Inkjet ink and inkjet recording method

Abstract

The present application provides an inkjet ink containing water, a water-soluble organic solvent, and particles containing a polymer P and a polymerizable monomer M, wherein, when the contained mass of the water-soluble organic solvent is set as Ws, and the contained mass of the polymerizable monomer M is set as Wm, the ratio of Ws / Wm is 1.1 or more, and the HSP distance ΔHSP(s-m) between the water-soluble organic solvent and the polymerizable monomer M is 15.0 MPa 1 / 2 ~ 25.0 MPa 1 / 2 .

Description

Technical Field

[0001] This disclosure relates to an inkjet ink and an inkjet recording method. Background Technology

[0002] There has been a lot of research on inkjet inks and inkjet recording methods.

[0003] For example, in Patent Document 1, an inkjet ink composition containing water, a chain polymer containing specific structural units and hydrophilic groups, and particles containing polymeric groups is disclosed as an inkjet ink composition capable of forming images with excellent adhesion to plastic substrates and excellent dispersion stability.

[0004] Furthermore, in Patent Document 2, an inkjet recording method with excellent curability, filling properties, adhesion, and ejection stability is disclosed, comprising the following steps: a first step, ejecting droplets of a photocurable ink composition from a printhead onto a recording medium and allowing them to fall to form an image, wherein the photocurable ink composition contains a solvent, a polymeric compound, and a photopolymerization initiator, wherein the polymeric compound is particles dispersed in the solvent; a second step, evaporating the solvent contained in the photocurable ink composition constituting the image; and a third step, irradiating the image after the second step with light, wherein when irradiation begins in the third step, the content of the polymeric compound contained in the photocurable ink composition constituting the image after the second step is 20 to 90% by mass relative to the total mass of the ink composition.

[0005] Previous technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 6584677

[0008] Patent Document 2: Japanese Patent No. 6047904 Summary of the Invention

[0009] The technical problem to be solved by the invention

[0010] However, sometimes there is a need to further improve the preservation stability of inkjet inks and the abrasion resistance of the recorded images.

[0011] The purpose of this disclosure is to provide an inkjet ink with excellent preservation stability and abrasion resistance of the recorded image, and an inkjet recording method that uses the above-mentioned inkjet ink to record an image with excellent abrasion resistance.

[0012] means for solving technical problems

[0013] The specific means to solve the above problems include the following methods.

[0014] <1> An inkjet ink comprising water, a water-soluble organic solvent, and particles containing a polymer P and a polymeric monomer M.

[0015] When the mass content of the water-soluble organic solvent is defined as Ws and the mass content of the polymerizable monomer M is defined as Wm, the Ws / Wm ratio is greater than or equal to 1.1.

[0016] The HSP distance ΔHSP(sm) between the water-soluble organic solvent and the polymerizable monomer M is 15.0 MPa. 1 / 2 ~25.0MPa 1 / 2 .

[0017] <2> according to <1> The inkjet ink, wherein,

[0018] The Ws / Wm ratio is 2.0 to 6.0.

[0019] <3> according to <1> or <2> The inkjet ink, wherein,

[0020] The HSP distance ΔHSP(sp) between the water-soluble organic solvent and polymer P is 8.0 MPa. 1 / 2 ~16.0MPa 1 / 2 .

[0021] <4> according to <1> ~ <3> In any one of the inkjet inks, wherein,

[0022] When the mass of water-soluble organic solvent is defined as Ws and the mass of polymer P is defined as Wp, the Ws / Wp ratio is 1.0 to 6.0.

[0023] <5> according to <1> ~ <4> In any one of the inkjet inks, wherein,

[0024] The polymer P contains a bond U that is at least one of a urethane bond and a urea bond.

[0025] <6> according to <1> ~ <5> In any one of the inkjet inks, wherein,

[0026] The glass transition temperature of polymer P is below 80℃.

[0027] <7> according to <1> ~ <6> In any one of the inkjet inks, wherein,

[0028] The weight-average molecular weight of polymer P is 10,000 to 50,000.

[0029] <8> according to <1> ~ <7> In any one of the inkjet inks, wherein,

[0030] The polymerizable monomer M contains monomers (M-1) with a viscosity of 10 mPa·s to 150 mPa·s at 25°C.

[0031] The proportion of monomer (M-1) in the total amount of polymerizable monomer M is more than 50% by mass.

[0032] <9> according to <1> ~ <8> In any one of the inkjet inks, wherein,

[0033] Water-soluble organic solvents include solvents with a boiling point below 190°C (S-1).

[0034] The proportion of solvent (S-1) in the total amount of water-soluble organic solvents is more than 50% by mass.

[0035] <10> An inkjet recording method, comprising:

[0036] Applying inkjet printing technology to a substrate <1> ~ <9> The process of using any one of the inkjet inks; and

[0037] The process of irradiating active energy lines onto inkjet ink applied to a substrate.

[0038] The time from the moment the inkjet ink lands on the substrate to the start of irradiation by the active energy line is less than 1.00 seconds.

[0039] Invention Effects

[0040] According to one aspect of this disclosure, an inkjet ink with excellent preservation stability and abrasion resistance of the recorded image is provided, as well as an inkjet recording method that uses the aforementioned inkjet ink to record an image with excellent abrasion resistance. Detailed Implementation

[0041] In this disclosure, the numerical range represented by “~” refers to the range in which the values ​​recorded before and after “~” are respectively taken as the minimum and maximum values.

[0042] In this disclosure, the amount of each component in a composition, when multiple substances equivalent to each component are present in the composition, refers to the total amount of the multiple substances present in the composition, unless otherwise stated.

[0043] In the numerical ranges described in segments in this disclosure, the upper or lower limit value recorded in a certain numerical range can be replaced with the upper or lower limit value of other numerical ranges described in segments. Alternatively, it can be replaced with the value shown in the embodiment.

[0044] In this disclosure, the term "process" is used not only to refer to an independent process, but also to include processes that cannot be clearly distinguished from other processes if the intended purpose of the process is achieved.

[0045] In this disclosure, "*" in chemical formulas indicates a bonding position.

[0046] In this disclosure, the concept of "image" includes not only patterned images (e.g., text, symbols, or graphics) but also field images.

[0047] In this disclosure, "light" is a concept that includes active energy rays such as gamma rays, beta rays, electron beams, ultraviolet rays, and visible light.

[0048] In this disclosure, ultraviolet light is sometimes referred to as “UV (Ultra Violet) light”.

[0049] In this disclosure, light produced by an LED (Light Emitting Diode) light source is sometimes referred to as "LED light".

[0050] In this disclosure, "(meth)acrylic acid" is a concept that includes both acrylic acid and methacrylic acid, "(meth)acrylate" is a concept that includes both acrylate and methacrylate, and "(meth)acryloyl" is a concept that includes both acryloyl and methacryloyl.

[0051] [Inkjet ink]

[0052] The inkjet ink disclosed herein (hereinafter, also referred to as "ink") contains water, a water-soluble organic solvent, and particles comprising polymer P and polymerizable monomer M. When the mass of the water-soluble organic solvent is defined as Ws and the mass of the polymerizable monomer M is defined as Wm, the Ws / Wm ratio is 1.1 or higher, and the HSP distance ΔHSP(sm) between the water-soluble organic solvent and the polymerizable monomer M is 15.0 MPa. 1 / 2 ~25.0MPa 1 / 2 .

[0053] The ink disclosed herein exhibits excellent preservation stability and abrasion resistance of the recorded images.

[0054] The reasons for this effect are speculated to be as follows.

[0055] In image recording, where an inkjet ink containing water and particles of polymers and polymerizable monomers is deposited onto a substrate and the deposited ink is cured by irradiating an active energy line and / or applying heat, it is sometimes necessary to balance the preservation stability of the ink with the abrasion resistance of the recorded image.

[0056] Specifically, in the image recording by the above method, curing mainly occurs inside the particles, while curing does not occur between the particles (i.e., connection between the particles). As a result, the strength of the entire film (i.e., the image) may be insufficient, and the abrasion resistance of the image may be insufficient. In the case of shortening the time from ink landing to the start of active energy ray irradiation (for example, when it is set to 1.00 seconds or less), the phenomenon that curing between the particles is difficult is particularly obvious.

[0057] In consideration of improving the abrasion resistance of the image, it is desired to promote the exudation of the polymerizable monomer from the particles in the ink applied to the substrate, thereby promoting the curing between the particles and promoting the curing of the entire film (i.e., the image). As a method for promoting the exudation of the polymerizable monomer from the particles, there is a method of promoting the exudation of the polymerizable monomer from the particles in the ink droplet applied to the substrate by shortening the HSP distance ΔHSP(s-m) between the water-soluble organic solvent and the polymerizable monomer.

[0058] However, if the exudation of the polymerizable monomer M from the particles is excessively promoted, the exudation of the polymerizable monomer from the particles may sometimes occur even in the ink before being applied to the substrate. As a result, the storage stability of the ink decreases.

[0059] Regarding the above problems, in the ink of the present disclosure, the Ws / Wm ratio is 1.1 or more, and ΔHSP(s-m) is 15.0 MPa 1 / 2 ~25.0 MPa 1 / 2 .

[0060] In the ink of the present disclosure, since the Ws / Wm ratio is 1.1 or more (substantially, a certain amount more of the water-soluble organic solvent is contained relative to the amount of the polymerizable monomer M in the particles), and ΔHSP(s-m) is 25.0 MPa 1 / 2 or less, when the ink is applied to the substrate, the polymerizable monomer M easily exudes from the particles in the ink on the substrate. Thereby, the curing between the particles (i.e., connection between the particles) is promoted, and the curing of the entire film (i.e., the image) is promoted. As a result, the abrasion resistance of the image is improved. <​​​​​​​​​​​In the ink disclosed herein, when the mass content of the water-soluble organic solvent is set as Ws and the mass content of the polymerizable monomer M is set as Wm, the Ws / Wm ratio is 1.1 or higher.

[0065] Since the Ws / Wm ratio is above 1.1, the abrasion resistance of the image is improved. This can be attributed to the fact that the ink contains a certain amount of water-soluble organic solvent relative to the amount of polymerizable monomer M, thereby promoting the exudation of polymerizable monomer M from specific particles.

[0066] From the viewpoint of further improving the abrasion resistance of the image, the Ws / Wm ratio is preferably 1.3 or more, more preferably 1.5 or more, and even more preferably 2.0 or more.

[0067] On the other hand, from the viewpoint of further improving the preservation stability of ink, the Ws / Wm ratio is preferably 6.5 or less, more preferably 6.3 or less, and even more preferably 6.0 or less.

[0068] An example of a particularly preferred range for the Ws / Wm ratio is 2.0 to 6.0.

[0069] <ΔHSP(sm)>

[0070] In the ink disclosed herein, the HSP distance ΔHSP(sm) between the water-soluble organic solvent and the polymerizable monomer M is 15.0 MPa. 1 / 2 ~25.0MPa 1 / 2 .

[0071] Since ΔHSP(sm) is 15.0 MPa 1 / 2 Therefore, the ink's storage stability is improved. This can be attributed to the suppression of excessive exudation of the polymerizable monomer M from specific particles.

[0072] From the perspective of further improving the storage stability of ink, ΔHSP(sm) is preferably 16.0 MPa. 1 / 2 The above, more preferably 17.0 MPa 1 / 2 above.

[0073] Since ΔHSP(sm) is 25.0 MPa 1 / 2 Therefore, the image's abrasion resistance is improved. This can be attributed to the promotion of the exudation of polymerizable monomer M from specific particles.

[0074] From the perspective of further improving the abrasion resistance of the image, ΔHSP(sm) is preferably 24.0 MPa. 1 / 2 Hereinafter, 23.0 MPa is preferred. 1 / 2 Hereinafter, 21.0 MPa is further preferred. 1 / 2 the following.

[0075] The HSP distance ΔHSP(sm) between the water-soluble organic solvent and the polymerizable monomer M in this disclosure is obtained by the following mathematical formula (X1).

[0076] ΔHSP(sm)=Σ(ΔHSP(si-mj)×M si ×M mj ...mathematical expression (X1)

[0077] In the mathematical expression (X1),

[0078] i and j each independently represent integers greater than 1.

[0079] M si This represents the mass fraction of the i-th solvent type relative to the total amount of water-soluble organic solvents contained in the ink (i.e., a value greater than 0 and less than 1).

[0080] M mj This represents the mass fraction of the j-th monomer type relative to the total amount of polymerizable monomer M contained in the ink (i.e., a value greater than 0 and less than 1).

[0081] ΔHSP(si-mj) represents the HSP distance between the i-th solvent type and the j-th monomer type.

[0082] For example, suppose the following situation:

[0083] The ink contains, as one of the three water-soluble organic solvents:

[0084] Solvent s1, with a mass fraction of 0.1 relative to the total amount of water-soluble organic solvents,

[0085] Solvent s2, with a mass fraction of 0.2 relative to the total amount of water-soluble organic solvent, and

[0086] Solvent s3 has a mass fraction of 0.7 relative to the total amount of water-soluble organic solvents.

[0087] and,

[0088] As one of the three polymerizable monomers M, it contains:

[0089] The monomer m1 has a mass fraction of 0.3 relative to the total amount of polymerizable monomer M.

[0090] The monomer m2 has a mass fraction of 0.3 relative to the total amount of polymerizable monomer M, and

[0091] The monomer m3 has a mass fraction of 0.4 relative to the total amount of polymerizable monomer M.

[0092] In this case,

[0093] Let the HSP distance between solvent s1 and monomer m1 be ΔHSP(s1-m1).

[0094] Let the HSP distance between solvent s1 and monomer m2 be ΔHSP(s1-m2).

[0095] Let the HSP distance between solvent s1 and monomer m3 be ΔHSP(s1-m3).

[0096] Let the HSP distance between solvent s2 and monomer m1 be ΔHSP(s2-m1).

[0097] Let the HSP distance between solvent s2 and monomer m2 be ΔHSP(s2-m2).

[0098] Let the HSP distance between solvent s2 and monomer m3 be ΔHSP(s2-m3).

[0099] Let the HSP distance between solvent s3 and monomer m1 be ΔHSP(s3-m1).

[0100] Let the HSP distance between solvent s3 and monomer m2 be ΔHSP(s3-m2).

[0101] When the HSP distance between solvent s3 and monomer m3 is set as ΔHSP(s3-m3),

[0102] ΔHSP(sm) is calculated using the mathematical formula (X) as described below.

[0103] ΔHSP(sm)

[0104] =Σ(ΔHSP(si-mj)×M si ×M mj )

[0105] =ΔHSP(s1-m1)×0.1×0.3

[0106] +ΔHSP(s1-m2)×0.1×0.3

[0107] +ΔHSP(s1-m3)×0.1×0.4

[0108] +ΔHSP(s2-m1)×0.2×0.3

[0109] +ΔHSP(s²-m²)×0.2×0.3

[0110] +ΔHSP(s²-m³)×0.2×0.4

[0111] +ΔHSP(s3-m1)×0.7×0.3

[0112] +ΔHSP(s3 - m2)×0.7×0.3

[0113] +ΔHSP(s3 - m3)×0.7×0.4

[0114] Next, the HSP distance (for example, ΔHSP(si - mj)) will be described.

[0115] The HSP distance is a value related to the compatibility of two substances to be compared (hereinafter, referred to as substance 1 and substance 2). The shorter the HSP distance, the higher the compatibility between substance 1 and substance 2.

[0116] The HSP distance is obtained by substituting the δD (dispersion term) (hereinafter, referred to as δD1 and δD2), δP (polarization term) (hereinafter, referred to as δP1 and δP2), and δH (hydrogen bond term) (hereinafter, referred to as δH1 and δH2) of substance 1 and substance 2 into the following mathematical formula (A). Here, the δD (dispersion term), δP (polarization term), and δH (hydrogen bond term) are three parameters that constitute the HSP (i.e., Hansen solubility parameter). [[ID=一十四]]The HSP distance between the i-th solvent type and the j-th monomer type, ΔHSP(si - mj), is obtained by substituting the dispersion term, polarization term, hydrogen bond term of the i-th solvent type, the dispersion term, polarization term, and hydrogen bond term of the j-th monomer type into δD1, δP1, δH1, δD2, δP2, and δH2 in the following mathematical formula (A), respectively.

[0118] [Mathematical formula 1]

[0119]

[0120] The dispersion term (δD), polarization term (δP), and hydrogen bond term (δH) in each compound conforming to the water-soluble organic solvent or the polymeric monomer M are determined as follows.

[0121] The structural formula of each compound is transformed into a Smiles symbol using a structural formula editing software (ChemBioDraw Ultra 13.0). Then, the bonding point * of the obtained Smiles symbol polymer is rewritten as X, and the values of δD, δP, and δH of each compound are calculated according to Y - MB of HSPiP (HSPiP4th edition 4.1.07).

[0122] <Ws / Wp ratio><00003​​In the ink disclosed herein, when the mass content of the water-soluble organic solvent is defined as Ws and the mass content of the polymer P is defined as Wp, the Ws / Wp ratio is preferably 0.9 to 6.4, more preferably 0.9 to 6.3, even more preferably 1.0 to 6.0, even more preferably 1.5 to 6.0, and even more preferably 2.0 to 6.0.

[0124] When the Ws / Wp ratio is above 0.9, the abrasion resistance of the image is further improved.

[0125] When the Ws / Wp ratio is below 6.4, the storage stability of the ink is further improved.

[0126] In this disclosure, when the polymer P contained in the ink contains neutralized anionic groups (e.g., salts of carboxyl groups (e.g., -COONa) as described later), the Ws / Wp ratio is calculated by treating the neutralized anionic groups (e.g., salts of carboxyl groups (e.g., -COONa)) in polymer P as unneutralized anionic groups (e.g., carboxyl groups). That is, Wp is the mass of polymer P containing neutralized anionic groups as unneutralized anionic groups.

[0127] <ΔHSP(sp)>

[0128] In the ink disclosed herein, the HSP distance ΔHSP(sp) between the polymer P and the water-soluble organic solvent is preferably 7.0 MPa. 1 / 2 ~20.0MPa 1 / 2 More preferably 8.0 MPa 1 / 2 ~16.0MPa 1 / 2 More preferably 8.5 MPa 1 / 2 ~15.5MPa 1 / 2 More preferably 9.0 MPa 1 / 2 ~15.0MPa 1 / 2 .

[0129] When ΔHSP(sp) is 7.0 MPa 1 / 2 Under the above conditions, the preservation stability of the ink is further improved.

[0130] When ΔHSP(sp) is 20.0 MPa 1 / 2 In the following cases, the image's abrasion resistance is further improved.

[0131] Specifically, ΔHSP(sp) is the value obtained by the following mathematical expression (X2).

[0132] ΔHSP(sp)=Σ(ΔHSP(si-pk)×M si ×Mpk ...mathematical expression (X2)

[0133] In the mathematical expression (X2),

[0134] i and k independently represent integers greater than 1.

[0135] M si This represents the mass fraction of the i-th solvent type relative to the total amount of water-soluble organic solvents contained in the ink (i.e., a value greater than 0 and less than 1).

[0136] M pk This represents the mass fraction of the k-th polymer type relative to the total amount of polymer P contained in the ink (i.e., a value greater than 0 and less than 1).

[0137] ΔHSP(si-pk) represents the HSP distance between the i-th solvent type and the k-th polymer type.

[0138] In this disclosure, when the polymer P contained in the ink contains neutralized anionic groups (e.g., salts of carboxyl groups (e.g., -COONa) as described later), the neutralized anionic groups in polymer P are treated as unneutralized anionic groups (e.g., carboxyl groups) in the calculation of ΔHSP(sp).

[0139] ΔHSP(si-pk) is obtained by applying the dispersion term, polarization term, hydrogen bonding term of the i-th solvent type, dispersion term, polarization term, and hydrogen bonding term of the k-th polymer type to δD1, δP1, δH1, δD2, δP2, and δH2 in the aforementioned mathematical formula (A), respectively.

[0140] The dispersion term (δD), polarization term (δP), and hydrogen bonding term (δH) of each compound that conforms to a water-soluble organic solvent (e.g., the i-th solvent type) are determined by the aforementioned method.

[0141] The dispersion term (hereinafter denoted as "δD(polymer k)") in the k-th polymer that conforms to polymer P.

[0142] The polarization term (hereinafter referred to as "δP(polymer k)") and

[0143] The hydrogen bond term (hereinafter referred to as "δH(polymer k)") was determined based on the method of KWSUH and JMCORBETT described in Journal of Applied Polymer Science, 12, p. 2359 (1968).

[0144] In detail, δD (polymer k), δP (polymer k), and δH (polymer k) are determined as follows.

[0145] Dissolve 500 mg of the sample (i.e., polymer k) completely in 10 mL of tetrahydrofuran (THF). Add deionized water dropwise to the resulting solution until the solution becomes turbid. Let the volume fraction at which the solution becomes turbid [deionized water / (deionized water + THF)] be Vw.

[0146] Dissolve 500 mg of the sample (i.e., polymer k) completely in 10 mL of tetrahydrofuran (THF). Add hexane dropwise to the resulting solution until the solution becomes turbid. Let the volume fraction [hexane / (hexane + THF)] at the point when the solution becomes turbid be Vh.

[0147] Using the obtained Vw and Vh, δD (polymer k), δP (polymer k), and δH (polymer k) are determined by the following mathematical formulas (D1), (P1), and (H1), respectively.

[0148] δD(polymer k)

[0149] = [Vw] 1 / 2 ×δD(W / T)+Vh 1 / 2 ×δD(H / T)〕 / 〔Vw 1 / 2 +Vh 1 / 2 ]

[0150] …Mathematical formula (D1)

[0151] δP(polymer k)

[0152] = [Vw] 1 / 2 ×δP(W / T)+Vh 1 / 2 ×δP(H / T)〕 / 〔Vw 1 / 2 +Vh 1 / 2 ]

[0153] …Mathematical formula (P1)

[0154] δH (polymer k)

[0155] = [Vw] 1 / 2 ×δH(W / T)+Vh 1 / 2 ×δH(H / T)〕 / 〔Vw 1 / 2 +Vh 1 / 2 ]

[0156] …Mathematical formula (H1)

[0157] In mathematical expression (D1), the following parameters are the values ​​obtained by the following mathematical expression.

[0158] δD(W / T)

[0159] =δD(THF)×(1-Vw)+δD(water)×Vw

[0160] δD(H / T)

[0161] =δD(THF)×(1-Vh)+δD(hexane)×Vh

[0162] δP(W / T)

[0163] =δP(THF)×(1-Vw)+δP(water)×Vw

[0164] δP(H / T)

[0165] =δP(THF)×(1-Vh)+δP(hexane)×Vh

[0166] δH(W / T)

[0167] =δH(THF)×(1-Vw)+δH(water)×Vw

[0168] δH(H / T)

[0169] =δH(THF)×(1-Vh)+δH(hexane)×Vh

[0170] In the above mathematical formula, the following values ​​are used as parameters.

[0171] δD(THF) = 16.8

[0172] δD(water) = 15.5

[0173] δD(hexane) = 14.9

[0174] δP(THF) = 5.7

[0175] δP(water)=16

[0176] δP(hexane)=0

[0177] δH(THF)=8

[0178] δH(water) = 42.3

[0179] δH(hexane)=0

[0180] The following describes the components that may be contained in the ink disclosed herein.

[0181] <Water>

[0182] The ink disclosed herein contains water.

[0183] The water content relative to the total amount of the ink disclosed herein is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and particularly preferably 50% by mass or more.

[0184] The upper limit of the water content relative to the total amount of ink disclosed herein is appropriately determined based on the content of other components, for example, 99% by mass, preferably 95% by mass, and more preferably 90% by mass.

[0185] Water-soluble organic solvents

[0186] The ink disclosed herein contains at least one water-soluble organic solvent.

[0187] This ensures the ejection of ink from the inkjet head.

[0188] In this disclosure, "water-soluble" in "water-soluble organic solvent" means the property of dissolving more than 1g of water at 25°C.

[0189] The amount of water-soluble organic solvent that can dissolve relative to 100g of water at 25°C is preferably 5g or more, and more preferably 10g or more.

[0190] The content of water-soluble organic solvent relative to the total amount of ink is preferably 1% to 35% by mass, more preferably 5% to 30% by mass, even more preferably 8% to 15% by mass, and even more preferably 10% to 20% by mass.

[0191] When the content of water-soluble organic solvent is 1% or more by mass, the ink's sprayability is further improved.

[0192] The storage stability of the ink is further improved when the content of water-soluble organic solvent is below 35% by mass.

[0193] Specific examples of water-soluble organic solvents are described below.

[0194] • Alcohols (e.g., methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, tert-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc.)

[0195] • Polyvalent alcohols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butanediol, hexanediol, pentanediol, glycerol, glycerol, thiodiethylene glycol, 2-methylpropanediol, etc.)

[0196] • Polyvalent alcohol ethers (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, tripropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc.)

[0197] • Amines (e.g., ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.)

[0198] • Amides (e.g., formamide, N,N-dimethylformamide, N,N-dimethylacetamide, etc.)

[0199] Heterocyclic compounds (e.g., 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, 2-oxazolidinone, 1,3-dimethyl-2-imidazolone, γ-butyrolactone, etc.)

[0200] • Sulfoxides (e.g., dimethyl sulfoxide, etc.)

[0201] • Sulfones (e.g., sulfolane, etc.)

[0202] Others (urea, acetonitrile, acetone, etc.)

[0203] (Water-soluble organic solvent with a boiling point below 190℃ (S-1))

[0204] The water-soluble organic solvent in the ink disclosed herein preferably contains at least one water-soluble organic solvent (S-1) with a boiling point of less than 190°C (hereinafter also simply referred to as "water-soluble organic solvent (S-1)").

[0205] As a result, the adhesion resistance of the recorded images is further improved.

[0206] In this disclosure, excellent anti-adhesion refers to the property of suppressing image adhesion (i.e., the phenomenon that the object being touched sticks to the image when it is stacked on top of the image).

[0207] In this disclosure, boiling point refers to the boiling point at 1 atmosphere (101325 Pa).

[0208] Examples of water-soluble organic solvents (S-1) include: propylene glycol (boiling point 188℃), propylene glycol monomethyl ether (boiling point 121℃), ethylene glycol monomethyl ether (boiling point 124℃), propylene glycol monoethyl ether (boiling point 133℃), ethylene glycol monoethyl ether (boiling point 135℃), propylene glycol monopropyl ether (boiling point 149℃), ethylene glycol monopropyl ether (boiling point 151℃), propylene glycol monobutyl ether (boiling point 170℃), ethylene glycol monobutyl ether (boiling point 171℃), 2-ethyl-1-hexanol (boiling point 187℃), dipropylene glycol monomethyl ether (boiling point 188℃), diethylene glycol dimethyl ether (boiling point 162℃), diethylene glycol diethyl ether (boiling point 188℃), and dipropylene glycol dimethyl ether (boiling point 175℃).

[0209] From the viewpoint of further improving the image's resistance to adhesion, the proportion of the water-soluble organic solvent (S-1) in the water-soluble organic solvent of the ink disclosed herein is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more.

[0210] The proportion of water-soluble organic solvent (S-1) with a boiling point below 190°C in the ink disclosed herein can be 100% by mass or less than 100% by mass.

[0211] When the ink contains a water-soluble organic solvent (S-1), the content of the water-soluble organic solvent (S-1) relative to the total amount of ink is preferably 1% to 35% by mass, more preferably 5% to 30% by mass, even more preferably 8% to 15% by mass, and even more preferably 10% to 20% by mass.

[0212] (Organic solvents with a boiling point exceeding 190°C)

[0213] The water-soluble organic solvent in the ink disclosed herein may contain at least one water-soluble organic solvent with a boiling point exceeding 190°C.

[0214] Examples of water-soluble organic solvents with boiling points exceeding 190°C include: 2-methyl-1,3-propanediol (MPdiol) (boiling point 214°C), ethylene glycol (boiling point 196°C), 1,2-butanediol (boiling point 193°C), glycerol (boiling point 290°C), 1,2-hexanediol (boiling point 223°C), 1,3-propanediol (boiling point 213°C), diethylene glycol (boiling point 245°C), diethylene glycol monobutyl ether (boiling point 230°C), triethylene glycol (boiling point 285°C), dipropylene glycol (boiling point 232°C), tripropylene glycol (boiling point 267°C), trimethylolpropane (boiling point 295°C), 2-pyrrolidone (boiling point 245°C), tripropylene glycol monomethyl ether (boiling point 243°C), and triethylene glycol monomethyl ether (boiling point 248°C).

[0215] <particles>

[0216] The ink disclosed herein contains at least one particle comprising a polymer P and a polymerizable monomer M (hereinafter also referred to as "specific particle").

[0217] In the ink disclosed herein, the presence of polymer P and polymerizable monomer M in specific particles contributes to the ink's preservation stability.

[0218] The preferred embodiment of the ink disclosed herein is as follows: in the ink applied to the substrate before application, the polymerizable monomer M is retained in specific particles, and in the ink applied to the substrate after application, the polymerizable monomer M is exuded from the specific particles.

[0219] (Polymer P)

[0220] The specific particle contains at least one polymer P.

[0221] Polymer P plays a role in retaining polymeric monomer M within specific particles in inks before they are applied to the substrate, thereby helping to improve the storage stability of the ink.

[0222] Polymer P can be either a chain polymer or a cross-linked polymer.

[0223] In this disclosure, a chain polymer refers to a polymer that does not have a cross-linked structure, and a cross-linked polymer refers to a polymer that has a cross-linked structure.

[0224] Chain polymers can have either cyclic or branched structures.

[0225] Regarding specific particles containing polymer P as a chain polymer, see, for example, Japanese Patent No. 6584677.

[0226] As a preferred method for the specific particles when polymer P is a cross-linked polymer, examples include microcapsules comprising a shell made of polymer P as a cross-linked polymer and a core containing polymeric monomers.

[0227] Regarding specific particles containing polymer P as a crosslinking polymer, see, for example, Japanese Patent No. 6510681.

[0228] -Weight-average molecular weight (Mw)-

[0229] The weight-average molecular weight (Mw) of polymer P is preferably 3,000 to 200,000, more preferably 4,000 to 150,000, even more preferably 5,000 to 100,000, even more preferably 8,000 to 80,000, and even more preferably 10,000 to 50,000.

[0230] When the Mw of polymer P is above 3000, the storage stability of the ink is further improved. This can be attributed to the fact that when the Mw of polymer P is above 3000, the function of polymer P (the function of retaining polymeric monomer M within specific particles; in other words, the function of inhibiting the exudation of polymeric monomer M from specific particles) can be more effectively utilized in the ink before it is applied to the substrate.

[0231] When the Mw of polymer P is below 200,000, the image's resistance to tack is further improved. This can be attributed to the fact that when the Mw of polymer P is below 200,000, the decrease in fluidity (i.e., thickening) during the drying process of the ink applied to the substrate is suppressed, which in turn promotes the evaporation of liquid components (i.e., water and water-soluble organic solvents) from the ink.

[0232] In this disclosure, number-average molecular weight (Mn) and weight-average molecular weight (Mw) refer to values ​​calculated using gel permeation chromatography (GPC) via polystyrene conversion.

[0233] As a column used, for example, TSKgel (registered trademark) SuperHZM-H, TSKgel (registered trademark) SuperHZ4000 and TSKgel (registered trademark) SuperHZ200 (all manufactured by Tosoh Corporation) are used.

[0234] - Glass transition temperature (Tg) -

[0235] There are no particular limitations on the glass transition temperature (Tg) of polymer P.

[0236] From the viewpoint of improving the mobility of polymer P and further improving the image quality (specifically, suppressing image roughness), the Tg of polymer P is preferably below 120°C, more preferably below 100°C, even more preferably below 80°C, and even more preferably below 70°C.

[0237] On the other hand, the Tg of polymer P is preferably 0°C or higher, more preferably 10°C or higher, even more preferably 20°C or higher, and even more preferably 30°C or higher.

[0238] In this disclosure, the glass transition temperature (Tg) of the polymer refers to the value determined using differential scanning calorimetry (DSC).

[0239] The glass transition temperature was determined according to the methods described in JIS K 7121 (1987) or JIS K 6240 (2011).

[0240] The glass transition temperature in this disclosure is the extrapolated glass transition onset temperature (hereinafter, sometimes referred to as Tig).

[0241] The method for determining the glass transition temperature is explained in more detail.

[0242] Once the glass transition temperature is determined, the device is held at a temperature approximately 50°C lower than the predicted glass transition temperature of the resin until it stabilizes. Then, at a heating rate of 20°C / minute, the temperature is heated to approximately 30°C higher than the temperature at the end of the glass transition, and differential thermal analysis (DTA) or DSC curves are generated.

[0243] The extrapolated glass transition onset temperature (Tig), i.e. the glass transition temperature in this disclosure, is obtained as the temperature at the intersection of the straight line drawn by extending the baseline of the low-temperature side of the DTA curve or DSC curve to the high-temperature side and the tangent line drawn at the point of maximum gradient of the curve in the step-like change portion of the glass transition.

[0244] When the ink contains two or more polymers P, the glass transition temperature (Tg) of polymer P refers to the weighted average of the glass transition temperatures of each polymer P.

[0245] Examples of polymers P include urethane polymers, urethane urea polymers, urea polymers, acrylic polymers, polyesters, polyolefins, polystyrene, polycarbonate, and polyamides.

[0246] Here, urethane polymers refer to polymers containing urethane bonds but not urea bonds, urea polymers refer to polymers containing urea bonds but not urethane bonds, and urethane-urea polymers refer to polymers containing both urethane bonds and urea bonds.

[0247] In addition, acrylic polymers refer to polymers (homopolymers or copolymers) that contain at least one raw material monomer selected from the group consisting of acrylic acid, derivatives of acrylic acid (e.g., acrylates), methacrylic acid, and derivatives of methacrylic acid (e.g., methacrylates).

[0248] -Key U-

[0249] Polymer P preferably contains a bond U, which is at least one of a urethane bond and a urea bond. In other words, polymer P is preferably a urethane polymer, a urethane urea polymer, or a urea polymer.

[0250] When polymer P contains bond U, in the ink deposited on the substrate, specific particles readily interact with each other due to the interaction of bonds U (e.g., hydrogen bonding). Therefore, the polymerization of polymeric monomers M (specifically monomer (M-1)) emanating from these specific particles facilitates the bonding of these particles. Consequently, curing between these particles is easier, thus improving the abrasion resistance of the image.

[0251] Bond U preferably contains a carbamate bond.

[0252] In other words, polymer P preferably contains urethane bonds and does not contain urea bonds, or contains both urethane bonds and urea bonds.

[0253] -Hydrophilic group-

[0254] Polymer P preferably contains at least one hydrophilic group.

[0255] This contributes to the dispersion stability of specific particles in the ink, resulting in improved storage stability of the ink.

[0256] From the viewpoint of further improving the preservation stability of ink, anionic or nonionic groups are preferred as hydrophilic groups, and anionic groups are more preferred.

[0257] For example, when comparing anionic and nonionic groups of the same molecular weight, inks with anionic groups exhibit superior improved storage stability. That is, anionic groups (particularly preferably at least one selected from the group consisting of carboxyl groups and their salts) can fully exert their effect on improving ink storage stability even when their molecular weight is small.

[0258] Examples of nonionic groups include groups with polyether structures, with a preferred example being a monovalent group containing polyalkylene oxides.

[0259] Anionic groups can be neutralized or unneutralized.

[0260] Examples of unneutralized anionic groups include carboxyl, sulfonyl, sulfate, phosphonic acid, and phosphate groups.

[0261] Neutralized anionic groups refer to anionic groups in the form of "salts" (e.g., carboxyl salts (e.g., -COONa)). Examples of neutralized anionic groups include carboxyl salts, sulfonyl salts, sulfate salts, phosphonic acid salts, and phosphate salts.

[0262] Neutralization can be achieved using, for example, alkali metal hydroxides (e.g., sodium hydroxide, potassium hydroxide, etc.) or organic amines (e.g., triethylamine, etc.).

[0263] From the viewpoint of further improving the preservation stability of the ink, anionic groups are preferred as hydrophilic groups in polymer P, more preferably at least one of the group consisting of free carboxyl groups, salts of carboxyl groups, sulfonyl groups, salts of sulfonyl groups, sulfate groups, salts of sulfate groups, phosphonic acid groups, salts of phosphonic acid groups, phosphate groups, and salts of phosphate groups, and even more preferably at least one of the group consisting of free carboxyl groups, salts of carboxyl groups, sulfonyl groups, and salts of sulfonyl groups.

[0264] The "salt" among the above-mentioned carboxyl salt, sulfonyl salt, sulfate salt, phosphonic acid salt, and phosphate salt is preferably an alkali metal salt or an organic amine salt, and more preferably an alkali metal salt.

[0265] K or Na are preferred as alkali metals in alkali metal salts.

[0266] Furthermore, when polymer P contains anionic groups (e.g., at least one selected from the group consisting of carboxyl groups and salts of carboxyl groups) as hydrophilic groups, when the total number of millimoles of anionic groups (e.g., carboxyl groups and salts of carboxyl groups) contained in 1g of polymer P is taken as the acid value of polymer P, from the viewpoint of dispersion stability, the acid value of polymer P is preferably 0.10 mmol / g to 2.00 mmol / g, more preferably 0.30 mmol / g to 1.50 mmol / g.

[0267] Furthermore, when polymer P has anionic groups as hydrophilic groups, the neutralization degree of the anionic groups in polymer P is preferably 50% to 100%, more preferably 70% to 90%.

[0268] Here, the degree of neutralization refers to the ratio of the number of neutralized anionic groups in polymer P to the total number of unneutralized anionic groups (e.g., carboxyl groups) and the number of neutralized anionic groups (e.g., salts of carboxyl groups) (i.e., the ratio of [number of neutralized anionic groups / (number of unneutralized anionic groups + number of neutralized anionic groups)]).

[0269] The degree of neutralization of the anionic groups in polymer P can be determined by neutralization titration.

[0270] -polymeric groups-

[0271] The specific particles not only contain polymer P, but also polymerizable monomer M (i.e., compounds containing polymerizable groups), which will be described later. Polymerizable monomer M contributes to improving the abrasion resistance of the film. Therefore, polymer P does not necessarily need to contain polymerizable groups.

[0272] However, from the viewpoint of further improving the abrasion resistance of the film, polymer P can contain polymeric groups.

[0273] As polymerizable groups that can be included in polymer P, photopolymerizable groups or thermal polymerizable groups are preferred.

[0274] As a photopolymerizable group, a free radical polymerizable group is preferred, a group containing an olefinic double bond is more preferred, and (meth)acryloyl, allyl, styrene, or vinyl groups are even more preferred. As a free radical polymerizable group, (meth)acryloyl is particularly preferred from the viewpoint of free radical polymerization reactivity and the hardness of the formed film.

[0275] As a thermopolymerizable group, epoxy group, oxetyl group, aziridinyl group, aziridyl group, ketone group, aldehyde group, or block isocyanate group are preferred.

[0276] Polymer P may contain only one polymeric group or two or more polymeric groups.

[0277] Polymer P contains polymeric groups, which can be confirmed, for example, by Fourier transform infrared spectroscopy (FT-IR) analysis.

[0278] When the number of millimoles of olefinic double bonds in 1g of polymer P is set as the C=C valence of polymer P, from the viewpoint of further improving image hardness, the C=C valence of polymer P is preferably 0.05 mmol or more, more preferably 0.10 mmol / g or more, even more preferably 0.30 mmol / g or more, and particularly preferably 0.50 mmol / g or more.

[0279] From the viewpoint of further improving the water resistance and alcohol resistance of the image, the C=C valence of polymer P is preferably 0.05 mmol / g or more, more preferably 0.10 mmol / g or more, even more preferably 0.30 mmol / g or more, even more preferably 0.50 mmol / g or more, even more preferably 0.60 mmol / g or more, and particularly preferably 0.70 mmol / g or more.

[0280] On the other hand, from the viewpoint of improving the curability of ink over time (i.e., suppressing the decrease in curability of ink caused by time), the C=C valence of polymer P is preferably 4.00 mmol / g or less, more preferably 3.00 mmol / g or less, even more preferably 2.00 mmol / g or less, and particularly preferably 1.50 mmol / g or less.

[0281] Polymer P may contain structures other than those described above (i.e., bond U, hydrophilic groups, and polymerizable groups).

[0282] Other structures include polysiloxane bonds (i.e., divalent polysiloxanes), monovalent polysiloxanes, monovalent fluorinated hydrocarbon groups, and divalent fluorinated hydrocarbon groups.

[0283] -Preferred structure of polymer P-

[0284] Polymer P preferably comprises structural units derived from isocyanate compounds (hereinafter also referred to as "NCO") and structural units derived from compounds containing active hydrogen groups.

[0285] The polymer P of the preferred embodiment described above comprises a bond U formed by the reaction of an isocyanate group of an isocyanate compound and an active hydrogen group of a compound containing an active hydrogen group.

[0286] The active hydrogen group is preferably hydroxyl, primary amino, or secondary amino.

[0287] For example, urethane groups are formed by the reaction of isocyanate groups and hydroxyl groups.

[0288] Additionally, urea groups are formed through the reaction of isocyanate groups with primary or secondary amino groups.

[0289] Hereinafter, isocyanate compounds and compounds containing active hydrogen groups that are sometimes used as raw materials for polymer P having the above-mentioned preferred structure are referred to as raw material compounds.

[0290] The isocyanate compound used as a raw material can be a single type or two or more types.

[0291] The raw material compound containing an active hydrogen group can be just one type or two or more types.

[0292] At least one of the isocyanate compounds used as raw material compounds, preferably a difunctional or higher isocyanate compound.

[0293] At least one of the compounds containing active hydrogen groups as raw material compounds, preferably compounds containing two or more active hydrogen groups.

[0294] Among the raw material compounds, at least one of the isocyanate compound and the compound containing an active hydrogen group preferably contains a hydrophilic group. This facilitates the manufacture of a polymer P containing a hydrophilic group. In this case, at least a portion of the hydrophilic groups in the final polymer P may also be neutralized hydrophilic groups from the raw material compounds.

[0295] A more preferred method is as follows: among the raw material compounds, at least one of the compounds containing an active hydrogen group is a compound containing both an active hydrogen group and a hydrophilic group.

[0296] When polymer P contains polymeric groups, at least one of the starting material compounds, namely the isocyanate compound and the compound containing active hydrogen groups, preferably contains polymeric groups. Therefore, it is easy to manufacture polymer P containing polymeric groups.

[0297] A more preferred method is as follows: among the raw material compounds, at least one of the compounds containing active hydrogen groups is a compound containing both active hydrogen groups and polymerizable groups.

[0298] As mentioned earlier, polymer P can be a chain polymer or a cross-linked polymer.

[0299] The chain polymer P can be produced by reacting a difunctional isocyanate compound with a compound containing two active hydrogen groups.

[0300] Crosslinked polymers, which are polymers P, can be manufactured by reacting isocyanate compounds with trifunctional or higher functions with compounds containing two or more active hydrogen groups.

[0301] Crosslinked polymers, which are polymers P, can also be manufactured by reacting a difunctional isocyanate compound with a compound containing three or more active hydrogen groups.

[0302] The preferred raw material compounds will be described below.

[0303] -Isocyanate compounds-

[0304] As isocyanate compounds, difunctional or higher isocyanate compounds are preferred, and difunctional to hexafunctional isocyanate compounds are more preferred.

[0305] When a difunctional isocyanate compound is used as a starting material, the polymer P contains the following structural unit (P1) as a structural unit derived from the difunctional isocyanate compound.

[0306] [Chemical Formula 1]

[0307]

[0308] In structural unit (P1), L 1 This indicates a divalent organic group with 1 to 20 carbon atoms; * indicates the bonding position.

[0309] As L 1 Specific examples can be cited from the residues remaining after removing two isocyanate groups (NCO groups) from the difunctional isocyanate compounds involved in the following specific examples.

[0310] Specific examples of difunctional isocyanate compounds are described below. However, the difunctional isocyanate compounds are not limited to the specific examples listed below.

[0311] [Chemical Formula 2]

[0312]

[0313] In addition, as a difunctional isocyanate compound, a difunctional isocyanate compound derived from the above specific examples may also be used. Examples include: DURANATE (registered trademark) D101, D201, A101 (manufactured by Asahi Kasei Corporation), etc.

[0314] Furthermore, the isocyanate compound with three or more functions is preferably a reaction product of at least one of the group consisting of difunctional isocyanate compounds and at least one of the group consisting of compounds containing three or more active hydrogen groups (e.g., polyols with three or more functions, polyamines with three or more functions, and polythiols with three or more functions).

[0315] The number of moles (molecules) of the difunctional isocyanate compound that reacts with a compound containing three or more active hydrogen groups is preferably 0.6 times or more, more preferably 0.6 to 5 times, even more preferably 0.6 to 3 times, and even more preferably 0.8 to 2 times, relative to the number of moles (equivalent number of active hydrogen groups) of the active hydrogen groups in the compound containing three or more active hydrogen groups.

[0316] As examples of difunctional isocyanates used to form trifunctional or higher isocyanate compounds, the difunctional isocyanate compounds mentioned above are examples of difunctional isocyanates.

[0317] As compounds containing three or more active hydrogen groups for forming isocyanates with three or more functions, examples include the compounds described in paragraphs 0057 to 0058 of International Publication No. 2016 / 052053.

[0318] Examples of isocyanate compounds with trifunctionality or higher include addition-type trifunctional or higher isocyanate compounds, isocyanurate-type trifunctional or higher isocyanate compounds, and biuret-type trifunctional or higher isocyanate compounds.

[0319] Commercially available addition-type trifunctional or higher isocyanate compounds include: TAKENATE (registered trademark) D-102, D-103, D-103H, D-103M2, P49-75S, D-110N, D-120N, D-140N, D-160N (all from Mitsui Chemicals Co., Ltd.), Desmodur (registered trademark) L75, UL57SP (Sumitomo Chemical Bayer Polyurethanes Co., Ltd.), CORONATE (registered trademark) HL, L (Tosoh Co., Ltd.), P301-75E (Asahi Kasei Corporation), etc.

[0320] Commercially available isocyanurate compounds with trifunctional or higher functions include: TAKENATE (registered trademark) D-127N, D-170N, D-170HN, D-172N, D-177N (all manufactured by Mitsui Chemicals Co., Ltd.), SUMIDURN3300, Desmodur (registered trademark) N3600, N3900, Z4470BA (all manufactured by Sumitomo Chemical Bayer Polyurethanes Co., Ltd.), CORONATE (registered trademark) HX, HK (all manufactured by Tosoh Co., Ltd.), DURANATE (registered trademark) TPA-100, TKA-100, TSA-100, TSS-100, TLA-100, TSE-100 (all manufactured by Asahi Kasei Corporation), etc.

[0321] Commercially available biuret-type trifunctional or higher isocyanate compounds include: TAKENATE (registered trademark) D-165N, NP1100 (manufactured by Mitsui Chemicals Co., Ltd.), Desmodur (registered trademark) N3200 (manufactured by Sumitomo Chemical Bayer Polyurethanes Co., Ltd.), DURANATE (registered trademark) 24A-100 (manufactured by Asahi Kasei Corporation), etc.

[0322] At least one of the isocyanate compounds used as raw material compounds may also be an isocyanate compound containing a hydrophilic group. For reference to isocyanate compounds containing a hydrophilic group, see paragraphs 0112-0118 and 0252-0254 of International Publication No. 2016 / 052053.

[0323] At least one of the isocyanate compounds used as raw material compounds may also be an isocyanate compound containing polymerizable groups. For reference to isocyanate compounds containing polymerizable groups, see paragraphs 0084-0089, 0203 and 0205 of International Publication No. 2016 / 052053.

[0324] -Compounds containing active hydrogen groups-

[0325] As a compound containing active hydrogen groups, it is preferred to be a compound containing two or more active hydrogen groups.

[0326] As a compound containing two or more active hydrogen groups, it is more preferably a polyol compound (i.e., a compound having two or more hydroxyl groups) or a polyamine compound (i.e., a compound having two or more amino groups).

[0327] When using a compound containing an active hydrogen group and a hydrophilic group as a raw material compound, the polymer P preferably contains at least one of the following structural units (PO).

[0328] [Chemical Formula 3]

[0329]

[0330] In structural unit (P0),

[0331] L 0 This indicates a divalent organic group.

[0332] Y 1 and Y 2 Each can be used independently to represent an oxygen atom, a sulfur atom, or -NR. 1 -base,

[0333] R 1 This refers to a hydrocarbon group containing 1 to 10 hydrogen or carbon atoms.

[0334] * indicates the bonding location.

[0335] In structural unit (P0), L 0 The divalent organic group can be either a group composed of carbon and hydrogen atoms, or a group containing carbon and hydrogen atoms and heteroatoms (e.g., oxygen, nitrogen, sulfur, etc.).

[0336] L 0 The divalent organic group represented may include at least one of a hydrophilic group and a polymerizable group.

[0337] As L 0 Specific examples can be given by removing two active hydrogen groups from specific examples of compounds containing two or more active hydrogen groups described later.

[0338] As R 1 Preferably, it has a hydrocarbon group with 1 to 6 hydrogen atoms or carbon atoms, and more preferably, it has a hydrocarbon group with 1 to 3 hydrogen atoms or carbon atoms.

[0339] Y 1 and Y 2 Preferably, each is an oxygen atom or -NR. 1 - radical, more preferably oxygen atom.

[0340] The following are specific examples of diol compounds that contain active hydrogen groups, but compounds containing active hydrogen groups are not limited to the specific examples shown below.

[0341] [Chemical Formula 4]

[0342]

[0343] In compounds (12) to (15), nC7H 15 nC9H 19 nC 11 H 23 and nC17 H 35 They represent n-heptyl, n-nonyl, n-undecyl, and n-heptadecyl, respectively.

[0344] Compound (16)PPG is polypropylene glycol, and n is the number of repetitions.

[0345] Compound (16-2)PEG is polyethylene glycol, and n is the number of repetitions.

[0346] Compound (17)PEs is a polyester diol, where n is the repetition number, and Ra and the two Rb are independently divalent hydrocarbon groups with 2 to 25 carbon atoms. The n Ra in compound (17)PEs can be the same or different. The (n+1) Rb in compound (17)PEs can be the same or different.

[0347] Compound (18)PC is a polycarbonate diol, where n is the repetition number, and the (n+1) Rcs are each independently an alkylene group with 2 to 12 carbon atoms (preferably 3 to 8, more preferably 3 to 6). The (n+1) Rcs in compound (18)PC can be the same or different.

[0348] Compound (19)PCL is polycaprolactone diol, n and m are the repeating numbers, and Rd is an alkylene group with 2 to 25 carbon atoms.

[0349] -Compounds containing active hydrogen groups and polymerizable groups-

[0350] Compounds containing active hydrogen groups can also be exemplified by compounds containing both active hydrogen groups and polymerizable groups.

[0351] Compounds containing active hydrogen groups and polymerizable groups are suitable as compounds for introducing polymerizable groups into polymer P (hereinafter also referred to as "compounds for introducing polymerizable groups").

[0352] The following are specific examples of diol compounds that contain active hydrogen groups and polymerizable groups, but compounds containing active hydrogen groups and polymerizable groups are not limited to the specific examples shown below.

[0353] [Chemical Formula 5]

[0354]

[0355] For compounds containing active hydrogen groups and polymerizable groups, please refer appropriately to paragraphs 0075 to 0089 of International Publication No. 2016 / 052053.

[0356] -Compounds containing active hydrogen groups and hydrophilic groups-

[0357] As compounds containing active hydrogen groups, compounds containing both active hydrogen groups and hydrophilic groups can also be cited.

[0358] Compounds containing active hydrogen groups and hydrophilic groups are suitable as compounds for introducing hydrophilic groups into polymer P (hereinafter also referred to as "compounds for introducing hydrophilic groups").

[0359] When using a compound containing an active hydrogen group and a hydrophilic group as a raw material compound, the polymer P preferably contains the following structural unit (P2).

[0360] [Chemical Formula 6]

[0361]

[0362] In structural unit (P2),

[0363] L 21 Organic groups representing trivalent carbon atoms from 1 to 20.

[0364] L 22 Represents a single bond or a divalent organic group with 1 to 20 carbon atoms.

[0365] A 1 Represents a carboxyl group, a salt of a carboxyl group, or a salt of a sulfonyl group.

[0366] * indicates the bonding location.

[0367] L 21 The number of carbon atoms in the trivalent organic groups representing 1 to 20 carbon atoms is preferably 2 to 20, more preferably 3 to 20, and even more preferably 4 to 20.

[0368] As L 21 The trivalent organic group represented is preferably a group formed by replacing at least one carbon atom of a trivalent hydrocarbon group with a heteroatom (preferably an oxygen atom, a sulfur atom, or a nitrogen atom).

[0369] L 22 The number of carbon atoms in the divalent organic groups representing 1 to 20 carbon atoms is preferably 1 to 10, more preferably 1 to 6.

[0370] As L 22 The divalent organic group represented is preferably a group formed by replacing at least one carbon atom of a divalent hydrocarbon group (preferably alkylene) or a divalent hydrocarbon group (preferably alkylene) with an oxygen atom or a sulfur atom (preferably oxygen).

[0371] L 22 It can also be a single key.

[0372] The following are specific examples of compounds containing active hydrogen groups and hydrophilic groups, but compounds containing active hydrogen groups and hydrophilic groups are not limited to the following specific examples. The carboxyl and sulfonyl groups in the following specific examples may also be neutralized (i.e., they may also be salts of carboxyl and sulfonyl groups).

[0373] [Chemical Formula 7]

[0374]

[0375] For compounds containing active hydrogen groups and hydrophilic groups, appropriate reference may be made to paragraphs 0112-0118 and 0252-0254 of International Publication No. 2016 / 052053.

[0376] The content of polymer P relative to the total solid content of the specific particles is preferably 10% to 90% by mass, more preferably 20% to 80% by mass, even more preferably 30% to 70% by mass, and even more preferably 40% to 60% by mass.

[0377] In this disclosure, the total solid content of a specific particle refers to the total amount after removing the solvent (i.e., water and organic solvents) from the specific particle. When the specific particle contains no solvent, the total solid content of the specific particle is the same as the total amount of the specific particle.

[0378] The content of polymer P relative to the total amount of ink is preferably 0.3% to 20% by mass, more preferably 0.5% to 15% by mass, and even more preferably 1% to 10% by mass.

[0379] <polymerizable monomer M>

[0380] A particular particle contains at least one polymerizable monomer M.

[0381] When the ink is applied to the substrate and cured, the polymerizable monomer M helps to link specific particles together, improving the image's abrasion resistance.

[0382] The polymerizable monomer M contained in a specific particle can be only one type or two or more types.

[0383] As the polymerizable monomer M contained in a specific particle, the compound described in paragraphs 0097 to 0105 of International Publication No. 2016 / 052053 may be used.

[0384] The molecular weight of the polymerizable monomer M is preferably 100 to 4000, more preferably 100 to 2000, even more preferably 100 to 1000, even more preferably 100 to 900, even more preferably 100 to 800, and particularly preferably 150 to 750.

[0385] As a polymerizable monomer M that can be included in a specific particle, a photopolymerizable monomer is preferred, and a free radical polymerizable monomer is more preferred.

[0386] Free radical polymerizable monomers have free radical polymerizable groups in their molecular structure.

[0387] The preferred form of the free radical polymerizable group of the free radical polymerizable monomer is the same as the preferred form of the free radical polymerizable group that may be contained in the aforementioned polymer P.

[0388] Examples of free radical polymerizable monomers include acrylate compounds, methacrylate compounds, styrene compounds, vinylnaphthalene compounds, N-vinyl heterocyclic compounds, unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes.

[0389] Free radical polymerizable monomers are preferably compounds with olefinic unsaturated groups.

[0390] When a specific particle contains a free radical polymerizable monomer, the specific particle may contain only one type of free radical polymerizable monomer, or it may contain two or more types.

[0391] Examples of acrylate compounds include: 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, tridecyl acrylate, 2-phenoxyethyl acrylate (PEA), bis(4-acryloyloxypolyethoxyphenyl)propane, polyester acrylate, epoxy acrylate, isobornyl acrylate (IBOA), dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentyl acrylate, cyclotrimethylolpropane methyl acetal acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-(2-vinyloxyethoxy)ethyl acrylate, octyl acrylate, decyl acrylate, isodecanyl acrylate, lauryl acrylate, and 3,3,5-trimethylcyclohexylpropylene. Acrylates, 4-tert-butylcyclohexyl acrylate, isoamyl acrylate, stearyl acrylate, isostearyl acrylate, 2-ethylhexyl diethylene glycol acrylate, 2-hydroxybutyl acrylate, 2-acryloyloxyethyl hydrogenated phthalic acid, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, vinyl ether acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyphthalic acid, 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid, lactone-modified acrylates, acryloylmorpholine, acrylamide, substituted acrylamides (e.g., N-hydroxymethylacrylamide and diacetone acrylamide) and other monofunctional acrylate compounds;

[0392] Polyethylene glycol diacrylate, polypropylene glycol diacrylate, polybutylene glycol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate (HDDA), 1,9-nonanediol diacrylate (NDDA), 1,10-decanediol diacrylate (DDDA), 3-methylpentanediol diacrylate (3MPDDA), neopentyl glycol diacrylate, tricyclodecanedimethylethanol diacrylate, bisphenol A ethylene oxide (EO) adduct diacrylate, bisphenol A propylene oxide (PO) adduct diacrylate, ethoxylated... Bisphenol A diacrylate, hydroxyneopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, alkoxylated dihydroxymethyltricyclodecane diacrylate, polybutylene glycol diacrylate, alkoxylated cyclohexanone dimethyl diacrylate, alkoxylated hexanediol diacrylate, dioxanediol diacrylate, cyclohexanone dimethyl diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate (TPGDA), neopentyl glycol glycidyl acrylate, and other difunctional acrylate compounds;

[0393] Trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol tetraacrylate, ethoxylated isocyanuric acid triacrylate, ε-caprolactone-modified tri-(2-acryloyloxyethyl)isocyanurate, di-trimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, caprolactone-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxylated tetraacrylate, glycerol propoxylated triacrylate, ethoxylated dipentaerythritol hexaacrylate, caprolactam-modified dipentaerythritol hexaacrylate, propoxylated glycerol triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, and other trifunctional or higher acrylate compounds.

[0394] Examples of monofunctional methacrylate compounds include: methyl methacrylate, n-butyl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylaminomethyl methacrylate, methoxy polyethylene glycol methacrylate, methoxy triethylene glycol methacrylate, hydroxyethyl methacrylate, phenoxyethyl methacrylate, and cyclohexyl methacrylate.

[0395] Difunctional methacrylate compounds such as polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane, and tetraethylene glycol dimethacrylate.

[0396] Examples of styrene compounds include: styrene, p-methylstyrene, p-methoxystyrene, β-methylstyrene, p-methyl-β-methylstyrene, α-methylstyrene, and p-methoxy-β-methylstyrene.

[0397] Examples of vinylnaphthalene compounds include: 1-vinylnaphthalene, methyl-1-vinylnaphthalene, β-methyl-1-vinylnaphthalene, 4-methyl-1-vinylnaphthalene, and 4-methoxy-1-vinylnaphthalene.

[0398] Examples of N-vinyl heterocyclic compounds include: N-vinylcarbazole, N-vinylpyrrolidone, N-vinylethylacetamide, N-vinylpyrrole, N-vinylphenthiazide, N-vinylacetanilide, N-vinylethylacetamide, N-vinylsuccinic acid imide, N-vinylphthalimide, N-vinylcaprolactam, and N-vinylimidazolium.

[0399] Other monomers that can polymerize on a free radical basis include: allyl glycidyl ether, diallyl phthalate, triallyl trimellitate, N-vinylformamide, and other N-vinylamides.

[0400] Among these free radical polymerizable monomers, those with less than difunctionality are preferably selected from at least one of the following monomers: 1,6-hexanediol diacrylate (HDDA), 1,9-nonanediol diacrylate (NDDA), 1,10-decanediol diacrylate (DDDA), 3-methylpentanediol diacrylate (3MPDDA), neopentanediol diacrylate, tricyclodecanediethanol diacrylate, diethylene glycol diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate (TPGDA), cyclohexanone dimethyl diacrylate, alkoxylated hexanediol diacrylate, polyethylene glycol diacrylate, and polypropylene glycol diacrylate.

[0401] Furthermore, as a free radical polymerizable monomer with trifunctionality or higher, it is preferably selected from at least one of the following monomers: trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, caprolactone-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxylated tetraacrylate, glycerol propoxylated triacrylate, ethoxylated dipentaerythritol hexaacrylate, caprolactam-modified dipentaerythritol hexaacrylate, propoxylated glycerol triacrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane triacrylate.

[0402] Specific particles can contain a combination of free radical polymerizable monomers with less than two functionalities and free radical polymerizable monomers with more than three functionalities. In this case, free radical polymerizable monomers with less than two functionalities mainly improve the adhesion between the film and the substrate, while free radical polymerizable monomers with more than three functionalities mainly improve the hardness of the film.

[0403] Examples of combinations of free radical polymerizable monomers with less than two functionalities and free radical polymerizable monomers with more than three functionalities include: combinations of difunctional acrylate compounds and trifunctional acrylate compounds, combinations of difunctional acrylate compounds and pentafunctional acrylate compounds, and combinations of monofunctional acrylate compounds and tetrafunctional acrylate compounds.

[0404] From the viewpoint of further improving the adhesion between the film and the substrate, at least one of the free radical polymerizable monomers that may be included in the specific particles is preferably a free radical polymerizable monomer with a cyclic structure (hereinafter also referred to as "cyclic free radical polymerizable monomer").

[0405] Examples of cyclic free radical polymerizable monomers include: cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, isobornyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentyl acrylate, ethoxylated isocyanuric acid triacrylate, and ε-caprolactone-modified tri-(2-acryloyloxyethyl)isocyanurate.

[0406] Alternatively, examples of cyclic free radical polymerizable monomers with more than two functionalities can be cited below.

[0407] From the viewpoint of further improving the adhesion between the film and the substrate, at least one of the free radical polymerizable monomers that may be contained in the specific particles is preferably a polymerizable monomer containing one or more cyclic structures and two or more (meth)acryloyl groups in a molecule (hereinafter also referred to as "bifunctional or higher cyclic free radical polymerizable monomers").

[0408] Examples of monomers that are difunctional or higher cyclic radical polymerizable include:

[0409] Tricyclodecanediethanol di(methacrylate),

[0410] Bisphenol A ethylene oxide (EO) adduct di(meth)acrylate,

[0411] Bisphenol A propylene oxide (PO) adduct di(meth)acrylate,

[0412] Ethoxylated bisphenol A di(meth)acrylate,

[0413] Alkoxylated dihydroxymethyltricyclodecane di(meth)acrylate,

[0414] Alkoxylated cyclohexanone diethanol di(meth)acrylate,

[0415] Cyclohexanone dimethyl di(meth)acrylate, etc.

[0416] When a specific particle contains a free radical polymerizable monomer, the proportion of difunctional or more cyclic free radical polymerizable monomers in the total free radical polymerizable monomer is preferably 10% to 100% by mass, more preferably 30% to 100% by mass, and particularly preferably 40% to 100% by mass.

[0417] In addition to the free radical polymerizable monomers listed above, commercially available products and industry-known free radical polymerizable and crosslinkable monomers can also be used, as described in Shinzo Yamashita's "Crosslinking Agent Handbook" (Taiseisha, 1981); Kiyoshi Kato's "UV·EB Curing Handbook (Raw Materials)" (Polymer Journal of Japan, 1985); Radtech Research Association's "Application and Market of UV·EB Curing Technology" (page 79, CMC, 1989); and Eiichiro Takiyama's "Polyester Resin Handbook" (Nikkan Kogyo Shimbun, 1988).

[0418] The content of polymerizable monomer M relative to the total solid content of a specific particle is preferably 10% to 90% by mass, more preferably 20% to 80% by mass, even more preferably 30% to 70% by mass, and even more preferably 40% to 60% by mass.

[0419] The content of polymerizable monomer M relative to the total amount of ink is preferably 0.3% to 20% by mass, more preferably 0.5% to 15% by mass, and even more preferably 1% to 10% by mass.

[0420] The polymerizable monomer M preferably contains a monomer (M-) with a viscosity of 10 mPa·s to 150 mPa·s at 25°C.

[0421] Since the viscosity of monomer (M-1) is below 150 mPa·s, the polymerizable monomer M (in this case, monomer (M-1)) is more readily exuded from specific particles on the substrate, resulting in improved abrasion resistance of the image.

[0422] Since the viscosity of monomer (M-1) is above 10 mPa·s, the storage stability of the ink is further improved.

[0423] As a monomer (M-1), any polymerizable monomer with a viscosity of 10 mPa·s to 150 mPa·s at 25°C is acceptable.

[0424] As a monomer (M-1), a monomer with a viscosity of 10 mPa·s to 150 mPa·s at 25°C can be appropriately selected from the free radical polymerizable monomers exemplified above.

[0425] Here, the viscosity of the polymerizable monomer is a value measured using a viscometer.

[0426] As a viscometer, for example, VISCOMETER TV-22 (Toki Sangyo Co., Ltd.) can be used.

[0427] From the viewpoint of further improving the preservation stability of ink and the abrasion resistance of images, the proportion of monomer (M-1) in the total amount of polymerizable monomer M is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more.

[0428] The proportion of monomer (M-1) in the total amount of polymerizable monomer M in the ink disclosed herein can be 100% by mass or less than 100% by mass.

[0429] When the polymerizable monomer M contains monomer (M-1), the content of monomer (M-1) relative to the total amount of ink is preferably 0.3% to 20% by mass, more preferably 0.5% to 15% by mass, and even more preferably 1% to 10% by mass.

[0430] Other examples of free radical polymerizable monomers selected as polymerizable monomers M include those described in Japanese Patent Application Publication No. 7-159983, Japanese Patent Application Publication No. 7-31399, Japanese Patent Application Publication No. 8-224982, Japanese Patent Application Publication No. 10-863, Japanese Patent Application Publication No. 9-134011, and Japanese Patent Publication No. 2004-514014.

[0431] Examples of commercially available free radical polymerizable monomers include: AH-600 (difunctional), AT-600 (difunctional), UA-306H (hexafunctional), UA-306T (hexafunctional), UA-306I (hexafunctional), UA-510H (defunctional), UF-8001G (difunctional), DAUA-167 (difunctional), Light Acrylate NPA (difunctional), and Light Acrylate. 3EG-A (difunctional) (manufactured by Kyoei Chemical Co., Ltd.), SR339A (PEA, monofunctional), SR506 (IBOA, monofunctional), CD262 (difunctional), SR238 (HDDA, difunctional), SR341 (3MPDDA, difunctional), SR508 (difunctional), SR306H (difunctional), CD560 (difunctional), SR833S (difunctional), SR444 (trifunctional), SR454 (trifunctional), SR492 (trifunctional), SR499 (trifunctional), CD501 (trifunctional), SR502 (trifunctional), SR9020 (trifunctional), CD9021 (trifunctional), SR9035 (trifunctional) SR494 (quadrifunctional), SR399E (pentafunctional) (all manufactured by Sartoma), A-NOD-N (NDDA, difunctional), A-DOD-N (DDDA, difunctional), A-200 (difunctional), APG-400 (difunctional), A-BPE-10 (difunctional), A-BPE-20 (difunctional), A-9300 (trifunctional), A-9300-1CL (trifunctional), A-TMPT (trifunctional), A-TMM-3L (trifunctional), A-TMMT (quadrifunctional), AD-TMP (quadrifunctional) (all manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), UV-7510B (trifunctional) (Nippon Synthetic Chemicals Co., Ltd.), KAYARAD DPCA-30 (hexafunctional), KAYARAD DPEA-12 (hexafunctional) (all manufactured by Nippon Kayaku Co., Ltd.), etc.

[0432] In addition, as free radical polymerizable monomers, commercially available products such as NPGPODA (neopentyl glycol propylene oxide adduct diacrylate), SR531, SR285, SR256 (all manufactured by Sartoma Corporation), A-DHP (dipentaerythritol hexaacrylate, Shin-Nakamura Chemical Industry Co., Ltd.), Aronix (registered trademark) M-156 (Toa Synthetic Co., Ltd.), V-CAP (BASF Corporation), and Viscoat#192 (Osaka Organic Chemical Industry Co., Ltd.) are preferred.

[0433] <Free radical polymerization initiators>

[0434] Specific particles may contain at least one of free radical polymerization initiators.

[0435] In this disclosure, a free radical polymerization initiator refers to a compound that absorbs light to generate free radicals.

[0436] The concept of free radical polymerization initiator as used in this disclosure does not include compounds that absorb light to generate free radicals and are equivalent to the aforementioned photoacid generators.

[0437] When a particular particle contains a free radical polymerizable monomer as a polymerizable monomer, it is preferable that the particular particle contains at least one of free radical polymerization initiators.

[0438] As a result, the abrasion resistance and adhesion of the formed film are further improved.

[0439] This can be attributed to the fact that the distance between the free radical polymerizable groups in the free radical polymerizable monomer and the free radical polymerization initiator increases, thereby increasing the curing sensitivity of the film (hereinafter also referred to as "sensitivity").

[0440] Furthermore, when specific particles contain free radical polymerization initiators, free radical polymerization initiators that were previously difficult to use due to their low dispersibility or solubility in water, despite their high sensitivity (e.g., free radical polymerization initiators with a solubility in water of 1.0% by mass or less at 25°C) can be used. This expands the range of free radical polymerization initiators that can be used, and consequently, the range of light sources that can be used. Therefore, the curing sensitivity can be improved compared to the past.

[0441] As for the free radical polymerization initiators mentioned above, which are difficult to use due to their high sensitivity but low dispersibility or solubility in water, carbonyl compounds and acylphosphine oxide compounds described later can be specifically cited, with acylphosphine oxide compounds being preferred.

[0442] In this way, by including specific particles in a substance with low solubility in water, the aqueous composition, namely the aqueous dispersion and ink of this disclosure, can contain such a substance.

[0443] Furthermore, compared to existing photocurable compositions, the aqueous dispersions containing free radical polymerization initiators in the specific particles exhibit superior ink storage stability. This can be attributed to the fact that the free radical polymerization initiator is contained within the specific particles, thereby inhibiting its aggregation or precipitation.

[0444] As a free radical polymerization initiator, for example, reference may be made to paragraphs 0091 to 0094 of International Publication No. 2016 / 052053.

[0445] As free radical polymerization initiators, more preferred are (a) carbonyl compounds such as aromatic ketones or (b) acylphosphine oxide compounds. Specifically, examples include: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (e.g., BASF's IRGACURE (registered trademark) 819), 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone (e.g., BASF's IRGACURE (registered trademark) 369), 2-methyl-1 -(4-methylthiophenyl)-2-morpholinopropane-1-one (e.g., BASF's IRGACURE (registered trademark) 907), 1-hydroxy-cyclohexyl-phenyl-one (e.g., BASF's IRGACURE (registered trademark) 184), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (e.g., DAROCUR (registered trademark) TPO, LUCIRIN (registered trademark) TPO (both manufactured by BASF)), etc.

[0446] From the perspective of improving sensitivity and adaptability to LED light, the preferred initiator for photopolymerization is (b) an acyl phosphine oxide compound, more preferably a monoacyl phosphine oxide compound (particularly preferably 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide) or a diacyl phosphine oxide compound (particularly preferably bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide).

[0447] The preferred wavelengths for LED light are 355nm, 365nm, 385nm, 395nm, or 405nm.

[0448] Specific particles containing free radical polymerization initiators can be manufactured, for example, by emulsifying a mixture comprising an oil phase component and an aqueous phase component containing polymer P (or a raw material compound used to manufacture polymer P), a free radical polymerizable monomer, and a photopolymerization initiator.

[0449] The content of the free radical polymerization initiator relative to the total solid content of the specific particles is preferably 0.1% to 15% by mass, more preferably 0.5% to 10% by mass, and even more preferably 1% to 6% by mass.

[0450] (Sensitizer)

[0451] Specific particles may contain at least one of the sensitizers.

[0452] When a particular particle contains at least one of photopolymerization initiators, the particular particle preferably contains at least one of sensitizers.

[0453] If specific particles contain sensitizers, they can further promote the decomposition of photopolymerization initiators caused by irradiation with active energy lines.

[0454] Sensitizers are substances that absorb specific active energy lines and become electronically excited. Once in this excited state, the sensitizer comes into contact with a photopolymerization initiator, resulting in electron transfer, energy transfer, and exothermic reactions. This promotes chemical changes in the photopolymerization initiator, such as decomposition, the formation of free radicals, and the generation of acids or bases.

[0455] Examples of sensitizers include: benzophenone, thioxanthones, isopropylthioxanthones, anthraquinones, 3-acylcoumarin derivatives, biphenyls, styryl ketones, 3-(aromatic acyl methylene)thiazoline, camphorquinone, eosin, rhodamine, erythrosine, etc.

[0456] In addition, as sensitizers, compounds represented by general formula (i) as described in Japanese Patent Application Publication No. 2010-24276 and compounds represented by general formula (I) as described in Japanese Patent Application Publication No. Hei 6-107718 may also be used appropriately.

[0457] Of the above, as a sensitizer, from the viewpoint of adaptability to LED light and reactivity with photopolymerization initiator, it is preferably selected from at least one of thioxanthone, isopropylthioxanthone, and benzophenone, more preferably from at least one of thioxanthone and isopropylthioxanthone, and even more preferably isopropylthioxanthone.

[0458] When a specific particle contains a sensitizer, it may contain only one sensitizer or two or more sensitizers.

[0459] When a particular particle contains a sensitizer, the content of the sensitizer relative to the solid content of the particular particle is preferably 0.1% to 20% by mass, more preferably 0.2% to 15% by mass, and even more preferably 0.3% to 10% by mass.

[0460] Specific particles containing photopolymerization initiators and sensitizers can be manufactured, for example, by emulsifying a mixture containing an oil phase component and an aqueous phase component, comprising polymer P (or a raw material compound used to manufacture polymer P), a free radical polymerizable monomer, a photopolymerization initiator, and a sensitizer.

[0461] (Other ingredients)

[0462] Specific particles may contain other components besides those mentioned above.

[0463] Other components include, for example, compounds comprising at least one selected from the group consisting of a polysiloxane bond (i.e., a divalent polysiloxane), a monovalent polysiloxane, a monovalent fluorinated hydrocarbon group, and a divalent fluorinated hydrocarbon group.

[0464] (Preparation method of aqueous dispersion of specific particles)

[0465] The ink disclosed herein can be manufactured by producing an aqueous dispersion containing the aforementioned specific particles and water, and by adding other components to the resulting aqueous dispersion as needed.

[0466] Furthermore, the ink disclosed herein is a form of aqueous dispersion of specific particles, and therefore, depending on the composition of the ink, it is also possible to manufacture the ink directly as an aqueous dispersion of specific particles (i.e., without adding other components).

[0467] There are no particular restrictions on the methods for producing aqueous dispersions of specific particles.

[0468] Methods A and B can be cited as methods for producing aqueous dispersions of specific particles.

[0469] -Preparation Method A-

[0470] Method A includes a process of obtaining an aqueous dispersion of specific particles by mixing an oil phase component containing an organic solvent, a polymer P, and a polymeric monomer with an aqueous phase component containing water and emulsifying the mixture.

[0471] Method A is suitable for manufacturing an aqueous dispersion containing specific particles of polymer P in the form of a chain polymer.

[0472] For manufacturing method A, please refer to publicly known documents such as Japanese Patent No. 6584677.

[0473] -Preparation Method B-

[0474] Method B includes a process of obtaining an aqueous dispersion of specific particles by mixing an oil phase component containing an organic solvent, a raw material compound containing a polymer P (e.g., a trifunctional or higher isocyanate compound, a compound having two or more active hydrogen groups, etc.) and a polymerizable monomer with an aqueous phase component containing water and emulsifying the mixture.

[0475] Method B is suitable as a method for manufacturing an aqueous dispersion containing specific particles (e.g., microcapsules) of polymer P in the form of a crosslinked polymer.

[0476] For method B, please refer to publicly available documents such as International Publication No. 2016 / 052053.

[0477] (pigment)

[0478] The ink disclosed herein may be an ink containing at least one colorant (so-called "colored ink") or an ink not containing colorant (so-called "transparent ink").

[0479] When the ink contains pigments, the pigments are preferably contained on the outside of the specific particles (i.e., the specific particles do not contain pigments).

[0480] As a colorant, there are no particular restrictions, and any known colorant such as pigments, water-soluble dyes, and disperse dyes can be selected. Among them, pigments are preferred from the perspective of excellent weather resistance and rich color reproduction.

[0481] There are no particular restrictions on pigments, and they can be selected appropriately according to the purpose. For example, well-known organic pigments and inorganic pigments can be cited. In addition, as pigments, resin particles dyed with dyes, commercially available pigment dispersions, and surface-treated pigments (e.g., substances obtained by dispersing pigments as a dispersion medium in water, liquid compounds, insoluble resins, etc., and substances after treating the surface of pigments with resins, pigment derivatives, etc.) can also be cited.

[0482] Examples of organic and inorganic pigments include: yellow pigments, red pigments, magenta pigments, blue pigments, cyan pigments, green pigments, orange pigments, purple pigments, brown pigments, black pigments, and white pigments.

[0483] When using pigments as colorants, pigment dispersants can be used as needed.

[0484] In addition, when using pigments as colorants, self-dispersible pigments with hydrophilic groups on the surface of pigment particles can be used as pigments.

[0485] Regarding pigments and pigment dispersants, please refer appropriately to paragraphs 0180 to 0200 of Japanese Patent Application Publication No. 2014-040529 and paragraphs 0122 to 0129 of International Publication No. 2016 / 052053.

[0486] When the ink disclosed herein contains pigment, the pigment content is preferably 0.1% to 20% by mass relative to the total amount of ink, more preferably 0.5% to 10% by mass, and particularly preferably 0.5% to 5% by mass.

[0487] (Other ingredients)

[0488] The ink disclosed herein may contain other components besides those described above, as needed.

[0489] Other components may or may not be contained in specific particles.

[0490] As a component that may or may not be contained in specific particles, the ink disclosed herein may contain surfactants, polymerization inhibitors, ultraviolet absorbers, etc.

[0491] In addition, the ink disclosed herein may contain water-soluble polymerizable monomers, water-soluble photopolymerization initiators, water-soluble resins, etc., on the outside of specific particles as needed.

[0492] For information on these components, see, for example, paragraphs 0134 to 0157 of International Publication No. 2016 / 052053.

[0493] (Preferred manufacturing method for ink)

[0494] There are no particular limitations on the method of manufacturing the ink disclosed herein, but a preferred method includes the following steps:

[0495] The process of manufacturing an aqueous dispersion of specific particles using the above-described method (method A or method B); and

[0496] The process of adding pigments, water-soluble organic solvents, and other components to an aqueous dispersion of specific particles and mixing them.

[0497] In addition, as another method of manufacturing the ink disclosed herein, an example is to directly manufacture the ink as a water dispersion of specific particles by using the above-described method for manufacturing water dispersions (method A or method B) to manufacture a water dispersion of specific particles (i.e., a method without adding other components to the water dispersion of specific particles).

[0498] (Optimal properties of ink)

[0499] The ink disclosed herein preferably has a viscosity of 3 mPa·s to 15 mPa·s, more preferably 3 mPa·s to 13 mPa·s, when the ink temperature is set to 25°C to 50°C. In particular, the ink disclosed herein preferably has a viscosity of 50 mPa·s or less when the ink temperature is set to 25°C. If the viscosity of the ink is within the above range, higher spraying stability can be achieved.

[0500] In addition, the viscosity of the ink is a value measured using a viscometer.

[0501] As a viscometer, for example, VISCOMETER TV-22 (Toki Sangyo Co., Ltd.) can be used.

[0502] [Inkjet recording method]

[0503] As an example of the inkjet recording method disclosed herein (hereinafter also referred to as "recording method X"), the following inkjet recording method can be cited:

[0504] include:

[0505] The process of applying the ink of the present disclosure onto a substrate by inkjet printing (hereinafter also referred to as the "application process"); and

[0506] The process of irradiating the ink applied to the substrate with active energy lines (hereinafter also referred to as the "irradiation process")

[0507] The time from the moment the ink falls onto the substrate to the start of irradiation by the active energy line is less than 1.00 seconds.

[0508] Recording method X may also include other procedures as needed.

[0509] Hereinafter, the operation of irradiating active energy lines is sometimes referred to as "exposure", and the time from the moment the ink falls onto the substrate to the start of irradiation of the active energy lines is sometimes referred to as "the time from ink falling to the start of exposure".

[0510] In recording method X, since the ink of this disclosure is used, the same effect as that obtained by the ink of this disclosure can be achieved.

[0511] In recording method X, a time of less than 1.00 seconds from ink application to the start of exposure contributes to improved image quality (e.g., suppressing image roughness).

[0512] In addition, generally speaking, when the time from ink application to the start of exposure is less than 1.00 seconds, the polymerizable monomer M in the ink applied to the substrate sometimes does not bleed sufficiently from specific particles, resulting in a decrease in the abrasion resistance of the image.

[0513] However, because the ink of this disclosure is used in recording method X, even though the time from ink application to the start of exposure is less than 1.00 second, the exudation of polymerizable monomer M from specific particles also occurs, ensuring the abrasion resistance of the image. In other words, as described in recording method X, the effects produced by the ink of this disclosure are particularly effective when the time from ink application to the start of exposure is short.

[0514] <Substrate>

[0515] There are no particular restrictions on the substrate used in recording method X; it can be a non-permeable substrate or a permeable substrate, but a non-permeable substrate is preferred.

[0516] Here, non-permeable substrates refer to substrates with a water absorption rate (in mass %, test time: 24 hours) of less than 10 in ASTM D570 of the ASTM test method.

[0517] The water absorption rate of the non-permeable substrate is preferably 5 or less.

[0518] Examples of non-permeable substrates include:

[0519] Paper laminated with plastics (e.g., polyethylene, polypropylene, polystyrene, etc.)

[0520] Metal sheets (e.g., aluminum, zinc, copper, etc.)

[0521] Plastic films (e.g., polyvinyl chloride (PVC) resin, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate (PET), polyethylene (PE), polystyrene (PS), polypropylene (PP), polycarbonate (PC), polyvinyl acetal, acrylic resin, etc.)

[0522] Paper laminated or vapor-deposited with the above-mentioned metals,

[0523] Plastic films laminated or deposited with the aforementioned metals,

[0524] Leather, etc.

[0525] Examples of leather include: natural leather (also known as "genuine leather") and synthetic leather (e.g., PVC (polyvinyl chloride) leather, PU (polyurethane) leather), etc. For further information on leather, see paragraphs 0163 to 0165 of Japanese Patent Application Publication No. 2009-058750.

[0526] For example, when forming a film on leather (e.g., vehicle seat cushions, bags, shoes, wallets, etc.) or plastic film as a non-permeable substrate, the formed film is required to have excellent abrasion resistance and adhesion.

[0527] In addition, when forming films on substrates other than leather and plastic films, the resulting film is sometimes required to have excellent abrasion resistance and adhesion.

[0528] The membrane formation method disclosed herein can meet such requirements.

[0529] From the perspective of increasing surface energy, the substrate can also be surface treated.

[0530] Examples of surface treatments include: corona treatment, plasma treatment, flame (frame) treatment, heat treatment, abrasion treatment, light irradiation treatment (UV treatment), flame treatment, etc., but are not limited to these treatments.

[0531] <Assignment Process>

[0532] The application process is a process of applying the ink disclosed herein to a substrate by inkjet printing.

[0533] (Ink application conditions, etc.)

[0534] Ink imparting via inkjet printing can be achieved by ejecting ink from the inkjet head of a known inkjet recording device.

[0535] As for inkjet heads, piezoelectric inkjet heads are preferred.

[0536] The preferred resolution of the inkjet head is 300 dpi or higher, more preferably 600 dpi or higher, and even more preferably 800 dpi or higher.

[0537] Here, dpi (dots per inch) represents the number of dots per 2.54 cm (1 inch).

[0538] The amount of ink ejected from the inkjet head (the amount of ink ejected per droplet) is preferably 1 pL (picoli) to 100 pL, more preferably 3 pL to 80 pL, and even more preferably 3 pL to 50 pL.

[0539] (Substrate temperature, etc.)

[0540] In the ink application process, the surface temperature of the substrate on the ink-attached side is preferably 20°C to 80°C, more preferably 25°C to 75°C, even more preferably 30°C to 70°C, and even more preferably 40°C to 70°C.

[0541] When the surface temperature of the substrate on the ink-attached side is between 20°C and 80°C, the image quality and abrasion resistance are further improved. This can be attributed to the easier achievement of the effect of monomer (M-1) leaching from specific particles.

[0542] (Heating of the substrate)

[0543] The recording method X preferably satisfies at least one of the following: a preheating process for heating the substrate before the application process; and heating of the substrate and application of ink during the application process.

[0544] As a result, the image quality and abrasion resistance are further improved. This can be attributed to the easier achievement of the effect of polymeric monomer M oozing from specific particles.

[0545] Furthermore, if the recording method X satisfies at least one of the above conditions, the surface temperature of the substrate can be easily adjusted to the preferred temperature described above.

[0546] In the various heating processes, including the preheating process and the heating in the imparting process, the heating device used to heat the substrate is not particularly limited, and examples include: heating drum, hot air, infrared lamp, infrared LED, infrared heater, hot oven, heating plate, infrared laser, infrared dryer, etc.

[0547] <Irradiation Process>

[0548] The irradiation process is the process of irradiating the ink applied to the substrate with active energy lines (in other words, the process of exposing the ink applied to the substrate).

[0549] By irradiation (i.e., exposure) by the active energy lines in this process, the polymerizable monomer M in the ink polymerizes, the ink cures, and an image is obtained. More specifically, as described above, after the ink adheres, the polymerizable monomer M effectively oozes out from the specific particles, thereby fully carrying out the curing between the specific particles (i.e., the bonding between the specific particles), resulting in an image with excellent image quality and abrasion resistance.

[0550] Examples of active energy lines include ultraviolet (UV) light, visible light, and electron beams, with UV light being the preferred choice.

[0551] Irradiation of the active energy lines of the ink applied to the substrate can be performed while the substrate and the ink applied to the substrate are heated.

[0552] The irradiation conditions and basic irradiation methods for active energy lines can be applied as disclosed in Japanese Patent Application Publication No. 60-132767.

[0553] In recording method X, as previously described, the time from the moment the ink falls to the start of irradiation by the active energy line is short (i.e., less than 1.00 seconds).

[0554] The ink application and irradiation of the active energy line in this method are preferably performed using an inkjet recording device having a unit comprising an inkjet head for irradiation of the active energy line and an active energy line source disposed near the inkjet head.

[0555] According to this unit, after ink is ejected from the inkjet head of the unit and falls onto the substrate, an active energy line can be irradiated from the active energy line source of the unit at a rapid timing of less than 1.00 seconds after the ink falls.

[0556] Examples of light sources used for irradiating active energy lines include mercury lamps, metal halide lamps, high-pressure mercury lamps, medium-pressure mercury lamps, low-pressure mercury lamps, ultraviolet fluorescent lamps, gas lasers, solid-state lasers, LEDs (light-emitting diodes), and LDs (laser diodes).

[0557] Among them, the light source used for irradiation of active energy lines is preferably a metal halide lamp, a high-pressure mercury lamp, a medium-pressure mercury lamp, a low-pressure mercury lamp, or an ultraviolet LED (hereinafter also referred to as UV-LED).

[0558] The peak wavelength of the ultraviolet light is preferably 200nm to 405nm, more preferably 220nm to 400nm, and even more preferably 340nm to 400nm.

[0559] The peak wavelength of the light (LED light) from the LED light source is preferably 200nm to 600nm, more preferably 300nm to 450nm, even more preferably 320nm to 420nm, even more preferably 340nm to 405nm, and even more preferably 355nm, 365nm, 385nm, 395nm or 405nm.

[0560] Examples of UV-LEDs include those manufactured by Nichia Chemical Co., Ltd., which have a main emission spectrum with wavelengths between 365 nm and 420 nm.

[0561] In addition, the UV-LED described in U.S. Patent No. 6,084,250, which emits active rays centered between 300 nm and 370 nm, can also be cited.

[0562] In addition, by combining several UV-LEDs, it is possible to irradiate ultraviolet light of different wavelength ranges.

[0563] The irradiation energy (i.e., exposure dose) of the active energy line is preferably 20 mJ / cm. 2 The above, more preferably 100 mJ / cm 2 The above is further optimized to 300 mJ / cm. 2 The above, especially preferred, is 500 mJ / cm. 2 The optimal value is 900 mJ / cm. 2 above.

[0564] There is no specific upper limit to the exposure level; the maximum can be 5 J / cm. 2 It can also be 1,500 mJ / cm 2 .

[0565] The optimal maximum illuminance of the LED on the substrate is 10mW / cm². 2 ~8,000mW / cm 2 More preferably 20mW / cm 2 ~5,000mW / cm 2 Further optimization of 30mW / cm 2 ~3000mW / cm 2 Further optimization of 50mW / cm 2 ~1000mW / cm 2 .

[0566] The irradiation time of the active energy line is preferably 0.01 seconds to 120 seconds, and more preferably 0.1 seconds to 90 seconds.

[0567] (Time from ink application to the start of exposure)

[0568] In recording method X, the time from ink application to the start of exposure (i.e., the time from the moment the ink applies to the substrate to the start of irradiation by the active energy line) is less than 1.00 seconds.

[0569] As mentioned earlier, a time of less than 1.00 seconds from ink application to the start of exposure helps improve image quality.

[0570] There is no particular limit to the lower limit of the time from ink application to the start of exposure. Examples of lower limits include 0.01 seconds, 0.05 seconds, and 0.10 seconds.

[0571] <Drying Process>

[0572] The recording method X preferably further includes a drying step of heating and drying the ink (i.e., the image) after irradiation with active energy lines.

[0573] As a result, the image's abrasion resistance is further improved, and image adhesion is further suppressed.

[0574] As a heating device for heating ink, it is not particularly limited and can be exemplified by, for example: heating drum, hot air, infrared lamp, infrared LED, infrared heater, hot oven, heating plate, infrared laser, infrared dryer, etc.

[0575] The heating temperature during the heating and drying process is preferably above 40°C, more preferably 40°C to 200°C, even more preferably 40°C to 100°C, even more preferably 40°C to 80°C, and even more preferably 45°C to 70°C.

[0576] Heating temperature refers to the temperature of the ink on the substrate, which can be measured using a temperature recorder equipped with an infrared thermal imaging device H2640 (manufactured by AVIONICS Co., Ltd., Japan).

[0577] The heating time can be appropriately set taking into account factors such as heating temperature, ink composition, and printing speed. The heating time is preferably 5 seconds or more, more preferably 5 seconds to 20 minutes, more preferably 10 seconds to 10 minutes, and even more preferably 20 seconds to 5 minutes.

[0578] [Example]

[0579] The present invention will be specifically described below through embodiments, but the present invention is not limited to the following embodiments.

[0580] Unless otherwise specified, "parts" refers to parts by weight.

[0581] Unless otherwise specified, "room temperature" means 25°C.

[0582] [Preparation of Polymer P]

[0583] As polymer P contained in specific particles, urethanes A to E and G to I, and acrylic acid F are prepared.

[0584] Details are shown below.

[0585] <Preparation of Carbamate A>

[0586] Add the following to the three-necked flask:

[0587] Dimethylolpropionic acid (DMPA) (7.8g)

[0588] Isoflurone diisocyanate (IPDI) (28.0g)

[0589] DURANOL T5652 (manufactured by Asahi Kasei Corporation, polycarbonate diol; hereinafter also referred to as T5652) (17.5g)

[0590] Bisphenol A epoxy diacrylate (21.2g)

[0591] Silaplane FM-DA11 (manufactured by JNC Corporation, a reactive organosilicon (a diol compound containing polysiloxane bonds); hereinafter also referred to as FM-DA11) (11.1g), and

[0592] Methyl ethyl ketone (55.0g) was heated to 70°C. 0.1g of NEOSTANN U-600 (manufactured by Nitto Kasei Corporation, an inorganic bismuth catalyst; hereinafter also referred to as U-600) was added, and the mixture was stirred at 70°C for 7 hours.

[0593] Next, isopropanol (IPA) (59.9 g) and methyl ethyl ketone (MEK) (84.7 g) as capping agents were added, and the mixture was stirred at 70°C for 7 hours. After stirring for 7 hours, the mixture was allowed to cool naturally to room temperature. Then, the concentration was adjusted with MEK to obtain a 30% by mass solution of carbamate A (solvent: a mixture of IPA and MEK).

[0594] Carbamate A has a weight-average molecular weight (Mw) of 30,000 and an acid value of 0.7 mmol / g. Carbamate A has an acryloyl group as a photopolymerizable group.

[0595] <Preparation of Carbamate B>

[0596] Add the following to the three-necked flask:

[0597] Dimethylolpropionic acid (DMPA) (10.7g)

[0598] Isoflurone diisocyanate (IPDI) (37.3g)

[0599] Polyethylene glycol (molecular weight 2000) (40.4g)

[0600] Bisphenol A epoxy diacrylate (29.0g), and

[0601] Methyl ethyl ketone (76.2 g) was heated to 70°C. 0.2 g of NEOSTANN U-600 was added, and the mixture was stirred at 70°C for 7 hours.

[0602] Next, isopropanol (IPA) (82.2 g) and methyl ethyl ketone (MEK) (115.5 g) were added as capping agents, and the mixture was stirred at 70°C for 7 hours. After stirring for 7 hours, the mixture was allowed to cool naturally to room temperature. Then, the concentration was adjusted with MEK to obtain a 30% by mass solution of carbamate B (solvent: a mixture of IPA and MEK).

[0603] Carbamate B has a weight-average molecular weight (Mw) of 30,000 and an acid value of 0.7 mmol / g. Carbamate B possesses an acryloyl group as a photopolymerizable group.

[0604] <Preparation of Carbamate C>

[0605] Add the following to the three-necked flask:

[0606] Dimethylolpropionic acid (DMPA) (7.2g)

[0607] Dicyclohexylmethane-4,4-diisocyanate (HMDI) (41.2g)

[0608] Tricyclodecanediethanol (11.0g)

[0609] Bisphenol A epoxy diacrylate (19.4g), and

[0610] Ethyl acetate (45.2 g) was heated to 70°C. 0.1 g of NEOSTANN U-600 was added, and the mixture was stirred at 70°C for 7 hours.

[0611] Next, isopropanol (IPA) (55.2 g) and ethyl acetate (76.3 g) as capping agents were added, and the mixture was stirred at 70°C for 7 hours. After stirring for 7 hours, the mixture was allowed to cool naturally to room temperature. Then, the concentration was adjusted with ethyl acetate to obtain a 30% by mass solution of carbamate C (solvent: a mixture of IPA and ethyl acetate).

[0612] The weight-average molecular weight (Mw) of urethane C is 30,000, and its acid value is 0.7 mmol / g. Urafrancite C possesses an acryloyl group as a photopolymerizable group.

[0613] <Preparation of Carbamate D>

[0614] Add the following to the three-necked flask:

[0615] Dimethylolpropionic acid (DMPA) (8.2g)

[0616] Isoflurone diisocyanate (IPDI) (24.5g)

[0617] Polypropylene glycol (molecular weight 2000) (38.7g)

[0618] Bisphenol A epoxy diacrylate (7.0g)

[0619] FM-DA11 (11.7g), and

[0620] Methyl ethyl ketone (58.1 g) was heated to 70°C. 0.1 g of NEOSTANN U-600 was added, and the mixture was stirred at 70°C for 7 hours.

[0621] Next, isopropanol (IPA) (63.1 g) and methyl ethyl ketone (MEK) (89.1 g) as capping agents were added, and the mixture was stirred at 70°C for 7 hours. After stirring for 7 hours, the mixture was allowed to cool naturally to room temperature. Then, the concentration was adjusted with MEK to obtain a 30% by mass solution of carbamate D (solvent: a mixture of IPA and MEK).

[0622] Carbamate D has a weight-average molecular weight (Mw) of 30,000 and an acid value of 0.7 mmol / g. Carbamate D has an acryloyl group as a photopolymerizable group.

[0623] <Preparation of Carbamate E>

[0624] Add the following to the three-necked flask:

[0625] Dimethylolpropionic acid (DMPA) (8.2g)

[0626] Isoflurone diisocyanate (IPDI) (24.5g)

[0627] PLACCEL 220N (manufactured by Cadena Rubin, polycaprolactone diol; also known as PCL220N) (38.7g)

[0628] Bisphenol A epoxy diacrylate (7.0g)

[0629] FM-DA11 (11.7g), and

[0630] Methyl ethyl ketone (58.1 g) was heated to 70°C. 0.1 g of NEOSTANN U-600 was added, and the mixture was stirred at 70°C for 7 hours.

[0631] Next, isopropanol (IPA) (63.1 g) and methyl ethyl ketone (MEK) (89.1 g) as capping agents were added, and the mixture was stirred at 70°C for 7 hours. After stirring for 7 hours, the mixture was allowed to cool naturally to room temperature. Then, the concentration was adjusted with MEK to obtain a 30% by mass solution of carbamate E (solvent: a mixture of IPA and MEK).

[0632] Carbamate E has a weight-average molecular weight (Mw) of 30,000 and an acid value of 0.7 mmol / g. Carbamate E has an acryloyl group as a photopolymerizable group.

[0633] <Preparation of Acrylic Acid F>

[0634] Ethyl acetate (64.9 g) was added to a three-necked flask and stirred at 70°C for 30 minutes under a nitrogen flow of 20 mL / min. Over a period of 4 hours, a mixed solution of methacrylic acid (MAA) (6.0 g), methyl methacrylate (60.0 g), n-butyl acrylate (34.0 g), V-65 (manufactured by Fujifilm and Koko Pure Chemicals Co., Ltd.) (5.4 g), ethyl acetate (10.8 g), and isopropanol (IPA) (32.5 g) was added dropwise while the mixture was cooled in an ice bath, followed by heating and stirring for 1 hour. Then, the mixture was heated to 80°C and stirred for 2 hours, allowed to cool naturally to room temperature, and the concentration was adjusted with ethyl acetate to obtain a 30% by mass solution of acrylic acid F (solvent: a mixture of IPA and ethyl acetate).

[0635] Acrylic acid F has a weight-average molecular weight (Mw) of 30,000 and an acid value of 0.7 mmol / g.

[0636] <Preparation of Carbamate G>

[0637] Add the following to the three-necked flask:

[0638] Dimethylolpropionic acid (DMPA) (7.5g)

[0639] Isoflurone diisocyanate (IPDI) (46.6g)

[0640] Tricyclodecanediethanol (21.2g)

[0641] Bisphenol A epoxy diacrylate (7.5g)

[0642] FM-DA11 (12.6g), and

[0643] Methyl ethyl ketone (64.5g) was heated to 70°C. 0.1g of NEOSTANN U-600 (manufactured by Nitto Kasei Corporation, an inorganic bismuth catalyst; hereinafter also referred to as U-600) was added, and the mixture was stirred at 70°C for 7 hours.

[0644] Next, isopropanol (IPA) (67.7 g) and methyl ethyl ketone (MEK) (95.5 g) as capping agents were added, and the mixture was stirred at 70°C for 7 hours. After stirring for 7 hours, the mixture was allowed to cool naturally to room temperature (25°C; the same below). Then, the concentration was adjusted with MEK to obtain a 30% by mass solution of carbamate G (solvent: a mixture of IPA and MEK).

[0645] Carbamate G has a weight-average molecular weight (Mw) of 30,000 and an acid value of 0.7 mmol / g. Carbamate G has an acryloyl group as a photopolymerizable group.

[0646] <Preparation of Carbamate H (Mw8000)>

[0647] Shorten the reaction time. Otherwise, prepare carbamate H (Mw8000) in the same manner as carbamate A (Mw30000).

[0648] <Preparation of Carbamate I (Mw70000)>

[0649] Extend the reaction time, and otherwise prepare carbamate I (Mw70000) in the same manner as carbamate A (Mw30000).

[0650] [Example 1]

[0651] <Preparation of Aqueous Dispersions of Specific Particles>

[0652] -Preparation of oil phase components-

[0653] A 30% (66.7 g) solution of carbamate A was prepared.

[0654] SR833S (20.0 g) as polymerizable monomer M

[0655] IRGACURE (registered trademark) 819 (1.5g) as a photopolymerization initiator, ITX (isopropylthioxanthone) (0.25g) as a sensitizer, and

[0656] Ethyl acetate (36.7 g) was mixed and stirred at room temperature for 30 minutes to obtain the oil phase.

[0657] SR833S is a difunctional free radical polymerizable monomer, specifically, tricyclodecanediethanol diacrylate (molecular weight 304).

[0658] IRGACURE (registered trademark) 819 is an acylphosphine oxide free radical polymerization initiator, specifically bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0659] -Preparation of aqueous phase components-

[0660] The aqueous phase is prepared by mixing distilled water (140g) and sodium hydroxide as a neutralizing agent and stirring for 15 minutes.

[0661] The amount of sodium hydroxide used as a neutralizing agent is adjusted to achieve a neutralization degree of 90% in the manufactured particles.

[0662] -Preparation of aqueous dispersions of specific particles-

[0663] The above oil phase components and the above aqueous phase components are mixed, and the resulting mixture is emulsified for 10 minutes at 12,000 rpm using a homogenizer at room temperature to obtain an emulsion.

[0664] The resulting emulsion was added to distilled water (60 g), the resulting liquid was heated to 50 °C and stirred at 50 °C for 5 hours, thereby removing ethyl acetate from the above liquid by distillation.

[0665] The liquid after distillation to remove ethyl acetate was diluted with distilled water to achieve a solid content of 20% by mass, thereby obtaining an aqueous dispersion of specific particles (specific particle content 20% by mass).

[0666] The volume-average dispersed particle size of a specific particle is 150 nm.

[0667] <Ink Preparation>

[0668] Prepare ink by mixing the following components.

[0669] -Composition of ink-

[0670] • Aqueous dispersion of the above-mentioned specific particles (specific particle content 20% by mass)

[0671] …52 copies

[0672] • Pigment dispersion (Pro-jet Cyan APD1000 (manufactured by FUJIFILM Imaging Colorants), pigment concentration 14% by mass)

[0673] …15 copies

[0674] Fluorinated surfactants (manufactured by DuPont, Capstone FS-31, 25% by mass solids)

[0675] …0.3 copies

[0676] Propylene glycol (PG)

[0677] …15 copies

[0678] ·water

[0679] …a total of 100 servings remain.

[0680] Table 2 shows the components of the above inks.

[0681] The ratio of the mass of water-soluble organic solvent Ws to the mass of polymerizable monomer M Wm is called the Ws / Wm ratio (hereinafter also referred to as "Ws / Wm").

[0682] The HSP distance ΔHSP(sm) between the water-soluble organic solvent and the polymerizable monomer M.

[0683] The ratio of the mass of water-soluble organic solvent Ws to the mass of polymer P Wp, Ws / Wp ratio (hereinafter also referred to as "Ws / Wp"), and

[0684] The HSP distance ΔHSP(sp) between polymer P and water-soluble organic solvent.

[0685] Furthermore, in each embodiment and comparative example, ΔHSP(sm) and ΔHSP(sp) were calculated using the δD, δP, and δH of each compound obtained by the aforementioned method.

[0686] Table 1 shows the δD, δP, and δH of each compound obtained by the aforementioned method.

[0687] [Table 1]

[0688]

[0689] <Image Recording>

[0690] Fill the ink cartridge included with the inkjet recording device (product name "DMP-2850", manufactured by Fujifilm) with the aforementioned ink, and record the image on the PVC (polyvinyl chloride) film as the substrate as follows.

[0691] The PVC film used as the substrate is "AVERY (registered trademark) 400GLOSS WHITE PERMANENT" manufactured by Avery Dennison.

[0692] The substrate is heated to bring the temperature of the side to which ink is applied (i.e., the side where the ink will land) to 50°C (preheating process). This preheating is performed using a pressure plate heater, which in the DMP-2850 is located upstream of the inkjet head in the substrate transport direction.

[0693] The ink is ejected from the inkjet head of the inkjet recording device onto a heated substrate (the ink application process). The ink ejection conditions are set to 900 dpi (dots per inch) and 1 dot = 10 pL. Ink application is performed while the substrate is kept heated, thereby causing the ink to land on the surface of the substrate, which is maintained at 50°C. The substrate heating is maintained using a pressure plate heater, which is located below the inkjet head in the DMP-2850 (i.e., the ink application area).

[0694] A 395nm LED lamp (product name "PEL UV CURE UNIT", manufactured by PRINTED ELECTRONICS) positioned near the inkjet head exposes the ink on the substrate to UV light (peak wavelength 395nm) (irradiation process). The UV light irradiation energy is set to 1000mJ / cm². 2 .

[0695] The time from ink application to exposure (i.e., the time from the moment the ink applies to the substrate to the start of UV light irradiation) was adjusted to 0.20 seconds (see Table 2).

[0696] Next, the exposed ink is heated and dried at 50°C for 180 seconds to obtain an image (drying process). The ink is dried by heating the substrate with the side opposite to the ink-applied side in contact with the heating plate.

[0697] <Evaluation>

[0698] The ink obtained above was used for the following evaluation.

[0699] The results are shown in Table 2.

[0700] (Ink storage stability)

[0701] Perform the following operation (hereinafter also referred to as the preservation test): Within 1 hour after the ink is prepared, place the sealed container containing the ink in a constant temperature room at 60°C, and leave the sealed container containing the ink in this state for two weeks.

[0702] The viscosity of the ink was measured before and after the storage test, and the rate of change of ink viscosity was calculated according to the following formula. The viscosity of the ink was measured using a VISCOMETER TV-22 (manufactured by TOKI SANGYO CO.LTD) at a temperature of 25°C.

[0703] Viscosity change rate = (Viscosity of ink after storage test) / (Viscosity of ink before storage test)

[0704] Based on the obtained viscosity change rate, the storage stability of the ink is evaluated according to the following evaluation criteria.

[0705] In the following evaluation criteria, the highest grade for ink preservation stability is "5".

[0706] -Evaluation criteria for preservation stability-

[0707] 5: Viscosity change rate is less than 1.1.

[0708] 4: The viscosity change rate is above 1.1 and below 1.2.

[0709] 3: The viscosity change rate is above 1.2 and below 1.3.

[0710] 2: The viscosity change rate is above 1.3 and below 2.

[0711] 1: The viscosity change rate is greater than 2.

[0712] <Image's abrasion resistance>

[0713] Following the image recording operation described above, a 10cm × 3cm rectangular solid image is recorded on the substrate (PVC film) at 100% recording capacity to obtain the recorded object.

[0714] The obtained recordings were placed in an environment of 25°C and 50% relative humidity for 24 hours. Using a vibratory friction tester, a load of 200g was applied to the image recording surface of the placed recordings, and they were rubbed 100 times with cotton cloth (fine cloth No. 3).

[0715] Visually inspect the image recording surface of the record after the above operations, and evaluate the abrasion resistance of the image according to the following evaluation criteria.

[0716] In the following evaluation criteria, the highest grade for the image's abrasion resistance is "5".

[0717] -Evaluation criteria for the abrasion resistance of images-

[0718] 5: The image does not contain any scratches.

[0719] 4: The image shows scratches, but the scratches do not reach the substrate.

[0720] 3: The image contains scratches, part of which extend to the substrate, but the area of ​​the substrate is larger than the area of ​​the original image (30cm²). 2 (0% and less than 5%).

[0721] 2: The image contains scratches, part of which extend to the substrate. The area of ​​the substrate is the same as the area of ​​the initial image (30cm²). 2 (5% or more but less than 50%)

[0722] 1. The image contains scratches, part of which extend to the substrate. The area of ​​the substrate is the same as the area of ​​the initial image (30cm²). 2 More than 50% of ).

[0723] (Image adhesion resistance)

[0724] Following the image recording procedure described above, a 5cm x 5cm square solid image is recorded on the substrate (PVC film) to obtain the recorded object.

[0725] A 6-size PVC film (hereinafter referred to as "PVC film 2") is placed on the image recording surface of the obtained record. A 300 g / cm² pressure is applied from above the PVC film 2 placed on the image recording surface. 2 The load, under this condition, is maintained at 40°C for 24 hours.

[0726] After 24 hours, the recording was separated from the PVC film 2, and the real-world image on the recording was visually observed. The image's resistance to adhesion was evaluated according to the following evaluation criteria.

[0727] In the following evaluation criteria, the highest level of image adhesion resistance, that is, the level in which image adhesion (i.e., the phenomenon of the object sticking to the image when it is stacked on top of the image) is most suppressed, is "5".

[0728] -Evaluation criteria for image adhesion resistance-

[0729] 5: No visual observation was made of image peeling or density reduction.

[0730] 4: A decrease in concentration was visually observed in at least a portion of the image, but no peeling of the image was visually observed.

[0731] 3: Visual observation revealed image peeling, but the peeled area exceeded the area of ​​the original image (25cm²). 2 (0% and less than 5%).

[0732] 2: Visually observe the peeling of the image; the peeled area is equal to the area of ​​the initial image recorded (25cm²). 2 (5% or more but less than 50%)

[0733] 1. Visually observe the peeling of the image; the peeled area is equal to the area of ​​the initial image recorded (25cm²). 2 More than 50% of ).

[0734] <Image Quality Evaluation>

[0735] Following the image recording operation described above, a 2cm × 2cm square solid image was recorded on the substrate (PVC film) at recording working states of 5%, 50%, 75%, and 100%, respectively, to obtain a recording object (i.e., a recording object having an image group consisting of four solid images).

[0736] The images on the recorded material were observed as a whole from distances of 20cm, 30cm, and 50cm. The image quality (coarseness) was evaluated according to the evaluation criteria shown below.

[0737] In the following evaluation criteria, the highest level of image quality (i.e., the level at which image graininess is most suppressed) is "5".

[0738] -Evaluation criteria for image quality-

[0739] 5: No roughness was observed in the image group as a whole in all observations from a distance of 20cm, 30cm, and 50cm.

[0740] 4: Roughness was visible in part of the image group when observed from a distance of 20cm, but no roughness was visible in the image group as a whole when observed from a distance of 30cm and 50cm.

[0741] 3: Roughness was visible in parts of the image group when observed from a distance of 20cm and 30cm, but no roughness was visible in the image group as a whole when observed from a distance of 50cm.

[0742] 2: In all observations from a distance of 20cm, 30cm, and 50cm, roughness was visible on a portion of the image set.

[0743] 1: In all observations from a distance of 20cm, 30cm, and 50cm, the image set as a whole showed roughness.

[0744] [Examples 2, 3, 6 and 7, and Comparative Example 1]

[0745] By adjusting the amount of polymeric monomer M added in the preparation of the aqueous dispersion of specific particles and the amount of aqueous dispersion of specific particles added in the preparation of ink, the content of polymeric monomer M relative to the total ink is changed as shown in Tables 2 and 3. Otherwise, the same operation as in Example 1 is performed.

[0746] The results are shown in Tables 2 and 3.

[0747] [Examples 4, 5, and 14, and Comparative Example 2]

[0748] By changing the amount of water-soluble organic solvent added in the ink preparation, the content of water-soluble organic solvent relative to the total ink is changed as shown in Tables 2 and 3. Otherwise, the same operation as in Example 1 is performed.

[0749] The results are shown in Tables 2 and 3.

[0750] [Examples 8-11, 15-18]

[0751] By changing the type of polymer P solution in the preparation of the aqueous dispersion of specific particles, the type of polymer P contained in the specific particles in the ink is changed as shown in Table 2. Otherwise, the same operation as in Example 1 is performed.

[0752] The results are shown in Table 2.

[0753] [Examples 12 and 13]

[0754] By adjusting the amount of polymer P (i.e., carbamate A) solution added in the preparation of the aqueous dispersion of specific particles and the amount of aqueous dispersion of specific particles added in the ink preparation, the content of polymer P (i.e., carbamate A) relative to the total ink was changed as shown in Table 2. Otherwise, the same operation as in Example 1 was performed.

[0755] The results are shown in Table 2.

[0756] [Examples 19-31 and 33, and Comparative Examples 3-7]

[0757] The water-soluble organic solvent and / or polymerizable monomer M are changed as shown in Tables 2 and 3, otherwise the same operation as in Example 1 is performed.

[0758] The results are shown in Tables 2 and 3.

[0759] [Example 32]

[0760] The time from ink application to exposure was changed as shown in Table 3, otherwise the same operation as in Example 1 was performed.

[0761] In Example 32, the exposure was performed without using a light source near the inkjet head, but instead using a conveyor-type LED exposure device located downstream of the inkjet head. The peak wavelength and irradiation energy of the UV light were set to be the same as in Example 1. The post-exposure heating and drying were also performed in the same manner as in Example 1.

[0762] The results are shown in Table 3.

[0763] [Table 2]

[0764]

[0765] [Table 3]

[0766]

[0767] -Explanation of Tables 2 and 3-

[0768] As components of the ink, only the water-soluble organic solvent, and the polymer P and polymeric monomer M in specific particles are shown, while other components of the ink are omitted.

[0769] The contents of the water-soluble organic solvent, polymer P, and polymeric monomer M are all relative to the total amount of ink.

[0770] The meanings of the abbreviations for water-soluble organic solvents are as follows.

[0771] PG: Propylene Glycol

[0772] ·1,2-BD: 1,2-Butanediol

[0773] MP Diol: 2-Methyl-1,3-propanediol

[0774] DEG: Diethylene glycol

[0775] • DPGmME: Dipropylene glycol monomethyl ether

[0776] ·EG: Ethylene glycol

[0777] The abbreviation for polymerizable monomer M has the following meaning.

[0778] SR833S: Tricyclodecanedimethylethanol diacrylate. Manufactured by Sartoma.

[0779] • GPO3A: The following trifunctional acrylate GPO3A (molecular weight 470).

[0780] SR295: Pentaerythritol tetraacrylate. Manufactured by Sartoma.

[0781] • A-400: Polyethylene glycol #400 diacrylate. Manufactured by Shin-Nakamura Industrial Co., Ltd.

[0782] • Viscoat#802: A mixture of tripentaerythritol acrylate, monopentaerythritol and dipentaerythritol acrylate, and polypentaerythritol acrylate. Molecular weight 805. Manufactured by Osaka Organic Chemical Industry Co., Ltd.

[0783] SR339: 2-Phenoxyethyl acrylate. Manufactured by Sartoma.

[0784] SR268: Tetraethylene glycol diacrylate. Manufactured by Sartoma.

[0785] FA-513A: Dicyclopentyl acrylate. Manufactured by Hitachi Chemical Co., Ltd.

[0786] SR238: 1,6-Hexanediol diacrylate. Manufactured by Sartoma.

[0787] [Chemical Formula 8]

[0788]

[0789] As shown in Tables 2 and 3, the following inks were used in each embodiment:

[0790] Contains water, water-soluble organic solvents, and particles containing polymer P and polymerizable monomer M.

[0791] The ratio of the mass of water-soluble organic solvent Ws to the mass of polymerizable monomer M Wm, Ws / Wm, is greater than 1.1.

[0792] The HSP distance ΔHSP(sm) between the water-soluble organic solvent and the polymerizable monomer M is 15.0 MPa. 1 / 2 ~25.0MPa 1 / 2 .

[0793] In these embodiments, the ink exhibits excellent preservation stability, and the image demonstrates excellent abrasion resistance. In these embodiments, the image also exhibits excellent anti-blocking properties and image quality.

[0794] Compared to the embodiments, in Comparative Examples 1, 2 and 7, where Ws / Wm is less than 1.1, the abrasion resistance of the images decreased.

[0795] When ΔHSP(sm) is below 15.0 MPa 1 / 2 In Comparative Examples 3-5, the storage stability of the ink decreased.

[0796] When ΔHSP(sm) exceeds 25.0 MPa 1 / 2 In Comparative Example 6, the abrasion resistance of the image decreased.

[0797] As can be seen from the results of Examples 1 to 3 and 6, when the Ws / Wm ratio is 2.0 or higher (Examples 1 to 3), the abrasion resistance of the image is further improved.

[0798] As can be seen from the results of Examples 1 to 3 and 7, when the Ws / Wm ratio is below 6.0 (Examples 1 to 3), the preservation stability of the ink is further improved.

[0799] The results of Examples 8 and 9 show that when ΔHSP(sp) is 8.0 MPa 1 / 2 Under the above conditions (Example 9), the preservation stability of the ink is further improved.

[0800] The results of Examples 10 and 11 show that when ΔHSP(sp) is 16.0 MPa 1 / 2 In the following cases (Example 10), the abrasion resistance of the image is further improved.

[0801] As can be seen from the results of Examples 1 to 5 and 12, when the ratio of the mass of water-soluble organic solvent Ws to the mass of polymer P Wp is 1.0 or higher (Examples 1 to 5), the abrasion resistance of the image is further improved.

[0802] The results of Examples 1-5, 13 and 14 show that when the Ws / Wp ratio is below 6.0 (Examples 1-5), the preservation stability of the ink is further improved.

[0803] As can be seen from the results of Examples 1 and 16, when the glass transition temperature Tg of polymer P is below 80°C (Example 1), the image quality is further improved.

[0804] As can be seen from the results of Examples 1 and 17, when the weight-average molecular weight of polymer P is above 10,000 (Example 1), the preservation stability of the ink is further improved.

[0805] As can be seen from the results of Examples 1 and 18, when the weight-average molecular weight of polymer P is below 50,000 (Example 1), the image's resistance to adhesion is further improved.

[0806] As can be seen from the results of Examples 19 to 22, when the polymerizable monomer M contains monomer (M-1) with a viscosity of 10 mPa·s to 150 mPa·s at 25°C, and the proportion of monomer (M-1) in the total amount of polymerizable monomer M is more than 50% by mass (Examples 20 and 21), the preservation stability of the ink and the abrasion resistance of the image are further improved.

[0807] As can be seen from the results of Examples 1, 29-31 and 33, when the proportion of solvents with a boiling point below 190°C (S-1) in the total amount of water-soluble organic solvents in the ink is more than 50% by mass (Examples 1 and 33), the image's resistance to sticking is further improved.

[0808] The entire disclosure of Japanese Patent Application No. 2020-163388, filed on September 29, 2020, is incorporated herein by reference.

[0809] All documents, patent applications and technical standards set forth in this specification are incorporated herein by reference to the same extent as each document, patent application and technical standard is specifically and separately described herein by reference.

Claims

1. An inkjet ink comprising water, a water-soluble organic solvent, and particles containing polymer P and polymerizable monomer M. When the mass content of the water-soluble organic solvent is defined as Ws and the mass content of the polymerizable monomer M is defined as Wm, the Ws / Wm ratio is 1.1 or higher. The HSP distance ΔHSP(sm) between the water-soluble organic solvent and the polymerizable monomer M is 15.0 MPa. 1 / 2 ~25.0MPa 1 / 2 , The polymer P is a chain polymer. The water-soluble organic solvent includes solvents with a boiling point below 190°C (S-1). The proportion of solvent (S-1) in the total amount of the water-soluble organic solvent is more than 60% by mass.

2. The inkjet ink according to claim 1, wherein, The Ws / Wm ratio is 2.0 to 6.

0.

3. The inkjet ink according to claim 1 or claim 2, wherein, The HSP distance ΔHSP(sp) between the water-soluble organic solvent and the polymer P is 8.0 MPa. 1 / 2 ~16.0MPa 1 / 2 .

4. The inkjet ink according to claim 1 or claim 2, wherein, When the mass content of the water-soluble organic solvent is defined as Ws and the mass content of the polymer P is defined as Wp, the Ws / Wp ratio is 1.0 to 6.

0.

5. The inkjet ink according to claim 1 or claim 2, wherein, The polymer P contains a bond U that is at least one of a carbamate bond and a urea bond.

6. The inkjet ink according to claim 1 or claim 2, wherein, The glass transition temperature of the polymer P is below 80°C.

7. The inkjet ink according to claim 1 or claim 2, wherein, The weight-average molecular weight of the polymer P is 10,000 to 50,000.

8. The inkjet ink according to claim 1 or claim 2, wherein, The polymerizable monomer M comprises monomer (M-1) with a viscosity of 10 mPa·s to 150 mPa·s at 25°C. The proportion of monomer (M-1) in the total amount of the polymerizable monomer M is more than 50% by mass.

9. An inkjet recording method, comprising: The process of applying inkjet ink as described in any one of claims 1 to 8 to a substrate by inkjet printing; as well as The process of irradiating the inkjet ink applied to the substrate with active energy lines. The time from the moment the inkjet ink lands on the substrate to the start of irradiation by the active energy line is less than 1.00 seconds.

Images