Image recording material, active energy ray curable ink, ink set, and method for producing an image recording material

Abstract

The present invention provides an image recording material, an active energy ray-curable ink, an ink set, and a method for manufacturing an image recording material. In the image recording material, a substrate and an image are provided. The image is a cured product of an ink containing scaly metal particles and a polymerizable compound. The scaly metal particles contain indium, and have an average equivalent circle diameter of 50 nm to 1000 nm. The ratio of the average equivalent circle diameter to the average thickness, i.e., the average aspect ratio, is 5 to 100. In a cross-section of the image, in a region within 100 nm from the surface of the image, the average angle formed by the longitudinal direction of the scaly metal particles and the surface of the substrate is 30° or less, and in a region more than 100 nm from the surface of the image, the average angle formed by the longitudinal direction of the scaly metal particles and the surface of the substrate exceeds 30°.

Description

Technical Field

[0001] The present invention relates to an image recording material, an active energy ray-curable ink, an ink set, and a method for manufacturing an image recording material. Background Art

[0002] In recent years, research has been conducted on a method for recording an image having a metallic luster using an active energy ray-curable ink containing a polymerizable compound and an image recording material manufactured by this method.

[0003] The image recording material is also referred to as a recording material, a printed matter, etc.

[0004] For example, Patent Document 1 discloses a method for manufacturing a printed matter capable of manufacturing a printed matter exhibiting excellent metallic luster.

[0005] The method for manufacturing a printed matter disclosed in Patent Document 1 includes:

[0006] A coating step of coating an ink composition containing an external stimulus film-forming resin that forms a film by an external stimulus composed of radiation or heat and metal flaky particles in the form of droplets on a substrate by an inkjet method;

[0007] A waiting step of allowing the above-mentioned flaky particles to approach the surface of the above-mentioned droplets and orient them substantially parallel to the surface by leaving a predetermined waiting time, and allowing the above-mentioned droplets to wet and spread; and

[0008] A film-forming step of forming a metallic luster layer exhibiting metallic luster by applying the above-mentioned external stimulus to the above-mentioned ink composition after the above-mentioned waiting step to form a film.

[0009] Moreover, Patent Document 2 discloses a method for manufacturing a printed matter capable of manufacturing a recording material in which a printed portion having a flashy feeling is set with high precision.

[0010] The method for manufacturing a printed matter disclosed in Patent Document 2 includes:

[0011] A first ink application step of applying a first ink containing a first polymerizable compound polymerized by irradiation with ultraviolet rays on a substrate by an inkjet method;

[0012] A first curing step of polymerizing / curing the above-mentioned first polymerizable compound by irradiation with ultraviolet rays to form a first layer;

[0013] A second ink application step of applying a second ink containing a second polymerizable compound polymerized by irradiation with ultraviolet rays and metal powder in an area where the above-mentioned first layer is formed by an inkjet method; and

[0014] In the second curing step, the second polymerizable compound is polymerized / cured by irradiation with ultraviolet light to form a second layer;

[0015] The injection amount of the first ink per unit area in the above region is 2.0 g / m 2 or more and 20.0 g / m 2 or less,

[0016] The time from the landing of the droplet of the first ink to the irradiation of the droplet with ultraviolet light is 0.0010 seconds or more and 1.0 second or less,

[0017] The injection amount of the second ink per unit area in the above region is 10% by volume or more and less than 80% by volume relative to the injection amount of the first ink,

[0018] The time from the landing of the droplet of the second ink to the irradiation of the droplet with ultraviolet light is 5.0 seconds or more and 60.0 seconds or less.

[0019] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-199061

[0020] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2015-89652 Summary of the Invention

[0021] Technical Problem to be Solved by the Invention

[0022] However, when recording an image with metallic luster using an active energy ray-curable ink containing a polymerizable compound, it is sometimes required to further improve the metallic luster of the image.

[0023] An object of the present invention is to provide an image recording material having an image as a cured product of an active energy ray-curable ink containing a polymerizable compound and having excellent metallic luster of the image, and an active energy ray-curable ink, an ink set, and a method for manufacturing an image recording material suitable for manufacturing the above image recording material.

[0024] Means for Solving the Technical Problem

[0025] Specific solutions for solving the above problems include the following methods.

[0026] <1> An image recording material having a substrate and an image disposed on the substrate,

[0027] The above image is a cured product of an active energy ray-curable ink containing scaly metal particles and a polymerizable compound,

[0028] The above-mentioned scaly metal particles contain indium, and have an average equivalent circle diameter of 50 nm to 1000 nm, and the ratio of the average equivalent circle diameter to the average thickness, i.e., the average aspect ratio, is 5 to 100.

[0029] In the cross-section of the above-mentioned image, in the region within 100 nm from the surface of the above-mentioned image, the average angle formed by the length direction of the above-mentioned scaly metal particles and the surface of the above-mentioned substrate is 30° or less, and in the region more than 100 nm from the surface of the above-mentioned image, the average angle formed by the length direction of the above-mentioned scaly metal particles and the surface of the above-mentioned substrate exceeds 30°.

[0030] <2> The image recording material according to <1>, wherein,

[0031] In the cross-section of the above-mentioned image, in the region within 100 nm from the surface of the above-mentioned image, the average angle formed by the length direction of the above-mentioned scaly metal particles and the surface of the above-mentioned substrate is 10° or less. <3> The image recording material according to <1> or <2>, wherein,

[0032] The above-mentioned scaly metal particles are exfoliation flakes of an indium-containing metal film.

[0033] <4> A radiation curable ink containing scaly metal particles and a polymerizable compound,

[0034] The above-mentioned scaly metal particles contain indium, and have an average equivalent circle diameter of 50 nm to 1000 nm, and the ratio of the average equivalent circle diameter to the average thickness, i.e., the average aspect ratio, is 5 to 100. <5> The radiation curable ink according to <4>, wherein,

[0035] The above-mentioned scaly metal particles are exfoliation flakes of an indium-containing metal film.

[0036] <6> The radiation curable ink according to <4> or <5>, wherein,

[0037] The above-mentioned polymerizable compound includes at least one of a monofunctional polymerizable compound and a bifunctional polymerizable compound,

[0038] The total proportion of the above-mentioned monofunctional polymerizable compound and the above-mentioned bifunctional polymerizable compound in the above-mentioned polymerizable compound is 50% by mass or more.

[0039] <7> The radiation curable ink according to any one of <4> to <6>, wherein,

[0040] The above-mentioned polymerizable compound includes a monofunctional polymerizable compound,

[0041] The proportion of the above-mentioned monofunctional polymerizable compound in the above-mentioned polymerizable compound is 90% by mass or more.

[0042] <8> The active energy ray-curable ink according to any one of <4> to <6>, wherein,

[0043] The above-mentioned polymerizable compound includes a polyfunctional polymerizable compound,

[0044] The proportion of the polyfunctional polymerizable compound in the above-mentioned polymerizable compound is 60% by mass or more.

[0045] <9> The active energy ray-curable ink according to any one of <4> to <8> further contains an organic solvent,

[0046] The content of the above-mentioned organic solvent is 1% by mass or more based on the total amount of the active energy ray-curable ink.

[0047] <10> The active energy ray-curable ink according to any one of <4> to <6>, wherein,

[0048] The above-mentioned polymerizable compound includes a polymerizable compound having a weight average molecular weight of 1000 or more,

[0049] The proportion of the polymerizable compound having a weight average molecular weight of 1000 or more in the above-mentioned polymerizable compound is 50% by mass or more.

[0050] <11> The active energy ray-curable ink according to <10> further contains an organic solvent,

[0051] The content of the above-mentioned organic solvent is 50% by mass or more based on the total amount of the active energy ray-curable ink.

[0052] <12> An ink set, comprising:

[0053] The active energy ray-curable ink according to any one of <4> to <11>; and

[0054] At least one of a primer liquid and a topcoat liquid,

[0055] The above-mentioned primer liquid does not contain scaly metal particles but contains a polymerizable compound. The polymerizable compound contained in the above-mentioned primer liquid includes at least one of a monofunctional polymerizable compound and a bifunctional polymerizable compound. The total proportion of the above-mentioned monofunctional polymerizable compound and the above-mentioned bifunctional polymerizable compound in the polymerizable compound contained in the above-mentioned primer liquid is 50% by mass or more,

[0056] The above-mentioned coating liquid does not contain scaly metal particles, but contains a polymerizable compound and an organic solvent. The proportion of the polymerizable compound with a weight-average molecular weight of 1000 or more in the polymerizable compounds contained in the above-mentioned coating liquid is 50% by mass or more, and the content of the organic solvent is 50% by mass or more relative to the total amount of the above-mentioned coating liquid.

[0057] <13>A method for manufacturing an image recording material, which uses the active energy ray-curable ink described in any one of <4> to <11>. The method for manufacturing the image recording material includes:

[0058] An ink application step of applying the above-mentioned active energy ray-curable ink onto a substrate; and

[0059] A curing step A of curing the above-mentioned active energy ray-curable ink applied onto the substrate by irradiation with active energy ray A to obtain an image,

[0060] The time from when the above-mentioned active energy ray-curable ink lands on the above-mentioned substrate to the start of irradiation of the above-mentioned active energy ray-curable ink with the above-mentioned active energy ray A is 0.5 seconds or more.

[0061] <14>The method for manufacturing an image recording material according to <13>, wherein,

[0062] The time from when the above-mentioned active energy ray-curable ink lands on the above-mentioned substrate to the start of irradiation of the above-mentioned active energy ray-curable ink with the above-mentioned active energy ray A is 1.0 second or more.

[0063] <15>The method for manufacturing an image recording material according to <13> or <14>, wherein,

[0064] The time from when the above-mentioned active energy ray-curable ink lands on the above-mentioned substrate to the start of irradiation of the above-mentioned active energy ray-curable ink with the above-mentioned active energy ray A is 5.0 seconds or less.

[0065] <16>The method for manufacturing an image recording material according to any one of <13> to <15>, wherein,

[0066] The irradiation of the above-mentioned active energy ray A is performed in an atmosphere with an oxygen concentration of 0.1% by volume or less. <17>The method for manufacturing an image recording material according to any one of <13> to <16>, wherein,

[0067] The content of the photoinitiator in the above-mentioned active energy ray-curable ink is less than 1% by mass relative to the total amount of the above-mentioned active energy ray-curable ink,

[0068] The above active energy ray A is an electron beam. <18> According to the method for manufacturing an image recording material according to any one of <13> to <17>, it further includes:

[0069] A semi-curing step, after the above ink application step and during the above curing step A, by irradiating an active energy ray P having an energy smaller than that of the above active energy ray A, the active energy ray-curable ink applied to the above substrate is semi-cured.

[0070] The above curing step A is a step of obtaining the above image by curing the above semi-cured active energy ray-curable ink by irradiation with the active energy ray A. <19> According to the method for manufacturing an image recording material according to any one of <13> to <18>, wherein

[0071] The above ink application step is a step of applying the active energy ray-curable ink to the above substrate by an inkjet method in a single-pass manner.

[0072] <20> According to the method for manufacturing an image recording material according to any one of <13> to <19>, it further includes:

[0073] A step of applying a primer solution to the above substrate before the above ink application step and semi-curing the applied primer solution to form a primer layer.

[0074] The above primer solution does not contain scaly metal particles but contains a polymerizable compound. The above polymerizable compound contained in the above primer solution includes at least one of a monofunctional polymerizable compound and a bifunctional polymerizable compound. The total proportion of the above monofunctional polymerizable compound and the above bifunctional polymerizable compound in the above polymerizable compound contained in the above primer solution is 50% by mass or more.

[0075] The above ink application step is a step of applying the active energy ray-curable ink to the above primer layer formed on the above substrate.

[0076] <21> According to the method for manufacturing an image recording material according to any one of <13> to <20>, it further includes:

[0077] A step of applying a topcoat solution to the above image after the above curing step A and curing the applied topcoat solution to form a topcoat layer.

[0078] The above topcoat solution does not contain scaly metal particles but contains a polymerizable compound and an organic solvent. The proportion of the polymerizable compound having a weight average molecular weight of 1000 or more in the above polymerizable compound contained in the above topcoat solution is 50% by mass or more. The content of the above organic solvent is 50% by mass or more relative to the total amount of the above topcoat solution.

[0079] Effect of the Invention

[0080] According to the present invention, there is provided an image recording material having an image which is a cured product of an energy ray-curable ink containing a polymerizable compound and having excellent metallic luster, and an energy ray-curable ink, an ink set, and a method for manufacturing an image recording material suitable for manufacturing the above image recording material. Detailed Description of the Invention

[0081] In the present invention, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value.

[0082] In the present invention, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, the amount of each component in the composition means the total amount of the above-mentioned plurality of substances present in the composition.

[0083] In the numerical ranges described stepwise in the present invention, the upper limit value or the lower limit value described within a certain numerical range can be replaced by the upper limit value or the lower limit value of other numerically described stepwise ranges, and can also be replaced by the values shown in the examples.

[0084] In the present invention, the term "step" includes not only independent steps, but also includes this term even when it cannot be clearly distinguished from other steps as long as the intended purpose of the step can be achieved.

[0085] In the present invention, a combination of preferred modes is a more preferred mode.

[0086] In the present invention, "light" is a concept including energy rays such as gamma rays, beta rays, electron beams, ultraviolet rays, and visible light.

[0087] In the present invention, ultraviolet rays are sometimes referred to as "UV (Ultra Violet) light".

[0088] In the present invention, "(meth)acrylate" is a concept including both acrylate and methacrylate, "(meth)acryloyl" is a concept including both acryloyl and methacryloyl, and "(meth)acrylic acid" is a concept including both acrylic acid and methacrylic acid.

[0089] In the present invention, "(poly)alkylene glycol" is a concept including alkylene glycol and polyalkylene glycol, "(poly)ethylene glycol" is a concept including ethylene glycol and polyethylene glycol, and "(poly)propylene glycol" is a concept including propylene glycol and polypropylene glycol.

[0090] 〔Image Recording Material〕

[0091] The image recording material of the present invention is an image recording material including a substrate and an image disposed on the substrate, wherein,

[0092] the above-mentioned image is a cured product of an active energy ray-curable ink containing flaky metal particles and a polymerizable compound,

[0093] the above-mentioned flaky metal particles contain indium, and have an average equivalent circle diameter of 50 nm to 1000 nm, and the ratio of the average equivalent circle diameter to the average thickness, i.e., the average aspect ratio, is 5 to 100,

[0094] In the cross-section of the above-mentioned image, in the region within 100 nm from the surface of the above-mentioned image, the average angle formed by the length direction of the above-mentioned flaky metal particles and the surface of the above-mentioned substrate is 30° or less, and in the region more than 100 nm from the surface of the above-mentioned image, the average angle formed by the length direction of the above-mentioned flaky metal particles and the surface of the above-mentioned substrate exceeds 30°.

[0095] As described above, when using an active energy ray-curable ink containing a polymerizable compound to record an image with metallic luster, it is sometimes required to further improve the metallic luster of the image.

[0096] Specifically, in the above case, and when the flaky metal particles in the ink are aluminum (Al) particles, the metallic luster of the image is sometimes insufficient.

[0097] Moreover, in the above case, and when the flaky metal particles in the ink are silver (Ag) particles, the Ag particles are easily affected by chemical reactions such as oxidation and sulfidation, and the metallic luster of the image (especially, the metallic luster over time) is sometimes insufficient.

[0098] Regarding these aspects, the image recording material of the present invention includes an image that is a cured product of an active energy ray-curable ink containing a polymerizable compound, and the metallic luster of the above-mentioned image is excellent.

[0099] Although the reason for achieving the above effect is not yet clear, it is considered that the following situations contribute to the above effect:

[0100] In the cross-section of the image, in the region within 100 nm from the surface of the image (hereinafter, also referred to as the "image surface layer portion"), the average angle formed by the length direction of the flaky metal particles and the surface of the substrate is 30° or less (in short, the flaky metal particles are oriented substantially parallel to the surface of the substrate); and

[0101] In the cross-section of the image, in a region more than 100 nm away from the surface of the image (hereinafter also referred to as "inside the image"), the average angle formed by the longitudinal direction of the scaly metal particles and the surface of the substrate exceeds 30° (in short, the scaly metal particles are randomly arranged without orientation).

[0102] In the image having the above structure, it is considered that light is reflected by the scaly metal particles whose orientation in the image surface layer portion is substantially parallel to the substrate, and the light transmission is suppressed by the randomly arranged scaly metal particles inside the image. It is considered that these effects in the image surface layer portion and inside the image interact with each other to obtain the metallic luster effect of the image.

[0103] In the present invention, the cross-section of the image refers to the cross-section in the thickness direction of the image (that is, the cutting surface when the image is cut along a plane perpendicular to the surface of the substrate).

[0104] In the present invention, the longitudinal direction of the scaly metal particles refers to the direction of the long side of the rectangle (that is, the minimum circumscribed rectangle) that encloses the outer shape of the scaly metal particles with the smallest area in the cross-section of the above image.

[0105] Moreover, the effect of improving the metallic luster of the image is excellent for indium (In)-containing scaly metal particles compared with Al- or Ag-containing scaly metal particles. It is considered that the reason is that, compared with Al- or Ag-containing scaly metal particles, the average angle formed by the longitudinal direction of the scaly metal particles and the surface of the substrate in the image surface layer portion is more likely to be oriented below 30° for In-containing scaly metal particles.

[0106] Hereinafter, each element in the image recording material of the present invention will be described.

[0107] <Substrate>

[0108] The image recording material of the present invention includes a substrate.

[0109] As the substrate, a permeable substrate such as paper or a non-permeable substrate can be used.

[0110] The image recording material of the present invention includes an image which is a cured product of an active energy ray-curable ink. Therefore, even when the substrate is a non-permeable substrate, it is easy to ensure the adhesion between the substrate and the image. Therefore, the image recording material of the present invention is particularly suitable as an image recording material having a non-permeable substrate as the substrate.

[0111] (Non-permeable substrate)

[0112] In the present invention, the non-permeable substrate refers to a substrate having a water absorption rate (mass%, 24 hours) lower than 0.2 according to ASTM D570 of the ASTM test method.

[0113] In the present invention, the permeable substrate refers to a substrate having a water absorption rate (mass%, 24 hours) of 0.2 or more in ASTM D570 of the ASTM test method.

[0114] Examples of the non-permeable substrate include glass, quartz, plastic film, and leather.

[0115] Examples of the resin constituting the plastic film include cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, acrylic resin, chlorinated polyolefin resin, polyethersulfone resin, polyethylene terephthalate (PET), polyethylene naphthalate, nylon, polyethylene, polystyrene (PS), polypropylene (PP), polycycloolefin resin, polyimide resin, polycarbonate (PC) resin, and polyvinyl acetal.

[0116] The plastic film may be a film containing only one of these resins or a film containing two or more of them.

[0117] Examples of the leather include natural leather (also referred to as "genuine leather") and synthetic leather (e.g., PVC (polyvinyl chloride) leather, PU (polyurethane) leather). Regarding the leather, for example, paragraphs 0163 to 0165 of Japanese Unexamined Patent Application Publication No. 2009-058750 can be referred to.

[0118] The thickness of the non-permeable substrate is not particularly limited, preferably 10 μm to 2000 μm, more preferably 20 μm to 1000 μm, further preferably 30 μm to 500 μm, and particularly preferably 30 μm to 400 μm.

[0119] (Permeable substrate)

[0120] In the present invention, the permeable substrate refers to a substrate having a water absorption rate (mass%, 24 hours) of 0.2 or more in ASTM D570 of the ASTM test method.

[0121] Examples of the permeable substrate include paper and cloth.

[0122] Examples of the paper include uncoated paper (e.g., fine paper, etc.), coated paper, paperboard, and the liner paper and cloth of corrugated paper. A coating may be provided on the paperboard.

[0123] As the permeable substrate, paperboard coated with coated paper and a coating is preferred. Since the penetration of the ink is slow in the paperboard coated with coated paper and a coating, the metallic luster of the recorded image is more likely to be strongly exhibited.

[0124] <Image>

[0125] The image recording material of the present invention has an image disposed on a substrate.

[0126] The image may be disposed on the substrate so as to be in contact with the substrate, or may be disposed via another layer (for example, a primer layer).

[0127] In the present invention, "image" refers to the entire film formed using ink, and "image recording" refers to the formation of an image (ie, film).

[0128] Furthermore, the concept of "image" in the present invention also includes a solid image.

[0129] The thickness of the image is preferably 0.2 μm to 50 μm, more preferably 0.5 μm to 30 μm, and even more preferably 1 μm to 10 μm.

[0130] (Cross-section of image)

[0131] In the present invention, the average angle formed by the length direction of the flaky metal particles in the surface part of the image in the cross section of the image (i.e., the area within 100 nm from the surface of the image) and the surface of the substrate, and the average angle formed by the length direction of the flaky metal particles in the image interior in the cross section of the image (i.e., the area more than 100 nm from the surface of the image) and the surface of the substrate are as described above, respectively.

[0132] The average angle between the length direction of the scaly metal particles in the surface layer of the image and the surface of the substrate in the cross section of the image is determined by observing the cross section of the image at a magnification of 50,000 times using a scanning electron microscope (SEM) (e.g., Nova200 FIB-SEM manufactured by Thermo Fisher Scientific KK).

[0133] Specifically, 100 flaky metal particles were selected from the SEM image, and the angle between the length direction of the flaky metal particle and the surface of the substrate was measured for each of the selected flaky metal particles.

[0134] Here, the angle formed between the longitudinal direction of the flaky metal particles and the surface of the substrate refers to an angle defined within a range of 0° to 90°.

[0135] The angle between the length direction of the flaky metal particles and the surface of the substrate was determined for 100 flaky metal particles, and the obtained results were simply averaged (number average) to determine the average angle between the length direction of the flaky metal particles and the surface of the substrate.

[0136] In the present invention, in addition to changing the observation position to the inside of the image, the average angle formed by the longitudinal direction of the scaly metal particles in the inner part of the cross-section of the image (i.e., the region more than 100 nm away from the surface of the image) and the surface of the substrate is obtained in the same manner as the average angle formed by the longitudinal direction of the scaly metal particles in the image surface layer part of the cross-section of the image and the surface of the substrate.

[0137] From the viewpoint of further improving the metallic luster of the image, the above-mentioned average angle in the image surface layer part is preferably 25° or less, more preferably 20° or less, further preferably 15° or less, and still further preferably 10° or less.

[0138] The lower limit of the above-mentioned average angle in the image surface layer part can be 0°.

[0139] From the viewpoint of further improving the metallic luster of the image, the above-mentioned average angle in the inner part of the image is preferably 35° or more, more preferably 40° or more, and further preferably 45° or more.

[0140] The above-mentioned average angle in the inner part of the image can be 90°.

[0141] (Composition of the image)

[0142] The image is a cured product of an active energy ray-curable ink containing scaly metal particles and a polymerizable compound.

[0143] The image is formed by irradiating an active energy ray-curable ink applied to a substrate with active energy rays and polymerizing the polymerizable compound in the active energy ray-curable ink. At this time, the morphology of the scaly metal particles remains unchanged and remains in the image.

[0144] Moreover, the polymerizable compound remains in the image in a state of being transformed into a resin (polymer) by polymerization.

[0145] The scaly metal particles contain indium, and have an average equivalent circle diameter of 50 nm to 1000 nm, and an average aspect ratio, which is the ratio of the average equivalent circle diameter to the average thickness, of 5 to 100.

[0146] The preferred mode of the scaly metal particles will be described in the item "active energy ray-curable ink" described later.

[0147] As described above, the image contains scaly metal particles and a resin derived from a polymerizable compound.

[0148] The image may contain other components as needed.

[0149] Regarding other components, reference can be appropriately made to the description in the item "active energy ray-curable ink" described later.

[0150] Active energy ray-curable ink

[0151] The active energy ray-curable ink of the present invention (hereinafter, also simply referred to as "the ink of the present invention") contains scaly metal particles and a polymerizable compound.

[0152] The scaly metal particles contain indium, and have an average equivalent circle diameter of 50 nm to 1000 nm, and an average aspect ratio, which is the ratio of the average equivalent circle diameter to the average thickness, of 5 to 100.

[0153] The ink of the present invention is suitable for manufacturing the image recording material of the present invention.

[0154] <Scaly metal particles>

[0155] The ink contains at least one kind of scaly metal particles.

[0156] The scaly metal particles contain indium (In).

[0157] The scaly metal particles may contain metal elements other than In.

[0158] The amount of In relative to the total amount of metal elements in the scaly metal particles is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 80% by mass or more.

[0159] The scaly metal particles may contain non-metal elements (for example, oxygen (O), nitrogen (N), carbon (C), etc.).

[0160] The amount of metal elements relative to the total amount of the scaly metal particles is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 80% by mass or more.

[0161] (Average equivalent circle diameter)

[0162] The average equivalent circle diameter of the scaly metal particles is 50 nm to 1000 nm.

[0163] By having an average equivalent circle diameter of 50 nm or more, the metallic luster of the image is improved.

[0164] By having an average equivalent circle diameter of 1000 nm or less, the stability of the ink for recording an image is improved. Therefore, when the ink is used as an inkjet ink, the ejectability of the ink from the inkjet head is improved.

[0165] The average equivalent circle diameter is preferably 100 nm to 800 nm, and more preferably 200 nm to 600 nm.

[0166] (Average aspect ratio)

[0167] The average aspect ratio, which is the ratio of the average equivalent circle diameter to the average thickness of the flaky metal particles, is 5 to 100.

[0168] When the average aspect ratio is 5 or more, the metallic luster of the image is improved.

[0169] When the average aspect ratio is 100 or less, the manufacturability (i.e., ease of manufacture) of the flaky metal particles is improved.

[0170] The average aspect ratio is preferably 5 to 50, more preferably 5 to 20.

[0171] In the present invention, the average equivalent circle diameter and the average thickness of the flaky metal particles respectively refer to the values measured as follows.

[0172] As a liquid sample, a flaky metal particle dispersion (flaky metal particle concentration: 20% by mass) containing flaky metal particles as a dispersed substance and propylene glycol monomethyl ether (PGME) as a dispersion medium is prepared.

[0173] The liquid sample is coated on a PET film to obtain a coating film.

[0174] The surface of the above coating film is observed by a scanning electron microscope (SEM) (for example, Nova200 type FIB-SEM manufactured by Thermo Fisher Scientific K.K. The same shall apply hereinafter). Fifty flaky metal particles are selected from the obtained SEM image, and the equivalent circle diameter of each flaky metal particle is measured. The arithmetic average of the equivalent circle diameters of the 50 flaky metal particles is obtained and taken as the average equivalent circle diameter of the flaky metal particles.

[0175] The cross-section of the above coating film is observed by SEM. Fifty flaky metal particles are selected from the obtained SEM image, and the thickness of each flaky metal particle is measured. The arithmetic average of the thicknesses of the 50 flaky metal particles is obtained and taken as the average thickness of the flaky metal particles.

[0176] (Average thickness)

[0177] The average thickness of the flaky metal particles is preferably 10 nm to 50 nm.

[0178] If the average thickness of the flaky metal particles is within the above range, the metallic luster of the image is further improved.

[0179] The average thickness of the flaky metal particles is more preferably 15 nm to 45 nm, and further preferably 20 nm to 40 nm.

[0180] The shape of the flaky metal particles is not particularly limited as long as it is flaky. Examples of the planar shape of the flaky metal particles include polygonal shapes, elliptical shapes, irregular shapes, etc.

[0181] The flaky metal particles are preferably peeling pieces of an indium-containing metal film.

[0182] The flaky metal particles of this method are preferably formed by forming an indium-containing metal film on a substrate and peeling the formed metal film from the substrate. Examples of the method for forming the indium-containing metal film include evaporation plating, sputtering, etc. Classification can be carried out as needed after peeling the metal film.

[0183] When preparing the ink, a dispersion of flaky metal particles can be used.

[0184] As the dispersion of flaky metal particles, commercially available products, concentrates of commercially available products, commercially available products with the solvent changed, commercially available products with at least a part of the dispersion medium changed to a polymerizable monomer, etc. can be used.

[0185] Examples of commercially available products of the dispersion of flaky metal particles include, for example, the dispersion of indium particles in the LEAFPOWDER (registered trademark) series manufactured by OIKE&Co.,Ltd. (for example, LEAF POWDER (registered trademark) 49CJ-1120).

[0186] The content of the flaky metal particles relative to the total solid content of the ink is preferably 0.5% by mass to 30% by mass, more preferably 1% by mass to 25% by mass.

[0187] In the present invention, the total solid content of the ink refers to the amount of all components except the solvent.

[0188] In the present invention, the preferred range of the content of a certain component relative to the total solid content of the ink is the same as the preferred range of the content of a certain component relative to the total amount of the image.

[0189] <Polymerizable compound>

[0190] The ink contains at least one polymerizable compound.

[0191] The polymerizable compound is a compound having a polymerizable group.

[0192] As the polymerizable group, a radical polymerizable group or a cationic polymerizable group is preferred, and a radical polymerizable group is more preferred.

[0193] The polymerizable compound may have only one kind of polymerizable group or may have two or more kinds.

[0194] As the polymerizable compound, a radically polymerizable compound (i.e., a compound having a radically polymerizable group) is preferred.

[0195] As the radically polymerizable group, an ethylenically unsaturated group is preferred, and at least one selected from the group consisting of (meth)acryloyl, allyl, styryl, and vinyl is more preferred, and (meth)acryloyl is further preferred.

[0196] Examples of the cationically polymerizable group include an epoxy group and an oxetanyl group.

[0197] The polymerizable compound may be a polymerizable monomer, may be a polymerizable polymer, or may be a composition of a polymerizable monomer and a polymerizable polymer.

[0198] Here, the polymerizable monomer refers to a polymerizable compound having a molecular weight of less than 1000, and the polymerizable polymer refers to a polymerizable compound having a weight average molecular weight (Mw) of 1000 or more. The concept of "polymerizable polymer" in the present invention also includes so-called oligomers.

[0199] The weight average molecular weight (Mw) of the polymerizable compound is preferably 30,000 or less, more preferably 20,000 or less, and further preferably 10,000 or less.

[0200] As the lower limit of Mw of the polymerizable compound, for example, 50, 60, 70, etc. can be cited.

[0201] In the present invention, the weight average molecular weight (Mw) refers to a value measured by gel permeation chromatography (GPC).

[0202] In the measurement based on gel permeation chromatography (GPC), as the measurement device, HLC (registered trademark)-8020GPC (TOSOH CORPORATION) is used. As the column, 3 TSKgel (registered trademark) Super Multipore HZ-H (4.6 mm ID × 15 cm, TOSOH CORPORATION) are used. As the eluent, THF (tetrahydrofuran) is used. And as the measurement conditions, the sample concentration is set to 0.45 mass%, the flow rate is set to 0.35 ml / min, the sample injection volume is set to 10 μL, and the measurement temperature is set to 40°C, and the measurement is performed using an RI detector.

[0203] The calibration curve is prepared based on 8 samples of "Standard sample TSK standard, polystyrene" of TOSOH CORPORATION: "F-40", "F-20", "F-4", "F-1", "A-5000", "A-2500", "A-1000", and "n-propylbenzene".

[0204] The polymerizable compound may be a monofunctional polymerizable compound or a polyfunctional polymerizable compound (i.e., a polymerizable compound having two or more functional groups).

[0205] Herein, a monofunctional polymerizable compound refers to a compound containing only one polymerizable group in one molecule, and a polyfunctional polymerizable compound refers to a compound containing two or more polymerizable groups in one molecule.

[0206] (Monofunctional polymerizable compound)

[0207] Examples of the monofunctional polymerizable compound include monofunctional (meth)acrylate, monofunctional (meth)acrylamide, monofunctional aromatic vinyl compound, monofunctional vinyl ether, and monofunctional N-vinyl compound.

[0208] As monofunctional (meth)acrylates, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, tert-octyl (meth)acrylate, isopentyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, octadecyl (meth)acrylate, isooctadecyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-n-butylcyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, borneol (meth)acrylate, isoborneol (meth)acrylate, 2-ethylhexyl diethylene glycol (meth)acrylate, butoxyethyl (meth)acrylate, 2-chloroethyl (meth)acrylate, 4-bromobutyl (meth)acrylate, cyanoethyl (meth)acrylate, benzyl (meth)acrylate, butoxymethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-(2-methoxyethoxy)ethyl (meth)acrylate, 2-(2-butoxyethoxy)ethyl (meth)acrylate, ethyl carbitol (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 1H,1H,2H,2H-perfluorodecyl (meth)acrylate, 4-butylphenyl (meth)acrylate, phenyl (meth)acrylate, 2,4,5-tetramethylphenyl ester, 4-chlorophenyl (meth)acrylate, 2-phenoxymethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, glycidyl (meth)acrylate, glycidyloxybutyl (meth)acrylate, glycidyloxyethyl (meth)acrylate, glycidyloxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, phenyl glycidyl ether (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, diethylaminopropyl (meth)acrylate, trimethoxysilylpropyl (meth)acrylate, trimethylsilylpropyl (meth)acrylate, poly(ethylene oxide) monomethyl ether (meth)acrylate, poly(ethylene oxide) (meth)acrylate, poly(ethylene oxide) monoalkyl ether (meth)acrylate, dipropylene glycol (meth)acrylate, poly(propylene oxide) monoalkyl ether (meth)acrylate, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyhexahydrophthalic acid, 2-formyloxyethyl-2-hydroxypropyl phthalate, butoxydiethylene glycol (meth)acrylate, trifluoroethyl (meth)acrylate, perfluorooctylethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, ethylene oxide (EO) modified phenol (meth)acrylate, EO modified cresol (meth)acrylate, EO modified nonylphenol (meth)acrylate, propylene oxide (PO) modified nonylphenol (meth)acrylate, EO modified 2-ethylhexyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentyl (meth)acrylate, (3-ethyl-3-oxetananylmethyl) (meth)acrylate, phenoxyethylene glycol (meth)acrylate, phenoxyethylene glycol (meth)acrylate, etc.,

[0209] As monofunctional (meth)acrylamide, for example, (meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-n-butyl (meth)acrylamide, N-tert-butyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, (meth)acryloylmorpholine, etc. can be cited.

[0210] As a monofunctional aromatic vinyl compound, for example, styrene, dimethylstyrene, trimethylstyrene, isopropylstyrene, chloromethylstyrene, methoxystyrene, acetoxystyrene, chlorostyrene, dichlorostyrene, bromostyrene, methyl vinyl benzoate, 3-methylstyrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene, 3-hexylstyrene, 4-hexylstyrene, 3-octylstyrene, 4-octylstyrene, 3-(2-ethylhexyl)styrene, 4-(2-ethylhexyl)styrene, allylstyrene, isopropenylstyrene, butenylstyrene, octenylstyrene, 4-tert-butoxycarbonylstyrene, and 4-tert-butoxystyrene can be mentioned.

[0211] As a monofunctional vinyl ether, for example, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, tert-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, 4-methylcyclohexylmethyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexylmethyl vinyl ether, diethylene glycol mono vinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, and phenoxypolyethylene glycol vinyl ether can be mentioned.

[0212] As a monofunctional N-vinyl compound, for example, N-vinylcaprolactam and N-vinylpyrrolidone can be mentioned.

[0213] The molecular weight of the monofunctional polymerizable compound is preferably 1000 or less, more preferably 500 or less, further preferably 300 or less, and still further preferably 210 or less.

[0214] As the lower limit of the molecular weight of the monofunctional polymerizable compound, for example, 50, 60, 70, etc. can be mentioned.

[0215] The monofunctional polymerizable compound preferably contains at least one of a monofunctional (meth)acrylate and a monofunctional N-vinyl compound.

[0216] (Polyfunctional polymerizable compound)

[0217] The polyfunctional polymerizable compound is a polymerizable compound having 2 or more functional groups.

[0218] -Bifunctional polymerizable compound-

[0219] Examples of the bifunctional polymerizable compound include bifunctional (meth)acrylate, bifunctional vinyl ether, and bifunctional polymerizable compounds containing a vinyl ether group and a (meth)acryloyl group.

[0220] Examples of the bifunctional (meth)acrylate include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butanediol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, hexanediol di(meth)acrylate, heptanediol di(meth)acrylate, EO-modified neopentyl glycol di(meth)acrylate, PO-modified neopentyl glycol di(meth)acrylate, EO-modified hexanediol di(meth)acrylate, PO-modified hexanediol di(meth)acrylate, octanediol di(meth)acrylate, nonanediol di(meth)acrylate, decanediol di(meth)acrylate, dodecanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, glycerol di(meth)acrylate, pentaerythritol di(meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, etc.

[0221] Examples of the bifunctional vinyl ether include 1,4-butanediol divinyl ether, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether, etc.

[0222] Examples of the bifunctional polymerizable compound containing a vinyl ether group and a (meth)acryloyl group include 2-(2-vinyloxyethoxy)ethyl (meth)acrylate.

[0223] -Polymerizable compounds with three or more functional groups-

[0224] Examples of the polymerizable compounds with three or more functional groups include (meth)acrylates with three or more functional groups and vinyl ethers with three or more functional groups.

[0225] As a (meth)acrylate having three or more functional groups, for example, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tri(meth)acryloyloxyethoxytrimethylolpropane, glycerol polyglycidyl ether poly(meth)acrylate, tetrakis(2-acryloyloxyethyl) isocyanurate, etc. can be cited.

[0226] As a vinyl ether having three or more functional groups, for example, trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerol trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexavinyl ether, EO-modified trimethylolpropane trivinyl ether, PO-modified trimethylolpropane trivinyl ether, EO-modified ditrimethylolpropane tetravinyl ether, PO-modified ditrimethylolpropane tetravinyl ether, EO-modified pentaerythritol tetravinyl ether, PO-modified pentaerythritol tetravinyl ether, EO-modified dipentaerythritol hexavinyl ether, PO-modified dipentaerythritol hexavinyl ether, etc. can be cited.

[0227] (urethane (meth)acrylate)

[0228] As a polyfunctional polymerizable compound, urethane (meth)acrylate can also be cited.

[0229] As urethane (meth)acrylate, a compound containing two or three (meth)acryloyl groups and at least one urethane bond is preferred.

[0230] As such urethane (meth)acrylate, the reaction product of a bifunctional isocyanate compound and a hydroxy group-containing (meth)acrylate (optionally with other active hydrogen group-containing compounds), namely urethane (meth)acrylate, can be cited.

[0231] As a bifunctional isocyanate compound, for example, the following can be cited:

[0232] Aliphatic diisocyanates such as methylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dipropyl ether diisocyanate, 2,2-dimethylpentane diisocyanate, 3-methoxyhexane diisocyanate, octamethylene diisocyanate, 2,2,4-trimethylpentane diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, 3-butoxyhexane diisocyanate, 1,4-butanediol dipropyl ether diisocyanate, thiodihexyl diisocyanate, etc.;

[0233] Aromatic diisocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, xylene diisocyanate, ethylbenzene diisocyanate, isopropylbenzene diisocyanate, tolidine diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 2,7-naphthalene diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, tetramethylxylylene diisocyanate, etc.;

[0234] Alicyclic diisocyanates such as hydrogenated xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, etc.; etc.

[0235] As the hydroxy group-containing (meth)acrylate, for example, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenyl glycidyl ether (meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, etc. can be cited.

[0236] As commercially available products of urethane (meth)acrylate, the following can be cited:

[0237] CN996 of Sartomer Company, Inc. (2-functional urethane acrylate, weight average molecular weight (Mw) = 2850),

[0238] UA-122P of SHIN-NAKAMURA CHEMICAL Co., Ltd. (2-functional urethane acrylate, Mw = 1100),

[0239] Shikoh (registered trademark) UV-6630B of Nippon Synthetic Chemical Industry Co., Ltd. (2-functional urethane acrylate, Mw = 3000),

[0240] Shikoh (registered trademark) UV-3310B (a bifunctional urethane acrylate, Mw = 5000), and

[0241] Shikoh (registered trademark) UV-7630B (a hexafunctional urethane acrylate, Mw = 2200), etc.

[0242] (Silicone compound having an ethylenically unsaturated group)

[0243] As the polyfunctional polymerizable compound, a silicone compound having an ethylenically unsaturated group can also be cited.

[0244] As the silicone compound having an ethylenically unsaturated group, silicone polyether acrylate is preferred, polyfunctional silicone polyether acrylate is more preferred, and 5- to 6-functional silicone polyether acrylate is further preferred.

[0245] (Epoxy (meth)acrylate)

[0246] As the above-mentioned bifunctional polymerizable compound and polymerizable compounds having 3 or more functional groups, epoxy (meth)acrylate can also be cited.

[0247] Here, epoxy (meth)acrylate refers to a reaction product obtained by reacting two or three epoxy groups in an epoxide containing two or three epoxy groups with the carboxyl group in (meth)acrylic acid.

[0248] Therefore, the structure of epoxy (meth)acrylate does not contain an epoxy group. In this regard, epoxy (meth)acrylate is different from the aforementioned epoxide which is an example of a cationic polymerizable monomer.

[0249] As epoxy (meth)acrylate, a reaction product of (meth)acrylic acid and an epoxy resin can be cited.

[0250] As the epoxy resin, for example, bisphenol A type epoxy resin, cresol novolac type epoxy resin, etc. can be cited.

[0251] The polymerizable compound contained in the ink preferably contains at least one of a monofunctional polymerizable compound and a bifunctional polymerizable compound.

[0252] At this time, the total proportion of the monofunctional polymerizable compound and the bifunctional polymerizable compound in the polymerizable compound contained in the ink is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 80% by mass or more.

[0253] Moreover, the total content of the monofunctional polymerizable compound and the bifunctional polymerizable compound is preferably 10% by mass or more with respect to the total amount of the ink.

[0254] The content of the polymerizable compound in the ink depends on the type of the polymerizable compound contained in the ink, and is preferably 10% by mass or more, more preferably 20% by mass or more, relative to the total amount of the ink.

[0255] The content of the polymerizable compound in the ink depends on the type of the polymerizable compound contained in the ink, and is preferably 40% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, relative to the total solid content amount of the ink (i.e., the total amount excluding the solvent).

[0256] <Organic solvent>

[0257] The ink of the present invention preferably contains at least one organic solvent.

[0258] The content of the organic solvent is preferably 1% by mass or more relative to the total amount of the ink.

[0259] When the content of the organic solvent is 1% by mass or more, the metallic luster of the image is further improved. Although the reason is not yet clear, it is considered that the scaly metal particles contribute to segregation on and / or near the surface of the image.

[0260] The upper limit of the content of the organic solvent relative to the total amount of the ink is, for example, 90% by mass or less.

[0261] As the organic solvent, known organic solvents that can be used in inks can be used. As known organic solvents, for example, the organic solvents described in the New Edition Solvent Pocket Book (edited by The Society of Synthetic Organic Chemistry, published in 1994) etc. can be cited.

[0262] As the organic solvent, for example, the following can be cited:

[0263] (Poly)alkylene glycol monoalkyl ethers such as ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, propylene glycol monomethyl ether (PGME), dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether;

[0264] (Poly)alkylene glycol dialkyl ethers such as ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol diethyl ether, tetraethylene glycol dimethyl ether;

[0265] (Poly)alkylene glycol acetates such as diethylene glycol acetate;

[0266] (Poly)alkylene glycol diacetates such as ethylene glycol diacetate, propylene glycol diacetate;

[0267] (Poly)alkylene glycol monoalkyl ether acetates such as ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, and ketones such as methyl ethyl ketone, cyclohexanone;

[0268] Lactones such as γ-butyrolactone;

[0269] Esters such as ethyl acetate, propyl acetate, butyl acetate, 3-methoxybutyl acetate (MBA), methyl propionate, and ethyl propionate;

[0270] Cyclic ethers such as tetrahydrofuran and dioxane;

[0271] Amides such as dimethylformamide and dimethylacetamide; etc.

[0272] Moreover, as the above-mentioned (poly)alkylene glycol, (poly)ethylene glycol and / or (poly)propylene glycol are preferable.

[0273] When the proportion of the polymerizable compound having a weight average molecular weight of 1000 or more in the polymerizable compounds in the ink is 50% by mass or more, the content of the organic solvent is preferably 50% by mass or more with respect to the total amount of the ink (refer to the third mode described later). Thereby, the ejection property of the ink from the inkjet head (hereinafter, also simply referred to as "the ejection property of the ink") is further improved.

[0274] At this time, the content of the organic solvent is more preferably 60% by mass or more, and further preferably 70% by mass or more with respect to the total amount of the ink.

[0275] <Photopolymerization initiator>

[0276] From the viewpoint of improving the sensitivity to ultraviolet rays, the ink of the present invention preferably contains at least one photopolymerization initiator.

[0277] As the photopolymerization initiator, a radical polymerization initiator that generates radicals by light irradiation is preferable.

[0278] Examples of the radical polymerization initiator include (a) alkylbenzophenone compounds, (b) acylphosphine oxide compounds, (c) aromatic onium salt compounds, (d) organic peroxides, (e) sulfur compounds (for example, thioxanthone compounds such as isopropylthioxanthone), (f) hexaarylbiimidazole compounds, (g) ketoxime ester compounds, (h) borate compounds, (i) azine onium compounds, (j) metallocene compounds, (k) active ester compounds, (l) compounds having a carbon-halogen bond, and (m) alkylamine compounds.

[0279] The photopolymerization initiator contained in the ink preferably includes an acylphosphine oxide compound.

[0280] Examples of the acylphosphine oxide compound include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,6-dimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2-methoxyphenylphosphine oxide, bis(2,6-dimethylbenzoyl)-2-methoxyphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-dimethoxyphenylphosphine oxide, bis(2,6-dimethylbenzoyl)-2,4-dimethoxyphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-dipentyloxyphenylphosphine oxide, bis(2,6-dimethylbenzoyl)-2,4-dipentyloxyphenylphosphine oxide, 2,4,6-trimethylbenzoyl ethoxyphenylphosphine oxide, 2,6-dimethylbenzoyl ethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyl methoxyphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphenylphosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2,6-dimethylbenzoyl methoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyl(4-pentyloxyphenyl)phenylphosphine oxide, 2,6-dimethylbenzoyl(4-pentyloxyphenyl)phenylphosphine oxide, and the like.

[0281] Among them, as the acylphosphine oxide compound, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyl diphenylphosphine oxide are preferred, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide is more preferred.

[0282] The radical polymerization initiator can be a low molecular weight photopolymerization initiator with a molecular weight less than 500, or a high molecular weight photopolymerization initiator with a molecular weight of 500 or more.

[0283] The molecular weight of the high molecular weight radical polymerization initiator is preferably 500 to 3000, more preferably 700 to 2500, and further preferably 900 to 2100.

[0284] Regarding the high molecular weight radical polymerization initiator, publicly known documents such as Japanese Patent Application Laid-Open No. 2017-105902 (paragraph 0038, etc.) and Japanese Patent Application Laid-Open No. 2017-522364 (paragraphs 0017 to 0053) can be referred to.

[0285] Examples of commercially available products of the radical polymerization initiator include:

[0286] Commercially available products of low molecular weight radical polymerization initiators, such as Omnirad TPO H, Omnirad 819, Omnirad 369, Omnirad 907, Omnirad 2959 (manufactured by IGM Resins B.V.);

[0287] Commercially available products of polymer radical polymerization initiators, such as Omnipole 910, Omnipole TX, Omnipole 9210 (manufactured by IGM Resins B.V.), Speedcure 7005, Speedcure 7010, Speedcure 7010L, Speedcure 7040 (manufactured by Lambson Limited); etc.

[0288] The ink of the present invention may contain two or more photoinitiators that absorb different wavelengths of light.

[0289] For example, in the manufacturing method of the image recording material described later, namely production method X, when pinning exposure (semi-curing) based on actinic ray P (for example, long-wavelength ultraviolet light) and curing exposure (formal curing) based on actinic ray A are successively performed, the ink may contain photoinitiator P that easily absorbs actinic ray P and photoinitiator A that easily absorbs actinic ray A. According to this method, the metallic luster and clarity of the image can be further improved.

[0290] The content of the photoinitiator is preferably 1% by mass to 20% by mass, more preferably 2% by mass to 15% by mass, further preferably 3% by mass to 10% by mass, and still further preferably 3% by mass to 8% by mass relative to the total amount of the ink.

[0291] When the content of the photoinitiator is 1% by mass to 20% by mass, the abrasion resistance of the image is further improved.

[0292] On the other hand, when the ink of the present invention is an ink cured by an electron beam as an actinic ray, the content of the photoinitiator relative to the total amount of the ink may be less than 1% by mass.

[0293] Here, the content of the photoinitiator being less than 1% by mass relative to the total amount of the ink means that the ink does not contain a photoinitiator, or even if it contains one, the content of the photoinitiator is less than 1% by mass relative to the total amount of the ink.

[0294] <Surfactant>

[0295] The ink may contain at least one surfactant.

[0296] Examples of the surfactant include those described in JP-A-62-173463 and JP-A-62-183457. Further examples of the surfactant include anionic surfactants such as dialkyl sulfosuccinates, alkylnaphthalenesulfonates, and fatty acid salts; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylenic diols, and polyoxyethylene / polyoxypropylene block copolymers; and cationic surfactants such as alkylamine salts and quaternary ammonium salts. The surfactant may be a fluorosurfactant or a silicone surfactant.

[0297] As the surfactant, a silicone surfactant (excluding the above-described silicone compound having an ethylenically unsaturated group) is preferred.

[0298] Examples of the silicone surfactant include polysiloxane compounds, and modified polysiloxane compounds in which an organic group is introduced into a part of the methyl groups of dimethylpolysiloxane are preferred. Examples of the modification include polyether modification, methylstyrene modification, alcohol modification, alkyl modification, aralkyl modification, fatty acid ester modification, epoxy modification, amine modification, amino modification, and mercapto modification. A plurality of organic groups may be introduced into a part of the methyl groups of dimethylpolysiloxane.

[0299] Among them, from the viewpoint of ejection stability, the silicone surfactant is preferably a polyether-modified polysiloxane compound.

[0300] Examples of the polyether-modified polysiloxane compound include SILWET L-7604, SILWET L-7607N, SILWET FZ-2104, and SILWET FZ-2161 (manufactured by Momentive Performance Materials Japan LLC.); BYK306, BYK307, BYK331, BYK333, BYK347, and BYK348 (manufactured by BYK-Chemie GmbH); and KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, and KF-6017 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0301] When the ink contains a surfactant, the content of the surfactant is preferably 0.001% by mass to 4.0% by mass, more preferably 0.01% by mass to 3.0% by mass, and still more preferably 0.05% by mass to 2.0% by mass, based on the total amount of the ink.

[0302] <Inhibitor>

[0303] The ink may contain at least one inhibitor.

[0304] Examples of the inhibitor include p-methoxyphenol, quinones (e.g., hydroquinone, benzoquinone, methoxybenzoquinone, etc.), phenothiazine, catechol derivatives, alkylphenols (e.g., dibutylhydroxytoluene (BHT), etc.), alkylbisphenols, zinc dimethyldithiocarbamate, copper dimethyldithiocarbamate, copper dibutyldithiocarbamate, copper salicylate, thiodipropionate esters, mercaptobenzimidazole, phosphite esters, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (TEMPOL), aluminum tris(N-nitroso-N-phenylhydroxylamine) (also known as: cupferron Al), etc.

[0305] Among these, at least one selected from p-methoxyphenol, catechol derivatives, quinones, alkylphenols, TEMPO, TEMPOL, and aluminum tris(N-nitroso-N-phenylhydroxylamine) is preferred, and at least one selected from p-methoxyphenol, hydroquinone, benzoquinone, BHT, TEMPO, TEMPOL, and aluminum tris(N-nitroso-N-phenylhydroxylamine) is more preferred.

[0306] When the ink contains an inhibitor, the content of the inhibitor is preferably 0.01% by mass to 2.0% by mass, more preferably 0.02% by mass to 1.0% by mass, and further preferably 0.03% by mass to 0.5% by mass, relative to the total amount of the ink.

[0307] <Resin>

[0308] The ink may contain at least one resin.

[0309] Examples of the resin include acrylic resins, urethane resins, polyester resins, polyolefin resins, amide resins, cellulose resins, etc.

[0310] As the resin, an acrylic resin is preferred.

[0311] The weight-average molecular weight of the resin is preferably 5,000 to 100,000, more preferably 10,000 to 100,000, and further preferably 20,000 to 80,000.

[0312] The weight-average molecular weight of the resin is measured by GPC. The measurement conditions of GPC are as described above.

[0313] When the ink contains a resin, the content of the resin is 1% by mass to 25% by mass, more preferably 3% by mass to 20% by mass, and further preferably 5% by mass to 15% by mass, relative to the total amount of the ink.

[0314] <Dispersant>

[0315] The ink may contain at least one dispersant.

[0316] As the dispersant, a polymer dispersant is preferred.

[0317] Herein, the "polymer dispersant" refers to a dispersant having a weight average molecular weight (Mw) of 1000 or more.

[0318] Examples of the polymeric dispersant include DISPERBYK-101, DISPERBYK-102, DISPERBYK-103, DISPERBYK-106, DISPERBYK-111, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-166, DISPERBYK-167, DISPERBYK-168, DISPERBYK-170, DISPERBYK-171, DISPERBYK-174, DISPERBYK-182 (manufactured by BYK-Chemie GmbH); EFKA4010, EFKA4046, EFKA4080, EFKA5010, EFKA5207, EFKA5244, EFKA6745, EFKA6750, EFKA7414, EFKA745, EFKA7462, EFKA7500, EFKA7570, EFKA7575, EFKA7580, EFKA7701 (manufactured by EFKA Additives B.V.); Disperse Aid6, Disperse Aid8, Disperse Aid15, Disperse Aid9100 (manufactured by SAN NOPCO LIMITED); various SOLSPERSE dispersants such as SOLSPERSE 3000, 5000, 9000, 12000, 13240, 13940, 17000, 22000, 24000, 26000, 28000, 32000, 36000, 39000, 41000, 71000 (manufactured by Noveon International, Inc.); Adeka Pluronic L31, F38, L42, L44, L61, L64, F68, L72, P95, F77, P84, F87, P94, L101, P103, F108, L121, P-123 (manufactured by ADEKA Corporation), Ionet S-20 (manufactured by Sanyo Chemical Industries, Ltd.); DISPARLON KS-860, 873SN, 874 (polymeric dispersant), #2150 (aliphatic polycarboxylic acid), #7004 (polyether ester type) (manufactured by Kusumoto Chemicals, Ltd.).

[0319] When the ink contains a dispersant, the content of the dispersant is preferably 0.05% to 10% by mass, more preferably 0.1% to 5% by mass, based on the total amount of the ink.

[0320] <Other Components>

[0321] The ink of the present invention may contain other components other than the above components as needed.

[0322] Examples of other components include colorants (e.g., pigments, dyes), waxes, antioxidants, anti-fading agents, conductive salts, basic compounds, etc.

[0323] <Inkjet Ink>

[0324] The ink of the present invention is preferably an inkjet ink.

[0325] Hereinafter, the preferred physical properties of the ink of the present invention when it is an inkjet ink will be described.

[0326] The surface tension of the ink of the present invention is preferably 20 mN / m to 50 mN / m, more preferably 28 mN / m to 50 mN / m.

[0327] When the surface tension of the ink is 20 mN / m or more, the ejection property of the ink is further improved.

[0328] When the surface tension of the ink is 50 mN / m or less, the image quality is further improved.

[0329] Here, the surface tension refers to the value measured at 25°C.

[0330] The surface tension can be measured, for example, using a surface tensiometer named "Automatic Surface Tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.)".

[0331] From the viewpoint of the ejection property of the ink, the viscosity of the ink of the present invention is preferably 5 mPa·s to 50 mPa·s, more preferably 10 mPa·s to 30 mPa·s, and still more preferably 10 mPa·s to 25 mPa·s.

[0332] Here, the viscosity refers to the value measured at 25°C.

[0333] The viscosity can be measured, for example, using a viscometer VISCOMETER RE-85L (manufactured by TOKI SANGYO CO., LTD.).

[0334] Next, the preferred embodiments of the ink of the present invention will be described.

[0335] (First Embodiment)

[0336] The ink according to the first mode is an ink in which the polymerizable compound contained in the ink includes a monofunctional polymerizable compound and the proportion of the monofunctional polymerizable compound in the polymerizable compound contained in the ink is 90% by mass or more.

[0337] The image recorded with the ink according to the first mode has excellent metallic luster, and also excellent line quality, stretchability, and metallic luster after stretching.

[0338] Here, excellent line quality means that bleeding in the line image is suppressed.

[0339] Stretchability and metallic luster after stretching are properties that may be required when a heat stretch (e.g., vacuum forming) is applied to an image recording object to produce a molded object (e.g., a three-dimensional object). If the stretchability of the image is low, the image may break when a heat stretch is applied to the image recording object.

[0340] Therefore, an image recording object having an image as a cured product of the ink according to the first mode is suitable as an image recording object for producing a molded object (e.g., a three-dimensional object) by heat stretching (e.g., vacuum forming).

[0341] The three-dimensional object is not particularly limited, and examples thereof include various covers such as covers for smartphones and covers for vehicles; various packaging materials; decorative films for home appliances, furniture, etc.

[0342] In the ink according to the first mode, the content of the monofunctional polymerizable compound is preferably 50% by mass, more preferably 60% by mass or more, and further preferably 70% by mass or more, relative to the total amount of the ink.

[0343] The ink according to the first mode preferably contains an organic solvent and the content of the organic solvent is 1% by mass or more relative to the total amount of the ink. In the ink according to the first mode, the content of the organic solvent is preferably 10% by mass or less, more preferably 5% by mass or less, relative to the total amount of the ink.

[0344] The ink according to the first mode preferably contains a resin.

[0345] (Second mode)

[0346] The ink according to the second mode is an ink in which the polymerizable compound contained in the ink includes a polyfunctional polymerizable compound and the proportion of the polyfunctional polymerizable compound in the polymerizable compound contained in the ink is 60% by mass or more.

[0347] The image recorded with the ink according to the second mode has excellent metallic luster, and also excellent line quality and dissolution resistance.

[0348] Here, dissolution resistance means the property that low-molecular-weight components in the image are not easily dissolved in water or organic solvents.

[0349] An image recording material having an image that is a cured product of the ink according to the second method is suitable as a food packaging material, for example.

[0350] In the ink according to the second method, the content of the bifunctional polymerizable compound is preferably 50% by mass, more preferably 60% by mass or more, and further preferably 70% by mass or more, relative to the total amount of the ink.

[0351] The ink according to the second method preferably contains an organic solvent, and the content of the organic solvent is 1% by mass or more relative to the total amount of the ink. In the ink according to the second method, the content of the organic solvent is preferably 10% by mass or less, more preferably 5% by mass or less, relative to the total amount of the ink.

[0352] (Third method)

[0353] The ink according to the third method is an ink in which the polymerizable compounds contained in the ink include polymerizable compounds having a weight average molecular weight of 1000 or more, and the proportion of the polymerizable compounds having a weight average molecular weight of 1000 or more in the polymerizable compounds contained in the ink is 50% by mass or more.

[0354] An image recorded with the ink according to the third method has excellent metallic luster, and also excellent line quality and abrasion resistance.

[0355] Moreover, since it contains the above-mentioned amount of polymerizable compounds having a weight average molecular weight of 1000 or more, in the cured ink (i.e., the image), the distance between crosslinking points becomes longer, and thus an effect of improving the flexibility of the image (for example, the followability of the image to bending deformation of the substrate) can also be expected.

[0356] Therefore, an image recording material having an image that is a cured product of the ink according to the third method is suitable as an image recording material having a flexible substrate (for example, leather).

[0357] As an image recording material, for example, leather products (such as automotive seat cushions, bags, shoes, wallets, etc.) can be cited.

[0358] The proportion of the polymerizable compounds having a weight average molecular weight of 1000 or more in the polymerizable compounds contained in the ink is more preferably 60% by mass or more, and further preferably 80% by mass or more.

[0359] The upper limit of Mw in the polymerizable compounds having a weight average molecular weight (Mw) of 1000 or more is preferably 30000 or less, more preferably 20000 or less, and further preferably 10000 or less.

[0360] The ink according to the third mode preferably further contains an organic solvent, and the content of the organic solvent is 50% by mass or more with respect to the total amount of the ink. Thereby, the ejection property of the ink is further improved.

[0361] In the ink according to the third mode, the content of the organic solvent is preferably 90% by mass or less with respect to the total amount of the ink.

[0362] 〔Ink set〕

[0363] The ink set of the present invention includes at least one of the aforementioned ink of the present invention (that is, the active energy ray-curable ink of the present invention), a primer solution, and an overcoat solution.

[0364] The ink set of the present invention includes the aforementioned ink of the present invention.

[0365] Therefore, the ink set of the present invention is also suitable for manufacturing the image recording material of the present invention.

[0366] The primer solution is a liquid that is applied to the substrate prior to the ink of the present invention and is used to form a primer layer. Thereby, an image recording material having a primer layer between the image and the substrate can be manufactured. The image recording material having a primer layer can form a high-definition image. Also, the adhesion between the image and the substrate is more excellent.

[0367] The overcoat solution (hereinafter, also referred to as "OC solution") is a liquid that is applied to the image recorded by the ink of the present invention and is used to form an overcoat layer (hereinafter, also referred to as "OC layer"). The OC layer is formed at least on the image. The OC layer may be formed across the image and the non-image forming area. The image recording material having an OC layer has more excellent image abrasion resistance.

[0368] Hereinafter, the primer solution and the overcoat solution will be described in more detail.

[0369] <Primer solution>

[0370] The primer solution does not contain scaly metal particles, but contains a polymerizable compound. The polymerizable compound contained in the primer solution includes at least one of a monofunctional polymerizable compound and a bifunctional polymerizable compound, and the total proportion of the monofunctional polymerizable compound and the bifunctional polymerizable compound in the polymerizable compound contained in the primer solution is 50% by mass or more.

[0371] Specific examples of the polymerizable compound contained in the primer solution are the same as those of the polymerizable compound contained in the ink.

[0372] The primer solution may contain other components (for example, a photoinitiator) other than the polymerizable compound.

[0373] Regarding other components other than the polymerizable compound, reference can be made to the components in the ink of the present invention.

[0374] The undercoat liquid preferably contains substantially no colorant (e.g., pigment).

[0375] Specifically, the content of the colorant is preferably less than 1% by mass relative to the total amount of the undercoat liquid.

[0376] Hereinafter, the preferred mode of the undercoat liquid will be described.

[0377] (Mode A)

[0378] The undercoat liquid related to Mode A is an undercoat liquid containing a monofunctional polymerizable compound, and the proportion of the monofunctional polymerizable compound in the polymerizable compounds contained in the undercoat liquid is 90% by mass or more.

[0379] As one of the preferred combinations of the ink and the undercoat liquid in the ink set of the present invention, a combination of the ink related to the first mode and the undercoat liquid related to Mode A can be cited.

[0380] (Mode B)

[0381] The undercoat liquid related to Mode B is an undercoat liquid containing a polyfunctional polymerizable compound, and the proportion of the polyfunctional polymerizable compound in the polymerizable compounds contained in the undercoat liquid is 60% by mass or more.

[0382] As one of the preferred combinations of the ink and the undercoat liquid in the ink set of the present invention, a combination of the ink related to the second mode and the undercoat liquid related to Mode B can be cited.

[0383] The content of the polymerizable compound is preferably 10% by mass to 90% by mass, more preferably 20% by mass to 80% by mass, further preferably 30% by mass to 70% by mass, and further preferably 40% by mass to 60% by mass relative to the total amount of the undercoat liquid related to Mode B.

[0384] -Isocyanate compound-

[0385] The undercoat liquid related to Mode B preferably contains at least one isocyanate compound.

[0386] The isocyanate compound is not particularly limited as long as it is a compound having an isocyanate group. From the viewpoint of improving curability, a polyfunctional isocyanate compound having two or more isocyanate groups in one molecule is preferred.

[0387] The undercoat liquid related to Mode B can be prepared by dividing it into a part A containing a polymerizable compound and a part B containing an isocyanate compound.

[0388] At this time, part A and part B can be mixed before being applied to the substrate and applied to the substrate as the undercoat liquid related to Mode B.

[0389] As a bifunctional isocyanate compound having two isocyanate groups in one molecule, for example, methylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dipropyl ether diisocyanate, 2,2-dimethylpentane diisocyanate, 3-methoxyhexane diisocyanate, octamethylene diisocyanate, 2,2,4-trimethylpentane diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, 3-butoxyhexane diisocyanate, 1,4-butanediol dipropyl ether diisocyanate, thiodihexyl diisocyanate and other aliphatic diisocyanates;

[0390] m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, xylene diisocyanate, ethylbenzene diisocyanate, cumene diisocyanate, tolidine diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 2,7-naphthalene diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, tetramethylxylylene diisocyanate and other aromatic diisocyanates; and

[0391] alicyclic diisocyanates such as hydrogenated xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate.

[0392] The isocyanate compound may be a trimer of a bifunctional isocyanate compound, i.e., a biuret or an isocyanurate, an adduct of a polyol such as trimethylolpropane and a bifunctional isocyanate compound, or an adduct of an alcohol such as methanol and a bifunctional isocyanate compound (i.e., a urethane formate).

[0393] Among them, from the viewpoint of the adhesion between the substrate and the image, the isocyanate compound is preferably an aliphatic isocyanate compound, more preferably an aliphatic isocyanate compound having two or more isocyanate groups in one molecule, and further preferably an aliphatic diisocyanate, an isocyanurate of an aliphatic diisocyanate, a urethane formate of an aliphatic diisocyanate and an alcohol, or an adduct of an aliphatic diisocyanate and a polyol, and particularly preferably an aliphatic diisocyanate or an isocyanurate of an aliphatic diisocyanate.

[0394] The isocyanate compound may be a commercially available product.

[0395] The isocyanate compound may be a commercially available product.

[0396] Examples of commercially available polyfunctional isocyanate compounds as adducts include Takenate (registered trademark) D-102, D-103, D-103H, D-103M2, P49-75S, D-110N, D-120N, D-140N, D-160N (above, Mitsui Chemicals, Inc.), Desmodule (registered trademark) L75, UL57SP (Sumika Bayer Urethane Co., Ltd.), CORONATE (registered trademark) HL, HX, L (Nippon Polyurethane Industry Co., Ltd.), P301-75E (Asahi Kasei Corporation), and the like.

[0397] Examples of commercially available polyfunctional isocyanate compounds as isocyanurate bodies include Takenate (registered trademark) D-127N, D-170N, D-170HN, D-172N, D-177N (above, Mitsui Chemicals, Inc.), SUMIDUR N3300, Desmodule (registered trademark) N3600, N3900, Z4470BA (above, Sumika Bayer Urethane Co., Ltd.), CORONATE (registered trademark) HX, HK (above, Nippon Polyurethane Industry Co., Ltd.), Duranate (registered trademark) TPA-100, TKA-100, TSA-100, TSS-100, TLA-100, TSE-100 (above, Asahi Kasei Corporation), and the like.

[0398] Examples of commercially available polyfunctional isocyanate compounds as biuret bodies include Takenate (registered trademark) D-165N, NP1100 (above, Mitsui Chemicals, Inc.), Desmodule (registered trademark) N3200 (Sumika Bayer Urethane Co., Ltd.), Duranate (registered trademark) 24A-100 (Asahi Kasei Corporation), and the like.

[0399] In the undercoat liquid related to Method B, the content of the isocyanate compound is preferably 2% to 90% by mass, more preferably 5% to 70% by mass, and further preferably 10% to 50% by mass, relative to the total amount in the undercoat liquid.

[0400] - Organic solvent -

[0401] The undercoat liquid involved in Method B may contain an organic solvent.

[0402] When the undercoat liquid involved in Method B contains an organic solvent, the content of the organic solvent is preferably 2% by mass to 90% by mass, more preferably 5% by mass to 70% by mass, and still more preferably 10% by mass to 50% by mass, based on the total amount of the undercoat liquid involved in Method B.

[0403] <Overcoat liquid>

[0404] The overcoat liquid does not contain scaly metal particles, but contains a polymerizable compound and an organic solvent.

[0405] The proportion of the polymerizable compound having a weight average molecular weight of 1000 or more in the polymerizable compounds contained in the overcoat liquid is 50% by mass or more, and the content of the organic solvent is 50% by mass or more based on the total amount of the overcoat liquid.

[0406] Except for not containing scaly metal particles, the preferred mode of the composition of the overcoat liquid is the same as the preferred composition of the ink involved in the third method.

[0407] As one of the preferred combinations of the ink and the overcoat liquid in the ink set of the present invention, the combination of the ink and the overcoat liquid involved in the third method can be cited.

[0408] The overcoat liquid preferably substantially does not contain a colorant (for example, a pigment).

[0409] Specifically, the content of the colorant is preferably less than 1% by mass based on the total amount of the overcoat liquid.

[0410] 〔Preferred mode of the method for manufacturing an image recording material (Manufacturing method X)〕

[0411] The image recording material of the present invention only needs to satisfy the foregoing conditions, and its manufacturing method is not particularly limited.

[0412] The image recording material of the present invention is preferably manufactured by the following Manufacturing method X.

[0413] Manufacturing method X is a method for manufacturing an image recording material, which uses the foregoing ink of the present invention (that is, an active energy ray curable ink), and the Manufacturing method X includes:

[0414] An ink application step of applying the ink onto a substrate; and

[0415] A curing step A of curing the ink applied onto the substrate by irradiation with active energy ray A to obtain an image,

[0416] The time from when the ink lands on the substrate until the start of irradiation of the ink with the active energy ray A (hereinafter, also referred to as "the time from ink landing to the start of irradiation with active energy ray A") is 0.5 seconds or more.

[0417] In Production Method X, by combining the case of using the ink of the present invention containing the aforementioned flaky metal particles with the case where the time from ink landing to the start of irradiation with active energy ray A is set to 0.5 seconds or more, in the image surface layer portion and the interior of the formed image, the average angle of the length direction of the flaky metal particles with respect to the surface of the substrate easily satisfies the aforementioned conditions.

[0418] Therefore, according to Production Method X, it is easy to produce the image recording material of the present invention that satisfies the aforementioned conditions and has excellent metallic luster of the image.

[0419] Although the reason for obtaining this effect is not yet clear, it is considered that by setting the time from ink landing to the start of irradiation with active energy ray A to 0.5 seconds or more, the time for the flaky metal particles to move in the image surface layer portion is ensured, and as a result, the flaky metal particles are easily oriented substantially parallel to the surface of the substrate.

[0420] In Production Method X, from the viewpoint of further improving the metallic luster of the image, the time from ink landing to the start of irradiation with active energy ray A is preferably 1.0 second or more.

[0421] From the viewpoint of further improving the line quality of the image (that is, further suppressing bleeding of the image), the time from ink landing to the start of irradiation with active energy ray A is preferably 5.0 seconds or less.

[0422] Hereinafter, each step in Production Method X will be described.

[0423] <Ink application step>

[0424] The ink application step in Production Method X includes applying ink to a substrate.

[0425] The preferred forms of the substrate and the ink are as described in the section on the image recording material, respectively.

[0426] In this step, it is preferable to apply the ink to the substrate by an inkjet method.

[0427] That is, in this step, it is preferable to eject the ink from the ejection holes (nozzles) of the inkjet head and apply it to the substrate.

[0428] As the method of applying the ink based on the inkjet method, either a single-pass method or a multi-pass method can be used, and from the viewpoint of the image recording speed, the single-pass method is preferred.

[0429] Here, the single-pass method refers to the following method: A line head in which ejection holes (nozzles) are arranged corresponding to the entire area of one side of the substrate is used as an inkjet head, the line head is fixedly arranged, and while the substrate is conveyed in a direction intersecting the arrangement direction of the ejection holes of the line head, ink is applied to the conveyed substrate.

[0430] In contrast, the multi-pass method (scanning method) refers to the following method: A short column head is used as an inkjet head, and the short column head is scanned over the substrate to apply ink.

[0431] In the single-pass method, by scanning the substrate in a direction intersecting the arrangement direction of the ejection holes, it is possible to form a pattern on the entire surface of the substrate without the need for a conveyance system such as a carriage for scanning the short head. Also, there is no need for complex scanning control of the movement of the carriage and the substrate, and only the substrate moves, so the recording speed can be increased compared to the multi-pass method.

[0432] Generally, compared with the multi-pass method, the single-pass method can achieve a higher recording speed. However, on the other hand, there is a tendency for the time from ink landing to the start of irradiation with active energy ray A to become shorter. Therefore, the time for the scaly metal particles to move in the surface layer of the image (the time for alignment to be substantially parallel to the substrate) is insufficient, and as a result, there is a tendency for it to be difficult to obtain the effect of metallic luster of the image.

[0433] However, according to Production Method X, by limiting the time from ink landing to the start of irradiation with active energy ray A to 0.5 seconds or more, even in the case of an inkjet method using the single-pass method, it is easy to obtain the effect of metallic luster of the image. In other words, when the inkjet method using the single-pass method is applied, the effect of improving the metallic luster of the image based on Production Method X is more effectively exerted.

[0434] The ejection amount of the ink ejected from the inkjet head is preferably 1 pL (picoliter) to 100 pL, more preferably 3 pL to 80 pL, and further preferably 3 pL to 50 pL.

[0435] The ink application step in Production Method X may include a step of heating and drying the ink applied to the substrate.

[0436] In particular, when using the ink of the third method containing 50% by mass or more of an organic solvent, in the ink application step, it is preferable to heat and dry the ink applied to the substrate.

[0437] The heating and drying is preferably performed by maintaining the surface temperature of the substrate at, for example, 40°C to 100°C (more preferably 40°C to 80°C, and further preferably 50°C to 70°C).

[0438] Moreover, as the heating and drying time, it is preferably 1 second or more, more preferably 5 seconds or more, and particularly preferably 8 seconds or more.

[0439] There is no particular limitation on the upper limit of the heating and drying time. As the upper limit, it is preferably 60 seconds, more preferably 30 seconds, and particularly preferably 20 seconds.

[0440] <Curing Step A>

[0441] Curing step A in Production Method X includes a step of obtaining an image by curing the ink (hereinafter, also referred to as "ink film") applied to a substrate by irradiation with active energy ray A.

[0442] In curing step A, by irradiating the ink film with active energy ray A, the polymerizable compounds in the ink film are polymerized to cure the ink film, thereby obtaining an image.

[0443] As active energy ray A, ultraviolet rays (UV light) or electron beams (EB) are preferred.

[0444] The peak wavelength of the ultraviolet rays is, for example, preferably 200 nm to 405 nm, more preferably 250 nm to 400 nm, and further preferably 300 nm to 400 nm.

[0445] As the light source for ultraviolet ray irradiation, mainly mercury lamps, gas lasers, and solid lasers are used. Well-known ones are mercury lamps, metal halide lamps, and ultraviolet fluorescent lamps. Moreover, UV-LED (light-emitting diode) and UV-LD (laser diode) are small in size, long in life, high in efficiency, and low in cost, and can be expected as light sources for ultraviolet ray irradiation. Among them, the light source for ultraviolet ray irradiation is preferably a metal halide lamp, high-pressure mercury lamp, medium-pressure mercury lamp, low-pressure mercury lamp, or UV-LED.

[0446] Moreover, Production Method X can be a mode in which the content of the photoinitiator in the ink is less than 1% by mass relative to the total amount of the ink and the active energy ray A is an electron beam.

[0447] In Production Method X of this mode, although the content of the photoinitiator in the ink is less than 1% by mass, the ink can be cured by irradiation with an electron beam. And in this mode, since the content of the photoinitiator is less than 1% by mass, elution of the photoinitiator from the image can be further suppressed. Therefore, for example, it is particularly suitable as a manufacturing method for image recording materials for food packaging.

[0448] Curing step A is preferably a step of formally curing the ink film.

[0449] Here, in short, formal curing means that the polymerizable compounds in the ink film are substantially all polymerized and the ink film is substantially completely cured.

[0450] Specifically, formal curing means polymerizing the polymerizable compound in the ink film until the curing rate of the ink film (i.e., the polymerization rate of the polymerizable compound determined by high-speed liquid chromatography) reaches 90% to 100% to cure the ink film.

[0451] In the present invention, the irradiation of the active energy ray A for formal curing is sometimes referred to as "curing exposure", and the active energy ray A for formal curing is sometimes referred to as "curing exposure light".

[0452] From the viewpoint of further improving the adhesion between the substrate and the image, the illuminance of the active energy ray A as the curing exposure light is preferably 1.0 W / cm or more, more preferably 2.0 W / cm or more, and still more preferably 4.0 W / cm or more.

[0453] There is no particular limitation on the upper limit of the illuminance of the active energy ray A as the curing exposure light. For example, the upper limit is 10 W / cm.

[0454] From the viewpoint of further improving the adhesion between the substrate and the image, the irradiation energy (i.e., exposure amount) of the active energy ray A as the curing exposure light is preferably 20 mJ / cm 2 or more, more preferably 80 mJ / cm 2 or more.

[0455] There is no particular limitation on the upper limit of the irradiation energy of the active energy ray A as the curing exposure light. For example, the upper limit is 240 mJ / cm 2 .

[0456] The irradiation of the active energy ray A is preferably performed in an atmosphere with an oxygen concentration of 0.1% by volume or less. Thereby, an image with polymerization inhibition caused by oxygen suppressed and more excellent adhesion to the substrate can be obtained.

[0457] As the atmosphere with an oxygen concentration of 0.1% by volume or less, the presence of an inert gas (for example, nitrogen, argon, helium) is preferred.

[0458] <Semi-curing process>

[0459] Production method X preferably further includes a semi-curing process, in which the ink film (i.e., the ink applied to the substrate) is semi-cured by irradiating the active energy ray P with an irradiation energy smaller than that of the active energy ray A after the ink application process and during the curing process A.

[0460] At this time, in the aforementioned curing process A, the semi-cured ink film is cured by irradiating the active energy ray A to obtain an image.

[0461] When production method X includes a semi-curing process, the line quality of the image is further improved (i.e., bleeding of the image is further suppressed).

[0462] Here, in short, semi-curing refers to temporarily curing the ink film by polymerizing only a part of the polymerizable compound in the ink film (that is, performing insufficient curing).

[0463] Specifically, semi-curing refers to temporarily curing the ink film by polymerizing a part of the polymerizable compound in the ink film to such an extent that the curing rate of the ink film (that is, the polymerization rate of the polymerizable compound determined by high-performance liquid chromatography. The same applies hereinafter) is less than 90%.

[0464] The curing rate of the semi-cured ink film is more preferably 80% or less, further preferably 70% or less, and still further preferably 50% or less.

[0465] The curing rate of the semi-cured ink film is preferably 10% or more, more preferably 20% or more, and further preferably 30% or more.

[0466] In the present invention, the irradiation of the active energy ray P for semi-curing is sometimes referred to as "pinning exposure", and the active energy ray P for semi-curing is sometimes referred to as "pinning exposure light".

[0467] The illuminance of the active energy ray P as the pinning exposure light is preferably 0.10 W / cm to 0.50 W / cm, more preferably 0.20 W / cm to 0.49 W / cm, and still further preferably 0.20 W / cm to 0.45 W / cm.

[0468] The irradiation energy (that is, the exposure amount) of the active energy ray P as the pinning exposure light is preferably 2 mJ / cm 2 ~20 mJ / cm 2 ,more preferably 4 mJ / cm 2 ~15 mJ / cm 2 .

[0469] <Undercoat formation step>

[0470] Production method X may further include a step of applying an undercoat liquid to a substrate and semi-curing the applied undercoat liquid to form an undercoat layer before the ink application step.

[0471] When the undercoat layer formation step is included, an image recording material having an undercoat layer inserted between the substrate and the image can be manufactured.

[0472] Regarding the preferred mode of the undercoat liquid (for example, the preferred combination of the ink and the undercoat liquid), as described in the section on the ink set.

[0473] The application of the undercoat liquid can be carried out by using known methods such as the coating method, the dipping method, and the inkjet recording method.

[0474] Coating methods include, for example, rod coater, air knife coater, blade coater, rod type coater, blade type coater, extrusion coater, reverse roll coater, transfer roll coater, gravure coater, roll kiss coater, casting coater, spray coater, curtain coater or extrusion coater.

[0475] The undercoat liquid is preferably applied in the same area as or a wider area than the ink film formed by the application of the ink, and is preferably applied so as to cover the entire area where the ink film is formed.

[0476] From the viewpoint of the flexibility of the recorded image, the thickness of the undercoat layer formed by the application of the undercoat liquid is preferably 0.5 μm to 6.0 μm, more preferably 2.0 μm to 4.0 μm.

[0477] Similar to the semi-curing process of the semi-cured ink, the semi-curing of the undercoat liquid can be carried out by irradiation with active energy rays.

[0478] The preferred mode of the irradiation conditions of the active energy rays at this time is the same as the preferred mode of the irradiation conditions of the active energy rays P in the semi-curing process of the semi-cured ink.

[0479] <Overcoat formation process>

[0480] Production method X may further include a process of applying an overcoat liquid on the image and curing the applied overcoat liquid to form an overcoat after the curing process A.

[0481] Regarding the preferred mode of the overcoat liquid (for example, the preferred combination of the ink and the overcoat liquid), refer to the description in the ink group section.

[0482] The application of the overcoat liquid can be carried out by using known methods such as coating methods, dipping methods, inkjet recording methods, etc.

[0483] Specific examples of the coating method for the application of the overcoat liquid are the same as the specific examples of the coating method for the application of the undercoat liquid described above.

[0484] Similar to the curing process A of the cured ink, the curing of the overcoat liquid can be carried out by irradiation with active energy rays.

[0485] The preferred mode of the irradiation conditions of the active energy rays at this time is the same as the preferred mode of the irradiation conditions of the active energy rays A in the curing process A of the cured ink.

[0486] The overcoat formation process preferably heats and dries the overcoat liquid before curing the overcoat liquid (i.e., before irradiating with active energy rays).

[0487] The preferred conditions for heating and drying the overcoat liquid are the same as the preferred conditions for heating and drying the ink.

[0488] Examples

[0489] Hereinafter, embodiments of the present invention will be shown, but the present invention is not limited to the following embodiments.

[0490] Hereinafter, unless otherwise specified, "parts" and "%" are based on mass.

[0491] Furthermore, hereinafter, "solvent" means an organic solvent.

[0492] 〔Example 1〕

[0493] <Preparation of Ink>

[0494] The components shown in Table 1 were mixed and stirred to obtain an ink. Using a stirrer (L4R manufactured by Silverson), stirring was carried out at room temperature (25 °C) under the conditions of 5,000 revolutions per minute for 20 minutes.

[0495] The average equivalent circle diameter and average aspect ratio of the flaky metal particles were measured by the aforementioned methods, respectively.

[0496] The content of the solvent relative to the total amount of the ink was determined based on the content of the solvent contained in the dispersion of the flaky metal particles and the charged amount of the dispersion of the flaky metal particles.

[0497] <Image Recording>

[0498] The above ink was introduced into the white throttle valve of an inkjet printer (Acuity LED 1600R manufactured by FUJIFILM Corporation) in a multi-pass mode (i.e., a reciprocating scanning mode).

[0499] As the substrate, a polycarbonate substrate ("Panlite" manufactured by TEIJIN LIMITED., thickness 400 μm) was prepared.

[0500] The above ink was ejected from the inkjet head of the above inkjet printer, and the above ink was applied to the above substrate in a multi-pass mode (marked as "M" in the ink application method column after Table 1) in a solid image shape (Solid image shape) with a 100% dot percentage and a line image shape of 2 dots.

[0501] The ink application conditions were set to 1200 dpi × 1200 dpi, 48 passes, and bi-directional printing conditions. Here, dpi is an abbreviation for dot per inch (the same hereinafter).

[0502] In this image recording, by setting the lamp power of the Acuity LED 1600R, the ink applied to the substrate was irradiated successively with a pinning exposure light (exposure light for semi-curing) as the active energy ray P and a curing exposure light (exposure light for final curing) as the active energy ray A.

[0503] The time from when the ink landed on the substrate until the pinning exposure light was irradiated on the ink (hereinafter, also referred to as "the time from ink landing to the start of semi-curing") was 0.1 second.

[0504] The time from when the ink landed on the substrate until the curing exposure light was irradiated on the ink (hereinafter, also referred to as "the time from ink landing to the start of final curing") was 2.0 seconds.

[0505] Here, the pinning exposure light was ultraviolet light with a peak wavelength of 385 nm, and the curing exposure light was ultraviolet light with a peak wavelength of 385 nm.

[0506] The irradiation energy of the pinning exposure light was set to 1000 mJ / cm 2 , and the irradiation energy of the curing exposure light was set to 200 mJ / cm 2 .

[0507] The irradiation of the curing exposure light on the ink on the substrate was carried out in a nitrogen purge atmosphere (specifically, in an atmosphere with an oxygen concentration of 0.1 vol% or less and a nitrogen concentration of 99.9 vol% or more).

[0508] Under the above conditions, the ink applied to the substrate was successively semi-cured and finally cured to record images (solid images and line images), thereby obtaining an image recording.

[0509] <Measurement of the average equivalent circle diameter and average thickness of the flaky metal particles>

[0510] The average equivalent circle diameter and average thickness of the flaky metal particles contained in the dispersion of the flaky metal particles were measured. The detailed measurement method is as described above.

[0511] The results are shown in Table 1.

[0512] <Measurement of the average angle of the flaky metal particles>

[0513] The cross-section of the image in the above image recording was observed, and the average angle (specifically, the average angle formed by the length direction of the flaky metal particles and the surface of the substrate) of the flaky metal particles in the surface layer part of the image (specifically, the region within 100 nm from the surface of the image) and in the interior of the image (specifically, the region more than 100 nm from the surface of the image) was measured respectively. The detailed measurement method is as described above.

[0514] The results are shown in Table 1.

[0515] <Image Evaluation>

[0516] The following evaluations were performed on the images in the above image recording materials.

[0517] The results are shown in Table 1.

[0518] (Metallic Luster)

[0519] The metallic luster of the solid image was visually observed and evaluated according to the following evaluation criteria.

[0520] In the following evaluation criteria, the grade with the most excellent metallic luster of the image is "AA".

[0521] -Evaluation Criteria for Metallic Luster-

[0522] AA: It has extremely excellent specular gloss, and the reflected image of the object is as clear as a mirror image.

[0523] A: It has excellent metallic luster and can distinguish what the object reflected is.

[0524] B: Although it is impossible to distinguish what the object reflected is, it has metallic luster.

[0525] C: It does not have metallic luster and appears gray.

[0526] (Line Quality)

[0527] The line quality of the image was evaluated as follows using the line image.

[0528] Using an image evaluation system (Dot Analyzer (DOT Analyzer "DA6000" manufactured by Oji Scientific Instruments Co., Ltd.)), the roughness of the line image (i.e., the deviation of the edge of the line image from the ideal edge obtained by the least squares method) was measured. Based on the obtained results, the line quality of the image was evaluated according to the following evaluation criteria.

[0529] In the following evaluation criteria, the grade with the most excellent line quality of the image is "A".

[0530] -Evaluation Criteria for Line Quality-

[0531] A: The roughness of the line image is less than 2.0.

[0532] B: The roughness of the line image is 2.0 or more and less than 4.0.

[0533] C: The roughness of the line image is 4.0 or more and less than 6.0.

[0534] D: The roughness of the line image is 6.0 or more and less than 8.0.

[0535] E: The roughness of the line image is 8.0 or more.

[0536] (Tensility)

[0537] A sample with dimensions of length 5 cm × width 2 cm was cut out from the solid image. The cut-out sample was subjected to heat stretching using the following testing machine and under the following conditions.

[0538] Testing machine: TENSILON (manufactured by SHIMADZU CORPORATION)

[0539] Conditions: Temperature 180°C, stretching speed 50 mm / minute

[0540] Based on the length of the sample at the time point when the image broke (hereinafter referred to as "length X2") and the length of the sample before heat stretching (hereinafter referred to as "length X1", specifically 5 cm), the heat stretching rate at the time point when the image broke was calculated using the following formula.

[0541] Heat stretching rate at the time point when the image broke (%) = {(length X2 - length X1) / length X1} × 100

[0542] For example, when length X2 is 10 cm, the heat stretching rate at the time point when the image broke was calculated as 100% as follows.

[0543] Heat stretching rate (%) = {(10 cm - 5 cm) / 5 cm} × 100 = 100%

[0544] Based on the heat stretching rate at the time point when the above image broke, the stretchability of the image was evaluated according to the following evaluation criteria.

[0545] In the following evaluation criteria, the grade with the most inhibited stretchability of the image is "A".

[0546] - Evaluation criteria for the heat stretchability of the image -

[0547] A: The heat stretching rate at the time point when the image broke is 150% or more.

[0548] B: The heat stretching rate at the time point when the image broke is 70% or more and less than 150%

[0549] C: The heat stretching rate at the time point when the image broke is less than 70%

[0550] (Metallic luster after stretching)

[0551] In the same manner as the evaluation of stretchability, cutting out and heat stretching of the samples were carried out.

[0552] However, in this evaluation, the heat stretching was fixed at a heat stretching rate of 150%.

[0553] Using the heat-stretched samples, the same evaluation as the aforementioned evaluation of metallic luster was carried out.

[0554] 〔Example 2〕

[0555] Except for the following points, the same operations as in Example 1 were carried out.

[0556] The results are shown in Table 1.

[0557] -Differences from Example 1-

[0558] In this image recording, by changing the setting of the lamp power of the Acuity LED1600R, the ink applied to the substrate was irradiated with curing exposure light for formal curing and not irradiated with pinning exposure light for semi-curing.

[0559] The time from ink landing to the start of formal curing (start of irradiation of curing exposure light) was set to 0.1 second.

[0560] 〔Example 3〕

[0561] Except for the following points, the same operations as in Example 1 were carried out.

[0562] The results are shown in Table 1.

[0563] -Differences from Example 1-

[0564] In this image recording, by changing the setting of the lamp power of the Acuity LED1600R, the ink applied to the substrate was irradiated with curing exposure light for formal curing and not irradiated with pinning exposure light for semi-curing.

[0565] In addition, in the same manner as in Example 1, the time from ink landing to the start of formal curing (start of irradiation of curing exposure light) was 2.0 seconds.

[0566] 〔Example 4〕

[0567] Except for the following points, the same operations as in Example 1 were carried out.

[0568] The results are shown in Table 1.

[0569] -Differences from Example 1-

[0570] In this image recording, by changing the setting of the lamp power of the Acuity LED 1600R, the curing exposure light for formal curing was irradiated on the ink applied to the substrate, while the pinning exposure light for semi-curing was not irradiated.

[0571] The time from ink landing to the start of formal curing (start of irradiation of the curing exposure light) was set to 6.0 seconds.

[0572] [Examples 5 and Comparative Examples 1 - 2]

[0573] The components in the ink (types of mainly dispersions of scaly metal particles) were changed as shown in Table 1, and otherwise, the same operations as in Example 1 were carried out.

[0574] The results are shown in Table 1.

[0575] [Table 1]

[0576]

[0577] (*1) Spherical Ag particles with a diameter of 40 nm.

[0578] -Explanation of Table 1-

[0579] The details of each component in Table 1 are as follows.

[0580] · In particle dispersion 1: A dispersion obtained by concentrating "LEAF POWDER (registered trademark) 9CJ - 1120" manufactured by OIKE & Co., Ltd. (containing 20 mass% of In particles (solid component) as the peeling sheet for the In film), with the content of In particles being 60 mass%. The dispersion medium is propylene glycol monomethyl ether (PGME).

[0581] · In particle dispersion 2: A dispersion obtained by replacing the solvent (PGME) in In particle dispersion 1 with a polymerizable compound (phenoxyethyl acrylate; PEA) by the decantation method. It contains 16 mass% of In particles (solid component) as the peeling sheet for the In film. The dispersion medium is mainly PEA. PGME remains 1 mass% with respect to the whole of dispersion 2.

[0582] · Al particle dispersion 1: It contains 5.1 mass% of "LEAF POWDER (registered trademark)" of OIKE & Co., Ltd., the high - brightness grade product of Al (particle thickness 20 nm) (Al particles (solid component) as the peeling sheet for the Al film). The dispersion medium is diethylene glycol diethyl ether (DEDG).

[0583] · Silver particle dispersion 1: containing 43% by mass of "OAG-IJS018" manufactured by Nagase ChemteX Corporation (spherical Ag particles (solid component). The dispersion medium is 2-(2-butoxyethoxy)ethanol).

[0584] · PEA: Phenoxyethyl acrylate

[0585] · IBOA: Isobornyl acrylate

[0586] · NVC: N-Vinylcaprolactam

[0587] · BR113: Acrylic polymer "DIANAL (registered trademark) BR113" manufactured by Mitsubishi Chemical Corporation

[0588] · 184: "Omnirad 184" manufactured by IGM Resins B.V. (1-Hydroxycyclohexyl-phenyl-ketone)

[0589] · 819: ( "Omnirad 819" manufactured by IGM Resins B.V.): Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide

[0590] · ITX: Isopropylthioxanthone

[0591] · UV12: "FLORSTAB UV12" manufactured by Kromachem Ltd (nitroso-based polymerization inhibitor; aluminum salt of tetra(N-nitroso-N-phenylhydroxylamine))

[0592] As shown in Table 1, the flaky metal particles are In particles. In the image recording materials of the examples where the average angle of the flaky metal particles on the surface layer of the image is 30° or less and the average angle of the flaky metal particles inside the image exceeds 30°, the metallic luster of the image is excellent. In the image recording materials of the examples, the line quality of the image, the stretchability of the image, and the metallic luster of the image after stretching are also excellent.

[0593] In contrast, in Comparative Example 1 where the flaky metal particles are Al particles, the metallic luster of the image is reduced.

[0594] Moreover, in Comparative Example 2 where spherical Ag particles are included instead of the flaky metal particles (In particles), the metallic luster of the image is reduced.

[0595] In Examples 1 and 5, in Example 1 where the content of the organic solvent in the ink is 1% by mass or more, the metallic luster of the image and the metallic luster after heating are more excellent.

[0596] In Examples 1 and 2, in Example 1 where the time from ink landing to the start of formal curing was 0.5 seconds or more, the metallic luster of the image and the metallic luster after heating were more excellent.

[0597] In Examples 1 and 3, in Example 1 where semi-curing (i.e., irradiation with pinning exposure light) was performed before formal curing (i.e., irradiation with curing exposure light), the line quality of the image was excellent.

[0598] 〔Example 101〕

[0599] <Preparation of Ink>

[0600] The components shown in Table 2 were mixed and stirred under the same stirring conditions as in Example 1 to obtain the ink.

[0601] <Image Recording>

[0602] The above ink was introduced into the cyan throttle valve of an inkjet printer (MIMAKI ENGINEERING CO., LTD. "JV400SUV") in a multi-pass mode (i.e., reciprocating scanning mode).

[0603] As the substrate, "Cuppuccino" (synthetic leather substrate made of polyvinyl chloride) manufactured by YAMAPLAS CO., LTD. was prepared.

[0604] The above ink was ejected from the inkjet head of the above inkjet printer and applied to the above substrate in a reciprocating scanning mode in the form of a solid image (Solid image) with a 100% dot percentage and a line image of 2 dots.

[0605] The ink application conditions were set to 1200 dpi × 900 dpi, 48 passes, and bi-directional printing conditions.

[0606] This JV400SUV does not have a pinning light source. Therefore, in this example, the ink applied to the substrate was heated and dried (70 °C, 300 seconds), and then curing exposure light (exposure light for formal curing) was irradiated without irradiating pinning exposure light.

[0607] The time from the ink landing on the substrate to the irradiation of the curing exposure light on the ink (hereinafter, also referred to as "the time from ink landing to the start of formal curing") was 300 seconds.

[0608] Here, as the curing exposure light source, a hot cathode tube was used. The irradiation energy of the curing exposure light was set to 400 mJ / cm 2 .

[0609] Under the above conditions, after heating and drying the ink applied to the substrate, formal curing was carried out to record images (solid images and line images), thereby obtaining an image recording material.

[0610] <Measurement of Average Equivalent Circle Diameter and Average Thickness of Flaky Metal Particles>

[0611] The same measurements as those for the average equivalent circle diameter and average thickness of the flaky metal particles in Example 1 were carried out.

[0612] The results are shown in Table 2.

[0613] <Measurement of Average Angle of Flaky Metal Particles>

[0614] The same measurements as those for the average angle of the flaky metal particles in Example 1 were carried out.

[0615] The results are shown in Table 2.

[0616] <Evaluation of Images>

[0617] Regarding the images in the above image recording material, the following evaluations were carried out.

[0618] The results are shown in Table 2.

[0619] (Metallic Luster, Line Quality)

[0620] The same evaluations as those for the metallic luster and line quality of the images in Example 1 were carried out.

[0621] (Wear Resistance)

[0622] Under the conditions of a load of 500 g and 100 wiping times, a Koka-type test of wiping the solid image in the image recording material with a cloth was carried out. Based on the obtained results, the wear resistance of the image was evaluated according to the following evaluation criteria.

[0623] In the following evaluation criteria, the grade with the most excellent wear resistance of the image is "AA".

[0624] -Evaluation Criteria for Wear Resistance of Images-

[0625] AA: No color shift occurred on the cloth wiped with the image, and the concentration of the image did not change.

[0626] A: Some color shift (color concentration less than 0.05) was observable on the cloth wiped with the image, but the concentration of the image did not change.

[0627] B: Some color shift (color concentration 0.05 or more) was observable on the cloth wiped with the image, but the concentration of the image did not change.

[0628] C: Color shift was observable on the cloth that wiped the image, and the color density of the image decreased.

[0629] 〔Example 102〕

[0630] <Preparation of the overcoating liquid>

[0631] The components shown in Table 2 were mixed and stirred under the same stirring conditions as in Example 1 to obtain the overcoating liquid.

[0632] <Formation of the overcoat layer>

[0633] The above overcoating liquid was introduced into the yellow throttle valve of the above JV400SUV, and the overcoating liquid was applied in a solid state to the entire image (i.e., the solid image and the line image) and the image non-formation area in the image recording material manufactured in Example 101. Then, drying and formal curing were carried out to form an overcoat layer (OC layer).

[0634] The conditions for applying the overcoating liquid were set to 1200 dpi × 900 dpi, 48 passes, and bi-directional printing conditions.

[0635] The conditions for drying and formal curing were set to be the same as those in Example 101.

[0636] An image recording material having a substrate, an image, and an OC layer was obtained as described above.

[0637] <Measurement of the average angle of the scaly metal particles>

[0638] The same measurement as the measurement of the average angle of the scaly metal particles in Example 101 was carried out. The surface of the image in this example refers to the interface between the image and the OC layer.

[0639] The results are shown in Table 2.

[0640] <Evaluation of the image>

[0641] The following evaluation was carried out on the image with the OC layer in the above image recording material (i.e., the laminate of the OC layer and the image).

[0642] The results are shown in Table 2.

[0643] (Metallic luster)

[0644] The metallic luster of the image with the OC layer in Example 102 was evaluated in the same manner as the metallic luster of the image in Example 101.

[0645] (Line quality)

[0646] The evaluation was set to be the same as the line quality of the image in Example 101, and the line quality of the image with the OC layer in Example 102 was evaluated.

[0647] (Abrasion resistance)

[0648] The abrasion resistance of the image in Example 101 was set as the same evaluation, and the abrasion resistance of the image with an OC layer in Example 102 was evaluated.

[0649] [Table 2]

[0650]

[0651] -Explanation of Table 2-

[0652] The details of each component in Table 2 are as follows. Among the components in Table 2, for components other than those shown below, refer to the explanation in Table 1.

[0653] ·MBA: Butyl methoxyacetate

[0654] ·Genomer 4215: Bifunctional urethane acrylate (Mw = 5000) manufactured by Rahn AG

[0655] ·2959: "Omnirad 2959" (1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-methylacetone) manufactured by IGM Resins B.V.

[0656] ·UV22: "IRGASTAB UV22" (quinone-based polymerization inhibitor) manufactured by BASF

[0657] ·UV-7630B: Hexafunctional urethane acrylate "Shikoh UV-7630B" (Mw = 2200) manufactured by Nippon Synthetic Chemical Industry Co., Ltd

[0658] ·KP109: "KP109" (50 mass% propylene glycol monomethyl ether solution of polyether-modified silicone compound, Mw12000, silicone structure content is 29 mass%) (silicone-based surfactant) manufactured by Shin-Etsu Chemical Co., Ltd.

[0659] As shown in Table 2, in the image recording materials of Examples 101 and 102 where the scaly metal particles are In particles, the average angle of the scaly metal particles in the surface layer of the image is 30° or less, and the average angle of the scaly metal particles inside the image exceeds 30°, the metallic luster of the image is excellent. In the image recording materials of each example, the line quality and abrasion resistance of the image are also ensured.

[0660] In Examples 101 and 102, in Example 102 in which a predetermined OC layer is provided, the metallic luster and abrasion resistance of the image are more excellent.

[0661] 〔Example 201〕

[0662] <Preparation of Undercoat Liquid 1>

[0663] The components shown in Table 3 were mixed and stirred under the same stirring conditions as in Example 1 to obtain Part A of Undercoat Liquid 1.

[0664] Part B of Undercoat Liquid 1 composed of the components shown in Table 3 was prepared.

[0665] Before image recording, Part A and Part B were mixed and used as Undercoat Liquid 1.

[0666] <Preparation of Ink>

[0667] The components shown in Table 3 were mixed and stirred under the same stirring conditions as in Example 1 to obtain the ink.

[0668] <Image Recording>

[0669] The above ink was introduced into the No. 6 throttle valve of an inkjet printer (Jet Press 540WV manufactured by FUJIFILM Corporation) in a single-pass mode.

[0670] As the substrate, “Taiko PET” (polyethylene terephthalate substrate, thickness 12 μm) manufactured by FUTAMURA CHEMICAL CO., LTD. was prepared.

[0671] Undercoat Liquid 1 was prepared by mixing Part A and Part B, and the prepared Undercoat Liquid 1 was coated on the above substrate through an anilox roll in the above inkjet printer and dried, thereby forming an undercoat layer with a thickness of 4 μm.

[0672] Next, the above ink was ejected from the inkjet head of the above inkjet printer, and the above ink was applied to the undercoat layer formed on the above substrate in a single-pass mode in a solid image shape (Solid image shape) with a 100% dot percentage and a line image shape of 2 dots.

[0673] The ink application conditions were set to 600 dpi × 600 dpi, single-pass (marked as “S” in the ink application method column after Table 3) and a substrate conveyance speed of 50 m / minute.

[0674] Next, the ink applied to the substrate was irradiated with a pinning exposure light (exposure light for semi-curing) as the active energy ray P and a curing exposure light (exposure light for final curing) as the active energy ray A in sequence. The time from the ink landing to the start of semi-curing was 0.1 second, and the time from the ink landing to the start of final curing was 2.0 seconds.

[0675] Here, both the pinning exposure light and the curing exposure light were ultraviolet rays with a peak wavelength of 385 nm.

[0676] The irradiation energy of the pinning exposure light was set to 350 mJ / cm 2 , and the irradiation energy of the curing exposure light was set to 6600 mJ / cm 2 .

[0677] The irradiation of the curing exposure light on the ink on the substrate was performed in a nitrogen purge atmosphere (specifically, in an atmosphere with an oxygen concentration of 0.1 vol% or less and a nitrogen concentration of 99.9 vol% or more).

[0678] Under the above conditions, the ink applied to the substrate was semi-cured and finally cured in sequence to record images (solid images and line images), thereby obtaining an image recording material.

[0679] <Evaluation of Images>

[0680] Regarding the images in the above image recording material, the following evaluations were performed.

[0681] The results are shown in Table 3.

[0682] (Metallic luster)

[0683] The same evaluation as the evaluation of the metallic luster of the images in Example 1 was performed.

[0684] (Line quality)

[0685] The same evaluation as the evaluation of the line quality of the images in Example 1 was performed.

[0686] (Dissolution resistance)

[0687] The dissolution resistance of the images was evaluated as follows.

[0688] A circular sample with a diameter of 10 cm was cut out from the part of the image recording material where a solid image was recorded. A 20-μm-thick LLDPE (linear low-density polyethylene) laminated film (hereinafter, this surface will be referred to as the laminated surface) was adhered to the solid image of the cut-out circular sample. The above-mentioned laminated surface was brought into contact with 50 mL of 100% ethanol as an extraction solvent, and in this state, extraction was carried out at 40 °C for 10 days through the laminated film. The obtained extract was analyzed by liquid chromatography (Prominence series: manufactured by SHIMADZU CORPORATION), and the monomer concentration in the extract was measured.

[0689] Based on the obtained results, the dissolution resistance of the image was evaluated according to the following evaluation criteria.

[0690] In the following evaluation criteria, the grade with the most excellent dissolution resistance of the image is "A".

[0691] -Evaluation criteria for dissolution resistance-

[0692] A: The monomer concentration in the extract is 50 mass ppb or less.

[0693] B: The monomer concentration in the extract is 50 mass ppb to 100 mass ppb.

[0694] C: The monomer concentration in the extract is 100 mass ppb or more.

[0695] 〔Example 202〕

[0696] In image recording, semi-curing (i.e., irradiation of pinning exposure light) was omitted, and otherwise, the same operations as in Example 201 were carried out.

[0697] The results are shown in Table 3.

[0698] 〔Example 203〕

[0699] The time from ink landing to the start of formal curing was changed to 0.1 second, and otherwise, the same operations as in Example 202 were carried out.

[0700] The results are shown in Table 3.

[0701] [Table 3]

[0702]

[0703] -Explanation of Table 3-

[0704] The detailed content of each component in Table 3 is as follows. Among the components in Table 3, for components other than the components shown below, refer to the explanations in Tables 1 to 2.

[0705] · 3MPDDA: 3-Methylpentanediol diacrylate

[0706] · DPHA: Dipentaerythritol hexaacrylate

[0707] · SR344: Polyethylene glycol(400) diacrylate

[0708] · BYK307: "BYK307" (silicone surfactant) manufactured by BYK JAPAN KK.

[0709] · D-170N: "Takenate D-170N" (isocyanate compound) manufactured by Mitsui Chemicals, Inc.

[0710] · Speedcure7010L: High molecular weight photoinitiator manufactured by Lambson Limited

[0711] · Solsperse32000: High molecular weight dispersant manufactured by The Lubrizol Corporation

[0712] As shown in Table 3, in the image recording materials of Examples 201 to 203 where the scaly metal particles are In particles, the average angle of the scaly metal particles in the surface layer of the image is 30° or less, and the average angle of the scaly metal particles inside the image exceeds 30°, the metallic luster of the image is excellent.

[0713] In the image recording materials of Examples 201 to 203, the line quality and dissolution resistance of the image are also excellent.

[0714] In Example 201 where semi-curing was performed before full curing in Examples 201 and 202, the line quality is more excellent.

[0715] In Example 202 where the time from ink landing to the start of full curing is 0.5 seconds or more in Examples 202 and 203, the metallic luster of the image is more excellent.

[0716] 〔Example 204〕

[0717] <Preparation of primer liquid 1>

[0718] The components shown in Table 4 were mixed and stirred under the same stirring conditions as in Example 1 to obtain primer liquid 2.

[0719] <Preparation of ink>

[0720] The components shown in Table 4 were mixed and stirred under the same stirring conditions as in Example 1 to obtain ink.

[0721] <Image recording>

[0722] As the base material, “PURE THERMO” (polypropylene base material, thickness 300 μm) manufactured by Idemitsu Unitech Co., Ltd. was used. As the undercoat liquid, undercoat liquid 2 was used. As the ink, the above-mentioned ink was used. Other than that, the same operations as in Example 201 were carried out, and thus an image recording material was obtained.

[0723] <Evaluation of Image>

[0724] Regarding the image in the above-mentioned image recording material, evaluations of metallic luster, line quality, stretchability, and metallic luster after stretching in Example 1 were carried out.

[0725] The results are shown in Table 4.

[0726] [Example 205]

[0727] In image recording, semi-curing (i.e., irradiation with pinning exposure light) was omitted. Other than that, the same operations as in Example 204 were carried out.

[0728] The results are shown in Table 4.

[0729] [Example 206]

[0730] The time from ink landing to the start of formal curing was changed to 0.1 second. Other than that, the same operations as in Example 205 were carried out.

[0731] The results are shown in Table 4.

[0732] [Table 4]

[0733]

[0734] -Explanation of Table 4-

[0735] The detailed content of each component in Table 4 is as follows. Among the components in Table 4, for components other than those shown below, refer to the explanations in Tables 1 to 3.

[0736] ·TEGORad2010: “TEGO (registered trademark) Rad2010” (5-6 functional silicone polyether acrylate) manufactured by Evonik Industries AG

[0737] ·TPO: “Omnirad TPO H” (2,4,6-trimethylbenzoyl diphenylphosphine oxide) manufactured by IGM Resins B.V.

[0738] As shown in Table 4, the scaly metal particles are In particles. In the image recording materials of Examples 204 to 206 where the average angle of the scaly metal particles in the surface layer of the image is 30° or less and the average angle of the scaly metal particles inside the image exceeds 30°, the metallic luster of the image is excellent. In the image recording materials of Examples 204 to 206, the line quality, stretchability, and metallic luster after stretching of the image are also excellent.

[0739] In Examples 204 and 205, in Example 204 where semi-curing was performed before full curing, the line quality is more excellent.

[0740] In Examples 205 and 206, in Example 205 where the time from ink landing to the start of full curing is 0.5 seconds or more, the metallic luster of the image is more excellent.

[0741] 〔Examples 301 to 303〕

[0742] <Preparation of Ink>

[0743] The components shown in Table 5 were mixed and stirred under the same stirring conditions as in Example 1 to obtain an ink.

[0744] <Image Recording>

[0745] As the ink, the above ink was used, and as the substrate, “VIEWTIFUL UV TP-188” manufactured by KIMOTO Co., Ltd. (a polyethylene terephthalate substrate with a thickness of 188 μm) was used. Except for this, image recording was performed in the same manner as in Example 1.

[0746] <Measurement and Evaluation>

[0747] The above ink and image recording material were subjected to the measurement and evaluation in Example 101.

[0748] The results are shown in Table 5.

[0749] 〔Examples 304 to 306〕

[0750] <Formation of OC Layer>

[0751] The entire image (i.e., the solid image and the line image) and the non-image formation area in the image recording material manufactured in Examples 301 to 303 were coated in a solid state with the overcoat liquid “Acuity LED 1600INKClear LL391” manufactured by FUJIFILM Corporation, and then full curing was performed, thereby forming an overcoat (OC layer).

[0752] Here, "Acuity LED 1600INK Clear LL391" does not contain flaky metal particles, but contains a polymerizable compound and an organic solvent. The proportion of the polymerizable compound having a weight average molecular weight of 1000 or more in the polymerizable compounds contained in the coating liquid is 50% by mass or more, and the content of the organic solvent is 50% by mass or more with respect to the total amount of the coating liquid.

[0753] The conditions for formal curing were set to be the same as those in Example 301.

[0754] An image recording material having a substrate, an image, and an OC layer was obtained as described above.

[0755] <Measurement and Evaluation>

[0756] The above ink and image recording material were subjected to the measurement and evaluation in Example 101.

[0757] The results are shown in Table 5.

[0758] [Table 5]

[0759]

[0760] -Explanation of Table 5-

[0761] The details of each component in Table 5 are as follows. Among the components in Table 5, for components other than the components shown below, refer to the descriptions in Tables 1 to 4.

[0762] ·CTFA: Cyclic trimethylolpropane formal acrylate (SR531, manufactured by Sartomer Japan Inc.)

[0763] ·EOTMPTA: Ethoxylated (3) trimethylolpropane triacrylate (SR454 D NS, manufactured by Sartomer Japan Inc.)

[0764] ·CN964A85: Bifunctional urethane acrylate manufactured by Sartomer Japan Inc.

[0765] As shown in Table 5, in the image recording materials of Examples 301 to 306 in which the flaky metal particles are In particles and the average angle of the flaky metal particles in the image surface layer portion is 30° or less and the average angle of the flaky metal particles inside the image exceeds 30°, the metallic luster of the image is excellent. In the image recording materials of each example, the line quality and abrasion resistance of the image are also ensured.

[0766] In Examples 301 to 306, in Examples 304 to 306 in which an OC layer was provided, the abrasion resistance of the image was more excellent.

[0767] In Examples 301 to 306, in Examples 301, 303, 304, and 306 where the time from ink landing to the start of formal curing is 0.5 seconds or more, the metallic luster of the image is more excellent.

[0768] [Example 401]

[0769] <Preparation of Undercoat Liquid 3>

[0770] The components shown in Table 6 were mixed and stirred under the same stirring conditions as in Example 1 to obtain Part A of Undercoat Liquid 3.

[0771] Part B of Undercoat Liquid 3 composed of the components shown in Table 6 was prepared.

[0772] Before image recording, Part A and Part B were mixed and used as Undercoat Liquid 3.

[0773] <Preparation of Ink>

[0774] The components shown in Table 6 were mixed and stirred under the same stirring conditions as in Example 1 to obtain the ink.

[0775] <Image Recording>

[0776] As the substrate, "Taiko PET" (polyethylene terephthalate substrate, thickness 50 μm) manufactured by FUTAMURA CHEMICAL CO., LTD. was prepared.

[0777] The above ink was introduced into an evaluation kit equipped with an inkjet head "SG1024MA" (single-pass method) manufactured by FUJIFILM Corporation, and the evaluation kit into which the ink was introduced was placed in front of an EB irradiation device of a CB200 / 45 / 300 (manufactured by ESI) pilot line.

[0778] Part A and Part B were mixed to prepare Undercoat Liquid 3, and the prepared Undercoat Liquid 3 was coated on the above substrate by a microgravure coater provided on the above pilot line, thereby forming an undercoat layer with a thickness of 4 μm.

[0779] Next, the above ink was ejected from the inkjet head of the above inkjet printer, and the above ink was applied to the undercoat layer formed on the above substrate in the form of a solid image (Solid image) with a 100% dot percentage and a line image with 2 dots, respectively.

[0780] The ink application conditions were set to conditions of 400 dpi × 400 dpi, single pass, and a substrate conveyance speed of 50 m / minute.

[0781] Next, EB (Electron beam) was irradiated onto the ink applied to the substrate.

[0782] The time from when the ink landed until EB irradiation started was 2.0 seconds.

[0783] The irradiation dose of EB was set to 40 KGly, and the acceleration voltage was set to 110 KV.

[0784] The EB irradiation of the ink on the substrate was performed in a nitrogen purge atmosphere (specifically, in an atmosphere with an oxygen concentration of 0.1 vol% or less and a nitrogen concentration of 99.9 vol% or more).

[0785] Under the above conditions, formal curing based on EB irradiation was performed on the ink applied to the substrate to record images (solid images and line images), thereby obtaining an image recording material.

[0786] <Measurement and Evaluation>

[0787] The above-mentioned ink and image recording material were subjected to the measurement and evaluation in Example 201.

[0788] The results are shown in Table 6.

[0789] [Table 6]

[0790]

[0791] -Explanation of Table 6-

[0792] The details of each component in Table 6 are as follows. Among the components in Table 6, for components other than the components shown below, refer to the explanations in Tables 1 to 5.

[0793] · A-200: "A-200" (polyethylene glycol #200 diacrylate) manufactured by SHIN-NAKAMURA CHEMICAL Co., Ltd.

[0794] As shown in Table 6, in the image recording material of Example 401 where the scaly metal particles are In particles, the average angle of the scaly metal particles in the image surface layer part is 30° or less, and the average angle of the scaly metal particles inside the image exceeds 30°, the metallic luster of the image is excellent. In the image recording material of Example 401, the line quality and dissolution resistance of the image are also excellent.

[0795] Regarding the invention of Japanese Patent Application No. 2020-114335 filed on July 1, 2020, the whole of it is incorporated herein by reference.

[0796] All documents, patent applications, and technical standards cited in this specification are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard cited by reference were specifically and individually set forth.

Claims

1. A method for manufacturing an image recording material, which uses an energy ray-curable ink containing scaly metal particles and a polymerizable compound, wherein the scaly metal particles contain indium, have an average equivalent circle diameter of 50 nm to 1000 nm, and an average aspect ratio, which is the ratio of the average equivalent circle diameter to the average thickness, of 5 to 100. The method for manufacturing the image recording material includes: an ink application step of applying the energy ray-curable ink onto a substrate; and a curing step A of curing the energy ray-curable ink applied onto the substrate by irradiation with energy ray A to obtain an image, wherein the time from when the energy ray-curable ink lands on the substrate to the start of irradiation of the energy ray-curable ink with energy ray A is 0.5 seconds or more, in a cross-section of the obtained image, in a region within 100 nm from the surface of the image, the average angle formed by the length direction of the scaly metal particles and the surface of the substrate is 30° or less, and in a region more than 100 nm from the surface of the image, the average angle formed by the length direction of the scaly metal particles and the surface of the substrate exceeds 30°.

2. The method for manufacturing an image recording material according to claim 1, wherein the time from when the energy ray-curable ink lands on the substrate to the start of irradiation of the energy ray-curable ink with energy ray A is 1.0 second or more.

3. The method for manufacturing an image recording material according to claim 1, wherein the time from when the energy ray-curable ink lands on the substrate to the start of irradiation of the energy ray-curable ink with energy ray A is 5.0 seconds or less.

4. The method for manufacturing an image recording material according to claim 1, wherein the irradiation with energy ray A is performed in an atmosphere with an oxygen concentration of 0.1% by volume or less.

5. The method for manufacturing an image recording material according to claim 1, wherein the content of the photoinitiator in the energy ray-curable ink is less than 1% by mass relative to the total amount of the energy ray-curable ink, and energy ray A is an electron beam.

6. The method for manufacturing an image recording material according to claim 1, further comprising: a semi-curing step of semi-curing the energy ray-curable ink applied onto the substrate by irradiation with energy ray P having an energy smaller than that of energy ray A after the ink application step and during the curing step A, wherein the curing step A is a step of curing the semi-cured energy ray-curable ink by irradiation with energy ray A to obtain the image.

7. The method for manufacturing an image recording material according to claim 1, wherein the ink application step is a step of applying the energy ray-curable ink onto the substrate by an inkjet method in a single-pass manner.

8. The method for manufacturing an image recording material according to claim 1, further comprising: A step of applying a primer solution onto the substrate before the ink application step and semi-curing the applied primer solution to form a primer layer. The primer solution does not contain flaky metal particles, but contains a polymerizable compound. The polymerizable compound contained in the primer solution includes at least one of a monofunctional polymerizable compound and a bifunctional polymerizable compound. The total proportion of the monofunctional polymerizable compound and the bifunctional polymerizable compound in the polymerizable compound contained in the primer solution is 50% by mass or more. The ink application step is a step of applying the active energy ray-curable ink onto the primer layer formed on the substrate.

9. The method for manufacturing an image recording material according to claim 1, further comprising: A step of applying an overcoat solution onto the image after the curing step A and curing the applied overcoat solution to form an overcoat layer. The overcoat solution does not contain flaky metal particles, but contains a polymerizable compound and an organic solvent. The proportion of the polymerizable compound having a weight average molecular weight of 1000 or more in the polymerizable compound contained in the overcoat solution is 50% by mass or more, and the content of the organic solvent is 50% by mass or more relative to the total amount of the overcoat solution.

10. The method for manufacturing an image recording material according to any one of claims 1 to 9, wherein, The flaky metal particles are flaky indium particles.

11. The method for manufacturing an image recording material according to any one of claims 1 to 9, wherein The polymerizable compound includes at least one of a monofunctional polymerizable compound and a bifunctional polymerizable compound. The total proportion of the monofunctional polymerizable compound and the bifunctional polymerizable compound in the polymerizable compound is 50% by mass or more.

12. The method for manufacturing an image recording material according to any one of claims 1 to 9, further containing an organic solvent. The content of the organic solvent is 1% by mass or more relative to the total amount of the active energy ray-curable ink.

13. The method for manufacturing an image recording material according to any one of claims 1 to 9, wherein The polymerizable compound includes a polymerizable compound having a weight average molecular weight of 1000 or more. The proportion of the polymerizable compound having a weight average molecular weight of 1000 or more in the polymerizable compound is 50% by mass or more.

14. The method for manufacturing an image recording material according to any one of claims 1 to 9, further containing an organic solvent. The content of the organic solvent is 50% by mass or more relative to the total amount of the active energy ray-curable ink.

15. The method for manufacturing an image recording material according to any one of claims 1 to 9 is an active energy ray-curable inkjet ink.

16. An image recording material obtained by the method for manufacturing an image recording material according to any one of claims 1 to 15.

Images