Recording method and ink composition for the recording method

Abstract

Provided are a recording method and an ink composition for the recording method that can effectively suppress a decrease in ejection stability of the ink composition and prevent the ink composition from being ejected to a desired position on the surface of a substrate. A recording method in which an ink composition for inkjet containing an organic solvent is ejected onto the surface of a substrate using an inkjet head having constituent members bonded by a cured product of an adhesive, and the organic solvent contains the following organic solvent (a). Organic solvent (a): at least one selected from the group consisting of an alkylamide-based solvent (a1), a cyclic amide-based solvent (a2), and a lactone-based solvent (a3).

Description

Technical Field

[0001] The present invention relates to a recording method and an ink composition for the recording method. Background Art

[0002] As the ink composition, an aqueous ink composition in which a coloring material is dissolved or dispersed in water or a mixed liquid of water and an organic solvent, and a non-aqueous ink composition in which a coloring material is dissolved or dispersed in an organic solvent that does not contain water are widely used.

[0003] For example, Patent Document 1 describes a non-aqueous or aqueous ink composition for inkjet containing a coloring material and an alkoxyalkylamide-based solvent such as 3-methoxy-N,N-dimethylpropanamide. According to Patent Document 1, it is described that this ink composition is suitable for printing on the surface of a medium such as a resin medium.

[0004] In addition, such an ink composition for inkjet is ejected onto the surface of a substrate through an inkjet head during actual recording (printing). For example, Patent Document 2 describes a technique related to an inkjet head, characterized in that the adhesive used in the bonding portion of the inkjet head is a specified adhesive. Patent Document 2 describes that it does not swell due to the ink composition, can be cured at a temperature that does not affect the piezoelectricity of the piezoelectric element, and can also easily control the coating film thickness.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2012-046671

[0008] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2001-301178 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] In addition, even when the ink composition containing the above-mentioned alkoxyalkylamide-based solvent is ejected onto the surface of a substrate through an inkjet head, bleeding of the printed characters is less, and a recording object (printed matter) with good image quality can be obtained.

[0011] However, although the ink composition containing 3-methoxy-N,N-dimethylpropanamide has less bleeding of the printed characters, when passing through the inkjet head, the ink composition comes into contact with the cured product of the adhesive, and sometimes the cured product of the adhesive is eroded. As a result, the ejection stability of the ink composition is reduced, the ink composition cannot be ejected to the desired position on the surface of the substrate, and the desired recording object (printed matter) cannot be obtained.

[0012] An object of the present invention is to provide a recording method with less bleeding that prints in the same manner as an ink composition containing an alkoxyalkylamide-based solvent and can effectively inhibit the erosion of the cured product of the adhesive that bonds the constituent members of an inkjet head.

[0013] Means for solving the problems

[0014] The inventors of the present invention conducted in-depth research to solve the above problems and found that if a recording method is used in which an ink composition containing a specified organic solvent is ejected onto the surface of a substrate by an inkjet head, the above problems can be solved, and thus the present invention was completed. Specifically, in the present invention, the following solutions are provided.

[0015] (1) A recording method, wherein an ink composition for inkjet containing an organic solvent is ejected onto the surface of a substrate by an inkjet head, the inkjet head having constituent members bonded by a cured product of an adhesive, and the organic solvent contains the following organic solvent (a).

[0016] Organic solvent (a): at least one selected from alkylamide-based solvents (a1), cyclic amide-based solvents (a2), and lactone-based solvents (a3)

[0017] (2) The recording method according to (1), wherein the adhesive that bonds the constituent members of the inkjet head contains an epoxy-based adhesive.

[0018] (3) The recording method according to (1) or (2), wherein the inkjet head has a member covering the ejection hole surface of the ink composition.

[0019] (4) The recording method according to any one of (1) to (3), wherein an ink storage mechanism is provided between the ink supply unit that supplies the ink composition and the inkjet head.

[0020] (5) A method for manufacturing a recorded object, wherein an ink composition for inkjet containing an organic solvent is ejected onto the surface of a substrate by an inkjet head, the inkjet head having constituent members bonded by a cured product of an adhesive, and the organic solvent contains the following organic solvent (a).

[0021] Organic solvent (a): at least one selected from alkylamide-based solvents (a1), cyclic amide-based solvents (a2), and lactone-based solvents (a3)

[0022] (6) An ink composition, which is an ink composition for inkjet ejected onto the surface of a substrate by an inkjet head, the inkjet head having constituent members bonded by a cured product of an adhesive, the ink composition containing an organic solvent, and the organic solvent containing the following organic solvent (a).

[0023] Organic solvent (a): at least one selected from alkyl amide solvents (a1), cyclic amide solvents (a2), and lactone solvents (a3)

[0024] (7) The ink composition according to (6), wherein the organic solvent (a) is an alkyl amide solvent (a1).

[0025] (8) The ink composition according to (7), wherein the alkyl amide solvent (a1) is represented by the following general formula (1).

[0026] [Chemical Formula 1]

[0027]

[0028] (In formula (1), R1 is hydrogen or an alkyl group having 1 or more and 4 or less carbon atoms, and R2 represents an alkyl group having 2 or more and 4 or less carbon atoms.)

[0029] (9) The ink composition according to (8), wherein the alkyl amide solvent (a1) contains at least one selected from N,N - diethylformamide, N,N - diethylpropanamide, and N,N - diethylacetamide.

[0030] (10) The ink composition according to (6), wherein the organic solvent (a) is a cyclic amide solvent (a2).

[0031] (11) The ink composition according to (10), wherein the cyclic amide solvent (a2) is represented by the following general formula (2).

[0032] [Chemical Formula 2]

[0033]

[0034] (In formula (2), R3 is an alkylene group having 4 or more and 5 or less carbon atoms, and R4 represents hydrogen or an alkyl group or unsaturated hydrocarbon group having 1 or more and 2 or less carbon atoms.)

[0035] (12) The ink composition according to (11), wherein the cyclic amide solvent (a2) contains at least one selected from ε - caprolactam, N - methylcaprolactam, and N - vinylcaprolactam.

[0036] (13) The ink composition according to (6), wherein the organic solvent (a) is a lactone solvent (a3).

[0037] (14) The ink composition according to (13), wherein the lactone solvent (a3) is represented by the following general formula (3).

[0038] [Chemical Formula 3]

[0039]

[0040] (In formula (3), R5 is an alkylene group having 3 to 5 carbon atoms, and R6 represents hydrogen or an alkyl group having 1 to 2 carbon atoms.)

[0041] (15) The ink composition according to (14), wherein the lactone-based solvent (a3) contains at least one selected from γ-butyrolactone, γ-valerolactone, δ-valerolactone, δ-caprolactone, and ε-caprolactone.)

[0042] Advantages of the Invention

[0043] Regarding the recording method of the present invention, even when ejected onto the surface of a substrate, bleeding of the printed characters is less, and it is possible to suppress a decrease in the ejection stability of the ink composition caused by the ink composition eroding the cured product of the adhesive that bonds the constituent members of the inkjet head, and it is possible to effectively suppress the ink composition from not being ejected to the desired position on the surface of the substrate.) BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram (cross-sectional view) showing an example of an inkjet head used in the recording method of the present embodiment.) DETAILED DESCRIPTION OF THE INVENTION

[0045] Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to any of the following embodiments and can be appropriately modified and implemented within the scope of the object of the present invention.)

[0046] <<Recording Method>>

[0047] The recording method of the present embodiment is a recording method of ejecting an ink composition for inkjet containing an organic solvent onto the surface of a substrate using an inkjet head having constituent members bonded by a cured product of an adhesive. And this ink composition is characterized in that, as the organic solvent, it contains at least one selected from an alkylamide-based solvent (a1), a cyclic amide-based solvent (a2), and a lactone-based solvent (a3) (organic solvent (a)).)

[0048] If it is such a recording method, even when ejected onto the surface of a substrate, bleeding of the printed characters is less, and it is possible to suppress a decrease in the ejection stability of the ink composition caused by the ink composition eroding the cured product of the adhesive, and it is possible to effectively suppress the ink composition from not being ejected to the desired position on the surface of the substrate.)

[0049] In addition, an ink composition containing at least one selected from an alkylamide-based solvent (a1), a cyclic amide-based solvent (a2), and a lactone-based solvent (a3) as an organic solvent (organic solvent (a)) can transport a recording medium (substrate) at high speed for recording because of less bleeding of the printed characters.

[0050] Specifically, the maximum speed among the recording speeds in the recording method of the present embodiment also depends on the type of the substrate, the type of the inkjet recording apparatus, etc., and is preferably 10 m 2 / h or more, more preferably 15 m 2 / h or more, and further preferably 20 m 2 / h or more. In addition, the maximum speed among the recording speeds in the recording method of the present embodiment is preferably 70 m 2 / h or less, more preferably 65 m 2 / h or less, and further preferably 60 m 2 / h or less.

[0051] In addition, when recording by transporting the recording medium (substrate) at high speed, it is preferable to control the surface temperature of the substrate by a heating mechanism. Thereby, the ink composition landing on the substrate (recording medium) can be dried at a higher speed, and bleeding of the printed characters can be made extremely small.

[0052] The surface temperature of the substrate heated by the heating mechanism is not particularly limited as long as the organic solvent contained in the ink composition can be volatilized. The lower limit of the surface temperature of the substrate is preferably 20°C or more, more preferably 30°C or more, and further preferably 40°C or more. The upper limit of the surface temperature of the substrate is preferably 70°C or less, more preferably 60°C or less, and further preferably 50°C or less.

[0053] Hereinafter, an example of the configuration of an inkjet recording apparatus capable of implementing the recording method of the present embodiment will be described. Note that, as an example of the configuration of the inkjet recording apparatus, a carriage type and serial printer type inkjet recording apparatus will be described, but the inkjet recording apparatus capable of implementing the recording method of the present embodiment may be an off-carriage type inkjet recording apparatus in which a cartridge is fixed outside, or a line printer type inkjet recording apparatus in which an inkjet head does not move and ejects an ink composition onto a recording medium (substrate).

[0054] 《Inkjet Recording Apparatus》

[0055] The inkjet recording apparatus is a carriage type inkjet recording apparatus including a cartridge (ink supply unit) mounted on a carriage, a supply mechanism for supplying the ink composition in the cartridge to an inkjet head, and a connection unit connecting the cartridge (ink supply unit) and the inkjet head.

[0056] In this inkjet recording apparatus, an inkjet head is mounted on a carriage that moves in a predetermined direction, and the inkjet head moves as the carriage moves, whereby an ink composition can be ejected onto a recording medium (substrate).

[0057] The ink composition in the ink cartridge can also be used for various colors of inks such as yellow, magenta, cyan, black, light magenta, light cyan, light black, orange, green, red, white, etc. The order of printing colors, the position, and the configuration of the inkjet head are not particularly limited.

[0058] Hereinafter, the constituent members of this inkjet recording apparatus will be described.

[0059] [Inkjet head]

[0060] An inkjet head is a constituent member of an inkjet recording apparatus that ejects an ink composition onto the surface of a substrate. In Figure 1 FIG. shows a schematic diagram illustrating an example of an inkjet head. This inkjet head 1 ejects the ink composition supplied from an ink cartridge (ink supply unit) from the ejection hole surface D onto the surface of a substrate (recording medium).

[0061] The inkjet head 1 can be a piezoelectric inkjet head using a piezoelectric element or a thermal inkjet head using a heating element, without particular limitation.

[0062] This inkjet head 1 preferably includes a member (such as a nozzle cap, etc.) that covers the ejection hole surface D of the ink composition. It can suppress a decrease in intermittent ejection performance due to drying of the ejection hole surface D, and can also suppress a decrease in ejection stability due to water absorption of the ink composition on the ejection hole surface.

[0063] In addition, since the organic solvent (a) has low volatility in the flow path, by covering the ejection hole surface, the volatility in the flow path can be made extremely small. Therefore, by ejecting an ink composition containing the organic solvent (a) using an inkjet head having a member covering the ejection hole surface, the intermittent ejection performance can be improved.

[0064] In particular, when the ink composition is dried at a higher speed by a heating mechanism, even during standby without inkjet ejection, the ink composition present near the ejection holes is likely to dry due to the heating mechanism. By covering the ejection hole surface D with a member during standby without inkjet ejection, drying of the ink composition present near the ejection holes due to the heating mechanism can be suppressed, thereby suppressing a decrease in intermittent ejection performance. And since the ink composition landed on the substrate (recording medium) can be dried at a higher speed by the heating mechanism, a recording can be manufactured at an extremely high speed.

[0065] The effect of improving intermittent ejection cannot be fully obtained when the conventional ink composition containing an alkoxyalkylamide-based solvent is ejected onto the surface of a substrate by the inkjet head 1 having a member covering the ejection hole surface D. That is, when an ink composition containing an organic solvent (a) is ejected onto the surface of a substrate, the effect is particularly significantly exhibited when it is ejected onto the surface of a substrate by an inkjet head having a member covering the ejection hole surface.

[0066] As Figure 1 shown, this inkjet head has a constituent member bonded by a cured product A of an adhesive, and contacts the cured product A of the adhesive when the ink composition passes through the inkjet head. The recording method of this embodiment can suppress a decrease in the ejection stability of the ink composition and effectively suppress the ink composition from not being ejected to a desired position on the surface of the substrate by including a step of ejecting a prescribed ink composition and ejecting it onto a recording medium (substrate). Hereinafter, the adhesive constituting the inkjet head will be described.

[0067] (Adhesive)

[0068] The adhesive is an adhesive that can be applied to join at least two members constituting an inkjet head such as an inkjet head using a piezoelectric element or a thermal inkjet head using a heating element.

[0069] The type of the adhesive that bonds the constituent members of the inkjet head is not particularly limited, and may include an epoxy resin, a urethane resin, a silicone resin, a vinyl acetate resin, and an acrylic resin. Among them, an adhesive containing an epoxy resin is preferably used. The epoxy resin has a strong adhesive force and can firmly bond the constituent members of the inkjet head. In addition, the ink composition containing the organic solvent (a) hardly erodes the cured product of the epoxy resin and does not swell the cured product of the epoxy resin. Therefore, by ejecting the inkjet head in which the adhesive bonding the constituent members is an epoxy resin adhesive onto the surface of a substrate, the ejection stability of the ink composition can be improved. Hereinafter, an adhesive containing an epoxy resin that can be used as an adhesive for bonding the constituent members of the inkjet head will be described.

[0070] Representative epoxy resins contained in the adhesive are, for example, bisphenol type epoxy resins represented by the following structural formula (4), phenol novolac type epoxy resins represented by the following structural formula (5), or cresol novolac type epoxy resins represented by the following structural formula (6) (where n = 0 to 10).

[0071] [Chemical formula 4]

[0072]

[0073] [Chemical formula 5]

[0074]

[0075]

Chemical Formula 6

[0076]

[0077] In addition to bisphenol A shown in the structural formula (4), the skeleton part of the epoxy resin of the structural formula (4) may also be a structure known as the main agent of conventional epoxy resin adhesives, such as tetrabromobisphenol A, bisphenol F, bisphenol AD, bisphenol Z, etc.

[0078] The epoxy resin contained in the adhesive is not limited to the representative epoxy resins exemplified above, as long as it is an epoxy resin having an epoxy group in the side chain.

[0079] By using a curing agent such as an amine-based curing agent, an acid anhydride-based curing agent, or a phenolic curing agent together with the epoxy resin, the epoxy resin can undergo a polymerization reaction to obtain a cured product.

[0080] When the adhesive contains an epoxy-based adhesive, the proportion of the epoxy resin contained in the cured product of the adhesive may be 10% by mass or more in the total amount of the cured product of the adhesive, preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 70% by mass or more, still further preferably 90% by mass or more, and most preferably 99% by mass or more.

[0081] [Ink Storage Mechanism]

[0082] Preferably, an ink storage mechanism different from the ink cartridge is provided between the ink cartridge and the inkjet head. The ink storage mechanism refers to a mechanism for temporarily storing the ink composition supplied from the ink cartridge. By providing the ink storage mechanism, the ejection stability of the ink composition can be further improved. It should be noted that the recording method of the present invention can also use an inkjet recording device without an ink storage mechanism to eject the ink composition onto the surface of the substrate.

[0083] Since the organic solvent (a) penetrates to a certain extent into components such as the inkjet head and the flow path (tube), when the ink composition is ejected by inkjet, the pressure in the flow path sometimes becomes unstable. By providing an ink storage mechanism between the ink supply unit and the inkjet head, the pressure in the flow path can be stabilized, and the ejection stability of the ink composition can be further improved.

[0084] In particular, even in a case where recording is performed while a recording medium (base material) is conveyed at high speed, the recording method of the present embodiment can reduce bleeding of printing. However, since high-speed printing is performed, there is a tendency for the moving speed of the carriage to increase and the ink ejection pressure to become unstable. Therefore, by ejecting an ink composition onto the surface of a base material using an inkjet recording apparatus having an ink storage mechanism between an ink supply unit and an inkjet head, the ink ejection pressure can be stabilized and the ejection stability of the ink composition can be maintained.

[0085] The ink storage mechanism may be a so-called sub-tank that stores an ink composition, or may be a damping mechanism that absorbs pressure fluctuations of the ink composition applied within the inkjet head.

[0086] [Heating mechanism]

[0087] The inkjet recording apparatus preferably includes a heating mechanism (drying mechanism). The heating mechanism refers to a mechanism that heats and dries the surface temperature of the base material and the ink composition that lands on the base material (recording medium).

[0088] The heating mechanism included in the inkjet recording apparatus may be a mechanism that directly contacts the base material for heating, such as a preheater, a plate heater, a post-heater, etc., or may be a mechanism that blows warm air onto the recording object, or a mechanism that heats the recording object by irradiating infrared rays or the like. In addition, a plurality of these heating mechanisms may be combined.

[0089] [Other mechanisms]

[0090] In the inkjet recording apparatus, for mechanisms other than those described above, conventionally known devices can be used. For example, it may or may not include a winding mechanism for a recording medium (base material) and a circulation mechanism for ink.

[0091] Next, an example of an ink composition capable of implementing the recording method of the present embodiment will be described.

[0092] 《Ink composition》

[0093] The ink composition used in the recording method of the present embodiment is an ink composition for inkjet containing an organic solvent, and is characterized in that, as the organic solvent, it contains at least one selected from an alkylamide-based solvent (a1), a cyclic amide-based solvent (a2), and a lactone-based solvent (a3) (organic solvent (a)).

[0094] The ink composition used in the recording method of the present embodiment may be an aqueous ink composition in which a coloring material is dissolved or dispersed in a mixed solution of water and an organic solvent, or may be an active energy ray-curable ink composition containing a polymerizable monomer, or may be a non-aqueous ink composition that intentionally does not contain water.

[0095] Hereinafter, the ink compositions used in the recording method of the present embodiment will be described using a water-free non-aqueous ink composition (oil-based ink composition) and an aqueous ink composition containing water as a main component. Since the water-free non-aqueous ink composition contains an organic solvent as a main component, it can be said that it is an ink composition that more easily erodes the cured product of the adhesive that bonds the constituent members of the inkjet head. Thus, in the non-aqueous ink composition where the problems of the present invention are likely to occur, by containing the above-mentioned organic solvent (a), it is possible to effectively suppress the erosion of the cured product of the adhesive that bonds the constituent members of the inkjet head.

[0096] <Non-aqueous ink composition>

[0097] The non-aqueous ink composition of the present embodiment is an ink composition that intentionally does not contain water and contains an organic solvent as a liquid medium.

[0098] It should be noted that in this specification, the term "intentionally does not contain water" means not considering the moisture in the atmosphere and the inevitably contained water from additives, etc. In the non-aqueous ink composition of the present embodiment, the content of water is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, further preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less in the total amount of the non-aqueous ink composition. The occurrence of defects such as clogging of the ink composition in the inkjet head disappears, and the ejection stability can be improved. In addition, by being a "non-aqueous ink composition", the drying speed becomes high, and printing (recording) on non-absorbent substrates such as resin substrates and metal substrates becomes easy.

[0099] Hereinafter, each component contained in the non-aqueous ink composition of the present embodiment will be described.

[0100] [Organic solvent]

[0101] The organic solvent contains an organic solvent (a).

[0102] Organic solvent (a): at least 1 selected from alkylamide solvents (a1), cyclic amide solvents (a2), and lactone solvents (a3)

[0103] Hereinafter, the organic solvent (a) and the other organic solvents contained in the organic solvent will be described in more detail respectively.

[0104] (Organic solvent (a))

[0105] The organic solvent (a) contains at least one selected from the group consisting of an alkylamide-based solvent (a1), a cyclic amide-based solvent (a2), and a lactone-based solvent (a3). Such an organic solvent (a) has low permeability to the resin, and thus does not erode the cured product of the adhesive that bonds the constituent members of the inkjet head. As a result, the ejection stability of the ink composition is improved, and the ink composition can be ejected to a desired position on the surface of the substrate.

[0106] Moreover, the organic solvent (a) penetrates the substrate to a certain extent, and the drying property on the substrate surface is also fast. Therefore, by printing (recording) using the ink composition containing the organic solvent (a), bleeding of the printed characters is less, and thus the printed characters are clear. Such an effect of less bleeding of the printed characters cannot be achieved when a solvent with a low boiling point is simply selected to improve the drying property.

[0107] Hereinafter, the alkylamide-based solvent (a1), the cyclic amide-based solvent (a2), and the lactone-based solvent (a3) contained in the organic solvent (a) will be described separately.

[0108] (1) Alkylamide-based solvent

[0109] The alkylamide-based solvent refers to a compound having an alkyl group (C n H 2n+1 -) and a -C(=O)-N- group (amide bond), and is a solvent containing a compound composed of hydrogen or an alkyl group and a -C(=O)-N- group. As the alkylamide-based solvent, for example, a solvent having the following structure can be preferably used.

[0110] [Chemical Formula 7]

[0111]

[0112] (In Formula (1), R1 is hydrogen or an alkyl group having 1 or more and 4 or less carbon atoms, and R2 represents an alkyl group having 2 or more and 4 or less carbon atoms.)

[0113] Specific examples of the alkylamide-based solvent include N,N-diethylformamide, N,N-diethylacetamide, N,N-dipropylformamide, N,N-dibutylformamide, N,N-diethylpropionamide, N,N-dipropylpropionamide, etc. Among them, from the viewpoint of particularly exhibiting the effects of the present invention, it is preferable to contain at least one selected from N,N-diethylformamide, N,N-diethylpropionamide, and N,N-diethylacetamide.

[0114] It should be noted that N,N-dimethylformamide and N,N-dimethylacetamide may be contained, but from the viewpoint of particularly exhibiting the effects of the present invention, it is preferable not to contain N,N-dimethylformamide and N,N-dimethylacetamide.

[0115] (2) Cyclic amide solvents

[0116] Cyclic amide solvents refer to solvents having a cyclic structure and having a -C(=O)-N- group in the cyclic structure. As cyclic amide solvents, solvents having the following structures can be preferably used, for example.

[0117] [Chemical Formula 8]

[0118]

[0119] (In formula (2), R3 is an alkylene group having 4 or more and 5 or less carbon atoms, and R4 represents hydrogen or an alkyl group or an unsaturated hydrocarbon group having 1 or more and 2 or less carbon atoms.)

[0120] Specific examples of cyclic amide solvents include N-methylcaprolactam, N-acetylcaprolactam, ε-caprolactam, N-vinylcaprolactam, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-ethyl-ε-caprolactam, N-propyl-ε-caprolactam, N-methyl-ε-caprolactam, etc. Among them, ε-caprolactam, N-methylcaprolactam, and N-vinylcaprolactam can be mentioned. Among them, it is preferable to contain at least one selected from ε-caprolactam, N-methylcaprolactam, and N-vinylcaprolactam.

[0121] It should be noted that N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and N-methyl oxazolidinone may be contained, but from the viewpoint of particularly exerting the effects of the present invention, it is preferable not to contain N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and N-methyl oxazolidinone.

[0122] (3) Lactone solvents

[0123] Lactone solvents refer to solvents having a cyclic ester structure. As lactone solvents, solvents having the following structures can be preferably used, for example.

[0124] [Chemical Formula 9]

[0125]

[0126] (In formula (3), R5 is an alkylene group having 3 or more and 5 or less carbon atoms, and R6 represents hydrogen or an alkyl group having 1 or more and 2 or less carbon atoms.)

[0127] Examples of lactone solvents include γ-butyrolactone, γ-valerolactone, γ-caprolactone, γ-heptalactone, δ-valerolactone, δ-caprolactone, δ-heptalactone, δ-octalactone, δ-nonalactone, δ-decalactone, δ-undecalactone, ε-caprolactone, etc.

[0128] Among lactone solvents, lactone solvents with 6 or more membered rings are preferred. Examples of lactone solvents with 6 or more membered rings include δ-valerolactone, δ-caprolactone, ε-caprolactone, etc.

[0129] When the non-aqueous ink composition contains at least one selected from the group consisting of an alkylamide solvent (a1), a cyclic amide solvent (a2), and a lactone solvent (a3) as the above-mentioned organic solvent (a), it becomes a non-aqueous ink composition that exhibits the effects of the present invention. Among them, from the viewpoint of particularly exhibiting the effects of the present invention, it is preferably contains at least one of an alkylamide solvent (a1) and a cyclic amide solvent (a2) as the organic solvent (a), and particularly preferably contains an alkylamide solvent (a1) as the organic solvent (a).

[0130] There is no particular limitation on the upper limit of the content of the organic solvent (a). In the total amount of the non-aqueous ink composition, it is preferably contained in an amount of 30.0% by mass or less, more preferably 20.0% by mass or less, and still more preferably 15.0% by mass or less.

[0131] There is no particular limitation on the lower limit of the content of the organic solvent (a). In the total amount of the non-aqueous ink composition, it is preferably contained in an amount of 3.0% by mass or more, more preferably 5.0% by mass or more, and still more preferably more than 5.0% by mass.

[0132] It should be noted that the numerical values of the upper and lower limits of the content of the above-mentioned organic solvent (a) are all common among the alkylamide solvent (a1), the cyclic amide solvent (a2), and the lactone solvent (a3).

[0133] It should be noted that it is preferably set so that the content of impurities derived from the organic solvent (a) (at least one selected from the group consisting of an alkylamide solvent (a1), a cyclic amide solvent (a2), and a lactone solvent (a3)) is 0.5% by mass or less in the total amount of the organic solvent (a) before mixing the organic solvent (a) with other components. Due to low-boiling impurities and the like contained in the organic solvent (a), adverse conditions such as dissolution and swelling may occur in the cured product of the adhesive. By setting the content of impurities derived from the organic solvent (a) to be 0.5% by mass or less in the total amount of the organic solvent (a) before mixing with other components, an ink composition that particularly exhibits the effects of the present invention is obtained. In addition, bleeding of printing caused by a decrease in recording drying properties due to high-boiling impurities contained in the organic solvent (a) can be more effectively suppressed.

[0134] As a method for purifying the organic solvent (a), it can be achieved by repeatedly distilling the organic solvent (a), or reducing the step of distillation temperature to minimize impurities, or repeatedly performing extraction, etc. In addition, in industrial manufacturing processes, in addition to the above processes, it can also be achieved by implementing pollution suppression measures, etc.

[0135] (Other organic solvents)

[0136] The organic solvent may contain organic solvents other than the above-mentioned organic solvent (a). Specifically, examples include glycol dialkyl ethers in which the OH groups at both ends of the glycol are substituted by alkyl groups, glycol monoalkyl ethers in which one OH group of the glycol is substituted by an alkyl group, carbonates, etc.

[0137] Examples of the glycol dialkyl ether include the glycol dialkyl ether represented by the following formula (7).

[0138] [Chemical Formula 10]

[0139]

[0140] (In formula (7), R7 and R9 are alkyl groups, R8 represents ethylene or propylene. n represents an integer of 2 to 4.)

[0141] Specific examples of the glycol dialkyl ether include 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 methyl propyl ether, diethylene glycol methyl isopropyl ether, diethylene glycol dibutyl ether, diethylene glycol methyl butyl ether, diethylene glycol ethyl butyl ether, diethylene glycol methyl-2-ethylhexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, propylene glycol diethyl ether, propylene glycol methyl ethyl 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 methyl ethyl 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 methyl ethyl ether, etc.

[0142] Among the glycol dialkyl ethers, glycol dialkyl ethers in which the total number of carbon atoms contained in R7 and R9 in formula (7) is 2 or more and 8 or less are preferred, glycol dialkyl ethers in which the total number of carbon atoms is 2 or more and 6 or less are more preferred, and glycol dialkyl ethers in which R7 is methyl or ethyl and R9 is ethyl in formula (7), and / or glycol dialkyl ethers in which R7 and R9 are methyl and R8 is propylene in formula (7) are further preferred.

[0143] The diol dialkyl ether in which the total number of carbon atoms contained in R7 and R9 is 2 or more and 6 or less has a higher volatility than, for example, diethylene glycol dibutyl ether (the total number of carbon atoms contained in R7 and R9 is 8), and thus becomes a non-aqueous ink composition excellent in recording drying property.

[0144] Specific examples of such diol dialkyl ethers in which the total number of carbon atoms contained in R7 and R9 is 2 or more and 6 or less include diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol methyl isopropyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, and the like.

[0145] Moreover, the diol dialkyl ether in which R7 in formula (7) is methyl or ethyl and R9 is ethyl, and / or the diol dialkyl ether in which R7 and R9 in formula (7) are methyl and R8 is propylene can more effectively suppress the erosion of the cured product of the binder as compared with, for example, diethylene glycol dimethyl ether (R7 and R9 are methyl, and R2 is ethylene).

[0146] Specific examples of such diol dialkyl ethers in which R7 in formula (7) is methyl or ethyl and R9 is ethyl include diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, and the like. Examples of the diol dialkyl ether in which R7 and R9 in formula (7) are methyl and R8 is propylene include dipropylene glycol dimethyl ether.

[0147] In addition, impurities such as polymers, by-products, and decomposition products are likely to be generated during the production of diol dialkyl ethers. For example, the content of impurities contained in commercially available diol dialkyl ethers sometimes reaches about 10% by mass in the total amount of the diol dialkyl ether. Therefore, it is preferable to set the content of impurities derived from the diol dialkyl ether to 0.5% by mass or less in the total amount of the diol dialkyl ether in advance before mixing with other constituent components. Sometimes, the odor deteriorates due to the low-boiling impurities contained in the diol dialkyl ether. In addition, due to the low-boiling impurities and the like contained in the diol dialkyl ether, adverse conditions such as dissolution and swelling may occur to the plastics and adhesives used in printing mechanism components such as inkjet heads. In addition, when the impurities contained in the diol dialkyl ether are high-boiling, bleeding may occur during printing due to the reduction of the recording drying property of the non-aqueous ink composition. By setting the content of impurities derived from the diol dialkyl ether to 0.5% by mass or less in the total amount of the diol dialkyl ether in advance before mixing with other constituent components, the above problems can be solved, and thus it becomes a non-aqueous ink composition that further exhibits the effects of the present invention.

[0148] Examples of impurities contained in the dialkyl glycol ethers include triethylene glycol (boiling point: 285°C), tetraethylene glycol (boiling point: 327°C), polyethylene glycol (boiling point: 330°C or higher), ethylene glycol monoethyl ether (boiling point: 135°C), ethylene glycol monomethyl ether (boiling point: 124°C), ethylene glycol diethyl ether (boiling point: 121°C), ethylene glycol dimethyl ether (boiling point: 98°C), diethyl ether (boiling point: 35°C), methyl ethyl ether (boiling point: 12°C), diethyl ketone (boiling point: 101°C), dimethyl ketone (boiling point: 57°C), methyl ethyl ketone (boiling point: 80°C), ethoxyethanol (boiling point: 135°C), ethanol (boiling point: 78°C), etc., but are not limited thereto.

[0149] As a method for purifying the dialkyl glycol ethers, it can be achieved by repeatedly distilling the dialkyl glycol ethers, or reducing the temperature step of distillation to minimize the presence of impurities, or repeatedly performing extraction, etc. In addition, in industrial manufacturing processes, in addition to the above processes, it can also be achieved by implementing pollution suppression measures, etc.

[0150] When the dialkyl glycol ethers are contained, the lower limit of the content of the dialkyl glycol ethers is not particularly limited, and it is preferably contained in an amount of 30.0% by mass or more, more preferably 40.0% by mass or more, and further preferably 50.0% by mass or more in the total amount of the non-aqueous ink composition.

[0151] The upper limit of the content of the dialkyl glycol ethers is not particularly limited, and it is preferably contained in an amount of 90.0% by mass or less, more preferably 80.0% by mass or less in the total amount of the non-aqueous ink composition.

[0152] Examples of the monoalkyl glycol ethers include ethylene glycol monon-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol monoter-butyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol monomethyl (or ethyl, propyl, isopropyl, n-butyl, isobutyl, ter-butyl, 2-ethylhexyl) ether, triethylene glycol monomethyl (or ethyl, propyl, isopropyl, n-butyl, isobutyl, ter-butyl, 2-ethylhexyl) ether, tetraethylene glycol monomethyl (or ethyl, propyl, isopropyl, n-butyl, isobutyl, ter-butyl, 2-ethylhexyl) ether, propylene glycol monon-butyl ether, propylene glycol monoisobutyl ether, propylene glycol monoter-butyl ether, propylene glycol mono-2-ethylhexyl ether, dipropylene glycol monomethyl (or ethyl, propyl, isopropyl, n-butyl, isobutyl, ter-butyl, 2-ethylhexyl) ether, tripropylene glycol monomethyl (or ethyl, propyl, isopropyl, n-butyl, isobutyl, ter-butyl) ether, tetrapropylene glycol monomethyl (or ethyl, propyl, isopropyl, n-butyl, isobutyl, ter-butyl, 2-ethylhexyl) ether, etc.

[0153] Examples of the carbonates include ethylene carbonate, propylene carbonate, etc.

[0154] In addition, it may also contain organic solvents other than the above-mentioned organic solvents. Specifically, oxazolidone solvents such as 3-methyl-2-oxazolidone, 3-ethyl-2-oxazolidone, and N-vinylmethyl oxazolidone can be cited; acetate solvents such as triethylene glycol butyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol methyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, dipropylene glycol methyl ether acetate, 1-methoxy-2-propyl acetate, 2-methylbutyl acetate, 3-methoxybutyl ether acetate, and cyclohexyl acetate; amide solvents different from alkylamide solvents (a1) and cyclic amide solvents (a2) such as 3-methoxypropanamide, 3-butoxypropanamide, N,N-dimethyl-3-methoxypropanamide, N,N-dibutyl-3-methoxypropanamide, N,N-dibutyl-3-butoxypropanamide, and N,N-dimethyl-3-butoxypropanamide; alkyl alcohols having 1 to 5 carbon atoms such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, isobutanol, and n-pentanol; monohydric alcohol solvents such as 3-methoxy-3-methyl-1-butanol, 3-methoxy-1-propanol, 1-methoxy-2-propanol, and 3-methoxy-n-butanol; ketones or ketol alcohols such as acetone, diacetone alcohol, methyl ethyl ketone, methyl n-propyl ketone, methyl isopropyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, methyl n-pentyl ketone, methyl hexyl ketone, methyl isopentyl 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; ethers such as tetrahydrofuran and dioxane; oxyethylene or oxypropylene copolymers such as polyethylene glycol and polypropylene glycol; diols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,3-propanediol, isobutylene glycol, triethylene glycol, tripropylene glycol, tetraethylene glycol, 1,3-propanediol, 2-methyl-1,2-propanediol, 2-methyl-1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, and 2-methyl-2,4-pentanediol; triols such as glycerol, trimethylolethane, trimethylolpropane, and 1,2,6-hexanetriol; tetrahydric alcohols such as meso-erythritol and pentaerythritol; alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, and N-butyldiethanolamine; acetates such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, hexyl acetate, and octyl acetate; lactates such as methyl lactate, ethyl lactate, butyl lactate, propyl lactate, ethylhexyl lactate, pentyl lactate, and isopentyl lactate;Saturated hydrocarbons such as n - hexane, iso - hexane, n - nonane, iso - nonane, dodecane, iso - dodecane, etc., unsaturated hydrocarbons such as 1 - hexene, 1 - heptene, 1 - octene, etc.; cyclic unsaturated hydrocarbons such as cyclohexene, cycloheptene, cyclooctene, 1,3,5,7 - cyclooctatetraene, cyclododecene, etc., aromatic hydrocarbons such as benzene, toluene, xylene, etc., morpholine - based solvents such as N - methylmorpholine, N - ethylmorpholine, N - formylmorpholine, etc., terpene - based solvents; diesters such as dimethyl oxalate, diethyl oxalate, dimethyl malonate, diethyl malonate, dipropyl malonate, dimethyl succinate, diethyl succinate, dimethyl glutarate, diethyl glutarate, etc. Preferably, a solvent with an appropriate HLB value is selected according to the combined resin, dispersant, etc.

[0155] [Colorant]

[0156] The colorant contained in the non - aqueous ink composition of this embodiment is not particularly limited and can be a dye - based or a pigment - based one. From the viewpoint of good resistance such as water resistance and light resistance of the recording, it is preferable to use a pigment (pigment - based colorant). In the non - aqueous ink composition of this embodiment, the pigments that can be used are not particularly limited, and examples include organic pigments or inorganic pigments used in conventional ink compositions. They can be used alone or in combination of two or more.

[0157] As specific organic pigments, for example, insoluble azo pigments, soluble azo pigments, derivatives from dyes, phthalocyanine - based organic pigments, quinacridone - based organic pigments, perylene - based organic pigments, violanthrone - based organic pigments, azomethine - based organic pigments, anthraquinone - based organic pigments (anthrone - based organic pigments), xanthene - based organic pigments, diketopyrrolopyrrole - based organic pigments, dioxazine - based organic pigments, nickel azo - based pigments, isoindolinone - based organic pigments, perinone - based organic pigments, thioindigo - based organic pigments, condensed azo - based organic pigments, benzimidazolone - based organic pigments, quinophthalone - based organic pigments, isoindoline - based organic pigments, quinacridone - based solid - solution pigments, perylene - based solid - solution pigments and other organic solid - solution pigments. As other pigments, lake pigments, carbon black, etc. can be cited.

[0158] If organic pigments are exemplified by Color Index (C.I.) numbers, examples include C.I. 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, C.I. Pigment Red 5, 7, 9, 12, 48, 49, 52, 53, 57:1, 97, 112, 122, 123, 146, 149, 150, 168, 177, 180, 184, 192, 202, 206, 208, 209, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, 254, 255, 269, 291, C.I. Pigment Orange 16, 36, 43, 51, 55, 59, 61, 64, 71, 73, C.I. Pigment Violet 19, 23, 29, 30, 37, 40, 50, C.I. Pigment Blue 15, 15:1, 15:3, 15:4, 15:6, 16, 22, 60, 64, C.I. Pigment Green 7, 36, 58, 59, 62, 63, C.I. Pigment Brown 23, 25, 26, C.I. Pigment Black 7, etc.

[0159] In the non-aqueous ink composition of the present embodiment, specific examples of dyes that can be used include azo dyes, benzoquinone dyes, naphthoquinone dyes, anthraquinone dyes, cyanine dyes, squarylium dyes, croconic acid dyes, merocyanine dyes, stilbene dyes, diarylmethane dyes, triarylmethane dyes, fluorane dyes, spiropyran dyes, phthalocyanine dyes, indigo dyes such as indigo, fumaric anhydride dyes, nickel complex dyes, and azulene dyes.

[0160] In the non-aqueous ink composition of the present embodiment, specific examples of inorganic pigments that can be used include titanium oxide, barium sulfate, calcium carbonate, zinc oxide, barium carbonate, silicon dioxide, talc, clay, synthetic mica, aluminum oxide, zinc white, lead sulfate, chrome yellow, zinc yellow, ferric oxide (red iron oxide (III)), cadmium red, ultramarine, Prussian blue, chromium oxide green, cobalt green, amber, titanium black, aluminum, titanium, indium, synthetic iron black, inorganic solid solution pigments, etc.

[0161] In the non-aqueous ink composition of the present embodiment, the average dispersed particle diameter of the pigment that can be contained is not particularly limited as long as the desired color development can be achieved. Although it varies depending on the type of pigment used, from the viewpoints of good dispersibility and dispersion stability of the pigment and sufficient coloring power, the volume average particle diameter is preferably in the range of 5 nm or more, more preferably 20 nm or more, and further preferably 30 nm or more. By making the volume average particle diameter the above lower limit value or more, the light resistance of the non-aqueous ink composition can be improved. The volume average particle diameter is preferably in the range of 300 nm or less, more preferably 200 nm or less, and further preferably 150 nm or less. By making the volume average particle diameter the above upper limit value or less, the ejection stability of inkjet can be improved. It should be noted that in the present embodiment, the volume average particle diameter of the pigment is the average particle diameter (D50) measured using a particle size distribution measuring device (particle size analyzer NANOTRAC WAVE manufactured by Microtrac BEL Co., Ltd.) under the condition of 25°C.

[0162] In addition, in the case of an ink set containing the non-aqueous ink composition of the present embodiment, the volume average particle diameter of the pigment contained in each non-aqueous ink composition may be the same or different.

[0163] In the non-aqueous ink composition of the present embodiment, the content of the pigment is not particularly limited as long as the desired image can be formed and can be appropriately adjusted. Specifically, although it varies depending on the type of pigment, it is preferably 0.05% by mass or more, more preferably 0.1% by mass or more in the total amount of the non-aqueous ink composition. In the total amount of the non-aqueous ink composition, it is preferably 20% by mass or less, more preferably 10% by mass or less. By making the content of the pigment in the range of 0.05% by mass or more and 20% by mass or less, the balance between the dispersion stability and the coloring power of the pigment can be excellent.

[0164] In addition, there is no particular limitation on the color for recording (printing) with the non-aqueous ink composition of the present embodiment, and it can be selected and used in combination according to the purpose according to the color. The color can also be used for inks of various colors such as yellow, magenta, cyan, black, light magenta, light cyan, light black, orange, green, red, white, etc.

[0165] [Resin]

[0166] For the purpose of improving the fixing property, water resistance and stretchability of the decorative layer formed from the non-aqueous ink composition, the non-aqueous ink composition of the present embodiment may contain a resin. As the resin, for example, an acrylic resin, a polystyrene resin, a polyester resin, a vinyl chloride resin, a vinyl acetate resin, a vinyl chloride-vinyl acetate copolymer resin, a polyethylene resin, a polyurethane resin, a rosin-modified resin, a phenol resin, a terpene resin, a polyamide resin, a vinyl toluene-α-methylstyrene copolymer, an ethylene-vinyl acetate copolymer, a cellulose resin, a silicone resin, an acrylamide resin, an epoxy resin, or a copolymer or mixture thereof can be used. Among them, an acrylic resin, a vinyl chloride-vinyl acetate copolymer resin, a cellulose resin, a polyester resin, and a polyurethane resin are preferably included. Among them, from the aspect of being able to improve water resistance, solvent resistance and stretchability, it is more preferable to contain at least one or more acrylic resins and vinyl chloride-vinyl acetate copolymer resins. In addition, if one or more acrylic resins and vinyl chloride-vinyl acetate copolymer resins are contained, when used as a non-aqueous ink composition for inkjet, the ejection responsiveness and ejection stability during high-speed recording can be further improved.

[0167] The acrylic resin is not particularly limited as long as it is a resin contained as the main component of the monomer constituting the (meth)acrylate monomer. The acrylic resin can be a homopolymer of one radical polymerizable monomer or any one of copolymers in which two or more radical polymerizable monomers are selectively used. In particular, the acrylic resin preferably used as the non-aqueous ink composition is a polymethyl methacrylate homopolymer or a copolymer of methyl methacrylate and at least one or more compounds selected from butyl methacrylate, ethoxyethyl methacrylate, and benzyl methacrylate. In addition, as commercially available (meth)acrylic resins, for example, "Paraloid B99N", "Paraloid B60", "Paraloid B66", "Paraloid B82" of Rohm and Haas Company can be exemplified.

[0168] The vinyl chloride resin may be a homopolymer composed of vinyl chloride monomer or a copolymer selected from two or more polymerizable monomers. Examples of copolymers of the vinyl chloride resin include vinyl chloride-vinyl acetate copolymer resins. Vinyl chloride-vinyl acetate copolymer resins are polymers 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," "SOLBIN CL," "SOLBIN CNL," "SOLBIN CLL," "SOLBIN CLL2," "SOLBIN C5R," "SOLBIN TA2," "SOLBIN TA3," "SOLBIN A," "SOLBIN AL," "SOLBIN TA5R," and "SOLBIN M5," and are used in the present invention.

[0169] 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.

[0170] Cellulose resins are resins with a cellulose skeleton obtained by biologically or chemically introducing functional groups from cellulose. Examples of cellulose resins include cellulose acetate butyrate resins, cellulose acetate propionate resins, cellulose acetate propionate butyrate resins, and other cellulose acetate alkylated resins (Japanese: セルロ一スアセテ一トアルキレ一ト訹訹� ...

[0171] The polyester resin refers to 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, it can be obtained and used under the trade names of "VYLON226", "VYLON270", "VYLON560", "VYLON600", "VYLON630", "VYLON660", "VYLON885", "VYLONGK250", "VYLONGK810", "VYLON GK890", etc. of Toyobo Co., Ltd., and "elitleUE-3200", "elitleUE-3285", "elitleUE-3320", "elitleUE-9800", "elitleUE-9885", etc. of Unitika Ltd.

[0172] The polyurethane resin refers to 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 the above-mentioned polyurethane resin, it can be obtained and used under the trade names of "UREANO KL-424", "UREANO KL-564", "UREANO KL-593", "UREANO 3262", etc. of Arakawa Chemical Industries, Ltd., and "Pandex 372E", "Pandex 390E", "Pandex394E", "Pandex 304", "Pandex 305E", "Pandex P-870", "Pandex P-910", "Pandex P-895", "Pandex 4030", "Pandex 4110", etc. of DIC Corporation.

[0173] In addition, these acrylic resins, vinyl chloride-vinyl acetate copolymer resins, cellulose resins, polyester resins, and polyurethane resins can be used alone, but it is preferable to use two of them in combination, and it is more preferable to use a resin obtained by mixing an acrylic resin and a vinyl chloride-vinyl acetate copolymer resin. By controlling the content ratio of the acrylic resin and the vinyl chloride-vinyl acetate copolymer resin, it is possible to control the color development, drying property, film physical properties, printing adaptability, etc. required for the non-aqueous ink composition. When mixing the acrylic resin and the vinyl chloride-vinyl acetate copolymer resin, the mixing ratio is not particularly limited and can be appropriately changed.

[0174] The weight-average molecular weight (relative molecular mass) of the resin is not particularly limited, 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 a usual GPC (gel permeation chromatography).

[0175] The mass % of the resin contained in the total amount of the non-aqueous ink composition of the present embodiment is not particularly limited. For example, it is preferably 0.05 mass % or more in the total amount of the non-aqueous ink composition, among which it is preferably 0.1 mass % or more, more preferably 0.5 mass % or more, still more preferably 1 mass % or more. The mass % of the resin contained in the total amount of the non-aqueous ink composition is not particularly limited. For example, it is preferably 20 mass % or less in the non-aqueous ink composition, among which it is more preferably 15 mass % or less.

[0176] [Dispersant]

[0177] In the non-aqueous ink composition of the present embodiment, a dispersant can be used as needed. As the dispersant, any dispersant used in a non-aqueous ink composition can be used. As the dispersant, a polymer dispersant can be used. As such a dispersant, the main chain is composed of polyester-based, polyacrylic acid-based, polyurethane-based, polyamine-based, polycaprolactone-based, etc., and has polar groups such as amino groups, carboxyl groups, sulfo groups, and hydroxyl groups as side chains. Among the 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 (manufactured by BYK-Chemie), Efka PX4310, PX4320, PX4330, PA4401, 4402, PA4403, 4570, 7411, 7477, PX4700, PX4701 (manufactured by BASF), TREPLUS D-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. can be used. Among the polycaprolactone-based dispersants, for example, AJISPER PB821, PB822, PB881 (manufactured by Ajinomoto Fine-Techno Co., Ltd.), Hinoact KF-1000, T-6000, T-7000, T-8000, T-8000E, 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, J200 (manufactured by Lubrizol Corporation), TEGO Dispers 652, 655, 685, 688, 690 (manufactured by Evonik Japan Co., Ltd.), etc. can be used.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. They can be used alone or their mixtures can be used.

[0178] Among the above dispersants, polycaprolactone-based dispersants are preferably used. It can effectively improve the dispersibility of pigments in the non-aqueous ink composition containing the organic solvent (a) and can effectively inhibit the generation of solid components in the non-aqueous ink composition.

[0179] The content of the dispersant is not particularly limited. The lower limit of the content of the dispersant is preferably in the range of 0.1% by mass or more, more preferably in the range of 0.5% by mass or more, and further preferably in the range of 0.8% by mass or more in the total amount of the non-aqueous ink composition. The content of the dispersant is not particularly limited. The upper limit of the content of the dispersant is preferably in the range of 5.0% by mass or less, more preferably in the range of 4.0% by mass or less, and further preferably in the range of 3.0% by mass or less in the total amount of the non-aqueous ink composition. Thereby, the pigments in the non-aqueous ink composition can be effectively dispersed and the generation of solid components in the non-aqueous ink composition can be effectively inhibited.

[0180] [Dispersing aid]

[0181] In the non-aqueous ink composition of the present embodiment, a dispersing aid can be used as needed. The dispersing aid adsorbs on the surface of the colorant (pigment), and the functional groups improve the affinity with the organic solvent and the dispersant in the non-aqueous ink composition, thereby improving the dispersion stability. As the dispersing aid, known pigment derivatives having functional groups such as acidic groups, basic groups, and neutral groups in the organic pigment residue can be used.

[0182] [Surfactant]

[0183] In the non-aqueous ink composition of the present embodiment, a surfactant may be added for the purpose of suppressing the volatilization of the ink composition in equipment such as the nozzle portion and the inside of the tube, preventing curing, or improving the redissolubility during curing, or for the purpose of reducing the surface tension and improving the wettability with the recording medium. For example, nonionic 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, NC-207 (manufactured by NOF Corporation), EMULGEN 106, 108, 707, 709, A-90, A-60 (manufactured by Kao Corporation), Flowlen G-70, D-90, TG-740W (manufactured by Kyoeisha Chemical Co., Ltd.), POEM J-0081HV (manufactured by RIKENVITAMIN Co., Ltd.), Adekatol NP-620, NP-650, NP-660, NP-675, NP-683, NP-686, Adekacol CS-141E, TS-230E (manufactured by ADEKA Corporation), etc., SORGEN 30V, 40, TW-20, TW-80, Noigen CX-100 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), etc. As the fluorine-based surfactant, a fluorine-modified polymer is preferably used. As a specific example, BYK-340 (manufactured by BYK-Chemie Japan) etc. can be exemplified. As the silicone-based surfactant, polyester-modified silicone and polyether-modified silicone are preferably used. As specific examples, BYK-313, 315N, 322, 326, 331, 347, 348, BYK-UV3500, 3510, 3530, 3570 (all manufactured by BYK-Chemie Japan) etc. can be exemplified. As the alkynediol-based surfactant, as specific examples, 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. can be exemplified.

[0184] The surfactant is not limited to the above, and any surfactant of anionic, cationic, amphoteric or nonionic type may be used, and it can be appropriately selected according to the addition purpose.

[0185] [Other components]

[0186] The non-aqueous ink composition of the present embodiment may contain antioxidants, stabilizers such as ultraviolet absorbers, epoxides, polycarboxylic acids, surface modifiers, leveling agents (acrylic, silicone, etc.), defoamers, pH adjusters, fungicides, preservatives, deodorants, charge control agents, wetting agents, and other known additives as optional components. Specific examples of antioxidants include, for example, hindered phenol antioxidants, amine antioxidants, phosphorus antioxidants, sulfur antioxidants, hydrazine antioxidants, etc. Specifically, BHA (2,3-butyl-4-methoxyphenol), BHT (2,6-di-tert-butyl-p-cresol), etc. can be exemplified. In addition, as the ultraviolet absorber, a benzophenone compound or a benzotriazole compound can be used. In addition, specific examples of epoxides include epoxy glycerol esters, epoxy fatty acid monoesters, and epoxy hexahydrophthalic acid esters. Specifically, ADKCIZER O-130P, ADK CIZER O-180A (manufactured by ADEKA Corporation), etc. can be exemplified. Specific examples of polycarboxylic acids include citric acid, maleic acid, etc.

[0187] <Water-based ink composition>

[0188] The water-based ink composition of the present embodiment has water as the main component and also contains the above-mentioned organic solvent (a). By being a water-based ink composition, the impact on the environment is small and it does not catch fire, so the safety for the operator is high. In addition, printing (recording) on absorbent substrates such as paper substrates becomes easy.

[0189] In the water-based ink composition of the present embodiment, as the water contained, it does not contain various ions, and deionized water is preferably used. The content of water is not particularly limited as long as it can disperse or dissolve each component, and it is preferably in the range of 10% by mass or more and 95% by mass or less in the total amount of the water-based ink composition. Among them, it is preferably in the range of 20% by mass or more and 95% by mass or less in the total amount of the ink composition, and particularly preferably in the range of 30% by mass or more and 90% by mass or less in the total amount of the ink composition.

[0190] Regarding the organic solvent (a) (at least one selected from the group consisting of alkylamide solvents (a1), cyclic amide solvents (a2), and lactone solvents (a3)), the organic solvent (a) described in the above non-aqueous ink composition can be preferably used. Preferred specific examples of the alkylamide solvent (a1), cyclic amide solvent (a2), and lactone solvent (a3) are the same as those of the organic solvent (a) described in the above non-aqueous ink composition.

[0191] The upper limit of the content of the organic solvent (a) is not particularly limited, and it is preferably contained in an amount of 30.0% by mass or less, more preferably 20.0% by mass or less, and still more preferably 15.0% by mass or less in the total amount of the water-based ink composition.

[0192] The lower limit of the content of the organic solvent (a) is not particularly limited, and it is preferably contained in an amount of 3.0% by mass or more, more preferably 5.0% by mass or more, based on the total amount of the aqueous ink composition.

[0193] In addition, other organic solvents other than the organic solvent (a) may be contained. Specifically, organic solvents having a boiling point of 150°C or higher and 300°C or lower can be cited. By containing an organic solvent having a boiling point of 150°C or higher, it is possible to suppress the odor of the ink composition due to the increased volatility of the solvent, and in addition, it is possible to suppress a decrease in the ejection stability of the ink composition due to the swelling or dissolution of the binder. By setting the boiling point of the other solvent to 300°C or lower, it is possible to more effectively suppress bleeding of the printed matter due to a decrease in recording drying properties.

[0194] Examples of other solvents having a boiling point of 280°C or higher and 300°C or lower include triethylene glycol (boiling point: 285°C), glycerol (boiling point: 290°C), trimethylolethane, trimethylolpropane, etc. Examples of other solvents having a boiling point of 250°C or higher and less than 280°C include tripropylene glycol (boiling point: 268°C), 1,6-hexanediol (boiling point: 250°C), 3-methyl-1,5-pentanediol (boiling point: 250°C), etc. Examples of other solvents having a boiling point of 200°C or higher and less than 250°C include dipropylene glycol (boiling point: 232°C), diethylene glycol (boiling point: 244°C), dipropylene glycol monomethyl ether acetate (boiling point: 209°C), diethylene glycol monobutyl ether acetate (boiling point: 247°C), 1,3-propanediol (boiling point: 214°C), 1,3-butanediol (boiling point: 208°C), 1,4-butanediol (boiling point: 230°C), 1,2-pentanediol (boiling point: 210°C), 1,2-hexanediol (boiling point: 223°C), 1,5-pentanediol (boiling point: 242°C), 2,2,4-trimethyl-1,3-pentanediol (boiling point: 232°C), 3-methyl-1,3-butanediol (boiling point: 203°C), 2-methyl-1,3-pentanediol (boiling point: 214°C), 2-ethyl-1,3-hexanediol (boiling point: 244°C), etc. Examples of other solvents having a boiling point of 180°C or higher and less than 200°C include ethylene glycol (boiling point: 197°C), propylene glycol (boiling point: 187°C), 1,2-butanediol (boiling point: 193°C), 2-methyl-2,4-pentanediol (boiling point: 198°C), etc.

[0195] The colorant contained in the aqueous ink composition of the present embodiment is not particularly limited and may be a dye-based or a pigment-based. From the viewpoint of good resistance such as water resistance and light resistance of the recording, it is preferable to use a pigment (pigment-based colorant). The pigment may be a pigment dispersion in which a pigment is dispersed in a water-soluble solvent by a pigment dispersant, or a pigment dispersion of a self-dispersing pigment in which a hydrophilic group is directly modified on the surface of the pigment. In the present embodiment, the pigments that can be used for the ink for inkjet recording may be used in combination of a plurality of the above-mentioned organic pigments and inorganic pigments, or a pigment dispersion dispersed in a water-soluble solvent by the above-mentioned pigment dispersant and a self-dispersing pigment described later may be used in combination.

[0196] As the self-dispersing pigment, for example, pigments modified with carbonyl, carboxyl, hydroxyl, sulfonic acid group, phosphorus-containing group, etc. which are hydrophilic groups can be cited. In addition, as commercially available products, for example, "CAB-O-JET200, CAB-O-JET250C, CAB-O-JET260M, CAB-O-JET270Y, CAB-O-JET740Y, CAB-O-JET300, CAB-O-JET400, CAB-O-JET450C, CAB-O-JET465M, CAB-O-JET470Y, CAB-O-JET480V, CAB-O-JET352K, CAB-O-JET554B, CAB-O-JET1027R" manufactured by Cabot, "Microjetblalack162, Aqua-Black001, BONJETBLACKCW-1, BONJETBLACKCW-2, BONJETBLACKCW-3" manufactured by Orient Chemical Industries Co., Ltd., "Aqua-Black162, Aqua-Black001" manufactured by Tokai Carbon Co., Ltd., LIOJETWDBLACK002C manufactured by TOYOINK Manufacturing Co., Ltd., "SFColor" manufactured by Sanyo Pigment Co., Ltd., "FujiSPColor" manufactured by Fuji Pigment Co., Ltd., "Hostajet" manufactured by Clariant Corporation, etc. can be cited.

[0197] In addition, the color for recording (printing) with the aqueous ink composition of the present embodiment is not particularly limited, and the colorant can be selected and used in combination according to the purpose. The color can also be used for inks of various colors such as yellow, magenta, cyan, black, light magenta, light cyan, light black, orange, green, red, white, etc.

[0198] For the purpose of improving the water resistance of printed matter (recorded matter), the aqueous ink composition of the present embodiment may contain a resin. When containing a resin, at least a part of the contained resin is preferably contained in the form of a resin emulsion. A resin emulsion refers to an aqueous dispersion in which the continuous phase is a water-soluble solvent and the dispersed particles are resin fine particles. By forming a resin emulsion, the resin can be dispersed in the aqueous ink composition for inkjet recording in the form of resin fine particles by electrostatic repulsion. The above resin emulsion generally has the property of thickening and coagulating when the water-soluble solvent as the continuous phase decreases due to evaporation, penetration, etc., and has the effect of promoting the fixing of the colorant on the recording medium.

[0199] The resin contained in the aqueous ink composition of the present embodiment is not particularly limited as long as it can exhibit the desired water resistance. For example, an acrylic resin, a polystyrene resin, a polyester resin, a vinyl chloride resin, a vinyl acetate resin, a vinyl chloride-vinyl acetate copolymer resin, a polyethylene resin, a urethane resin, a silicone resin, an acrylamide resin, an epoxy resin, or a copolymer or mixture thereof can be used. From the aspect of improving solvent resistance in addition to water resistance, these substances are preferred. Among them, an acrylic resin is preferably contained from the aspect of enabling excellent ejection stability, water resistance, and solvent resistance.

[0200] As the acrylic resin, there is no particular limitation as long as it is a resin contained as the main component of the monomers constituting the (meth)acrylate monomer. As the (meth)acrylate monomer, known compounds can be used, and monofunctional (meth)acrylate can be preferably used. For example, (meth)acrylic acid alkyl esters, (meth)acrylic acid aralkyl esters, (meth)acrylic acid alkoxyalkyl esters, etc. can be cited.Specifically, examples include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-methylcyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, dicyclopentenoxyethyl (meth)acrylate, dicyclohexyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, allyl (meth)acrylate, propargyl (meth)acrylate, phenyl (meth)acrylate, naphthyl (meth)acrylate, anthryl (meth)acrylate, anthrylnonyl (meth)acrylate, piperonyl (meth)acrylate, salicylyl (meth)acrylate, furyl (meth)acrylate, furfuryl (meth)acrylate, tetrahydrofuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, pyranyl (meth)acrylate, benzyl (meth)acrylate, phenethyl (meth)acrylate, tolyl (meth)acrylate, glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylethyl (meth)acrylate, 1,1,1-trifluoroethyl (meth)acrylate, perfluoroethyl (meth)acrylate, perfluoropropyl (meth)acrylate, perfluoroisopropyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, triphenylmethyl (meth)acrylate, cumyl (meth)acrylate, 3-(N,N-dimethylamino)propyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, trimethoxysilylpropyl (meth)acrylate, triethoxysilylpropyl (meth)acrylate, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldimethoxysilane and other (meth)acrylates, etc.

[0201] As monomers constituting the acrylic resin, an acid group-containing monomer having an acid group, a hydroxyl group-containing monomer having a hydroxyl group, and an amino group-containing monomer having an amino group may be included. As the above-mentioned acid group-containing monomer having an acid group, for example, carboxyl group-containing aliphatic monomers such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, crotonic acid, citraconic acid, maleic anhydride, monomethyl maleate, monobutyl maleate, monomethyl itaconate, monobutyl itaconate, vinylbenzoic acid, mono(2-hydroxyethyl) (meth)acrylate oxalate, carboxyl-terminated caprolactone-modified (meth)acrylate, etc., and carboxyl group-containing monomers having an ethylenically unsaturated double bond and a carboxyl group can be cited. As the above-mentioned hydroxyl group-containing monomer having a hydroxyl group, there is no particular limitation as long as it has an unsaturated double bond and a hydroxyl group. For example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone-modified hydroxy (meth)acrylate, α-(hydroxymethyl) (meth)acrylate methyl ester, α-(hydroxymethyl) (meth)acrylate ethyl ester, α-(hydroxymethyl) (meth)acrylate n-butyl ester, 1,4-cyclohexanedimethanol mono(meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc. can be cited. As the above-mentioned amino group-containing monomer, there is no particular limitation as long as it has an unsaturated double bond and an amino group. For example, acrylamide compounds such as (meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-n-propyl (meth)acrylamide, N-isopropyl (meth)acrylamide, methylenebis(meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, dimethylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl acrylamide, diacetone acrylamide, etc., nitrogen atom-containing (meth)acrylate compounds such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, ethylene oxide adduct of morpholine (meth)acrylate, etc., N-vinylpyrrolidone, N-vinylpyridine, N-vinylimidazole, N-vinylpyrrole, N-vinyl oxazolidinone, N-vinylsuccinimide, N-vinylmethyl carbamate, N,N-methylvinylacetamide, (meth)acryloyloxyethyltrimethylammonium chloride, 2-isopropylidene-2-oxazoline, 2-vinyl-2-oxazoline, (meth)acrylonitrile, etc.

[0202] In addition, as monomers constituting the acrylic resin, other monomers may be included as needed in addition to the above-mentioned (meth)acrylate monomers, etc. Such other monomers are not particularly limited as long as they can copolymerize with the above-mentioned (meth)acrylate monomers and can form a resin with desired water resistance and solvent resistance. They can be monofunctional monomers having one ethylenically unsaturated double bond or polyfunctional monomers having two or more ethylenically unsaturated double bonds. For example, vinyl monomers such as vinyl acetate, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, N-vinylpyrrolidone, vinylpyridine, N-vinylcarbazole, vinylimidazole, vinyl ether, vinyl ketone, and vinylpyrrolidone can be used; aromatic vinyl monomers such as styrene, α-, o-, m-, p-alkyl, nitro, cyano, amide, and ester derivatives of styrene, vinyltoluene, and chlorostyrene; olefin monomers such as ethylene, propylene, and isopropylene; diene monomers such as butadiene and chloroprene; vinyl cyanide compound monomers such as acrylonitrile and methacrylonitrile. In addition, diacrylate compounds such as polyethylene glycol diacrylate, triethylene glycol diacrylate, and 1,3-butanediol diacrylate can be used; triacrylate compounds such as trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate; dimethacrylate compounds such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and triethylene glycol dimethacrylate; trimethacrylate compounds such as trimethylolpropane trimethacrylate and trimethylolethane trimethacrylate; divinylbenzene, etc. It should be noted that the acrylic resin can be formed using these monomers, but there is no particular limitation on the copolymerization form of the monomers. For example, it can be a block copolymer, a random copolymer, a graft copolymer, etc. The resin emulsion can be produced, for example, by carrying out an emulsion polymerization reaction and then neutralizing after the reaction. As the emulsifier, ordinary polymeric surfactants can be used, or reactive surfactants having unsaturated bonds can also be used. There is no particular limitation on the synthesis method. For example, water, monomers, emulsifiers, and polymerization initiators can be mixed in the presence of reactive surfactants, non-reactive surfactants, polyvinyl alcohol, cellulose derivatives, etc. to carry out emulsion polymerization. In addition, the resin emulsion can also be obtained not by carrying out an emulsion polymerization reaction but by mixing resin particles and surfactants with water. For example, it can be obtained by adding resin particles containing (meth)acrylate or styrene and (meth)acrylate and surfactants to water and mixing them.

[0203] Examples of commercially available resin emulsions include ACRIT WEM-031U, WEM-200U, WEM-321, WEM-3000, WEM-202U, and WEM-3008 (manufactured by Taisei Fine Chemical Co., Ltd., acrylic-urethane resin emulsions), ACRIT UW-550CS, UW-223SX, AKW107, and RKW-500 (manufactured by Taisei Fine Chemical Co., Ltd., acrylic resin emulsions), LUBRIJET N240 (manufactured by Lubrizol, acrylic resin emulsions), SUPERFLEX 150, 210, 470, 500M, 620, 650, E2000, E4800, and R5002 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., urethane resin emulsions), and VINYBLAN 701FE35, 701FE50, 701FE65, 700, 701, 711, 737, 747 (manufactured by Nissin Chemical Co., Ltd., vinyl chloride-acrylic resin emulsion), VINYBLAN 2706, 2685 (manufactured by Nissin Chemical Co., Ltd., acrylic resin emulsion), MOVINYL (Japanese: モビニ一ル) 743N, 6600, 7470, 7720 (manufactured by Nippon Synthetic Chemical Co., Ltd., acrylic resin emulsion), etc., but not limited to these.

[0204] From the perspective of dispersion stability in the ink composition and inkjet ejectability, the volume average particle size of the resin emulsion is preferably from 30 nm to 300 nm, more preferably from 50 nm to 250 nm. It should be noted that in this embodiment, the volume average particle size of the resin emulsion is the volume average particle size (D50) measured at 25°C using a particle size distribution analyzer (MicrotracBEL Co., Ltd., particle size analyzer NANOTR ACWAVE).

[0205] The aqueous ink composition of this embodiment may contain a surfactant as another additive. The surfactant that can be used in the aqueous ink composition of this embodiment is not particularly limited; examples include polysiloxane compounds, anionic surfactants, nonionic surfactants, fluorine-based surfactants, alkylene oxide-modified acetylene glycol surfactants, and unmodified alkylene oxide acetylene glycol surfactants. Among these, the inclusion of any of unmodified alkylene oxide acetylene glycol surfactants, alkylene oxide-modified acetylene glycol surfactants, and polysiloxane compounds as a surface tension modifier is preferred because it improves the wettability and spreadability of the aqueous ink composition on the recording medium.

[0206] As an alkylene oxide non-modified acetylenic diol surfactant, specifically, 2,5-dimethyl-3-hexyne-2,5-diol, 3,6-dimethyl-4-octyne-3,6-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,5-dimethyl-1-hexyne-3-ol, 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3-hexyne-2,5-diol, 2-butyn-1,4-diol, etc. can be cited. In addition, as commercially available products, Surfynol 61, 82, 104 (all manufactured by Air Products) and the like can be used.

[0207] As an alkylene oxide modified acetylenic diol surfactant, specifically, Surfynol 420, 440, 465, 485, TG, 2502, Dynol 604, 607 (all manufactured by Air Products), Surfynol SE, MD-20, OLFIN EE1004, E1010, PD-004, EXP4300, PD-501, PD-502, SPC (all manufactured by Nissin Chemical Industry Co., Ltd.), ACETYLENOL EH, E40, E60, E81, E100, E200 (all manufactured by Kawaken Fine Chemicals Co., Ltd.) and the like can be cited.

[0208] Regarding polysiloxane compounds, as commercially available products, for example, FZ-2122, FZ-2110, FZ-7006, FZ-2166, FZ-2164, FZ-7001, FZ-2120, SH8400, FZ-7002, FZ-2104, 8029 ADDITIVE, 8032 ADDITIVE, 57 ADDITIVE, 67 ADDITIVE, 8616 ADDITIVE (all manufactured by Toray Dow Corning Co., Ltd.), KF-6012, KF-6015, KF-6004, KF-6013, KF-6011, KF-6043, KP-104, 110, 112, 323, 341 (all manufactured by Shin-Etsu Chemical Co., Ltd.), BYK-300 / 302, BYK-301, BYK-306, BYK-307, BYK-320, BYK-325, BYK-330, BYK-331, BYK-333, BYK-337, BYK-341, BYK-342, BYK-344, BYK-345 / 346, BYK-347, BYK-348, BYK-349, BYK-375, BYK-377, BYK-378, BYK-UV3500, BYK-UV3510, BYK-310, BYK-315, BYK-370, BYK-UV3570, BYK-322, BYK-323, BYK-3455, BYK-Silclean3700 (all manufactured by BYK-Chemie GmbH), SILFACE SAG503A, SILFACE SJM-002, SILFACE SJM-003 (all manufactured by Nissin Chemical Industry Co., Ltd.), TEGOTwin4000, TEGOTwin4100, TEGOWet240, TEGOWet250, TEGOWet240 (all manufactured by Evonik Degussa GmbH), etc. These additives can be used in both aqueous ink compositions and non-aqueous ink compositions. In the non-aqueous ink of the present embodiment, among them, a polyether group-modified polysiloxane compound having a polyether group can be preferably used.

[0209] In addition, as specific examples of anionic surfactants, nonionic surfactants, fluorine-based surfactants, and alkylene oxide-modified alkynediol-based surfactants, EMAL, Latemul, NEOPELEX, DEMOL (all are anionic surfactants; manufactured by Kao Corporation), Sannol, Lipolan, Lipon, Lipal (all are anionic surfactants; manufactured by LION Corporation), NOIGEN, Epan, Solgen (all are nonionic surfactants; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Emulgen, AMIET, Emasol (all are nonionic surfactants; manufactured by Kao Corporation), NAROACTY, Emulmin, Sannonic (all are nonionic surfactants; manufactured by Sanyo Chemical Industries, Ltd.), Megafac (fluorine-based surfactant; manufactured by DIC Corporation), Surflon (fluorine-based surfactant; manufactured by AGC SEMICHEMICAL), AEROSOL TR-70, TR-70HG, OT-75, OT-N, MA-80, IB-45, EF-800, A-102 manufactured by Cytec Industries Japan Co., Ltd., Pelex OT-P, Pelex CS, Pelex TR, Pelex TA manufactured by Kao Corporation, Newcol 290-A, Newcol 290-KS, Newcol 291-M, Newcol 291-PG, Newcol291-GL, Newcol 292-PG, Newcol 293, Newcol 297 (all are anionic surfactants) manufactured by Nippon Emulsion Co., Ltd., Emulgen 320P, Emulgen 350, Emulgen 430, Emulgen 130K, Emulgen 150 manufactured by Kao Corporation, NOIGEN TDS-120, NOIGEN TDS-200D, NOIGEN TDS-500F manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Blaunon SR-715, Blaunon SR-720, Blaunon SR-730, Blaunon SR-750, Blaunon EN-1520A, Blaunon EN-1530, Blaunon EN-1540 manufactured by Aoki Yushi Industry Co., Ltd., Newcol 2310, Newcol2320, Newcol 2327, Newcol 1545, Newcol 1820 manufactured by Nippon Emulsion Co., Ltd., NIKKOL BPS20, NIKKOL BPS30 (all are nonionic surfactants) manufactured by Nikko Chemicals Co., Ltd., etc.The content of these surfactants can be appropriately adjusted according to the content of the solvent, resin, pigment, and other surfactants. In addition, these surfactants can be used alone or in combination of two or more. The content of the surfactant can be appropriately adjusted according to the ink miscibility, cleanability, wettability of the inner wall of the flow path, and inkjet ejection property, and is preferably contained in an amount of 0.05% by mass or more and 5% by mass or less, more preferably 0.5% by mass or more and 3% by mass or less. It should be noted that these surfactants can be suitably used for aqueous ink compositions.

[0210] Next, the substrate (recording medium) that can be used in the recording method of the present embodiment will be described.

[0211] [Substrate]

[0212] As the substrate (recording medium) that can be used for the non-aqueous ink composition of the present embodiment, there is no particular limitation, and it can be an absorbent substrate such as paper or cloth, a non-absorbent substrate such as a resin substrate, a metal plate, or glass, or a substrate having a receiving layer that has been surface-coated, and various substrates can be used. As the resin, polyvinyl chloride-based polymers, acrylics, PET, polycarbonate, PE, PP, etc. can be used. In particular, since the organic solvent (a) is a solvent having high permeability to polyvinyl chloride-based polymers, a substrate (recording medium) having a hard or soft polyvinyl chloride-based polymer on the surface is particularly preferably used as the substrate (recording medium). As the substrate (recording medium) having a polyvinyl chloride polymer on the surface, a polyvinyl chloride substrate (film or sheet) etc. can be exemplified.

[0213] [Method for manufacturing a recording object]

[0214] A recording method of ejecting an ink composition for inkjet containing the above-mentioned organic solvent (a) onto the surface of a substrate can also be defined as a method for manufacturing a recording object.

[0215] If it is such a method for manufacturing a recording object, even when ejected onto the surface of the substrate, bleeding of the printing is less, and it is possible to effectively suppress a decrease in the ejection stability of the ink composition due to the ink composition eroding the cured product of the adhesive that bonds the constituent members of the inkjet head, so that the ink composition cannot be ejected to the desired position on the surface of the substrate.

[0216] Examples

[0217] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited by any of these descriptions.

[0218] 1. Preparation of non-aqueous ink composition

[0219] The non-aqueous ink compositions of the examples and comparative examples were prepared from each component such that an organic solvent (a), other solvents, a resin, a dispersant, an additive, and a pigment (colorant) were in the proportions shown in the following table. Specifically, a paint stirrer was used, and zirconia beads were used to disperse each component to prepare the non-aqueous ink composition. The unit is parts by mass. For the organic solvent (a) and the glycol dialkyl ether, the impurity concentration was determined by gas chromatography before mixing.

[0220] (1) Preparation of acrylic resin

[0221] 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 1.2 g of a specified amount of tert-butyl peroxy-2-ethylhexanoate (polymerization initiator) was added dropwise over 1.5 hours. After the addition was complete, the reaction was carried out at 100 °C for 2 hours and then cooled to obtain a colorless transparent polymer solution of methyl methacrylate. Then, the solvent was thoroughly distilled off from this polymer solution to obtain a polymer of methyl methacrylate having a polymerization average molecular weight (polystyrene conversion value) of 30,000 (denoted as "acrylic resin" in the table).

[0222] (2) Preparation of vinyl chloride-vinyl acetate copolymer resin

[0223] Into an autoclave equipped with a stirring device, after nitrogen replacement, 100 parts of deionized water, 40 parts of methanol, 32 parts of vinyl chloride, 5 parts of vinyl acetate, 0.2 part of glycidyl methacrylate, 3.55 parts of hydroxypropyl acrylate, 0.1 part of hydroxypropyl methylcellulose (suspending agent), 0.026 part of di-2-ethylhexyl peroxydicarbonate (polymerization initiator), and 0.57 part of di-3,5,5-trimethylhexyl peroxide (polymerization initiator) were charged. While stirring in a nitrogen atmosphere, the temperature was raised to 63 °C. Immediately after reaching 63 °C, 48 parts of vinyl chloride were continuously pressured in over 6 hours, and a mixture of 0.6 part of glycidyl methacrylate and 10.65 parts of hydroxypropyl acrylate was continuously pressured in over 5.4 hours to carry out a copolymerization reaction. When the internal pressure of the autoclave reached 0.3 MPa, the residual pressure was released, and the mixture was cooled. The resin slurry was taken out, filtered, and dried to obtain a vinyl chloride-based copolymer resin. At this time, the polymerization average molecular weight (polystyrene conversion value) of the vinyl chloride-vinyl acetate copolymer resin was 40,000 (denoted as "vinyl chloride-vinyl acetate copolymer" in the table).

[0224] [Evaluation 1]

[0225] (Component adaptability)

[0226] The component compatibility (the component compatibility of the inkjet head) of the non-aqueous ink compositions of the examples and comparative examples was evaluated. Specifically, 0.2 g of a cured product obtained by drying an epoxy resin adhesive (two-component curable epoxy adhesive "1500", manufactured by CEMEDINE Co., Ltd.) used in the components of the inkjet head at 60°C for 1 day was immersed in the non-aqueous ink compositions of the examples and comparative examples, and left at 60°C for 1 week to conduct an immersion test, and the weight change of the cured product was measured (in the table, denoted as "component compatibility").

[0227] Evaluation criteria

[0228] Evaluation 5: The weight change rate is less than 3%, and the material of the epoxy adhesive has not deteriorated.

[0229] Evaluation 4: The weight change rate is 3% or more and less than 5%, and the material of the epoxy adhesive has not deteriorated.

[0230] Evaluation 3: The weight change rate is 5% or more and less than 10%, and the material of the epoxy adhesive has not deteriorated.

[0231] Evaluation 2: The weight change rate is 10% or more and less than 15%, and the material of the epoxy adhesive has not deteriorated.

[0232] Evaluation 1: The weight change rate is 15% or more and / or there is deterioration of the material of the epoxy adhesive.

[0233] (Evaluation of linear printing)

[0234] The printing of the non-aqueous ink compositions of the examples and comparative examples was evaluated. Specifically, the non-aqueous ink compositions of the examples and comparative examples were recorded (printed) on a recording medium (polyvinyl chloride film (IMAGin JT5829R: manufactured by MACtac)) by an inkjet method using an inkjet printer in a high-quality printing mode (printing speed 10 m 2 / h) at a substrate surface temperature of 40°C to form a line with a line width of 200 μm extending in the sub-scanning direction of the inkjet head. The obtained recording was observed with a magnifying glass (5×), and the line width was evaluated according to the following evaluation criteria (in the table, denoted as "linear shape"). It should be noted that the adhesive for bonding the constituent members of the inkjet head included in this inkjet printer is an epoxy resin adhesive. It should be noted that in this evaluation, the adhesive for bonding the constituent members includes an epoxy resin adhesive, and an inkjet printer is used, and this inkjet printer has an inkjet head having a member (nozzle cover) covering the ejection hole surface of the non-aqueous ink composition, and an ink storage mechanism (damper) is provided between the ink supply unit (ink cartridge) and the inkjet head.

[0235] Evaluation 5: The outline of the line is continuously formed in a certain shape, without defects or bulges in a 1-cm length, and is a straight line.

[0236] Evaluation 4: The outline of the line is continuously formed in a certain shape, with 1 to 10 defects or bulges in a 1-cm length, but is a straight line.

[0237] Evaluation 3: The outline of the line is continuously formed in a certain shape, but has more than 11 defects or bulges in a 1-cm length and is not a shape close to a straight line.

[0238] Evaluation 2: The outline of the line does not form a certain shape, but no interruption is observed.

[0239] Evaluation 1: A part where the line is interrupted is observed.

[0240] (Bleeding evaluation)

[0241] Similar to the above-recorded drying evaluation, in the high-quality printing mode (printing speed 10 m 2 / h), at a substrate surface temperature of 40 °C, an image of 6-pt text with a color different from the solid part is printed in the solid part of each color on a recording medium (PVC film with adhesive (IMAGin JT5829R: manufactured by MACtac)). After drying the obtained recording for 5 minutes in an oven at 60 °C, the bleeding of the recording is visually observed.

[0242] Evaluation criteria

[0243] Evaluation 4: No bleeding of the ink is observed, and the 6-pt text is clear.

[0244] Evaluation 3: Slight bleeding of the ink is observed, but it does not damage the design.

[0245] Evaluation 2: Bleeding of the ink is observed, but the 6-pt text can be recognized.

[0246] Evaluation 1: Obvious bleeding of the ink is observed, and the 6-pt text cannot be visually recognized.

[0247]

Table 1

[0248]

[0249]

Table 2

[0250]

[0251] As can be seen from the above table, the bleeding of the non-aqueous ink composition in the examples containing the organic solvent (a) is less, and it is possible to suppress the decrease in the ejection stability of the non-aqueous ink composition caused by the erosion of the cured product of the binder, and it is possible to effectively suppress the non-aqueous ink composition from not being ejected to the desired position on the substrate surface. In addition, as shown in Examples 38 to 52, even when containing colorants of various colors, the results are the same as those of Example 3 containing carbon black.

[0252] Among them, for example, when comparing Example 3, Example 7, Example 9 (containing an alkylamide-based solvent (a1)), Example 12, Example 14, Example 15 (containing a cyclic amide-based solvent (a2)), Example 16 to 19, and Example 22 (containing a lactone-based solvent (a3)) which contain 15.0% by mass of the organic solvent (a) in the total amount of the non-aqueous ink composition, compared with Example 16 and Example 17 containing a 5-membered ring lactone-based solvent, Example 3, Example 7, Example 9, Example 12, Example 14, Example 15, Example 18, Example 19, and Example 22 containing an alkylamide-based solvent (a1), a cyclic amide-based solvent (a2), or a lactone-based solvent having 6 or more membered rings as the organic solvent (a) have more excellent member adaptability.

[0253] In addition, when comparing Example 3, Example 7, Example 9 (containing an alkylamide-based solvent (a1)), Example 12, Example 14, Example 15 (containing a cyclic amide-based solvent (a2)), Example 16 to 19, and Example 22 (containing a lactone-based solvent (a3)) which contain 15.0% by mass of the organic solvent (a) in the total amount of the non-aqueous ink composition, compared with Example 18 and Example 19 containing a lactone-based solvent having 6 or more membered rings, Example 3, Example 7, Example 9, Example 12, Example 14, Example 15, Example 16, and Example 17 containing an alkylamide-based solvent (a1), a cyclic amide-based solvent (a2), or a 5-membered ring lactone-based solvent as the organic solvent (a) have better linear printing and no bleeding. Among them, the linear printing of Example 3, Example 7, and Example 9 containing an alkylamide-based solvent (a1) is particularly good.

[0254] In addition, for example, when comparing Example 1 to Example 4 containing diethylformamide (alkylamide-based solvent (a1)) as the organic solvent (a), Example 2, Example 3, and Example 4 containing the organic solvent (a) at a ratio of 25.0% by mass or less have particularly excellent member adaptability and good printing evaluation.

[0255] On the other hand, regarding Example 53 and Example 54 containing an alkoxyalkylamide-based solvent instead of the organic solvent (a), the member adaptability is poor compared with Example 1 to Example 52.

[0256] In addition, Example 55 to Example 57 which contain neither the organic solvent (a) nor the alkoxyalkylamide-based solvent have good member adaptability, but compared with Example 1 to Example 52, bleeding occurs, and furthermore, the linear printing also deteriorates.

[0257] [Evaluation 2]

[0258] For the non-aqueous ink compositions of Example 3, Example 16, Example 53, and Example 55, in the above inkjet printer, a member (printhead cover) covering the ejection hole surface of the ink composition, an inkjet head including a cured product of an epoxy resin adhesive or a urethane resin adhesive, and an ink storage mechanism (damper) were appropriately installed / removed, and the intermittent ejection property, ejection stability, and bleeding property were evaluated.

[0259] (Intermittent ejection property)

[0260] The intermittent ejection property of the non-aqueous ink compositions of Example 3, Example 16, Example 53, and Example 55 was evaluated. Specifically, the non-aqueous ink compositions of Example 3, Example 16, Example 53, and Example 55 were filled in the inkjet printer, and on a recording medium (PVC film with paste (IMAGin JT5829R: manufactured by MACtac)), in a two-way high-quality printing mode (printing speed 10 m 2 / h) or a high-speed printing mode (printing speed 30 m 2 / h), intermittent printing was continuously performed on the above recording medium at a substrate surface temperature of 30 °C, 40 °C, and 50 °C for a long time at normal temperature, and the presence or absence of missing dots, flight bending, and ink scattering was observed, and the occurrence times were counted and evaluated. At this time, the inkjet head in which the adhesive for bonding the constituent members is an epoxy resin adhesive (denoted as printhead adhesive: epoxy in the table) and the inkjet head in which the adhesive for bonding the constituent members is a urethane resin adhesive (denoted as printhead adhesive: urethane in the table) were replaced, and the intermittent ejection property was evaluated.

[0261] Evaluation 5: During the 24-hour test period, the occurrence of missing dots, flight bending, or ink scattering is less than 10 times.

[0262] Evaluation 4: During the 24-hour test period, the occurrence of missing dots, flight bending, or ink scattering is 10 times or more and less than 20 times.

[0263] Evaluation 3: During the 24-hour test period, the occurrence of missing dots, flight bending, or ink scattering is 20 times or more and less than 30 times.

[0264] Evaluation 2: During the 24-hour test period, the occurrence of missing dots, flight bending, or ink scattering is 30 times or more and less than 40 times.

[0265] Evaluation 1: During the 24-hour test period, the occurrence of missing dots, flight bending, or ink scattering is 40 times or more.

[0266] (Ejection stability)

[0267] The ejection stability of the non-aqueous ink compositions of Example 3, Example 16, Example 53, and Example 55 was evaluated. Specifically, the non-aqueous ink compositions of Example 3, Example 16, Example 53, and Example 55 were filled in an inkjet printer, and on a recording medium (PVC film with paste (IMAGin JT5829R: manufactured by MACtac)), in a bi-directional high-quality printing mode (printing speed 10 m 2 / h) or a high-speed printing mode (printing speed 30 m 2 / h), solid images and thin lines were printed in a continuous printing manner at a substrate surface temperature of 40°C, and the occurrence of ink dot missing, flight bending, and ink scattering was visually observed and the number of occurrences was measured. At this time, the inkjet head in which the adhesive for bonding the constituent members was an epoxy resin adhesive (in the table, denoted as nozzle adhesive: epoxy) was replaced with an inkjet head in which the adhesive for bonding the constituent members was a urethane resin adhesive (in the table, denoted as nozzle adhesive: urethane), and the ejection stability was evaluated.

[0268] Evaluation 5: During the 3-hour test period, the occurrence of ink dot missing, flight bending, or ink scattering was less than 5 times.

[0269] Evaluation 4: During the 3-hour test period, the occurrence of ink dot missing, flight bending, or ink scattering was 5 times or more and less than 10 times.

[0270] Evaluation 3: During the 3-hour test period, the occurrence of ink dot missing, flight bending, or ink scattering was 10 times or more and less than 15 times.

[0271] Evaluation 2: During the 3-hour test period, the occurrence of ink dot missing, flight bending, or ink scattering was 15 times or more and less than 20 times.

[0272] Evaluation 1: During the 3-hour test period, the occurrence of ink dot missing, flight bending, or ink scattering was 20 times or more.

[0273] (Bleeding evaluation)

[0274] The bleeding property of the non-aqueous ink compositions of Example 3, Example 16, Example 53, and Example 55 was evaluated. Specifically, the non-aqueous ink compositions of Example 3, Example 16, Example 53, and Example 55 were filled in an inkjet printer, and on a recording medium (PVC film with paste (IMAGin JT5829R: manufactured by MACtac)), in a high-quality printing mode (printing speed 10 m 2 / h) or a high-speed printing mode (printing speed 30 m 2 / h), an image with 6-pt text having a color different from that of the solid part is printed in the solid part of each color on the surface of the substrate at a substrate surface temperature of 40°C. After drying the obtained recording material in an oven at 60°C for 5 minutes, bleeding of the recording material is visually observed. At this time, the inkjet head whose adhesive for bonding the constituent members is an epoxy resin adhesive (denoted as nozzle adhesive: epoxy in the table) and the inkjet head whose adhesive for bonding the constituent members is a urethane resin adhesive (denoted as nozzle adhesive: urethane in the table) are replaced, and the bleeding property is evaluated.

[0275] Evaluation criteria

[0276] Evaluation 4: No bleeding of the ink is observed, and the 6-pt text is clear.

[0277] Evaluation 3: Slight bleeding of the ink is observed, but the design is not impaired.

[0278] Evaluation 2: Bleeding of the ink is observed, but the 6-pt text can be recognized.

[0279] Evaluation 1: Obvious bleeding of the ink is observed, and the 6-pt text cannot be visually recognized.

[0280]

Table 3

[0281]

[0282] As can be seen from Table 3, when a non-aqueous ink composition containing an organic solvent (a) (Examples 3 and 16) is ejected onto the surface of the substrate, and when ejected onto the surface of the substrate using an inkjet head having a member covering the ejection hole surface, the intermittent ejection property is particularly good. On the other hand, in Example 53 containing an alkoxyalkylamide solvent instead of the organic solvent (a), even when ejected onto the surface of the substrate using an inkjet head having a member covering the ejection hole surface, the intermittent ejection property is insufficient.

[0283] In addition, when a non-aqueous ink composition containing an organic solvent (a) (Examples 3 and 16) is ejected onto the surface of the substrate, and when ejected onto the surface of the substrate using an inkjet head having an ink storage mechanism, the ejection stability is particularly good. On the other hand, in Example 55 containing an alkoxyalkylamide solvent instead of the organic solvent (a), even when ejected onto the surface of the substrate using an inkjet head having a member covering the ejection hole surface, the ejection stability is insufficient.

[0284] In addition, when a non-aqueous ink composition containing an organic solvent (a) (Examples 3 and 16) is ejected onto the surface of a substrate, and when it is ejected onto the surface of a substrate using an inkjet head whose adhesive for bonding constituent members is a urethane-based resin adhesive, the intermittent ejection property and ejection stability are evaluated as Grade 3. It is thought that this is because the non-aqueous ink composition containing an organic solvent (a) (Examples 3 and 16) swells the urethane-based resin adhesive, etc., and as a result, the ejection pressure becomes unstable. From this, it can be seen that when using a non-aqueous ink composition containing an organic solvent (a) (Examples 3 and 16) and ejecting it onto the surface of a substrate, by using an inkjet head whose adhesive for bonding constituent members is an epoxy-based resin adhesive to eject it onto the surface of a substrate, the ejection stability of the ink composition can be particularly improved.

[0285] It should be noted that by ejecting a non-aqueous ink composition containing an organic solvent (a) (Examples 3 and 16) onto the surface of a substrate, even when transporting and recording in a high-speed printing mode (printing speed 30 m 2 / h), the evaluation of bleeding of the printed characters is Grade 3. Compared with the case of transporting and recording in a high-quality printing mode (printing speed 10 m 2 / h), the resulting recording medium has some bleeding, but it does not impair the designability. It can be seen that it is a non-aqueous ink composition that can transport and record the recording medium (substrate) at high speed and withstand the recording.

[0286] In addition, by ejecting a non-aqueous ink composition (Examples 3 and 16) onto the surface of a substrate using an inkjet head equipped with a member (printhead cover) covering the ejection hole surface, even when the temperature of the substrate is raised to 50 °C using a heating mechanism, the intermittent ejection property is good. From this, it can be seen that if it is a recording method of ejecting a non-aqueous ink composition containing an organic solvent (a) onto the surface of a substrate using an inkjet head equipped with a member covering the ejection hole surface, it is possible to suppress the drying of the ink composition present near the ejection hole and thus suppress the decrease in the intermittent ejection property, and it is possible to quickly dry the ink composition landing on the substrate (recording medium). Therefore, it is possible to manufacture a recording medium at extremely high speed.

[0287] In addition, if the non-aqueous ink composition (Examples 3 and 16) is transported in a high-speed printing mode (printing speed 30 m 2 / h) and ejected onto the surface of a substrate using an inkjet head in a state without an ink storage mechanism, the ejection stability evaluation is Grade 3. It is thought that this is because by performing high-speed printing, the moving speed of the carriage becomes faster and the ink ejection pressure becomes unstable. On the other hand, if in a state with an ink storage mechanism, in a high-speed printing mode (printing speed 30 m 2 / h), the non-aqueous ink composition (Examples 3 and 16) is transported and ejected onto the surface of the substrate using an inkjet head, and the ejection stability is evaluated as Evaluation 5. From this, it can be seen that by using an inkjet recording apparatus having an ink storage mechanism between the ink supply unit and the inkjet head to eject the ink composition onto the surface of the substrate, the ink ejection pressure can be stabilized, and the ejection stability of the ink composition can be maintained.

[0288] 2. Preparation of Aqueous Ink Composition

[0289] Using a colorant (pigment dispersion), a resin (resin emulsion), an organic solvent (a), other solvents, and water (ion-exchanged water), aqueous ink compositions of Examples and Comparative Examples are prepared in accordance with the respective components so as to have the ratios shown in the following table. The production methods of the pigment dispersion and the resin (resin emulsion) are as follows. It should be noted that for the organic solvent (a), the impurity concentration is determined by gas chromatography before mixing.

[0290] (1) Preparation of Pigment Dispersant

[0291] A mixture of 63 g of methyl methacrylate, 27 g of butyl acrylate, 30 g of butyl methacrylate, 15 g of acrylic acid, 15 g of methacrylic acid, and 3.6 g of tert-butyl peroxy-2-ethylhexanoate is added dropwise to 200 g of toluene maintained at 100°C over 1.5 hours. After the addition is complete, the reaction is carried out at 100°C for 2 hours and then cooled to obtain a resin solution. The resin is purified from the resin solution using hexane to obtain a pigment dispersion resin having a polymerization average molecular weight (polystyrene conversion value) of 20,000 and an acid value of 143 mg KOH / g.

[0292] 2.5 g of the above-obtained pigment dispersion resin and 0.6 g of N,N-dimethylaminoethanol are dissolved in 80 g of water (ion-exchanged water), 15 g of C.I. Pigment 122 and 0.05 g of an antifoaming agent ("Surfynol 104PG" manufactured by Air Products Co., Ltd.) are added, and zirconia beads are used to disperse the mixture using a paint stirrer to obtain a pigment dispersion.

[0293] (2) Preparation of Resin Emulsion

[0294] After thoroughly purging a flask equipped with a mechanical stirrer, a thermometer, a nitrogen inlet tube, a reflux tube, and a dropping funnel with nitrogen, 0.75 g of a reactive surfactant (manufactured by Kao Corporation, trade name: Latemul PD-104), 0.04 g of potassium persulfate, 1.5 g of methacrylic acid, and 150 g of pure water were charged and stirred and mixed at 25°C. A mixture of 115.5 g of methyl methacrylate, 18 g of 2-ethylhexyl acrylate, and 15 g of butyl acrylate was added dropwise thereto to prepare a pre-emulsion. Separately, after thoroughly purging a flask equipped with a mechanical stirrer, a thermometer, a nitrogen inlet tube, a reflux tube, and a dropping funnel with nitrogen, 3 g of a reactive surfactant (manufactured by Kao Corporation, trade name: Latemul PD-104), 0.01 g of potassium persulfate, and 200 g of pure water were stirred and mixed at 70°C. Then, the above-prepared pre-emulsion was added dropwise to the flask over 3 hours. After further heating and aging at 70°C for 3 hours, it was cooled, the pH was adjusted to 8 with N,N-dimethylethanolamine, and it was filtered through #150 mesh (made of Japanese fabric) to obtain 500 g of a resin emulsion having a solid content of 30% by mass (glass transition temperature 64°C, acid value 7 mgKOH / g, volume average particle diameter: 90 nm). It should be noted that the volume average particle diameter (D50) of the resin emulsion was measured at 25°C using a particle size distribution measuring device (particle size analyzer NANOTRAC WAVE manufactured by MicrotracBEL Corporation).

[0295] [Evaluation 1]

[0296] For the aqueous ink compositions of the examples and comparative examples, "component adaptability", "printing evaluation of a linear shape", and "bleeding evaluation" were evaluated in the same manner as Evaluation 1 of the above non-aqueous ink composition.

[0297]

Table 4

[0298]

[0299] From the above table, it can be seen that the aqueous ink composition of the example containing the organic solvent (a) can suppress a decrease in the ejection stability of the aqueous ink composition caused by the aqueous ink composition eroding the cured product of the adhesive that bonds the constituent members of the inkjet head, and can effectively suppress the aqueous ink composition from not being ejected to the desired position on the substrate surface.

[0300] Among them, Example 58, Example 59, and Example 62 containing an alkylamide-based solvent (a1), a cyclic amide-based solvent (a2), or a lactone-based solvent with a ring size of 6 or more as the organic solvent (a) have more excellent component adaptability compared to Example 61 containing a lactone-based solvent with a 5-membered ring. In particular, Example 58 and Example 59 containing an alkylamide-based solvent (a1) and a cyclic amide-based solvent (a2) as the organic solvent (a) have particularly excellent component adaptability.

[0301] In addition, the linear printing of Example 58 and Example 59 containing an alkylamide-based solvent (a1) or a cyclic amide-based solvent (a2) is particularly good.

[0302] It should be noted that the aqueous ink composition of Example 59 has a lower impurity concentration from the organic solvent (a) compared to Example 60 with the same composition ratio, has good component adaptability and linear printing, and less bleeding.

[0303] On the other hand, regarding Example 63 containing an alkoxyalkylamide-based solvent instead of the organic solvent (a), although there is no bleeding, the component adaptability is poor compared to Examples 58 - 62.

[0304] In addition, Example 64 containing neither the organic solvent (a) nor the alkoxyalkylamide-based solvent has good component adaptability, but compared to Examples 58 - 62, bleeding occurs, and in addition, the linear printing also deteriorates.

[0305] [Evaluation 2]

[0306] For the aqueous ink compositions of Example 58, Example 61, Example 63, and Example 64, the intermittent ejection property, ejection stability, and bleeding property were evaluated in the same manner as [Evaluation 2] of the above non-aqueous ink composition.

[0307]

Table 5

[0308]

[0309] As can be seen from Table 5, when the aqueous ink composition containing the organic solvent (a) (Example 58, Example 61) is ejected onto the surface of the substrate, and when ejected onto the surface of the substrate using an inkjet head with a member covering the ejection hole surface, the intermittent ejection property is particularly good. On the other hand, for Example 63 containing an alkoxyalkylamide-based solvent instead of the organic solvent (a) and Example 64 containing neither the organic solvent (a) nor the alkoxyalkylamide-based solvent, even when ejected onto the surface of the substrate using an inkjet head with a member covering the ejection hole surface, the intermittent ejection property is insufficient.

[0310] In addition, it is known that when a water-based ink composition containing an organic solvent (a) (Examples 58 and 61) is ejected onto the surface of a substrate, particularly good ejection stability is achieved when it is ejected onto the surface of a substrate using an inkjet head equipped with an ink storage mechanism. On the other hand, in the case of Example 63 containing an alkoxyalkylamide-based solvent instead of the organic solvent (a) and Example 64 containing neither the organic solvent (a) nor the alkoxyalkylamide-based solvent, the ejection stability is insufficient even when ejected onto the surface of a substrate using an inkjet head equipped with a member covering the ejection hole surface.

[0311] Furthermore, when a water-based ink composition containing an organic solvent (a) (Examples 58 and 61) is ejected onto the surface of a substrate, and when it is ejected onto the surface of a substrate using an inkjet head whose binder for bonding constituent members is a urethane-based resin binder, the intermittent ejection property and ejection stability are rated as Evaluation 3. It is considered that this is because the water-based ink composition containing an organic solvent (a) (Examples 58 and 61) swells the urethane-based resin binder, etc., and as a result, the ejection pressure becomes unstable. From this, it can be seen that when a water-based ink composition containing an organic solvent (a) (Examples 58 and 61) is ejected onto the surface of a substrate, by using an inkjet head whose binder for bonding constituent members is an epoxy-based resin binder to eject onto the surface of a substrate, the ejection stability of the ink composition can be particularly improved.

[0312] It should be noted that by ejecting a water-based ink composition containing an organic solvent (a) (Examples 58 and 61) onto the surface of a substrate, even when transported and recorded in a high-speed printing mode (printing speed 30 m 2 / h), the evaluation of bleeding of the printed characters is Evaluation 3. Compared with the case of transporting and recording in a high-quality printing mode (printing speed 10 m 2 / h), the resulting recording medium slightly shows bleeding, but the appearance is not impaired. It can be seen that it is a water-based ink composition that can transport and record the recording medium (substrate) at high speed and withstand the recording.

[0313] In addition, by ejecting a water-based ink composition (Examples 58 and 61) onto the surface of a substrate using an inkjet head equipped with a member (print head cover) covering the ejection hole surface, even when the temperature of the substrate is raised to 50 °C using a heating mechanism, the intermittent ejection property is good. From this, it can be seen that if it is a recording method of ejecting a water-based ink composition containing an organic solvent (a) onto the surface of a substrate using an inkjet head equipped with a member covering the ejection hole surface, it is possible to suppress the drying of the ink composition present near the ejection hole and thus suppress the reduction of the intermittent ejection property, and it is possible to quickly dry the ink composition landing on the substrate (recording medium). Therefore, it is possible to manufacture a recording medium at an extremely high speed.

[0314] Further, if the aqueous ink composition (Examples 58 and 61) is discharged onto the surface of the substrate by conveyance in the high-speed printing mode (printing speed: 30 m 2 / h) without the ink storage mechanism and using an inkjet head, the ejection stability is evaluated as Evaluation 3. It is considered that this is because the moving speed of the carriage becomes faster by high-speed printing, and the ink ejection pressure becomes unstable. On the other hand, if the aqueous ink composition (Examples 58 and 61) is discharged onto the surface of the substrate by conveyance in the high-speed printing mode (printing speed: 30 m 2 / h) with the ink storage mechanism and using an inkjet head, the ejection stability is evaluated as Evaluation 5. Thus, it is understood that by discharging the ink composition onto the surface of the substrate using an inkjet recording apparatus having an ink storage mechanism between the ink supply unit and the inkjet head, the ink ejection pressure can be stabilized and the ejection stability of the ink composition can be maintained.

Claims

1. A recording method, wherein, An ink composition for inkjet containing an organic solvent is ejected onto the surface of a substrate, and the inkjet head includes constituent members bonded by a cured product of an adhesive. The organic solvent contains the following organic solvent (a). In the ink composition, the water content is 5.0% by mass or less based on the total amount of the non-aqueous ink composition. Organic solvent (a): at least one selected from alkylamide solvents (a1), cyclic amide solvents (a2), and lactone solvents (a3). The alkylamide solvent (a1) is represented by the following general formula (1). The cyclic amide solvent (a2) is represented by the following general formula (2). The lactone solvent (a3) is represented by the following general formula (3). ···（1） In formula (1), R1 is hydrogen or an alkyl group having 1 or more and 4 or less carbon atoms, and R2 represents an alkyl group having 2 or more and 4 or less carbon atoms. ···（2） In formula (2), R3 is an alkylene group having 4 or more and 5 or less carbon atoms, and R4 represents hydrogen or an alkyl group or unsaturated hydrocarbon group having 1 or more and 2 or less carbon atoms. ···（3） In formula (3), R5 is an alkylene group having 5 carbon atoms, and R6 represents hydrogen or an alkyl group having 1 or more and 2 or less carbon atoms.

2. The recording method according to claim 1, wherein, The adhesive that bonds the constituent members of the inkjet head contains an epoxy-based adhesive.

3. The recording method according to claim 1 or 2, wherein, The inkjet head includes a member that covers the ejection hole surface of the ink composition.

4. The recording method according to claim 1 or 2, wherein An ink storage mechanism is provided between the ink supply section that supplies the ink composition and the inkjet head.

5. A method for manufacturing a recording medium, wherein, An ink composition for inkjet containing an organic solvent is ejected onto the surface of a substrate, and the inkjet head includes constituent members bonded by a cured product of an adhesive. The organic solvent contains the following organic solvent (a). In the ink composition, the water content is 5.0% by mass or less based on the total amount of the non-aqueous ink composition. Organic solvent (a): at least one selected from alkylamide solvents (a1), cyclic amide solvents (a2), and lactone solvents (a3). The alkylamide solvent (a1) is represented by the following general formula (1). The cyclic amide solvent (a2) is represented by the following general formula (2). The lactone solvent (a3) is represented by the following general formula (3). ···（1） In formula (1), R1 is hydrogen or an alkyl group having 1 or more and 4 or less carbon atoms, and R2 represents an alkyl group having 2 or more and 4 or less carbon atoms. ···（2） In formula (2), R3 is an alkylene group having 4 or more and 5 or less carbon atoms, and R4 represents hydrogen or an alkyl group or unsaturated hydrocarbon group having 1 or more and 2 or less carbon atoms. ···（3） In formula (3), R5 is an alkylene group having 5 carbon atoms, and R6 represents hydrogen or an alkyl group having 1 or more and 2 or less carbon atoms.

6. An ink composition, which is an ink composition for inkjet ejected onto the surface of a substrate by an inkjet head, and the inkjet head includes constituent members bonded by a cured product of an adhesive. The ink composition contains an organic solvent. The organic solvent contains the following organic solvent (a). In the ink composition, the water content is 5.0% by mass or less based on the total amount of the non-aqueous ink composition. Organic solvent (a): at least one selected from alkylamide solvents (a1), cyclic amide solvents (a2), and lactone solvents (a3). The alkylamide-based solvent (a1) is represented by the following general formula (1). The cyclic amide-based solvent (a2) is represented by the following general formula (2). The lactone-based solvent (a3) is represented by the following general formula (3). ···（1） In formula (1), R1 is hydrogen or an alkyl group having 1 or more and 4 or less carbon atoms, and R2 represents an alkyl group having 2 or more and 4 or less carbon atoms. ···（2） In formula (2), R3 is an alkylene group having 4 or more and 5 or less carbon atoms, and R4 represents hydrogen or an alkyl group or an unsaturated hydrocarbon group having 1 or more and 2 or less carbon atoms. ···（3） In formula (3), R5 is an alkylene group having 5 carbon atoms, and R6 represents hydrogen or an alkyl group having 1 or more and 2 or less carbon atoms.

7. The ink composition according to claim 6, wherein, The organic solvent (a) is an alkylamide-based solvent (a1).

8. The ink composition according to claim 7, wherein, The alkylamide-based solvent (a1) contains at least one selected from N,N-diethylformamide, N,N-diethylpropanamide, and N,N-diethylethanamide.

9. The ink composition according to claim 6, wherein, The organic solvent (a) is a cyclic amide-based solvent (a2).

10. The ink composition according to claim 9, wherein The cyclic amide-based solvent (a2) contains at least one selected from ε-caprolactam, N-methylcaprolactam, and N-vinylcaprolactam.

11. The ink composition according to claim 6, wherein, The organic solvent (a) is a lactone-based solvent (a3).

12. The ink composition according to claim 11, wherein, The lactone-based solvent (a3) contains ε-caprolactone.

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