Inkjet ink composition and recording method

Abstract

The present invention relates to an inkjet ink composition and a recording method, and provides an inkjet ink composition which is excellent in blocking resistance, dry rub resistance, wet rub resistance, ethanol resistance, adhesion, clogging recovery, and intermittent printing stability. An aqueous inkjet ink composition containing a binder resin, the binder resin including an acrylic resin and a polyether-based polyurethane resin, the acrylic resin being a block copolymer including a structural unit derived from isobornyl (meth)acrylate.

Description

Technical Field

[0001] This invention relates to inkjet ink compositions and recording methods. Background Technology

[0002] Inkjet recording methods, employing relatively simple devices, are capable of recording high-resolution images and have seen rapid development in various aspects. For example, Patent Document 1 discloses a white ink composition containing white pigment, which is an aqueous inkjet ink composition capable of forming a white image with excellent filling properties even when using a processing liquid. This white ink composition is used for recording by adhering a processing liquid containing a coagulant to a recording medium. The recording medium is a low-absorbency or non-absorbent recording medium containing a dispersant for dispersing the white pigment and a fixing resin; the dispersant is a nonionic dispersant.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2021-187095

[0004] In inkjet ink compositions containing binder resins, properties such as abrasion resistance and adhesion are not yet adequate. Summary of the Invention

[0005] The inkjet ink composition of the present invention is a water-based ink containing a binder resin, which includes an acrylic resin (hereinafter also referred to as "acrylic resin A") and a polyether polyurethane resin (hereinafter also referred to as "polyurethane resin B"), wherein the acrylic resin is a block copolymer containing structural units derived from isoborneol methacrylate.

[0006] The recording method of the present invention includes an adhesion step in which ink using the above-described inkjet ink composition is ejected from an inkjet head and adhered to a recording medium. Attached Figure Description

[0007] Figure 1 This diagram illustrates an example of a recording device used in the recording method of this embodiment.

[0008] Figure 2 Table 1 shows the monomer composition of the acrylic resins used in the examples.

[0009] Figure 3 Table 2 shows the monomer composition of the polyurethane resin used in the examples.

[0010] Figure 4 Table 3 shows the composition of each composition used in the examples and their evaluation results.

[0011] Figure 5 Table 4 shows the composition of each composition used in the examples and their evaluation results.

[0012] Figure 6 Table 5 shows the composition of each composition used in the examples and their evaluation results.

[0013] Explanation of reference numerals in the attached figures

[0014] 10: Recording device; 11: Conveyor path; 12: Feeding section; 14: Conveying section; 16: Belt conveyor section; 18: Recording section; 20: Fd discharge section; 22: Fd mounting section; 24: Reversal path section; 26: Fu discharge section; 28: Fu mounting section; 30: Feeding tray; 32: Feeding roller; 34: Conveyor drive roller; 36: Conveyor driven roller; 38: First roller; 40: Second roller; 42: Circular belt; 42a: Upper section of the circular belt; 44: Support body; 46: Head holder; 48: Inkjet head; 50: First branch; 52: Reversal path; 54: Second branch; 56: Discharge roller pair; 64: Discharge drive roller; 68: Drive shaft; 76: Mounting surface; 78: Protrusion; 80: First force-applying component; 82: Second force-applying component; 84, 86: Support shaft; P: Recording medium. Detailed Implementation

[0015] Hereinafter, this embodiment will be described in detail with reference to the accompanying drawings, but the present invention is not limited thereto and various modifications can be made without departing from its spirit. Furthermore, in the drawings, the same reference numerals are used to label the same elements, and repeated descriptions are omitted. Additionally, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Moreover, the scale of the drawings is not limited to the scale shown.

[0016] 1. Inkjet ink composition

[0017] The inkjet ink composition involved in this embodiment contains a binder resin, which is an aqueous ink comprising acrylic resin A and polyether polyurethane resin B. Acrylic resin A is a block copolymer comprising structural units derived from isoborneol methacrylate.

[0018] Inkjet inks are also used for various plastic films such as biaxially oriented polypropylene (OPP) and polyethylene terephthalate (PET). Biaxially oriented polypropylene is a non-polar resin, while PET is a polar resin, resulting in different tendencies in ink adhesion and abrasion resistance. Typically, adhesive resins are used in inks to improve adhesion and abrasion resistance to recording media. However, when recording with the same ink on these plastics with different properties, it is difficult to produce an ink that exhibits excellent adhesion and abrasion resistance to any plastic film.

[0019] In addition, sometimes the binder resin added to the ink is difficult to form a smooth film on the recording medium, making it difficult to achieve the effect of a binder. For example, on the recording medium, as the ink dries, the organic solvent in the ink becomes more concentrated (the content in the ink increases), making it easier for the binder resin to dissolve in the organic solvent and form a smooth film. However, even so, there are cases where the binder resin is difficult to dissolve, and even heating in subsequent processes makes it difficult to form a smooth film.

[0020] Therefore, in this embodiment, an acrylic resin and a polyether polyurethane resin comprising a block copolymer of structural units derived from isoborneol methacrylate are used as adhesive resins. Isoborneol methacrylate is rigid and has high steric hindrance, thus acrylic resin A is rigid and hard, resulting in an ink with excellent dry rubbing resistance, wet rubbing resistance, ethanol resistance, and adhesion relative to non-polar recording media. Furthermore, polyurethane resin B has a highly hydrophilic polyether structure, thus exhibiting high affinity for the hydrophilic portions of the recording medium and pigments, resulting in an ink with excellent adhesion, dry rubbing resistance, and wet rubbing resistance even relative to highly polar recording media.

[0021] Furthermore, by encapsulating polyurethane resin B, which is difficult to dissolve on the recording medium even in inks rich in organic solvents, with acrylic resin A, which is readily soluble in organic solvents and easily forms a smooth film, the overall coating becomes a smooth film. As a result, it is believed that the effects of dry rubbing resistance, wet rubbing resistance, ethanol resistance, and adhesion based on acrylic resin A and polyurethane resin B can be obtained relative to various polarity recording media.

[0022] Hereinafter, the possible components and manufacturing methods of the ink composition relating to this embodiment will be described in detail.

[0023] 1.1. Pigments

[0024] The ink composition in this embodiment may also contain a colorant. There are no particular limitations on the colorant; any type of pigment or dye can be used. Examples of pigments include inorganic pigments such as carbon black and titanium dioxide, as well as organic pigments. Examples of dyes include acid dyes, direct dyes, reactive dyes, and basic dyes. Preferably, the ink composition in this embodiment contains a pigment.

[0025] Examples of organic pigments include azo lake pigments, insoluble monoazo pigments, insoluble diazo pigments, condensed azo pigments, and chelated azo pigments; polycyclic pigments such as phthalocyanine pigments, quinacridone pigments, perylene pigments, pyrene pigments, anthraquinone pigments, dioxazine pigments, thioindole pigments, isoindolineone pigments, and quinophthalone pigments; dye chelates such as basic dye chelates and acid dye chelates; and nitro pigments and nitroso pigments.

[0026] Examples of inorganic pigments include titanium dioxide, iron oxide yellow, iron oxide brown, chromium oxide, Prussian blue, ultramarine, molybdenum red, iron oxide black, lead yellow, composite oxide pigments, and carbon black.

[0027] Examples of carbon black used as a black pigment include CI (Colour Index Generic Name) Pigment Black 1, 7, and 11. Commercially available carbon black products include, for example, No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 2200B (trade name manufactured by Mitsubishi Chemical Corporation), Raven 5750, 5250, 5000, 3500, 1255, 700 (trade name manufactured by Columbia Carbon Company), Rega1 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400 (trade name manufactured by CABOT Corporation), ColorBlack FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, and Printex. 35, U, V, 140U, SpecialBlack 6, 5, 4A, 4 (trade names manufactured by Degussa). Carbon black can also be manufactured using known methods such as the contact process, furnace process, and thermal process.

[0028] Examples of white pigments include CI pigments 6, 18, and 21.

[0029] Examples of yellow pigments include CI pigment yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, and 180.

[0030] Examples of magenta pigments include CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57:1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168, 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, or CI Pigment Violet 19, 23, 32, 33, 36, 38, 43, 50.

[0031] Examples of cyan pigments include CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:34, 15:4, 16, 18, 22, 25, 60, 65, 66, CI Umbrella Blue 4, and 60.

[0032] In addition, as pigments other than black, white, yellow, magenta and cyan, examples include CI pigments green 7 and 10, CI pigments brown 3, 5, 25, 26, and CI pigments orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43, and 63.

[0033] Specific examples of dyes include: CI Acid Yellow 17, 23, 42, 44, 79, 142; CI Acid Red 52, 80, 82, 249, 254, 289; CI Acid Blue 9, 45, 249; CI Acid Black 1, 2, 24, 94; CI Edible Black 1, 2; CI Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142. 144, 173, CI Direct Red 1, 4, 9, 80, 81, 225, 227, CI Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, CI Direct Black 19, 38, 51, 71, 154, 168, 171, 195, CI Reactive Red 14, 32, 55, 79, 249, CI Reactive Black 3, 4, 35.

[0034] The pigment content relative to the total amount of the ink composition is preferably 0.1% to 10% by mass, 2% to 6% by mass, or 3% to 5% by mass. With the pigment content within the above range, there is a tendency to further improve resistance to tack, resistance to dry rubbing, resistance to wet rubbing, tackiness, clogging recovery, and intermittent printing stability.

[0035] The pigment content relative to the total amount of the ink composition is preferably 0.1% to 10% by mass, 2% to 6% by mass, or 3% to 5% by mass. By keeping the pigment content within the above range, there is a tendency to further improve resistance to tack, resistance to dry rubbing, resistance to wet rubbing, tackiness, clogging recovery, and intermittent printing stability.

[0036] 1.2. Adhesive Resin

[0037] The ink composition in this embodiment comprises an acrylic resin A and a polyether polyurethane resin B, which are block copolymers containing structural units derived from isoborneol methacrylate. By including acrylic resin A and polyurethane resin B, it becomes an ink with excellent resistance to tack, dry rubbing, wet rubbing, ethanol resistance, and tack relative to various polarity recording media.

[0038] 1.2.1. Acrylic Resin A

[0039] Acrylic resin A is a block copolymer containing structural units derived from isobornyl methacrylate, preferably a self-emulsifying resin. An acrylic resin is a resin that contains at least an acrylic monomer as a constituent component. The acrylic monomer is a monomer having a (meth)acrylic acid group, such as (meth)acrylic acid, (meth)acrylate, or (meth)acrylamide. It can also be a copolymer of an acrylic monomer and other monomers.

[0040] Self-emulsifying resins are resins that can stabilize into resin emulsions in aqueous compositions without the use of emulsifiers. When ink drying intensifies and the organic solvent becomes more concentrated, acrylic resin A, being a self-emulsifying resin, dissolves in the ink. When the water concentration increases again, it can re-emulsify (redisperse). The dissolution and dispersion of the resin are reversible, resulting in inks with excellent redispersibility, clogging recovery, and intermittent printing stability. Furthermore, on recording media, when ink drying intensifies and the organic solvent becomes more concentrated, acrylic resin A diffuses into the solvent through dissolution, easily forming a smooth film on the recording medium. This is particularly true in non-polar recording media, where it exhibits excellent dry rubbing resistance, wet rubbing resistance, and adhesion.

[0041] As a block copolymer, there are no particular limitations; for example, it can be a diblock copolymer, a triblock copolymer, or it can have more blocks. Diblock copolymers are preferred.

[0042] Furthermore, a block can be composed of a single monomer or two or more monomers. In addition, in a block containing two or more monomers, the two or more monomers can be arranged randomly.

[0043] The content of structural units derived from isoborneol methacrylate in acrylic resin A is preferably 10-80% by mass, 25-70% by mass, 40-65% by mass, 45-60% by mass, or 50-55% by mass relative to the total amount of acrylic resin A. By keeping the content of structural units derived from isoborneol methacrylate within the above range, there is a tendency to further improve the resistance to tack, dry friction, wet friction, ethanol resistance, and adhesion.

[0044] The total content of structural units derived from isoborneol methacrylate and other acrylic monomers relative to the total amount of acrylic resin A is preferably 50% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, 99% by mass or more, or 99.9% by mass or more. It can also be 100% by mass.

[0045] By ensuring the total content of structural units derived from acrylic monomers is within the aforementioned range, there is a tendency to further improve resistance to adhesion, dry friction, wet friction, ethanol, and tack. Furthermore, the acrylic monomers in this embodiment contain (meth)acrylic acid, (meth)acrylate, and (meth)acrylamide in their molecules.

[0046] Furthermore, acrylic resin A can also be composed of acrylic monomers and monomers other than acrylic monomers. Examples of monomers other than acrylic monomers include vinyl monomers. However, if vinyl monomers are included, there is a tendency for the resin to have low solubility when the ink drying is accelerated and it is rich in organic solvents. On the other hand, if vinyl monomers are included, there is a tendency for the resin to have higher hydrophobicity. However, the acrylic resin A of this embodiment has a structure with dense and highly hydrophobic A blocks, which makes the hydrophobicity of the A blocks more apparent. Therefore, even without vinyl monomers, the hydrophobicity of the A blocks can be improved.

[0047] There are no particular limitations on the monomers that constitute acrylic resin A; for example, hydrophobic monomers and hydrophilic monomers can be used. As a hydrophobic monomer, there are no particular limitations. Examples include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, lauryl methacrylate, stearyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, isoamyl methacrylate, isooctyl methacrylate, isodecyl methacrylate, isododecyl methacrylate, isooctadecyl methacrylate, dicyclopentyl methacrylate, and other alkyl methacrylates; styrene, α-methylstyrene, 2-methylstyrene, vinyltoluene, divinylbenzene, chlorostyrene, phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, and other monomers containing aromatic groups. In addition, isobornyl methacrylate is also a hydrophobic monomer.

[0048] As hydrophilic monomers, there are no particular limitations. Examples include unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citracic acid, and 2-methacryloyloxymethylsuccinic acid; unsaturated sulfonic acid monomers such as styrene sulfonic acid, 2-acrylamide-2-methylpropane sulfonic acid, and 3-sulfopropyl methacrylate; unsaturated phosphate monomers such as vinylphosphonic acid, vinyl phosphate, bis(methacryloyloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, and diphenyl-2-methacryloyloxyethyl phosphate; and cyclic trimethylolpropane acetal (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and (2-methyl-2-ethyl-1,3-dioxolane-4-yl)methacrylate. ) Ether-containing monomers such as methyl acrylate; N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylamide, N,N-dimethylarylamine, vinylpyrrolidone, 2-vinylpyridine, 4-vinylpyridine, 2-methyl-6-vinylpyridine, 5-ethyl-2-vinylpyridine and other unsaturated tertiary amine monomers; ionic monomers such as N,N-dimethylaminoethyl methacrylate quaternary ammonium salt, N,N-diethylaminoethyl methacrylate quaternary ammonium salt, N,N-dimethylaminopropyl methacrylate quaternary ammonium salt and other unsaturated ammonium salt monomers.

[0049] There are no particular limitations on the method for obtaining block copolymers; examples include free radical polymerization and living radical polymerization. Among these, living radical polymerization is preferred for obtaining a precise block copolymer structure. Living radical polymerization is not particularly limited; examples include the NMP method using nitrile radicals, the ATRP method utilizing the redox reaction of metal complexes, the RAFT method using dithiocarboxylic acid esters, methods using cobalt catalysts, the TEP method using tellurium compounds, iodine transfer polymerization using iodine, and the RTCP method using iodides as initiators and organic compounds as catalysts.

[0050] As an initiator, any known initiator used for free radical polymerization is acceptable, without particular limitation. Examples include azo compounds such as azobis(isobutyronitrile) and 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile); and peroxides such as benzoyl peroxide and dicumyl peroxide.

[0051] Preferably, the acrylic resin A comprises a block polymer consisting of an A block and a B block with an acid value higher than that of the A block. Examples of such AB block polymers include block polymers having a highly hydrophobic A block and a B block with a higher hydrophilicity than that of the A block.

[0052] A particularly preferred type is an AB block copolymer having one A block and one B block in one molecular chain.

[0053] Because the hydrophobic structure of this acrylic resin A is concentrated on block A and the hydrophilic structure is concentrated on block B, it easily forms a micelle structure with the hydrophobic blocks facing the center and the hydrophilic blocks facing the outside, making it easy to self-disperse in inks.

[0054] Furthermore, due to the hydrophobic, densely packed A-blocks, if the drying of the ink intensifies and the organic solvent becomes more concentrated, the acrylic resin A readily dissolves and is incorporated into the ink. This allows for reversible dispersion and dissolution.

[0055] Preferably, acrylic resin A is dissolved in an organic solvent containing the same composition as the organic solvent in the ink.

[0056] This leads to a further improvement in clogging recovery and intermittent printing stability. Furthermore, the dense hydrophobic regions result in excellent solubility in organic solvents, making it easier to form smooth films and further improving resistance to adhesion, dry rubbing, wet rubbing, ethanol, and tack.

[0057] The monomers constituting the B block include monomers with acidic groups, and may also include monomers without acidic groups if necessary. Conversely, the monomers constituting the A block include monomers without acidic groups, and may also include monomers with acidic groups, provided that the acid value does not exceed that of the B block.

[0058] Examples of unsaturated carboxylic acid monomers with acidic groups include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethylsuccinic acid; unsaturated sulfonic acid monomers include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and (meth)acrylic acid-3-sulfonate propyl ester; and unsaturated phosphate monomers include vinylphosphonic acid, vinyl phosphate, bis(methacryloyloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, and diphenyl-2-methacryloyloxyethyl phosphate.

[0059] Furthermore, there are no particular limitations on the monomers that do not have acidic groups; for example, other monomers such as hydrophobic monomers can be cited.

[0060] The content of monomers with acidic groups in the B-block is preferably 1-50% by mass, 5-40% by mass, 10-30% by mass, or 15-25% by mass relative to the total amount of monomers in the B-block. With the content of monomers with acidic groups in the B-block within the above range, there is a tendency to further improve abrasion resistance, clogging recovery, and redispersibility.

[0061] In this embodiment, the block polymer composed of an A block and a B block with an acid value higher than that of the A block is preferably an A block polymer having two or more hydrophobic monomers and a B block copolymer having one or more hydrophobic monomers and one or more hydrophilic monomers. The hydrophobic monomers contained in the A block and the B block can also be the same.

[0062] Furthermore, the acid value in this embodiment can be calculated based on the proportion of monomers with acidic groups in the block monomers, or it can be determined by the method shown in the examples.

[0063] The preferred acid value of acrylic resin A is 25~100 mgKOH / g, 30~70 mgKOH / g, or 40~60 mgKOH / g. By keeping the content of acrylic resin A within the above range, the resistance to tack, dry friction, wet friction, ethanol, and adhesion tend to be further improved.

[0064] The preferred acid values ​​for the B-block are 50~200 mgKOH / g, 80~150 mgKOH / g, and 100~140 mgKOH / g.

[0065] The acid value of block A can be 0 mg KOH / g or more than 0 mg KOH / g, but since it is lower than the acid value of block B, it is preferably below 30 mg KOH / g, below 20 mg KOH / g, below 10 mg KOH / g, below 5 mg KOH / g, or below 3 mg KOH / g.

[0066] The preferred number-average molecular weight of acrylic resin A is 10,000~25,000, 14,000~22,000, 15,000~21,000, 16,000~20,000, or 16,500~18,000. By having a number-average molecular weight within these ranges, the resistance to tack, dry rubbing, wet rubbing, ethanol resistance, and adhesion tend to be further improved.

[0067] The polydispersity (PDI) of acrylic resin A is preferably 1~5, 1.1~2, 1.2~1.6, or 1.27~1.5. With a polydispersity within the above range, the resistance to tack, dry rubbing, wet rubbing, ethanol resistance, and adhesion tend to be further improved.

[0068] The preferred biomass content of acrylic resin A is 30-100% by mass, 40-70% by mass, and 50-65% by mass. Within this range, the biomass content tends to further improve the ink's resistance to tack, dry rubbing, wet rubbing, ethanol resistance, and adhesion, while also producing a more environmentally friendly ink. Biomass content refers to the dry mass percentage of the biomass raw material used. Biomass raw materials refer to substances other than fossil resources from organic resources derived from plants and animals. In this embodiment, monomers manufactured from raw materials derived from plants and animals can be cited as an example.

[0069] The biomass of the compound can be determined by a known method based on the concentration of 14C determined using accelerator mass spectrometry (AMS).

[0070] The average particle size of acrylic resin A relative to the total amount of the ink composition is preferably 30-200 nm, 50-140 nm, 60-130 nm, 65-110 nm, or 70-90 nm. With the average particle size of acrylic resin A within the above range, there is a tendency for further improvements in adhesion resistance, dry rubbing resistance, wet rubbing resistance, ethanol resistance, and tackiness.

[0071] The glass transition points of acrylic resin A are preferably 50~150℃, 80~140℃, and 100~120℃. Under these conditions, the resistance to tack, dry friction, wet friction, ethanol resistance, and adhesion tend to be further improved.

[0072] The glass transition point can be determined by DSC.

[0073] The content of acrylic resin A relative to the total amount of the ink composition is preferably 0.1 to 10% by mass, 0.5 to 5% by mass, and 1 to 3% by mass. With the content of acrylic resin A within the above range, there is a tendency for further improvement in resistance to tack, resistance to dry rubbing, resistance to wet rubbing, resistance to ethanol, and adhesion.

[0074] 1.2.2. Polyurethane Resin B

[0075] Polyurethane resin B is a polyurethane resin containing a polyether backbone. Polyurethane resin B has a highly hydrophilic polyether structure, thus exhibiting high affinity for the highly hydrophilic portions of recording media and pigments, resulting in inks with excellent adhesion, dry rubbing resistance, and wet rubbing resistance compared to highly polar recording media.

[0076] On the other hand, due to its highly hydrophilic polyether structure, polyurethane resin B tends to be difficult to dissolve even as the organic solvent in the ink becomes more concentrated during drying, and it is difficult to form a smooth film even with heating in subsequent processes. However, in the ink of this embodiment, by using the aforementioned acrylic resin A and polyurethane resin B together, an ink with excellent adhesion, dry rubbing resistance, and wet rubbing resistance is achieved.

[0077] Because acrylic resin A is easily soluble, it can easily encapsulate polyurethane resin B to form a smooth film. Both the B block of acrylic resin A and polyurethane resin B have high hydrophilicity and high affinity, so it is speculated that they will form a tough coating film.

[0078] Furthermore, when the polyurethane resin is a polyester backbone rather than a polyether backbone, it is presumed that a strong and tough coating cannot be formed because it lacks a polyether backbone that has high affinity and hydrophilicity to the B block of acrylic resin A. Additionally, its wet rubbing resistance and ethanol resistance are not excellent.

[0079] Polyurethane resin is a general term for resins with a urethane backbone. It refers to resins containing urethane bonds, urea bonds, or urethane-formaldehyde bonds formed by the reaction of isocyanate groups with hydroxyl, amino, urethane bond groups, carboxyl groups, or other groups containing active hydrogen. Polyurethane resin B is, for example, obtained by polymerizing a polyisocyanate and a polyol containing a polyether backbone.

[0080] Polyurethane resin B can be a self-emulsifying resin that is stabilized into a resin emulsion without the use of an emulsifier, or it can be an emulsifying resin that is stabilized into a resin emulsion using an emulsifier.

[0081] Furthermore, even the self-emulsifying polyurethane resin B does not undergo reversible dissolution and redispersibility like the acrylic resin A. Even when using such a polyurethane resin B, encapsulating it with the acrylic resin A allows it to dissolve in the solvent, resulting in a smooth overall coating. Therefore, by combining polyurethane resin B and acrylic resin A, an ink with excellent resistance to tack, dry rubbing, wet rubbing, ethanol, and adhesion is produced.

[0082] Polyurethane resin B preferably has an aromatic ring backbone and / or an alicyclic backbone. Such polyurethane resin B tends to have further improved dry rubbing resistance, wet rubbing resistance, and ethanol resistance. The aromatic ring backbone and the alicyclic backbone can be derived from diisocyanate, polyol, or other monomers. It is preferred to derive them from diisocyanate.

[0083] If polyurethane resin B has an aromatic ring backbone, it has particularly excellent abrasion resistance and ethanol resistance, and is therefore preferred.

[0084] The preferred acid values ​​of polyurethane resin B are 40~130 mgKOH / g, 50~120 mgKOH / g, 60~100 mgKOH / g, 70~90 mgKOH / g, and 78~84 mgKOH / g. By keeping the acid value of polyurethane resin B within these ranges, its resistance to tack, dry rubbing, wet rubbing, ethanol resistance, and adhesion tend to be further improved.

[0085] The preferred mass ratio of polyurethane resin B to acrylic resin A is 1 / 3 to 3, 0.5 to 2, 2 / 3 to 1.5, or 0.8 to 1.2. By maintaining the mass ratio of polyurethane resin B to acrylic resin A within the above ranges, there is a tendency to further improve storage stability, color development, transfer resistance, abrasion resistance, and bubble removal properties.

[0086] The content of polyurethane resin B relative to the total amount of the ink composition is preferably 0.1 to 10% by mass, 0.5 to 5% by mass, and 1 to 3% by mass. With the content of polyurethane resin B within the above range, there is a tendency for further improvement in resistance to tack, resistance to dry rubbing, resistance to wet rubbing, resistance to ethanol, and adhesion.

[0087] The total content of acrylic resin A and polyurethane resin B relative to the total amount of the ink composition is preferably 0.5-20% by mass, 1-10% by mass, and 2-5% by mass. With the total content within the above range, there is a tendency for further improvement in resistance to tack, resistance to dry rubbing, resistance to wet rubbing, resistance to ethanol, and adhesion.

[0088] 1.1.2.1. Polyisocyanates

[0089] Polyisocyanates are compounds with two or more isocyanate groups in their molecular structure. There are no particular limitations. Examples include aliphatic polyisocyanates and aromatic polyisocyanates.

[0090] As aliphatic polyisocyanates, there are no particular limitations. Examples include tetramethylene diisocyanate, dodecamethylene diisocyanate, 1,5-pentane diisocyanate, 1,6-hexane diisocyanate, 2,2,4-trimethylhexane diisocyanate, 2,4,4-trimethylhexane diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, and other polyisocyanates with chain structures; isophorone diisocyanate, hydrogenated phenyl diisocyanate, 4,4′-methylene bis(cyclohexyl)isocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexyl diisocyanate, isophorone diisocyanate, and polyisocyanates with cyclic structures of 1,3-bis(methyl)cyclohexane, etc.

[0091] As an aromatic polyisocyanate, there is no particular limitation, for example, toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,5-naphthyl diisocyanate, phenylenediamine diisocyanate, 1,3-phenylenediamine diisocyanate, 1,4-phenylenediamine diisocyanate, 2,4-toluene diisocyanate, m-phenylenediamine diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, and α,α,α',α'-tetramethylphenylenediamine diisocyanate.

[0092] 1.1.2.2. Polyols

[0093] Polyols are compounds having two or more hydroxyl groups in their molecular structure. The polyol used in this embodiment is not particularly limited, and examples include low-molecular-weight polyols, polyether polyols, polyester polyols, and polycarbonate polyols.

[0094] Examples of low-molecular-weight polyols include, for example, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-cyclohexanediol, 1,4-cyclohexanediol, 4,4-dihydroxyphenylpropane, 4,4-dihydroxyphenylmethane, hydrogenated bisphenol A, dimethylol urea and its derivatives; glycerol, trimethylolpropane, 1,2,5-hexanetriol, 1,2,6-hexanetriol, pentaerythritol, trimethylol melamine and its derivatives; and so on.

[0095] As a polyether polyol, there is no particular limitation; examples include addition polymers of epoxides and polyols, and copolymers of polyalkylene glycols and polyalkylene glycols.

[0096] There are no particular limitations on the term "epoxide alkane," and examples include ethylene oxide, propylene oxide, butane oxide, and α-olefin oxides. Examples of low-molecular-weight polyols that undergo addition polymerization with epoxide alkane can be cited as examples of polyols.

[0097] Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Examples of alkylene glycol copolymers include ethylene glycol-propylene glycol copolymers.

[0098] There are no particular limitations on the type of polyol used in polyesters; examples include esters and acid salts. As for the acid component constituting the ester, it is acceptable as long as it has two or more acidic groups; there are no particular limitations. Examples include aromatic dicarboxylic acids such as phthalic acid, naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, and tetrahydrophthalic acid; alicyclic dicarboxylic acids such as the hydrides of these aromatic dicarboxylic acids; and aliphatic dicarboxylic acids such as malonic acid, succinic acid, tartaric acid, oxalic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, alkyl succinic acid, linolenic acid, maleic acid, fumaric acid, mesocaric acid, citracic acid, and itaconic acid. Anhydrides, salts, and derivatives (alkyl esters, acyl halides) of these compounds can also be used as acid components. Furthermore, as for the component that forms an ester bond with the acid component, there are no particular limitations as long as it has two or more hydroxyl groups; examples include polyols such as diols and triols; and diols such as (poly)alkylene glycols. Examples of low-molecular-weight polyols, such as polyols and diols, can be cited as examples of polyols.

[0099] There are no particular limitations on the polycarbonate polyol; for example, alkane diols such as polyhexamethylene carbonate diol can be cited. Additionally, polycarbonate diols obtained by reacting carbonate components such as alkylene carbonate, diaryl carbonate, and dialkyl carbonate, phosgene, and aliphatic diol components can be cited.

[0100] 1.3. Wax emulsion

[0101] The ink composition in this embodiment preferably includes a wax emulsion. By including a wax emulsion, the resistance to tack, dry rubbing, wet rubbing, ethanol resistance, and tack of the recorded material tend to be further improved. In this specification, "wax emulsion" mainly refers to a substance formed by dispersing solid wax particles in water using a surfactant.

[0102] Examples of waxes include animal waxes, plant waxes, and petroleum waxes. Examples of animal waxes include lanolin and beeswax. Examples of plant waxes include avocado oil, linseed oil, almond oil, fennel oil, perilla oil, olive oil, orange oil, neroli oil, cocoa butter, chamomile oil, carrot oil, cucumber oil, bitter almond oil, papaya seed oil, walnut oil, wheat germ oil, sesame oil, rice oil, rice bran oil, camellia oil, safflower oil, salad oil, shea butter, soybean oil, camellia seed oil, evening primrose oil, camellia oil, corn oil, rapeseed oil, peach kernel oil, passion fruit oil, castor oil, sunflower seed oil, grapeseed oil, hazelnut oil, macadamia nut oil, cottonseed oil, meadowfoam seed oil, peanut oil, rosehip oil, turtle oil, cocoa butter, palm oil, palm kernel oil, wood wax, carnauba wax, coconut oil, and waxes made from the hydrogenation of these oils and their derivatives.

[0103] Examples of petroleum waxes include polyethylene wax, polypropylene wax, polyolefin waxes, polyoxyalkylene alkyl ether waxes, paraffin wax, microcrystalline wax, and petrolatum. In this specification, "paraffin wax" refers to a mixture of hydrocarbons with a weight average molecular weight of approximately 300-500, primarily composed of straight-chain alkanes (n-alkanes) with approximately 20-30 carbon atoms and containing small amounts of isoalkanes.

[0104] The wax emulsion content relative to the total amount of ink is preferably 0.1-5% by mass, 0.3-3% by mass, 0.5-2% by mass, and 0.7-1.5% by mass. With the wax emulsion content within the above range, there is a tendency for further improvement in resistance to tack, resistance to dry rubbing, resistance to wet rubbing, resistance to ethanol, and adhesion.

[0105] 1.4. Organosilicon acrylic resin

[0106] The ink composition in this embodiment preferably further comprises an organosilicon acrylic resin. By including an organosilicon acrylic resin, there is a tendency to further improve dry rubbing resistance, wet rubbing resistance, and tack resistance.

[0107] Examples of silicone acrylic resins include (graft) copolymers of (meth)acrylic acid monomers and dialkylsiloxane monomers, acrylic-silicone copolymers, acrylic-modified organosiloxanes, acrylic-silicone copolymers, organosilicone-modified (meth)acrylic acid polymers, and polyorganosiloxanes obtained by graft copolymerization of (meth)acrylic esters. Commercially available silicone acrylic resins can be used; for example, CHALINE LC190 (trade name, manufactured by Nissin Chemical Industry Co., Ltd.) is a commercially available product.

[0108] The content of silicone acrylic resin relative to the total amount of ink is preferably 0.1-5% by mass, 0.3-3% by mass, 0.5-2% by mass, and 0.7-1.5% by mass. With the silicone acrylic resin content within the above range, there is a tendency to further improve the resistance to tack, dry rubbing, wet rubbing, ethanol resistance, and adhesion.

[0109] 1.5. Organic solvents

[0110] The ink composition in this embodiment may also contain an organic solvent. Particularly preferred is the presence of an octanol / water partition coefficient (logP). ow Organic solvent A has a value of 0 to 1. By including organic solvent A in the ink composition, when the ink drying intensifies and the content of organic components becomes dominant, the binder resin tends to dissolve more easily in the ink, and the clogging recovery is more likely to be further improved. In addition, since it is easy to form a smooth film on the recording medium, the resistance to tack, dry rubbing, wet rubbing, ethanol resistance, and adhesion tend to be further improved. The ink composition in this embodiment may also contain logP as needed. ow Organic solvent B with a value outside the range of 0 to 1.

[0111] logP of organic solvent A ow The preferred values ​​are 0.1~1, 0.2~0.9, 0.3~0.8, 0.4~0.7, and 0.5~0.6. (This is achieved through logP...) ow A value above 0 indicates higher solubility of the adhesive resin, as shown by logP. ow A value below 1 indicates superior compatibility with water. Therefore, through logP... ow When the values ​​are within the above range, the ink composition tends to have further improved resistance to tack, dry rubbing, wet rubbing, ethanol, tack, and clogging recovery.

[0112] In this embodiment, the octanol / water partition coefficient logP ow The value refers to the value defined in OECD Test Guideline 107. The octanol / water partition coefficient is expressed as logP. ow logK ow etc. logP ow A higher value indicates higher hydrophobicity, while a lower value indicates higher hydrophilicity.

[0113] logP of the compound ow The value can be obtained by various methods, such as by determination according to the method specified in JIS Z 7260-117. Alternatively, it can be calculated using Hansen Solubility Parameter Software (HSPIP).

[0114] Additionally, the ink composition of this embodiment may also contain logP. ow Organic solvent B with a value less than 0.

[0115] There are no particular limitations on organic solvents A and B; examples include monools, diols, ethers, polyols with three or more hydroxyl groups, ketones, and lactam compounds. One organic solvent may be used alone, or two or more may be used in combination.

[0116] Examples of monools include methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, tert-butanol, isobutanol, n-pentanol, 2-pentanol, 3-pentanol and tert-pentanol, 2-phenoxyethanol, benzyl alcohol, phenoxypropanol, etc.

[0117] Examples of diols include alkanediols and condensates of alkanediols that have a structure formed by the condensation of intermolecular hydroxyl groups. Alkanediols are compounds formed by replacing two hydroxyl groups with alkane groups. Examples of condensates of alkanediols that have a structure formed by the condensation of intermolecular hydroxyl groups include condensates of alkanediols with 2 to 4 carbon atoms.

[0118] Examples of diols include condensates formed by the condensation of intermolecular hydroxyl groups in alkyl diols such as ethylene glycol, propylene glycol, 1,2-propanediol, 1,2-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, 1,3-propanediol, 1,4-butanediol, and 1,6-hexanediol; and condensates formed by the condensation of intermolecular hydroxyl groups in alkyl diols such as tetramethylenediol, hexamethylenediol, diethylene glycol, triethylene glycol, tetraethylenediol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, and (poly)tetramethylenediol.

[0119] There are no particular limitations on the class of ethers; examples include alkyl ethers and ethylene glycol ethers. Examples of alkyl ethers include dimethyl ether, methyl ethyl ether, diethyl ether, isopropyl methyl ether, and isopropyl ethyl ether.

[0120] Examples of ethylene glycol ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol monoethyl ether. Alkylene glycol monoalkyl ethers such as monobutyl ether; and alkylene glycol dialkyl ethers such as dimethyl ether, diethyl ether, dibutyl ether, diethylene glycol dimethyl ether, diethyl ether, dibutyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl butyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, triethylene glycol methyl butyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol diethyl ether, tripropylene glycol dimethyl ether, etc.

[0121] Examples of polyols having three or more hydroxyl groups include glycerol. Examples of ketones include acetone, methyl ethyl ketone, and diethyl ketone. Examples of lactam compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-hydroxyethylpyrrolidone (HEP).

[0122] Organic solvent A is the octanol / water partition coefficient logP among the organic solvents mentioned above. ow Organic solvents with a value of 0 to 1. Examples of such organic solvents A include isopropyl methyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, 1,2-hexanediol, methyl ethyl ketone, isopropanol, and methyl ethyl ketone.

[0123] The content of organic solvent A relative to the total amount of the ink composition is preferably 0.5-15% by mass, 3-12% by mass, 5-10% by mass, or 7-9% by mass. With the content of organic solvent A within the above range, there is a tendency to further improve the resistance to tack, dry rubbing, wet rubbing, ethanol resistance, tackiness, and clogging recovery.

[0124] The content of organic solvent B relative to the total amount of the ink composition is preferably 1-20% by mass, 5-15% by mass, 7-14% by mass, 9-13% by mass, or 10-12% by mass. With the content of organic solvent B within the above range, there is a tendency to further improve the resistance to tack, dry rubbing, wet rubbing, ethanol resistance, adhesion, and clogging recovery.

[0125] When organic solvents A and B are included, the total content of the organic solvents is preferably 0.5-30% by mass, 10-27% by mass, 15-25% by mass, 16-22% by mass, or 17-21% by mass relative to the total amount of the ink composition. With the organic solvent content within the above range, there is a tendency for further improvements in resistance to tack, resistance to dry rubbing, resistance to wet rubbing, resistance to ethanol, tackiness, and clogging recovery.

[0126] 1.6. Surfactants

[0127] The ink composition in this embodiment may also contain a surfactant. There are no particular limitations on the surfactant; examples include silicone-based surfactants, acetylene glycol-based surfactants, and fluorinated surfactants.

[0128] As for acetylene glycol-based surfactants, there are no particular limitations; examples include 2,4,7,9-tetramethyl-5-decane-4,7-diol and its epoxide adducts. Commercially available acetylene glycol-based surfactants include Olfin E1010, EXP4200, Surfynol SE, Surfynol 440, Surfynol 104, Surfynol 465, and Surfynol DF110D (trade name manufactured by Nissin Chemical Industry Co., Ltd.).

[0129] As a fluorinated surfactant, there are no particular limitations; examples include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl betaines, and perfluoroalkyl amine oxides.

[0130] As for silicone-based surfactants, there are no particular limitations; examples include polysiloxane compounds and polyether-modified silicones. Commercially available silicone-based surfactants include, for example, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348, BYK-349, BYK-UV3500, BYK-UV3510, BYK-UV3530, and BYK-UV3570 (trade names manufactured by BYK Corporation).

[0131] The surfactant content is preferably 0.1-3% by mass, 0.3-2% by mass, 0.4-1.5% by mass, and 0.5-1.0% by mass relative to the total amount of the ink composition. With the surfactant content within the above range, adhesion, clogging recovery, and intermittent printing stability tend to be further improved.

[0132] 1.7. pH adjuster

[0133] The ink composition in this embodiment may also include a pH adjuster. There are no particular limitations on the pH adjuster; examples include inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid; inorganic bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, and ammonia; organic acids such as adipic acid, citric acid, and succinic acid; and organic bases such as triethanolamine, diethanolamine, monoethanolamine, triisopropanolamine, diisopropanolamine, and tris(hydroxymethyl)aminomethane. One pH adjuster may be used alone, or two or more may be used in combination.

[0134] The pH adjuster content relative to the total amount of the ink composition is preferably 0.01 to 3% by mass, 0.05 to 1% by mass, and 0.1 to 0.5% by mass. With the pH adjuster content within the above range, there is a tendency for further improvement in ethanol resistance, tackiness, clogging recovery, and intermittent printing stability.

[0135] 1.8. Chelating agents

[0136] The ink composition in this embodiment may also contain a chelating agent. The chelating agent is capable of removing specified ions from the inkjet ink composition.

[0137] As chelating agents, there are no particular limitations. Examples include EDTA, EDTA-2Na (disodium dihydrogen ethylenediaminetetraacetate), EDTA-3Na (trisodium monohydrogen ethylenediaminetetraacetate), EDTA-4Na (tetrasodium ethylenediaminetetraacetate), and EDTA-3K (tripotassium monohydrogen ethylenediaminetetraacetate), as well as ethylenediaminetetraacetic acid and its salts; DTPA, DTPA-2Na (disodium diethylenetriaminepentaacetate), and DTPA-5Na (pentasodium diethylenetriaminepentaacetate), as well as NTA and NTA-2Na (nitrogen triacetic acid). Disodium salt) and NTA-3Na (trisodium salt of triacetate) and other triacetic acids and their salts; ethylenediamine-N,N'-disuccinic acid and its salts, 3-hydroxy-2,2'-iminodisuccinic acid and its salts, L-aspartic acid-N,N'-diacetic acid and its salts, L-glutamic acid diacetic acid and its salts, N-(1-carboxymethyl)iminodiacetic acid and its salts, N-(2-hydroxyethyl)iminodiacetic acid and its salts, ethylenediaminetetramethylenephosphonic acid and its salts, ethylenediaminetetramethoxyphosphate and its salts, ethylenediamine pyrophosphate and its salts, and ethylenediamine metaphosphate and its salts.

[0138] The content of the chelating agent relative to the total amount of the ink composition is preferably 0.001 to 1% by mass, 0.005 to 0.5% by mass, and 0.01 to 0.1% by mass. With the chelating agent content within the above range, there is a tendency for further improvement in adhesion, clogging recovery, and intermittent printing stability.

[0139] 1.6. Water

[0140] The inkjet ink composition of this embodiment is a water-based ink containing water. A water-based inkjet ink composition refers to an inkjet ink composition that contains at least water as the main solvent component of the ink.

[0141] The water content relative to the total amount of the inkjet ink composition is preferably 40-99% by mass, 50-90% by mass, 60-85% by mass, 70-80% by mass, or 70-76% by mass. By keeping the water content within the above range, there is a tendency to further improve ethanol resistance, tackiness, clogging recovery, and intermittent printing stability.

[0142] 1.7. Other ingredients

[0143] The ink composition may also contain components other than those mentioned above. Other components may include various additives such as solubilizers, viscosity modifiers, antioxidants, preservatives, mildew inhibitors, and corrosion inhibitors.

[0144] 2. Recording Method

[0145] The recording method in this embodiment includes an adhesion step, in which a specified inkjet head is used to eject the aforementioned inkjet ink composition from the inkjet head and adhere it to the recording medium. Furthermore, a heating step for heating the recording medium may be included during and / or after the ink adhesion step.

[0146] 3. Recording device

[0147] The recording apparatus in this embodiment includes the ink composition described above and an inkjet head having a nozzle for ejecting the ink composition to a recording medium. Preferably, it also includes a supply flow path for allowing the ink composition to flow and connecting to the inkjet head, and a filter unit provided in the supply flow path of the inkjet head.

[0148] Figure 1 This illustrates an example of an inkjet recording apparatus that can be used in this embodiment. (See reference...) Figure 1 The inkjet recording apparatus according to this embodiment will be described in further detail. Figure 1 The XYZ coordinate system shown represents the length of the recording medium in the X direction, the width of the recording medium on the transport path within the recording device in the Y direction, and the height of the device in the Z direction.

[0149] The recording device 10 is, for example, a line inkjet printer capable of high-speed and high-density printing. The recording device 10 includes a feeding section 12 for storing recording media P such as paper, a transport section 14, a belt transport section 16, a recording section 18, an Fd (face down) discharge section 20 as a "discharge section", an Fd (face down) mounting section 22 as a "mounting section", a flipping path section 24 as a "flipping transport mechanism", an Fu (face up) discharge section 26, and a Fu (face up) mounting section 28.

[0150] The feeding unit 12 is disposed at the lower part of the recording device 10. The feeding unit 12 includes a feeding tray 30 for receiving the recording medium P and a feeding roller 32 for feeding the recording medium P received in the feeding tray 30 to the transport path 11.

[0151] The recording medium P, stored in the feed tray 30, is fed to the conveying section 14 via the feed roller 32 along the conveying path 11. The conveying section 14 includes a conveying drive roller 34 and a conveying driven roller 36. The conveying drive roller 34 is driven to rotate by a drive source (not shown). In the conveying section 14, the recording medium P is clamped between the conveying drive roller 34 and the conveying driven roller 36 and conveyed to the belt conveying section 16 located downstream of the conveying path 11.

[0152] The belt conveyor 16 includes: a first roller 38 located on the upstream side of the conveying path 11; a second roller 40 located on the downstream side; an annular belt 42 rotatably mounted on the first roller 38 and the second roller 40; and a support body 44 supporting the upper section 42a of the annular belt 42 between the first roller 38 and the second roller 40.

[0153] The annular belt 42 is driven by a first roller 38 or a second roller 40 (not shown) to move from the +X direction to the -X direction in the upper section 42a. Therefore, the recording medium P conveyed from the conveying section 14 is further conveyed downstream of the conveying path 11 in the belt conveying section 16.

[0154] The recording unit 18 includes a linear inkjet head 48 and a head holder 46 for holding the inkjet head 48. Alternatively, the recording unit 18 can also be a serial recording unit in which the inkjet head is mounted on a carriage that reciprocates along the Y-axis. The inkjet head 48 is configured to face the upper section 42a of the annular belt 42 supported by the support body 44. When a recording medium P is conveyed in the upper section 42a of the annular belt 42, the inkjet head 48 ejects ink toward the recording medium P to perform recording. Simultaneously, the recording medium P is conveyed downstream of the conveying path 11 by the belt conveyor 16.

[0155] A first branch 50 is provided downstream of the transport path 11 of the conveyor section 16. The first branch 50 is configured to switch between the transport path 11, which transports the recording medium P to the Fd discharge section 20 or the Fu discharge section 26, and a flip path 52, which flips the recording surface of the recording medium P and transports the recording medium P to the recording section 18 again. Furthermore, the recording medium P transported by the first branch 50 switched to the flip path 52 flips its recording surface during transport on the flip path 52, and is transported to the recording section 18 again with the side opposite to the original recording surface facing the inkjet head 48.

[0156] A second branch 54 is also provided downstream of the first branch 50 along the transport path 11. The second branch 54 is configured to switch the transport direction of the recording medium P so as to transport the recording medium P toward the Fd discharge section 20 or toward the Fu discharge section 26.

[0157] The recording medium P, which is conveyed toward the Fd discharge section 20 in the second branch 54, is discharged from the Fd discharge section 20 and placed in the Fd mounting section 22. At this time, the recording surface of the recording medium P is mounted facing the Fd mounting section 22. Additionally, the recording medium P, which is conveyed toward the Fu discharge section 26 in the second branch 54, is discharged from the Fu discharge section 26 and placed in the Fu mounting section 28. At this time, the recording surface of the recording medium P is mounted facing the side opposite to the Fu mounting section 28.

[0158] 4. Recording media

[0159] There are no particular limitations on the recording medium used in this embodiment; for example, absorbent recording media, low-absorbent recording media, or non-absorbent recording media can be cited.

[0160] Examples of absorbent recording media include ordinary paper such as electrophotographic paper with high ink penetration, and inkjet paper with an ink-absorbing layer composed of silica particles or alumina, or an ink-absorbing layer composed of hydrophilic polymers such as polyvinyl alcohol or polyvinylpyrrolidone.

[0161] Examples of low-absorbency recording media include art paper, coated paper, and cast-coated paper used for general offset printing, which have relatively low ink penetration.

[0162] Examples of non-absorbent recording media include films and sheets made of plastics such as polyvinyl chloride, polyethylene, polypropylene, biaxially oriented polypropylene (OPP), polyethylene terephthalate (PET), polycarbonate, polystyrene, and urethane; metal plates such as iron, silver, copper, and aluminum; or metal plates, plastic films, stainless steel, and cast alloy plates manufactured by vapor deposition of the aforementioned metals; and recording media in which plastic films such as polyvinyl chloride, polyethylene, polypropylene, polyethylene terephthalate (PET), polycarbonate, polystyrene, and urethane are bonded (coated) onto a paper substrate.

[0163] Among non-absorbent recording media made of plastics, polar recording media such as PET and non-polar recording media such as OPP can be cited. While they may differ in their ink adhesion, abrasion resistance, etc., it is useful that the same ink, as long as it is the ink of this embodiment, can be used to record on these plastics with different properties.

[0164] The ink in this embodiment can be an ink for recording polar plastics. Alternatively, it can be an ink for recording non-polar plastics. It can also be an ink for recording both polar and non-polar plastics.

[0165] Furthermore, the recording method of this embodiment can perform ink adhesion when recording polar plastics. Alternatively, ink adhesion can also be performed when recording non-polar plastics.

[0166] Furthermore, the recording device of this embodiment can be a recording device that uses the ink of this embodiment for recording polar plastics and non-polar plastics.

[0167] 5. Records

[0168] The recording medium of this embodiment is obtained by adhering the above-described ink composition to a recording medium. The recording medium of this embodiment, using the above-described ink composition, can be recorded using inks that exhibit excellent resistance to tack, dry rubbing, wet rubbing, ethanol resistance, adhesion, clogging recovery, and intermittent printing stability.

[0169] Example

[0170] The present invention will now be described in more detail using examples and comparative examples. The present invention is not limited to the following examples.

[0171] exist Figures 4-6 Tables 3 to 5 in the present invention record the composition of each ink composition of the examples and comparative examples and their evaluation results.

[0172] 1. Preparation of inkjet ink composition

[0173] The dispersions were prepared by mixing and stirring in the manner described in Tables 3-5, resulting in inkjet ink compositions for each example. Furthermore, in the tables, each value represents the mass percentage of the solid component.

[0174] The detailed information on the product ingredients used in Tables 3 to 5 is as follows.

[0175] pigment

[0176] • Cy, Bk (refer to the preparation examples below)

[0177] Acrylic Resin A

[0178] • A1~A6 (Refer to the preparation examples below)

[0179] Polyurethane resin B

[0180] • U1~U7 (Refer to the preparation examples below)

[0181] Random acrylic resin

[0182] • A7 (random acrylic resin, see preparation example below)

[0183] Polyester-based polyurethane resin

[0184] • AP201 (trade name "Hydran AP201", polyester polyurethane resin, manufactured by DIC Corporation)

[0185] • U8 (Polyester-based polyurethane resin. Refer to the preparation example below)

[0186] wax emulsion

[0187] • AQ513 (trade name "AQUACER513", polyethylene wax emulsion, manufactured by BYK)

[0188] Organosilicon acrylic resin

[0189] ·LC190 (trade name "CHALINE LC190", silicone acrylic resin, manufactured by Nissin Chemical Industry Co., Ltd.)

[0190] organic solvents

[0191] ·12HD (1,2-hexanediol, logP) ow (Value 0.57)

[0192] ·BDG (diethylene glycol monobutyl ether, logP) ow (Value 0.56)

[0193] ·PG (propylene glycol, logP) ow (Value -0.92)

[0194] ·14BG (1,4-butanediol, logP) ow (Value -0.85)

[0195] surfactants

[0196] • BYK349 ​​(trade name, silicone surfactant, manufactured by BYK Corporation)

[0197] •DF110D (trade name "Surfynol104", acetylene glycol surfactant, manufactured by Nissin Chemical Industry Co., Ltd.)

[0198] pH adjuster

[0199] • TEA (triethanolamine)

[0200] Chelating agents

[0201] ·EDTA2Na (Disodium dihydrogen ethylenediaminetetraacetic acid)

[0202] water

[0203] · Ion-exchange water

[0204] 1.1. Preparation of Pigment Dispersion

[0205] Pigment Dispersion Bk

[0206] 500g of carbon black, 1000g of water-soluble resin, and 14000g of water were mixed to obtain a mixture. The water-soluble resin was a styrene-acrylic acid copolymer with an acid value of 100mgKOH / g and a weight-average molecular weight of 10,000, obtained by neutralizing it with a 0.1mol / L sodium hydroxide aqueous solution. After dispersing the mixture for 1 hour using a shaker with 1mm zirconia beads, impurities were removed by centrifugation, followed by vacuum filtration using a 5.0μm microporous filter (Millipore). The concentration of the pigment solids was then adjusted to obtain a pigment dispersion Bk with a pH of 9.0. Pigment dispersion Bk contains pigment dispersed by the water-soluble resin (resin dispersant), with a pigment content of 30.0% by mass and a resin content of 15.0% by mass.

[0207] Pigment dispersion Cy

[0208] After purging the reaction vessel equipped with a stirrer, thermometer, reflux pipe, and dropping funnel with nitrogen, 300 parts by weight of methyl ethyl ketone (MEK) were added. Then, 40 parts by weight of styrene, 40 parts by weight of ethyl methacrylate, 5 parts by weight of lauryl acrylate, 5 parts by weight of lauryl methacrylate, 5 parts by weight of AM-90G (trade name: methoxy polyethylene glycol acrylate, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), 5 parts by weight of acrylic acid, 0.2 parts by weight of ammonium persulfate, and 0.3 parts by weight of tert-dodecyl mercaptan were added dropwise to the reaction vessel over 4 hours, while simultaneously allowing the polymer dispersant to polymerize. Then, MEK was added to the reaction vessel to prepare a 40% by weight solution of the polymer dispersant.

[0209] Regarding the aforementioned polymer dispersant solution, gel permeation chromatography (GPC) was performed using a Hitachi, Ltd. L7100 system with tetrahydrofuran as the solvent. The weight-average molecular weight converted from styrene was determined to be 58,000. Furthermore, the polydispersity value was 3.1.

[0210] 40 parts by weight of the above polymer dispersant solution, 30 parts by weight of cromofain blue (trade name, CI Pigment Blue 15:3, manufactured by Daihatsu Seika Co., Ltd.), 100 parts by weight of 0.1 mol / L sodium hydroxide aqueous solution, and 30 parts by weight of methyl ethyl ketone were mixed and dispersed eight times using Altimizer 25005 (product name manufactured by Sugino Machinery Co., Ltd.). Then, 300 parts by weight of deionized water were added, and all methyl ethyl ketone and a portion of the water were distilled off using a rotary evaporator. The solution was then neutralized and adjusted to pH 9 with 0.1 mol / L sodium hydroxide. Next, the solution was dispersed until the volume average particle size of the cyan pigment reached 100 nm while measuring the volume average particle size using a particle size analyzer. The solution was then filtered through a 3 μm membrane filter to obtain a pigment dispersion (Cy) with a solid content (polymer dispersant and pigment) of 15% by weight.

[0211] 1.2. Preparation of Adhesive Resin

[0212] 1.2.1. Preparation of acrylic resins

[0213] Preparation of acrylic resin A1

[0214] In a reaction vessel equipped with a stirrer, thermometer, reflux pipe, and nitrogen inlet pipe, 236.3 parts by weight of diethylene glycol monobutyl ether (BDG) as a solvent, 2.3 parts by weight of 2-iodo-2-cyanopropane (CPI), 3.7 parts by weight of 2,2-azobis(4-methoxy-2,4-dimethylpentanonitrile) (trade name "V-70", manufactured by Fujifilm and Koh Genuine Pharmaceutical Co., Ltd.) (V-70) as a polymerization initiator, 0.1 parts by weight of N-iodosuccinimide (NIS), 68.7 parts by weight of tetrahydrofurfuryl methacrylate (THFMA) and 68.7 parts by weight of isobornyl methacrylate (IBXMA) as monomers.

[0215] The raw materials were charged into the reaction vessel and stirred while being purged with nitrogen. Polymerization was carried out at 45°C for 4 hours to synthesize polymer (polymer block A). A portion of the reaction solution was sampled and its solids content was determined to be 37.4%, and the polymerization conversion calculated based on the solids content was almost 100%. The polystyrene equivalent number-average molecular weight (Mn) of polymer block A, determined by GPC with tetrahydrofuran (THF) as the developing solvent, was 10000, and the polydispersity (PDI = weight-average molecular weight (Mw) / number-average molecular weight (Mn)) was 1.2. Hereinafter, the molecular weight was determined by this method. The glass transition temperature (Tg) of polymer block A was calculated based on the Tg of the monomer homopolymer and the composition ratio, and was 101.5°C. The Tg of the THFMA homopolymer was calculated at 60°C, and the Tg of the IBXMA homopolymer was calculated at 155°C. Hereinafter, the Tg was calculated using this method.

[0216] After cooling the solution of polymer block A to 40°C, 2.7 parts by mass of V-70 as a polymerization initiator, 18.0 parts by mass of THFMA as a monomer, 54.1 parts by mass of IBXMA, and 18.0 parts by mass of methacrylic acid (MAA) were added to the reaction vessel. Polymerization was carried out at 40°C for 4 hours to form polymer block B, yielding an AB diblock copolymer. The polymerization was confirmed to be essentially complete by determining the solids content and the amount of residual monomer using gas chromatography. A sample of the reaction solution showed a solids content of almost 50%, indicating a polymerization conversion of almost 100%. The number-average molecular weight (Mn) of the obtained AB diblock copolymer was 17000, the PDI was 1.3, and the GPC peak of polymer block A shifted towards the higher molecular weight side, confirming it as an AB diblock copolymer. That is, the number-average molecular weight (Mn) of polymer block B was 7000. Furthermore, the acid value of polymer block B, calculated based on the aforementioned MAA content, was 130.3 mg KOH / g. Additionally, the Tg of polymer block B is 143.3℃. The Tg of the homopolymer of MAA is calculated to be 228℃. A portion of the polymer solution was precipitated in methanol and filtered. After thorough washing with methanol and drying, a resin solid was obtained. The acid value was determined to be 51.5 mg KOH / g by titration with an ethanolic 0.1 mol / L potassium hydroxide solution.

[0217] Next, at room temperature, a mixture of 14.0 parts by mass of 28% ammonia and 458.6 parts by mass of ion-exchanged water was added for neutralization and emulsification to obtain a self-emulsifying acrylic resin A1. Furthermore, water was added in an amount adjusted to a polymer content of 25%. The solid content of acrylic resin A1 was 25.1%. After thoroughly diluting acrylic resin A1 with water, the number-average particle size of the emulsion particles, measured using a dynamic light scattering particle size distribution measuring device (particle size analyzer, trade name "nanoSAQRA", manufactured by Otsuka Electronics Co., Ltd.), was 75 nm. The pH was 8.9. The viscosity, measured using an E-type viscometer, was 3.6 Pa·s at 25°C.

[0218] Preparation of acrylic resins A2~A5

[0219] Except for the monomers used and the amount of ammonia added for neutralization, which follow the formulation shown in Table 1, self-emulsifying acrylic resins A2 to A5 were obtained in the same manner as acrylic resin A1. All units are parts by mass. Table 1 also summarizes the 14C concentration of each monomer, the isoborneol methacrylate content, biomass density, number-average molecular weight (Mn), polydispersity (PDI), acid value, solids content, average particle size, pH, viscosity, and acid value of each acrylic resin A.

[0220] THFMA (Tetrahydrofurfuryl methacrylate) IBXMA (Isobornyl Methacrylate) EMA (ethyl methacrylate) BzMA (Benzyl Methacrylate) LMA (Lauryl methacrylate) TCDMA (Tricyclodecyl Methacrylate) MAA (Methacrylic Acid) Preparation of acrylic resin A6 without structural units derived from isobornyl (meth)acrylate In a reaction vessel equipped with a reflux pipe, gas introduction device, thermometer, and stirrer, 198.2 parts by weight of diethylene glycol monobutyl ether, 1.0 parts by weight of iodine, 3.7 parts by weight of 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile), and 66.1 parts by weight of tricyclodecyl methacrylate were added, along with 0.17 parts by weight of diphenylmethane as a catalyst. Polymerization was carried out at 45°C for 5 hours while nitrogen was introduced, yielding a solution of polymer block A.

[0221] Next, the polymerization temperature was lowered to 40°C, and 44.0 parts by mass of tricyclodecyl methacrylate, 17.2 parts by mass of methacrylic acid, and 1.2 parts by mass of 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile) were added to the solution of the A polymer block obtained above. Polymerization was then carried out for 4 hours, followed by heating to 70°C and polymerization for 1 hour, thereby forming the B polymer block and obtaining a solution of the AB block polymer.

[0222] After cooling the solution of the AB block polymer obtained above, 66.1 parts by weight of diethylene glycol monobutyl ether were added, and the mixture was dried at 150°C for 1 hour to obtain a polymer with a solid content of 33.0%.

[0223] Preparation of random acrylic resin A7

[0224] In a reaction vessel equipped with a stirrer, reflux condenser, dropping device, and thermometer, 900g of ion-exchanged water and 3g of sodium lauryl sulfate were added. The mixture was heated to 70°C while being purged with nitrogen under stirring. Maintaining the internal temperature at 70°C, 4g of potassium persulfate was added as a polymerization initiator. After dissolving, an emulsion prepared by stirring 450g of ion-exchanged water and 3g of sodium lauryl sulfate with the addition of 20g of acrylamide, 300g of styrene, 640g of butyl acrylate, and 30g of methacrylic acid was continuously added dropwise over 4 hours. After the addition was complete, the mixture was allowed to mature for 3 hours. The resulting aqueous emulsion was cooled to room temperature, and then ion-exchanged water and a 5% sodium hydroxide aqueous solution were added to adjust the solid content to 40% by weight and the pH to 8.

[0225] 1.2.2. Preparation of polyurethane resin

[0226] Preparation of polyurethane resin U1

[0227] In a reaction vessel equipped with a stirrer, reflux cooling pipe, and thermometer, 260 parts by weight of polytetramethylene glycol (PTMG2000, manufactured by Mitsubishi Chemical: number average molecular weight 2000), 138 parts by weight of 2,2-dimethylolpropionic acid (DMPA), and 130 parts by weight of methyl ethyl ketone (MEK: bp 79.6℃) were added under a nitrogen gas flow. The mixture was heated to 65℃ to dissolve the DMPA. Then, 280 parts by weight of isophorone diisocyanate and 0.26 parts by weight of urethane esterification catalyst XK-614 (manufactured by Kusunoki Chemical) were added, and the mixture was heated to 75℃ for 5 hours to carry out the urethane esterification reaction, yielding an isocyanate-terminated urethane prepolymer.

[0228] Next, the reaction mixture was cooled to 70°C, and 800 parts by mass were extracted from the mixture in which 40 parts by mass of triethanolamine were added and mixed. This extracted mixture was then added to a solution of 540 parts by mass of water and 40 parts by mass of triethanolamine under vigorous stirring. Then, 160 parts by mass of ice were added, followed by 28 parts by mass of a 35% by mass aqueous solution of dicycloheptandimethylamine to initiate a chain extension reaction. Methyl ethyl ketone and a portion of water were distilled off to achieve a solids concentration of 30%, yielding polyurethane resin emulsion U1 (30% polyurethane resin, 70% water, acid value 80 mg KOH / g).

[0229] Preparation of polyurethane resin U2~7

[0230] Except that the isophorone diisocyanate is the polyisocyanate shown in Table 2, polyurethane resins U2 to U7 are obtained in the same manner as polyurethane resin U1.

[0231] IPDI (Isophorone Diisocyanate) TDI (2,4-Toluene diisocyanate) MDI (4,4'-diphenylmethane diisocyanate) XDI (m-phenylenedimethyl isocyanate) HDI (1,6-hexamethylene diisocyanate) HMDI (4,4′-methylenebis(cyclohexyl isocyanate)) PDI (1,5-pentanediisocyanate) Preparation of polyurethane resin U8 In a reaction vessel equipped with a stirrer, reflux condenser, and thermometer, 330 parts by weight of DIC-made POLYLIGHT OD-X-2420 (molecular weight 2000), 30 parts by weight of 2,2-dimethylolpropionic acid (DMPA), and 130 parts by weight of methyl ethyl ketone (MEK: bp 79.6℃) were added under a nitrogen atmosphere. The mixture was heated to 65℃ to dissolve the DMPA. Then, 125 parts by weight of 2,4-toluene diisocyanate (TDI) and 0.26 parts by weight of urethane esterification catalyst XK-614 (trade name, manufactured by Kusunoki Chemicals) were added. The mixture was heated to 75℃ and subjected to an urethane esterification reaction for 5 hours to obtain an isocyanate-terminated urethane prepolymer.

[0232] Next, the reaction mixture was cooled to 70°C, and almost the total amount of 690 parts by mass was extracted from the mixture in which 40 parts by mass of triethanolamine were added and mixed. This was then added to a mixed solution of 540 parts by mass of water and 40 parts by mass of triethanolamine under vigorous stirring. Then, 160 parts by mass of ice and 110 parts by mass of a 35% by mass dicycloheptandimethylamine aqueous solution were added to initiate a chain extension reaction. Methyl ethyl ketone and a portion of water were distilled off to achieve a solids concentration of 30%, yielding polyurethane resin U8 (polyurethane resin content 30%, water 70%, acid value 22 mg KOH / g).

[0233] 2. Evaluation Methods

[0234] 2.1. Resistance to adhesion

[0235] As a recording test machine, a modified PX-G930 printer (manufactured by Seiko Epson, modified with a platen heater) was used to record a solid image of 1.0 inch × 0.5 inch with a recording duty cycle of 100% on OPP film (untextured roll, 25μm thick, manufactured by Toyobo). Printing was performed at a platen temperature of 60°C and an ink dot density of 1440 dpi × 1440 dpi. The sample was then tested using a Tester Industrial Co., Ltd. CO-201 adhesion tester at 5 kgf / cm². 2 (50mm) Under conditions of 50°C and 24 hours (n=3), the back side (non-corona-electrode side) of each substrate was bonded to the printed side, and visual observation and evaluation were performed. The PET film (FUTAMURA Chemical Taiko Polyester Film FE2001 50μm) was evaluated in the same way.

[0236] A: No transfer printing at all.

[0237] B: Slight transfer.

[0238] C: Blurry transfer.

[0239] D: Clearly transfer.

[0240] 2.2. Dry friction resistance

[0241] Using a modified PX-G930 printer (manufactured by Seiko Epson, with a modified platen heater), solid printing of each ink composition was performed on OPP film at a recording duty cycle of 100% to obtain a recorded image. The settings included an ink droplet weight of 13 ng, a recording resolution of 720 × 720 dpi, a platen temperature of 55°C, and drying at 70°C for 1 minute after printing. The same evaluation was performed on PET film.

[0242] The evaluation was conducted using the AB-301 abrasion resistance evaluation device (trade name, manufactured by Tester Industrial Co., Ltd.) based on JIS L0849 2013. One day after printing, a 1.0-inch × 0.5-inch recording material was rubbed with a dry, fine white cotton cloth under a load of 200g for 100 reciprocating cycles. The stains on the white cotton cloth, the stains around the recording area, and the peeling of the printed area were then visually inspected, and the dry abrasion resistance was evaluated according to the evaluation criteria shown below. The same evaluation was performed on PET film.

[0243] Evaluation Criteria

[0244] A: There are no stains on the fine white cotton or around the recording area, and there is no peeling of the recording area.

[0245] B: There are almost no stains on the fine white cotton or around the recording area, and there is almost no peeling of the recording area.

[0246] C: There are few stains on the fine white cotton and around the recording area, and almost no peeling of the recording area.

[0247] D: There are stains on fine white cotton and around the recording area, and there is peeling of the recording area.

[0248] 2.3.Wet friction resistance

[0249] In the dry rubbing resistance test, the same evaluation was conducted, except that instead of rubbing with a dry fine white cotton cloth under a 200g load for 100 cycles, rubbing was performed with a water-wetted fine white cotton cloth under a 250g load for 15 cycles. The wet rubbing resistance was evaluated according to the evaluation criteria shown below. The same evaluation was conducted for PET films.

[0250] Evaluation Criteria

[0251] A: There are no stains on the fine white cotton or around the recording area, and there is no peeling of the recording area.

[0252] B: There are almost no stains on the fine white cotton or around the recording area, and there is almost no peeling of the recording area.

[0253] C: There are few stains on the fine white cotton and around the recording area, and almost no peeling of the recording area.

[0254] D: There are stains on fine white cotton and around the recording area, and there is peeling of the recording area.

[0255] 2.4. Ethanol resistance

[0256] In the wet friction resistance test, the same evaluation was conducted, except that fine white cotton cloth moistened with ethanol was used instead of water-moistened fine white cotton cloth. Ethanol resistance was evaluated according to the evaluation criteria shown below. The same evaluation was conducted for PET film.

[0257] Evaluation Criteria

[0258] A: There are no stains on the fine white cotton or around the recording area, and there is no peeling of the recording area.

[0259] B: There are almost no stains on the fine white cotton or around the recording area, and there is almost no peeling of the recording area.

[0260] C: There are few stains on the fine white cotton and around the recording area, and almost no peeling of the recording area.

[0261] D: There are stains on fine white cotton and around the recording area, and there is peeling of the recording area.

[0262] 2.5. Adhesion Evaluation

[0263] Using the same recording testing machine, ink compositions were printed on corona-treated OPP film (trade name "FOS-AQ#60", manufactured by FUTAMURA Chemical Co., Ltd.) at 100% duty cycle under conditions of 13 ng ink drop weight, 720x720 dpi recording resolution, and 55°C platen temperature. The film was then dried at 90°C for 10 minutes to produce recorded material. The ink residue in the recording area and the transfer to the tape were observed during a cross-cutting test based on JIS-K5600, and the adhesion was evaluated according to the following evaluation criteria. The same evaluation was performed on PET film.

[0264] Evaluation Criteria

[0265] A: There was no peeling of the membrane recording section, nor any transfer to the tape.

[0266] B: The peeling rate of the membrane recording section is less than 5%.

[0267] C: Peeling of the membrane recording section exceeds 5% but is less than 10%.

[0268] D: Peeling of the membrane recording section exceeds 10%.

[0269] 2.6. Blockage Recovery Test

[0270] Using the same recording test equipment, the clogging resilience was evaluated under an environment of 40°C and 20% relative humidity. First, it was confirmed that the inkjet ink composition was being ejected normally from all nozzles. Then, the ink was left to stand for one month at 40°C and 20% relative humidity. After this period, the number of cleaning cycles required to resume normal ejection from all nozzles was measured, and the clogging resilience was evaluated according to the following evaluation criteria.

[0271] Evaluation Criteria

[0272] A: Cleaning frequency is less than 3 times.

[0273] B: Cleaning frequency is 4-6 times.

[0274] C: Cleaning frequency is 7-9 times.

[0275] D: Even after 10 cleaning cycles, not all nozzles were restored.

[0276] 2.7. Intermittent Printing Stability

[0277] Using the same recording and testing equipment, the intermittent printing stability during intermittent printing was evaluated at an environment of 40°C and 20% relative humidity. First, it was confirmed that the ink composition was being ejected normally from all nozzles. Then, after ejecting the ink composition onto an A4-sized OHP film, a 2-minute rest period was set at 40% temperature and 20% relative humidity, and the ink composition was ejected again onto A4-sized photo paper. During the second ejection, the positional offset of the first ink droplet adhering to the A4-sized photo paper from the target position was measured using an optical microscope. Based on the obtained ink droplet positional offset, the intermittent printing stability was evaluated according to the following evaluation criteria.

[0278] A 2-minute rest period is set for non-circulating ink without circulating the ink through the printhead. A modified printhead capable of circulating ink is used, equipped with a circulation mechanism that discharges ink from the ink passage between the pressure chamber and the nozzle to the outside of the printhead, mixes the discharged ink with new ink, and supplies it back to the printhead. A 2-minute rest period is set while circulating the ink.

[0279] Evaluation Criteria

[0280] AA: The position of the ink dot is offset by less than 5μm.

[0281] A: The positional offset of the ink dot exceeds 5μm but is less than 10μm.

[0282] B: The positional offset of the ink dot exceeds 10μm but is less than 20μm.

[0283] C: The positional offset of the ink dot exceeds 20μm but is less than 30μm.

[0284] D: The positional offset of the ink dot exceeds 30μm.

[0285] 3. Evaluation Results

[0286] As shown in Tables 3-5, the inkjet ink composition of this embodiment tends to have further improved dry rubbing resistance, wet rubbing resistance, and tack. Furthermore, it also tends to have further improved tack resistance, ethanol resistance, clogging recovery, and intermittent printing stability.

Claims

1. An inkjet ink composition, characterized in that, It is a water-based inkjet ink composition. The inkjet ink composition contains a binder resin. The adhesive resin comprises an acrylic resin and a polyether polyurethane resin, wherein the acrylic resin is a block copolymer containing structural units derived from isoborneol methacrylate.

2. The inkjet ink composition according to claim 1, characterized in that, The content of the structural unit derived from isoborneol ester (meth)acrylate is 50% by mass or more relative to the total amount of the acrylic resin.

3. The inkjet ink composition according to claim 1, characterized in that, The block copolymer has an A block and a B block that is more hydrophilic than the A block.

4. The inkjet ink composition according to claim 1, characterized in that, The acid value of the acrylic resin is 25~100 mgKOH / g.

5. The inkjet ink composition according to claim 1, characterized in that, The acrylic resin contains structural units derived from acrylic monomers. The content of the structural units derived from acrylic monomers is 90% by mass or more relative to the total amount of the acrylic resin.

6. The inkjet ink composition according to claim 1, characterized in that, The polyether-based polyurethane resin includes polyether-based polyurethane resins having an aromatic ring backbone and / or an alicyclic backbone.

7. The inkjet ink composition according to claim 1, characterized in that, The mass ratio of the polyether-based polyurethane resin to the acrylic resin is 1 / 3 to 3.

8. The inkjet ink composition according to claim 1, characterized in that, The inkjet ink composition contains organic solvents. The organic solvent includes organic solvent A with an octanol / water partition coefficient of 0 to 1.

9. The inkjet ink composition according to claim 1, characterized in that, The inkjet ink composition contains pigments.

10. The inkjet ink composition according to claim 1, characterized in that, The inkjet ink composition also contains a wax emulsion.

11. The inkjet ink composition according to claim 1, characterized in that, The inkjet ink composition also contains an organosilicon acrylic resin.

12. A recording method, characterized in that, The recording method includes an ink adhesion step, in which the inkjet ink composition of any one of claims 1 to 11 is ejected from the inkjet head and adhered to the recording medium.

Images