the "bleeding" and "solid coverage" were evaluated in the same manner as above. The heating mechanism and the fixing mechanism for fixing the substrate, both of which were provided in the inkjet recording apparatus, were turned on and off as shown in Table 4 below. When the heating mechanism was not used, printing was carried out at room temperature (23°C to 25°C), and when the suction mechanism was not used, printing was carried out with air suction turned off.

[0169] (Filled in completely) In the same manner as in the bleeding evaluation described above, a recording medium (adhesive polyvinyl chloride film (IMAGin JT5829R: manufactured by MACtac)) was printed in bidirectional high-speed mode (360x720dpi) to check for filling (whiteout) in the solid printed areas (marked as "solid filling" in the table). Evaluation criteria Evaluation 4: A uniform solid color is formed Rating 3: Slight color unevenness can be seen with the naked eye, but the design is not impaired. Rating 2: Color unevenness can be visually confirmed Rating 1: Unevenness occurs and the design is significantly impaired

[0170] [Table 10]

[0171] As can be seen from Table 10, by using an inkjet recording device equipped with a heating mechanism and a fixing mechanism for fixing the substrate, turning each mechanism on, and drying the non-aqueous ink composition while the substrate (recording medium) is fixed by the fixing mechanism for fixing the substrate, and then ejecting the non-aqueous ink composition containing organic solvent (a) and organic solvent (b) by the inkjet method, it can be seen that the resulting recorded matter has good "bleed-through" and "solid coverage".

Claims

1. A non-aqueous ink composition containing an organic solvent and ejected by an inkjet method, The organic solvent is an organic solvent (a) having a static surface tension of less than 35 mN / m and a flash point of 80°C or less; an organic solvent (b) having a static surface tension of 35 mN / m or more and a flash point of 80°C or more; Contains the organic solvent (b) contains a carbonate ester, The content of the carbonate ester is 5% by mass or less of the total amount of the non-aqueous ink composition. Non-aqueous ink compositions.

2. The organic solvent (a) contains at least one selected from the group consisting of amide solvents, glycol ether dialkyls, glycol ether monoalkyls, acetates, dibasic acid esters, and lactate esters. The non-aqueous ink composition of claim 1 .

3. The organic solvent (a) contains an alkylamide solvent as an amide solvent. The non-aqueous ink composition of claim 2.

4. Further containing resin, The resin has an intrinsic viscosity of 90 mL / g or more at 25°C in an amount of 5 mass % or less of the total amount of resin. The non-aqueous ink composition according to any one of claims 1 to 3.

5. The ink is ejected by an inkjet method using an inkjet recording apparatus equipped with a heating mechanism and a fixing mechanism for fixing the substrate. The non-aqueous ink composition according to any one of claims 1 to 4.

6. Using an inkjet recording device equipped with a plastic tube, ink is ejected through the plastic tube by an inkjet method. The non-aqueous ink composition according to any one of claims 1 to 5.

7. Used for resin substrates The non-aqueous ink composition according to any one of claims 1 to 6.

8. The non-aqueous ink composition according to any one of claims 1 to 7 is ejected onto the surface of a substrate by an inkjet method. Recording method.

9. The non-aqueous ink composition according to any one of claims 1 to 7 is ejected onto the surface of a substrate by an inkjet method. A method for producing recorded materials.

10. A recording layer of the non-aqueous ink composition according to any one of claims 1 to 7 formed on the surface of a substrate. Recorded material.

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