Method for producing laminate, and inkjet ink

Abstract

Disclosed is a method for producing a laminate, the method including a step for recording an image by applying an inkjet ink containing a pigment onto a base material for image recording containing a polymer that comprises vinyl chloride as a constituent unit, by an inkjet recording system, and a step for laminating a base material for lamination containing a polymer that comprises vinyl chloride as a constituent unit on the image without interposing another layer therebetween, wherein the inkjet ink contains a polymerizable compound A which is a compound containing two or more (meth)acryloyl groups and a polymerizable compound B which is a compound containing one (meth)acryloyl group, and the content mass ratio (polymerizable compound A / polymerizable compound B) is 0.001-0.120. Also disclosed is an inkjet ink.

Description

Method for manufacturing a laminate and inkjet ink

[0001] The present disclosure relates to a method for manufacturing a laminate and an inkjet ink.

[0002] Conventionally, various studies have been made on techniques for manufacturing a laminate using inkjet ink. For example, Patent Document 1 discloses an inkjet ink set including an inkjet coloring ink and an inkjet clear ink. The inkjet coloring ink contains an ultraviolet curable monomer, a coloring pigment, and a photoinitiator. The inkjet clear ink contains an ultraviolet curable monomer, an ultraviolet curable oligomer, and a photoinitiator. Patent Document 1 further discloses manufacturing a printed matter including a thermoplastic resin substrate (for example, a polyvinyl chloride resin), a coloring ink layer, a clear ink layer, and a thermal laminate layer covering at least the clear ink layer using this inkjet ink set. Further, Patent Document 2 discloses a laminate including a recording medium containing at least one of a urethane resin and a vinyl chloride resin, a colored image which is an inkjet recording object disposed on the recording medium, a clear ink layer containing a vinyl chloride-vinyl acetate copolymer disposed on at least the colored image on the recording medium, and a laminate substrate containing at least one of a urethane resin and a vinyl chloride resin thermally fused on the clear ink layer.

[0003] Patent Document 1: JP-A-2023-157372 Patent Document 2: WO 2019 / 087807

[0004] For example, as disclosed in Patent Documents 1 and 2 above, there is a known technique in which an image is recorded on an image recording substrate containing a polymer that includes vinyl chloride as a constituent unit using an inkjet ink containing a pigment, and a laminating substrate containing a polymer that includes vinyl chloride as a constituent unit is laminated onto the obtained image via another layer such as a clear ink layer. Through the inventors' studies, it has been found that in the above technique, when a laminating substrate is laminated onto an image recorded on an image recording substrate without another layer (e.g., a clear ink layer), image distortion due to lamination (i.e., image distortion due to heat during lamination) may occur, and / or the lamination strength of the resulting laminate (i.e., the peel strength between the image recording substrate and the laminating substrate) may decrease.

[0005] This disclosure has been made in view of these circumstances, and one embodiment of this disclosure aims to solve the problem of producing a laminate body and an inkjet ink that can produce a laminate body in which image distortion due to lamination is suppressed and the laminate body has excellent lamination strength.

[0006] This disclosure includes the following embodiments: <1> A method for producing a laminate, comprising the steps of: recording an image on an image recording substrate containing a polymer containing vinyl chloride as a constituent unit by applying an inkjet ink containing a pigment using an inkjet recording method; and laminating a laminate substrate containing a polymer containing vinyl chloride as a constituent unit onto the image without interposing any other layers, wherein the inkjet ink contains polymerizable compound A, which is a compound containing two or more (meth)acryloyl groups, and polymerizable compound B, which is a compound containing one (meth)acryloyl group, and the ratio of the mass content of polymerizable compound A to the mass content of polymerizable compound B in the inkjet ink is 0.001 to 0.120. <2> The method for producing a laminate according to <1>, wherein polymerizable compound A has a molecular weight of 145 to 2700 per (meth)acryloyl group. <3> A method for producing a laminate according to <1> or <2>, wherein the total content of polymerizable compound A and polymerizable compound B is 45% by mass or more of the total amount of inkjet ink. <4> A method for producing a laminate according to any one of <1> to <3>, wherein polymerizable compound B contains a compound with a molecular weight of 190 or less, and the proportion of the compound with a molecular weight of 190 or less in polymerizable compound B is 80% by mass or more. <5> A method for producing a laminate according to any one of <1> to <4>, wherein the inkjet ink further contains an N-vinyl compound. <6> A method for producing a laminate according to <5>, wherein in the inkjet ink, the ratio of the total content of polymerizable compound A and polymerizable compound B to the content of the N-vinyl compound is 1.1 to 7.0.<7> An inkjet ink comprising polymerizable compound A, which is a compound containing two or more (meth)acryloyl groups; polymerizable compound B, which is a compound containing one (meth)acryloyl group; and an N-vinyl compound, wherein polymerizable compound A has a molecular weight of 145 to 2700 per (meth)acryloyl group; polymerizable compound B contains compound B1, which is a compound with a molecular weight of 190 or less and containing one (meth)acryloyl group; the proportion of compound B1 in polymerizable compound B is 80% by mass or more; the ratio of the mass content of polymerizable compound A to the mass content of polymerizable compound B is 0.001 to 0.120; and the ratio of the total mass content of polymerizable compound A and polymerizable compound B to the mass content of the N-vinyl compound is 1.1 to 7.0. <8> The inkjet ink according to <7>, wherein the total content of polymerizable compound A and polymerizable compound B is 45% by mass or more of the total amount of inkjet ink.

[0007] According to one embodiment of the present disclosure, a method for manufacturing a laminate and an inkjet ink are provided that can produce a laminate with suppressed image distortion due to lamination and excellent laminate strength.

[0008] This figure shows the character image used to evaluate image distortion caused by lamination in the example.

[0009] In this specification, numerical ranges indicated using "~" mean a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in this specification, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Also, in numerical ranges described in this specification, the upper or lower limit stated in one numerical range may be replaced with the value shown in the example. In this specification, the amount of each component in a composition means the total amount of multiple substances present in the composition if there are multiple substances corresponding to each component in the composition, unless otherwise specified. In this specification, a combination of two or more preferred embodiments is a more preferred embodiment. In this specification, the term "process" is included not only in the sense of an independent process, but also in the sense of a process that cannot be clearly distinguished from other processes, as long as the intended purpose of that process is achieved.

[0010] In this specification, “image” means any film formed by applying ink, and “image recording” means the formation of an image (i.e., a film). The concept of “image” in this specification also includes solid images. In this specification, “(meth)acryloyl group” is a concept that includes both acryloyl group and methacryloyl, “(meth)acrylate” is a concept that includes both acrylate and methacrylate, and “(meth)acrylic” is a concept that includes both acrylic and methacrylic.

[0011] [Method for Manufacturing a Laminated Body] The method for manufacturing a laminated body according to the present disclosure comprises: a step of recording an image on an image recording substrate containing a polymer containing vinyl chloride as a constituent unit by applying an inkjet ink containing a pigment (hereinafter also simply referred to as "ink") using an inkjet recording method (hereinafter also referred to as the "image recording step"); and a step of laminating a laminate substrate containing a polymer containing vinyl chloride as a constituent unit onto the image without interposing any other layers (hereinafter also referred to as the "laminating step"); wherein the ink contains polymerizable compound A, which is a compound containing two or more (meth)acryloyl groups, and polymerizable compound B, which is a compound containing one (meth)acryloyl group, and the ratio of the mass content of polymerizable compound A to the mass content of polymerizable compound B in the inkjet ink is 0.001 to 0.120.

[0012] As described above, the inventors' studies have revealed that when a laminate substrate containing a polymer containing vinyl chloride as a constituent unit is laminated onto an image recorded on an image recording substrate containing a polymer containing vinyl chloride as a constituent unit, without interposing another layer (e.g., a clear ink layer), image distortion due to lamination (i.e., image distortion due to heat during lamination) may occur, and / or the lamination strength of the resulting laminate (i.e., the peel strength between the image recording substrate and the lamination substrate) may decrease. In relation to this problem, the method for manufacturing a laminate according to the present disclosure suppresses image distortion due to lamination and makes it possible to manufacture a laminate with excellent lamination strength. The reason for this effect is that the ink contains polymerizable compound A, which is a compound containing two or more (meth)acryloyl groups, and polymerizable compound B, which is a compound containing one (meth)acryloyl group, in a balance where the ratio of the mass content of polymerizable compound A to the mass content of polymerizable compound B (hereinafter also referred to as the mass content ratio [polymerizable compound A / polymerizable compound B]) is 0.001 to 0.120. The reason why the above-mentioned effect is achieved by the method for producing the laminate of this disclosure will be explained in more detail below.

[0013] Image distortion caused by lamination is thought to occur because the image is damaged by the heat and / or pressure during lamination. In the method for manufacturing a laminate according to this disclosure, image distortion caused by lamination is suppressed by having a mass ratio of [polymerizable compound A / polymerizable compound B] of 0.001 or more in the ink. This is thought to be because polymerizable compound A, which is a compound containing two or more (meth)acryloyl groups and is contained in the ink, improves the intensity of the recorded image, and as a result, the heat and / or pressure resistance of the laminate is improved.

[0014] One possible cause of insufficient laminate strength is a decrease in the miscibility between the image and the laminating substrate in the laminate, which reduces adhesion between the image and the laminating substrate, resulting in a decrease in laminate strength. Here, miscibility between the image and the laminating substrate refers to how easily the curable components (i.e., polymerizable compounds) in the image mix with the laminating substrate. The better the miscibility between the image and the laminating substrate, the better the adhesion between the image and the laminating substrate, and the higher the laminate strength. In the method for manufacturing a laminate according to this disclosure, the laminate strength of the laminate is excellent because the mass ratio of [polymerizable compound A / polymerizable compound B] is 0.120 or less. This is because the decrease in the miscibility between the image and the laminating substrate is suppressed when the mass ratio of [polymerizable compound A / polymerizable compound B] is 0.120 or less.

[0015] The method for manufacturing the laminated body described herein will be explained in more detail below.

[0016] <Image Recording Process> The method for manufacturing a laminate according to the present disclosure includes an image recording process. The image recording process is a process of recording an image by applying an ink containing a pigment to an image recording substrate containing a polymer that includes vinyl chloride as a constituent unit, using an inkjet recording method.

[0017] (Image recording substrate) In the image recording process, an image is recorded on an image recording substrate. This results in an image recording object that includes the image recording substrate and the image recorded on the image recording substrate.

[0018] The image recording substrate contains a polymer that includes vinyl chloride as a constituent unit.

[0019] A polymer containing vinyl chloride as a constituent unit may be a homopolymer of vinyl chloride (i.e., polyvinyl chloride), or it may be a copolymer containing vinyl chloride and other monomers other than vinyl chloride as constituent units.

[0020] Examples of copolymers containing vinyl chloride and other monomers other than vinyl chloride as constituent units include vinyl chloride-urethane copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, and vinyl chloride-ethylene-vinyl acetate copolymer.

[0021] In particular, the image recording substrate preferably contains polyvinyl chloride.

[0022] The image recording substrate may contain components other than polymers containing vinyl chloride as a constituent unit. Examples of other components include plasticizers, stabilizers, antioxidants, ultraviolet absorbers, binder resins, and white pigments.

[0023] The image recording substrate may have a layer containing a polymer with vinyl chloride as a constituent unit and a surface treatment layer, but from the viewpoint of obtaining adhesion between the image recording substrate and the image by dissolving the ink in the image recording substrate, it is preferable that the surface treatment layer is omitted. In other words, it is preferable that the surface of the image recording substrate to which the ink is applied contains a polymer with vinyl chloride as a constituent unit.

[0024] The thickness of the image recording substrate is not particularly limited, but is preferably 0.1 μm to 1000 μm, more preferably 0.1 μm to 800 μm, and even more preferably 1 μm to 500 μm.

[0025] (Ink) In the image recording process, an image is recorded using an ink containing a pigment (i.e., inkjet ink). The ink and image in this disclosure are distinguished from known clear inks and clear ink layers (see, for example, Patent Document 1 (JP 2023-157372 A) and Patent Document 2 (International Publication No. 2019 / 087807)) in that they each contain a pigment.

[0026] The ink further contains polymerizable compound A, which is a compound containing two or more (meth)acryloyl groups, and polymerizable compound B, which is a compound containing one (meth)acryloyl group. In the inkjet ink, the ratio of the mass content of polymerizable compound A to the mass content of polymerizable compound B is 0.001 to 0.120.

[0027] - Pigments - The ink contains at least one type of pigment. The type of pigment is not particularly limited and may be either an organic pigment or an inorganic pigment. Examples of pigments include those described in "Dictionary of Pigments" edited by Seijiro Ito (published in 2000), "Industrial Organic Pigments" by W. Herbst and K. Hunger, Japanese Patent Publication No. 2002-12607, Japanese Patent Publication No. 2002-188025, Japanese Patent Publication No. 2003-26978, and Japanese Patent Publication No. 2003-342503.

[0028] The pigment content is preferably 0.1% to 20% by mass, and more preferably 0.5% to 10% by mass, relative to the total amount of ink.

[0029] The ink may contain a pigment dispersant as needed.

[0030] Regarding pigments and pigment dispersants, prior art documents such as paragraphs 0152 to 0158 of Japanese Patent Publication No. 2011-225848 and paragraphs 0132 to 0149 of Japanese Patent Publication No. 2009-209352 can be appropriately referred to.

[0031] -Polymerizable Compound A- The ink contains at least one polymerizable compound A. Polymerizable compound A is a compound containing two or more (meth)acryloyl groups.

[0032] Polymerizable compound A has a molecular weight per (meth)acryloyl group of preferably 100 to 10000, more preferably 120 to 8000, even more preferably 145 to 2700, even more preferably 200 to 2000, and even more preferably 500 to 1500. When the molecular weight per (meth)acryloyl group of polymerizable compound A is 100 or more, the lamination strength is further improved. This is thought to be because when the molecular weight per (meth)acryloyl group of polymerizable compound A is 100 or more, the distance between crosslinking points in the cured film image is increased, which suppresses the image from becoming too hard, and as a result, the mixability between the image and the laminating substrate is further improved. When the molecular weight per (meth)acryloyl group of polymerizable compound A is 10000 or less, image distortion due to lamination is further suppressed. The reason why image distortion due to lamination is further suppressed when the molecular weight per (meth)acryloyl group of polymerizable compound A is 10,000 or less is thought to be that in the cured film image, the distance between crosslinking points becomes smaller, which improves the image intensity, and as a result, the heat and pressure resistance of the laminate improves.

[0033] Here, the molecular weight per (meth)acryloyl group of polymerizable compound A is the value obtained by dividing the molecular weight of polymerizable compound A by the number of (meth)acryloyl groups contained in one molecule of polymerizable compound A.

[0034] In this disclosure, when polymerizable compound A has a molecular weight distribution, the molecular weight of polymerizable compound A refers to the weight-average molecular weight (Mw) of polymerizable compound A.

[0035] The number of (meth)acryloyl groups (i.e., the number of functional groups) in polymerizable compound A is preferably 2 to 6, more preferably 2 to 5, even more preferably 2 to 4, and still more preferably 2 to 3.

[0036] The molecular weight of polymerizable compound A is preferably 100 to 20,000, more preferably 200 to 15,000, even more preferably 280 to 10,000, and even more preferably 500 to 4,000.

[0037] As polymerizable compound A, a (meth)acrylate with two or more functionalities (i.e., a compound containing two or more (meth)acryloyloxy groups) is preferred.

[0038] Examples of (meth)acrylates with two or more functions include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butylene glycol 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, octanediolic acid di(meth)acrylate, nonanediol di(meth)acrylate Decanediol di(meth)acrylate, dodecanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, tri Examples include methylolpropane EO-added 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, glycerin polyglycidyl ether poly(meth)acrylate, and tris(2-acryloyloxyethyl) isocyanurate.

[0039] In addition, examples of the polymerizable compound A include difunctional or higher-functional urethane (meth)acrylate, difunctional or higher-functional bisphenol A epoxy (meth)acrylate, and difunctional or higher-functional epoxy novolac (meth)acrylate.

[0040] As the polymerizable compound A, difunctional or higher-functional (preferably difunctional or trifunctional) urethane (meth)acrylate is particularly preferred.

[0041] As the polymerizable compound A, commercially available products may be used. Examples of commercially available products include Ebecryl 4101 (trifunctional urethane acrylate, Mw: refer to the examples described later) manufactured by Daicel Ornex Co., Ltd., Genome 4215 (difunctional urethane acrylate, Mw: refer to the examples described later) manufactured by Rahn AG, UV3520EA (difunctional urethane acrylate, Mw: refer to the examples described later) manufactured by Mitsubishi Chemical Corporation, CN996 (difunctional urethane acrylate, Mw = 2850) manufactured by Sartomer Company, UA-122P (difunctional urethane acrylate, Mw = 1100) manufactured by Shin-Nakamura Chemical Co., Ltd., Violet Light UV-6630B (difunctional urethane acrylate, Mw = 3000) manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Violet Light UV-3310B (difunctional urethane acrylate, Mw = 5000) manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Violet Light UV-7630B (hexafunctional urethane acrylate, Mw = 2200) manufactured by Nippon Synthetic Chemical Industry Co., Ltd., and the like.

[0042] The content of the polymerizable compound A in the ink is preferably 0.1% by mass to 15.0% by mass, more preferably 0.2% by mass to 10.0% by mass, still more preferably 0.2% by mass to 8.0% by mass, and still more preferably 0.3% by mass to 6.0% by mass based on the total amount of the ink.

[0043] - Polymerizable Compound B - The ink contains at least one kind of polymerizable compound B. The polymerizable compound B is a compound containing one (meth)acryloyl group.

[0044] As the polymerizable compound B, monofunctional (meth)acrylate (that is, a compound containing one (meth)acryloyloxy group) is preferred.

[0045] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, tert-octyl (meth)acrylate, isoamyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, and cyclohexyl (meth)acrylate. 4-n-butylcyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, bornyl (meth)acrylate, isobornyl (meth)acrylate, 2-ethylhexyldiglycol (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-meth Xyethoxyethyl (meth)acrylate, 2-(2-butoxyethoxy)ethyl (meth)acrylate, 2,2,2-tetrafluoroethyl (meth)acrylate, 1H,1H,2H,2H-perfluorodecyl (meth)acrylate, 4-butylphenyl (meth)acrylate, phenyl (meth)acrylate, 2,4,5-tetramethylphenyl (meth)acrylate, 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 trimethylolpropaneformal (meth)acrylate,Phenylglycidyl ether (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, diethylaminopropyl (meth)acrylate, trimethoxysilylpropyl (meth)acrylate, trimethylsilylpropyl (meth)acrylate, polyethylene oxide monomethyl ether (meth)acrylate, polyethylene oxide (meth)acrylate, polyethylene oxide monoalkyl ether (meth)acrylate, dipropylene glycol (meth)acrylate, polypropylene oxide monoalkyl ether (meth)acrylate, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyhexahydrophthalic acid, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, ethoxydiethylene glycol (meth)acrylate, butoxydi Examples include ethylene 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, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, (3-ethyl-3-oxetanylmethyl) (meth)acrylate, phenoxyethylene glycol (meth)acrylate, 2-carboxyethyl (meth)acrylate, and 2-(meth)acryloyloxyethyl succinate.

[0046] From the viewpoint of further improving the laminate strength, it is preferable that polymerizable compound B contains at least one compound with a molecular weight of 190 or less (i.e., a compound with a molecular weight of 190 or less containing one (meth)acryloyl group). In this case, the proportion of compounds with a molecular weight of 190 or less in polymerizable compound B is preferably 10% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, even more preferably 70% by mass or more, and even more preferably 80% by mass or more. The proportion of compounds with a molecular weight of 190 or less in polymerizable compound B may be 100% by mass, 95% by mass or 90% by mass.

[0047] There are no particular limitations on the compounds with a molecular weight of 190 or less (i.e., compounds with a molecular weight of 190 or less containing one (meth)acryloyl group), but cyclohexyl acrylate, ethoxydiethylene glycol acrylate, tetrahydrofurfuryl acrylate, N,N-dimethylacrylamide, 4-hydrochydibutyl acrylate, benzyl acrylate, (3-ethyloxetan-3-yl)methyl acrylate, or 2-oxotetrahydrofuran-3-yl acrylate are preferred.

[0048] The content of polymerizable compound B in the ink is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, and even more preferably 45% by mass or more, based on the total amount of ink. The upper limit of the content of polymerizable compound B in the ink is, for example, 90% by mass, 80% by mass, etc.

[0049] As mentioned above, in the ink, the ratio of the mass content of polymerizable compound A to the mass content of polymerizable compound B (i.e., also called the mass content ratio [polymerizable compound A / polymerizable compound B]) is 0.001 to 0.120, as mentioned above. From the viewpoint of suppressing image distortion due to lamination, the mass content ratio [polymerizable compound A / polymerizable compound B] is 0.001 or more, preferably 0.005 or more, and more preferably 0.010 or more. From the viewpoint of improving the lamination strength in the laminated body, the mass content ratio [polymerizable compound A / polymerizable compound B] is 0.120 or less, preferably 0.100 or less, more preferably 0.050 or less, and even more preferably 0.030 or less.

[0050] The total content of polymerizable compound A and polymerizable compound B in the ink is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, and even more preferably 45% by mass or more, based on the total amount of ink. The upper limit of the total content of polymerizable compound A and polymerizable compound B in the ink is, for example, 90% by mass, 80% by mass, etc.

[0051] -N-vinyl compound- The ink contains at least one N-vinyl compound. The N-vinyl compound functions as a polymerizable compound, similar to polymerizable compound A and polymerizable compound B. When the ink contains an N-vinyl compound, the adhesion between the image and the image recording substrate and / or the adhesion between the image and the laminating substrate is improved, resulting in improved lamination strength in the laminate.

[0052] Examples of N-vinyl compounds include N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylcarbazole, N-vinylimidazole, N-vinylphthalimide, N-vinylacetamide, N-vinylformamide, and 5-methyl-3-vinyl-2-oxazolidinone.

[0053] The N-vinyl compound is preferably at least one selected from the group consisting of N-vinylcaprolactam and 5-methyl-3-vinyl-2-oxazolidinone.

[0054] The N-vinyl compound content is preferably 7% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and even more preferably 20% by mass or more, based on the total amount of ink. Examples of upper limits for the N-vinyl compound content in the ink include 50% by mass, 45% by mass, and 40% by mass.

[0055] In the ink, the ratio of the total mass content of polymerizable compound A and polymerizable compound B to the mass content of N-vinyl compound (hereinafter also referred to as "mass content ratio [(polymerizable compound A + polymerizable compound B) / N-vinyl compound]") is preferably 0.3 to 9.0, preferably 0.5 to 8.0, and more preferably 1.1 to 7.0. When the mass content ratio [(polymerizable compound A + polymerizable compound B) / N-vinyl compound] is 0.3 to 9.0, image distortion due to lamination is further suppressed.

[0056] -Other polymerizable compounds- The ink may contain at least one other polymerizable compound other than polymerizable compound A, polymerizable compound B, and N-vinyl compound. Preferably, the other polymerizable compound is selected from compounds containing an ethylenically unsaturated group (e.g., vinyl group, allyl group, etc.) (excluding polymerizable compound A, polymerizable compound B, and N-vinyl compound).

[0057] -Polymerization Initiator- The ink preferably contains at least one polymerization initiator. A photoradical polymerization initiator is preferred as the polymerization initiator, as it absorbs light and generates radicals that are polymerization initiating species.

[0058] Examples of polymerization initiators include alkylphenone compounds, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having carbon-halogen bonds, and alkylamine compounds.

[0059] In particular, the polymerization initiator is preferably at least one selected from the group consisting of acylphosphine compounds and thio compounds, preferably at least one selected from the group consisting of acylphosphine oxide compounds and thioxanthone compounds, and more preferably a combination of acylphosphine oxide compounds and thioxanthone compounds.

[0060] Examples of acylphosphine oxide compounds include monoacylphosphine oxide compounds and bisacylphosphine oxide compounds, with bisacylphosphine oxide compounds being preferred.

[0061] Examples of monoacylphosphine oxide compounds include isobutyryldiphenylphosphine oxide, 2-ethylhexanoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide, o-toluyldiphenylphosphine oxide, p-t-butylbenzoyldiphenylphosphine oxide, 3-pyridylcarbonyldiphenylphosphine oxide, acryloyldiphenylphosphine oxide, benzoyldiphenylphosphine oxide, pivaloylphenylphosphine vinyl ester, and Examples include dipoylbisdiphenylphosphine oxide, pivaloyldiphenylphosphine oxide, p-toluyldiphenylphosphine oxide, 4-(t-butyl)benzoyldiphenylphosphine oxide, terephthaloylbisdiphenylphosphine oxide, 2-methylbenzoyldiphenylphosphine oxide, versatoyldiphenylphosphine oxide, 2-methyl-2-ethylhexanoyldiphenylphosphine oxide, 1-methylcyclohexanoyldiphenylphosphine oxide, methyl pivaloylphenylphosphinate, and isopropyl pivaloylphenylphosphinate.

[0062] Examples of bisacylphosphine oxide compounds include bis(2,6-dichlorobenzoyl)phenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-ethoxyphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2-naphthylphosphine oxide, and bis(2,6-dichlorobenzoyl (L)-1-naphthylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-chlorophenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,4-dimethoxyphenylphosphine oxide, bis(2,6-dichlorobenzoyl)decylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-octylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2, 5-dimethylphenylphosphine oxide, bis(2,6-dichloro-3,4,5-trimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichloro-3,4,5-trimethoxybenzoyl)-4-ethoxyphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-2,5-dimethylphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-4-ethoxyphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-2- Examples include naphthylphosphine oxide, bis(2-methyl-1-naphthoyl)-4-propylphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-2,5-dimethylphenylphosphine oxide, bis(2-methoxy-1-naphthoyl)-4-ethoxyphenylphosphine oxide, bis(2-chloro-1-naphthoyl)-2,5-dimethylphenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0063] In particular, the acylphosphine oxide compound preferably contains at least one selected from the group consisting of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (product name "Omnirad 819", manufactured by IGM Resins B.V.) and 2,4,6-trimethylbenzoyldiphenylphosphine oxide (product name "Omnirad TPO-H", manufactured by IGM Resins B.V.).

[0064] Thioxanthone compounds include thioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-dodecylthioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, 1-methoxycarbonylthioxanthone, 2-ethoxycarbonylthioxanthone, 3-(2-methoxyethoxycarbonyl)thioxanthone, and 4-butoxycarbonyl Bonylthioxanthone, 3-butoxycarbonyl-7-methylthioxanthone, 1-cyano-3-chlorothioxanthone, 1-ethoxycarbonyl-3-chlorothioxanthone, 1-ethoxycarbonyl-3-ethoxythioxanthone, 1-ethoxycarbonyl-3-aminothioxanthone, 1-ethoxycarbonyl-3-phenylsulfurylthioxanthone, 3,4-di[2-(2-methoxyethoxy)ethoxycarbonyl]thioxanthone, 1-E Toxycarbonyl-3-(1-methyl-1-morpholinoethyl)thioxanthone, 2-methyl-6-dimethoxymethylthioxanthone, 2-methyl-6-(1,1-dimethoxybenzyl)thioxanthone, 2-morpholinomethylthioxanthone, 2-methyl-6-morpholinomethylthioxanthone, n-allylthioxanthone-3,4-dicarboximide, n-octylthioxanthone-3,4-dicarboximide, N-(1,1,3,3-tetra) Examples include methylbutyl)thioxanthone-3,4-dicarboximide, 1-phenoxythioxanthone, 6-ethoxycarbonyl-2-methoxythioxanthone, 6-ethoxycarbonyl-2-methylthioxanthone, thioxanthone-2-polyethylene glycol ester, and 2-hydroxy-3-(3,4-dimethyl-9-oxo-9H-thioxanthone-2-yloxy)-N,N,N-trimethyl-1-propaneaminium chloride.

[0065] The thioxanthone compound may be a commercially available product. Examples of commercially available products include Lambson's SPEEDCURE series (e.g., SPEEDCURE 7010, SPEEDCURE CPTX, SPEEDCURE ITX, etc.).

[0066] If the ink contains a polymerization initiator, the amount of polymerization initiator is preferably 2% by mass or more, and more preferably 5% by mass or more, relative to the total amount of ink, from the viewpoint of improving the curability of the ink. The upper limit of the polymerization initiator content is not particularly limited, but for example, it is 10% by mass.

[0067] - Surfactants - The ink contains at least one surfactant.

[0068] However, from the viewpoint of improving the affinity between the image recording substrate and the ink, it is preferable that the ink does not contain surfactants, or that the surfactant content relative to the total amount of ink is less than 0.1% by mass. If the ink contains a surfactant, a commonly known surfactant can be used as the surfactant.

[0069] -Polymerization inhibitor- The ink of this disclosure preferably contains at least one polymerization inhibitor.

[0070] Examples of polymerization inhibitors include p-methoxyphenol, quinones (e.g., hydroquinone, benzoquinone, methoxybenzoquinone, etc.), phenothiazines, catechols, alkylphenols (e.g., dibutylhydroxytoluene (BHT), etc.), alkylbisphenols, zinc dimethyldithiocarbamate, copper dimethyldithiocarbamate, copper dibutyldithiocarbamate, copper salicylate, thiodipropionates, mercaptobenzimidazole, phosphites, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (TEMPO), and tris(N-nitroso-N-phenylhydroxylamine)aluminum salt (also known as cuperone Al).

[0071] In particular, the polymerization inhibitor preferably contains at least one selected from the group consisting of p-methoxyphenol, catechols, quinones, alkylphenols, TEMPO, TEMPOL, and tris(N-nitroso-N-phenylhydroxylamine)aluminum salt, and more preferably contains at least one selected from the group consisting of p-methoxyphenol, hydroquinone, benzoquinone, BHT, TEMPO, TEMPOL, and tris(N-nitroso-N-phenylhydroxylamine)aluminum salt.

[0072] If the ink contains a polymerization inhibitor, the amount of polymerization inhibitor is preferably 0.01% to 2.0% by mass, more preferably 0.02% to 1.0% by mass, and even more preferably 0.03% to 0.5% by mass, based on the total amount of ink.

[0073] -Polymer Additives- The inks of this disclosure preferably contain at least one polymer additive.

[0074] As polymer additives, resins are preferred, and acrylic resins are more preferred. In this disclosure, acrylic resin means a resin containing constituent units derived from compounds having a (meth)acryloyl group (e.g., (meth)acrylic acid esters).

[0075] Examples of acrylic resins used as polymer additives include resin T, which is an acrylic resin containing at least one group selected from the group consisting of fluorinated hydrocarbon groups, polysiloxane groups, and hydrocarbon groups having 12 or more carbon atoms. For such resin T, refer to paragraphs 0084-0132 of International Publication No. 2024 / 075540 and paragraphs 0074-0120 of International Publication No. 2024 / 075495 as appropriate.

[0076] If the ink contains polymer additives, the amount of polymer additives is preferably 0.1% to 10.0% by mass, more preferably 0.3% to 8.0% by mass, and even more preferably 0.5% to 5.0% by mass, relative to the total amount of ink.

[0077] -Water- The ink may contain a small amount of water. Specifically, the water content relative to the total amount of ink is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less. It is preferable that the ink is a non-aqueous ink that is substantially free of water.

[0078] -Other Components- The ink may contain other components not listed above. Examples of other components include ultraviolet absorbers, co-sensitizers, antioxidants, fade inhibitors, and conductive salts. For other components, publicly available documents such as Japanese Patent Publication No. 2011-225848 and Japanese Patent Publication No. 2009-209352 can be appropriately referred to.

[0079] - Physical properties of the ink - From the viewpoint of ejection performance, the viscosity of the ink is preferably 4 mPa·s to 50 mPa·s, more preferably 4 mPa·s to 30 mPa·s, and even more preferably 4 mPa·s to 15 mPa·s.

[0080] Viscosity refers to the value measured at 25°C. Viscosity is measured using a viscometer, for example, a VISCOMETER RE-85L (manufactured by Toki Sangyo Co., Ltd.).

[0081] From the viewpoint of ejection performance, the surface tension of the ink is preferably 60 mN / m or less, more preferably 20 mN / m to 50 mN / m, and even more preferably 25 mN / m to 45 mN / m.

[0082] Surface tension refers to the value measured at 25°C. Surface tension is measured using a surface tension meter, for example, the "Automatic Surface Tensionometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.)".

[0083] - An example of a preferred embodiment of the ink - An example of a preferred embodiment of the ink in this disclosure is an ink containing polymerizable compound A, polymerizable compound B, and an N-vinyl compound, wherein polymerizable compound A has a molecular weight of 145 to 2700 per (meth)acryloyl group, polymerizable compound B contains one (meth)acryloyl group and has a molecular weight of 190 or less, the proportion of compounds with a molecular weight of 190 or less in polymerizable compound B is 80% by mass or more, the content mass ratio [polymerizable compound A / polymerizable compound B] is 0.001 to 0.120, and the content mass ratio [(polymerizable compound A + polymerizable compound B) / N-vinyl compound] is 1.1 to 7.0.

[0084] In this example, the total content of polymerizable compound A and polymerizable compound B in the ink is preferably 45% by mass or more.

[0085] (Ink application) The image recording process involves applying the above-mentioned ink to the image recording substrate using an inkjet recording method to record an image.

[0086] There are no particular restrictions on the ink ejection method in an inkjet recording system, and any known method may be used, such as a charge control method that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that utilizes the vibration pressure of a piezoelectric element, an acoustic inkjet method that converts an electrical signal into an acoustic beam and irradiates the ink to eject ink using the radiation pressure, and a thermal inkjet (bubble jet®) method that heats the ink to form bubbles and utilizes the resulting pressure.

[0087] As an inkjet recording method, the method described in Japanese Patent Publication No. 54-59936 is particularly effective, as it involves the ink undergoing a rapid volume change due to the action of thermal energy, and the force resulting from this state change ejects the ink from the nozzle. As an inkjet recording method, the method described in paragraphs 0093 to 0105 of Japanese Patent Publication No. 2003-306623 can also be applied.

[0088] Ink is applied to the image recording substrate using an inkjet recording method by ejecting ink from the nozzles of the inkjet head.

[0089] Inkjet head systems include the shuttle system, which uses a short serial head to scan the recording medium in the width direction while recording, and the line system, which uses a line head in which recording elements are arranged to cover the entire width of one side of the recording medium.

[0090] In the line method, image recording can be performed across the entire surface of the recording medium by scanning it in a direction intersecting the arrangement direction of the recording elements. The line method eliminates the need for a transport system such as a carriage that scans the short head, which is required in the shuttle method. Furthermore, compared to the shuttle method, the line method eliminates the need for complex scanning control of the carriage movement and the recording medium, as only the recording medium moves. For this reason, the line method enables faster image recording compared to the shuttle method.

[0091] Ink application is preferably carried out using an inkjet head having a resolution of 300 dpi or higher (more preferably 600 dpi or higher, and even more preferably 800 dpi or higher). Here, dpi is an abbreviation for dots per inch, and 1 inch is equal to 2.54 cm.

[0092] From the viewpoint of obtaining a high-definition image, the amount of ink droplets ejected from the nozzle of the inkjet head is preferably 1 pL (picoliters) to 10 pL, and more preferably 1.5 pL to 6 pL.

[0093] (Heating step) The image recording step may include a step of heating the ink applied to the image recording substrate after the ink has been applied to the substrate (hereinafter also referred to as the "heating step").

[0094] The heating temperature is preferably 30°C to 90°C, and more preferably 30°C to 50°C.

[0095] Heating methods include, for example, infrared (IR), hot air, and the use of heating devices (e.g., heaters, hot plates, heating furnaces, etc.).

[0096] Heating can be performed by heating the ink from at least one of the image recording surface and the non-image recording surface of the image recording substrate.

[0097] (Irradiation with active energy rays) The image recording step preferably includes applying ink to an image recording substrate and irradiating the applied ink with active energy rays. In this case, it may further include drying the ink on the image recording substrate before and / or after irradiation with active energy rays. The preferred state of drying is as described above. In this case, an image is obtained by irradiating the ink on the image recording substrate with active energy rays and / or drying it.

[0098] By irradiating ink applied to an image recording substrate with active energy rays, the polymerization reaction of polymerizable compounds contained in the ink proceeds. This fixes the image and improves its hardness and other properties.

[0099] Examples of active energy rays include ultraviolet light, visible light, and electron beams. Of these, ultraviolet light is preferred as the active energy ray.

[0100] The peak wavelength of ultraviolet light is preferably 200 nm to 405 nm, and more preferably 220 nm to 390 nm.

[0101] The amount of ultraviolet light exposure was 20 mJ / cm². ２ ~5J / cm ２ Preferably, it is 100 mJ / cm ２ ~1,500mJ / cm ２ It is more preferable that this be the case. The irradiation conditions and basic irradiation method can be those disclosed in Japanese Patent Publication No. 60-132767. Specifically, the irradiation method is preferably one in which light sources are provided on both sides of the head unit including the ink ejection device and the head unit and light sources are scanned in a so-called shuttle manner, or one in which the irradiation is performed by a separate light source that does not involve driving.

[0102] Discharge lamps and laser light sources (gas lasers and solid-state lasers, etc.) are mainly used as light sources for ultraviolet irradiation. As discharge lamps, mercury lamps, metal halide lamps, and ultraviolet fluorescent lamps are widely known. In addition, semiconductor light sources such as UV-LEDs (light-emitting diodes) and UV-LDs (laser diodes) are small, have a long lifespan, are highly efficient, and are low cost, and are expected to be used as light sources for ultraviolet irradiation. Among these, metal halide lamps, high-pressure mercury lamps, medium-pressure mercury lamps, low-pressure mercury lamps, or UV-LEDs are preferred as light sources for ultraviolet irradiation.

[0103] <Laminating Process> The method for manufacturing a laminated body according to the present disclosure includes a laminating process. The laminating process is a process of laminating a laminating substrate containing a polymer with vinyl chloride as a constituent unit onto an image recorded on an image recording substrate in the image recording process described above, without any other layers in between.

[0104] (Laminating Substrate) The laminating substrate contains a polymer that includes vinyl chloride as a constituent unit. Preferred embodiments of the laminating substrate are the same as preferred embodiments of the image recording substrate, and therefore no further explanation is provided.

[0105] (Laminating Method) In the laminating process, the laminating substrate is laminated (i.e., heat-pressed) onto the image recorded on the image recording substrate in the image recording process described above, without any other layers in between. That is, in the laminating process, the image recording object, which includes the image recording substrate and the image, and the laminating substrate are laminated together with the image and the laminating substrate in contact. This results in a laminated body having a laminated structure of laminating substrate / image / image recording substrate.

[0106] From the viewpoint of suppressing thermal decomposition, the upper limit of the lamination temperature (i.e., the heat-sealing temperature) is preferably 200°C, more preferably 160°C, and even more preferably 140°C.

[0107] Note that the heat-pressing temperature refers to the surface temperature of the substrate used for lamination.

[0108] The lamination pressure (i.e., the heat-sealing pressure) is preferably 0.1 MPa to 20 MPa, and more preferably 0.5 MPa to 15 MPa.

[0109] The lamination time (i.e., the heat-pressing time) is, for example, between 10 and 500 seconds.

[0110] The laminate obtained by the manufacturing method of the laminate according to this disclosure can be used, for example, as flooring or walling material for transportation equipment (railways, buses, etc.) or as flooring or walling material for buildings.

[0111] The present disclosure will be further described below with reference to examples, but the present disclosure is not limited to the following examples unless it exceeds the spirit of the disclosure.

[0112] [Examples 1 to 12, Comparative Examples 1 to 3] <Preparation of Magenta Pigment Dispersion> The following components are mixed and stirred for 20 minutes at 5000 rpm at 25°C using a mixer (Silverson L4R) to obtain a preliminary dispersion. The obtained preliminary dispersion is placed in a disperser motor mill M50 (Eiger), and dispersed using zirconia beads with a diameter of 0.65 mm at a peripheral speed of 9 m / s for 4 hours to obtain a magenta pigment dispersion.

[0113] - Magenta pigment: Pigment Red 254 (hereinafter also referred to as "PR254") (product name "Irgazin Red L 3670 HD", manufactured by DIC Corporation) ... 20 parts by mass - Dispersant "EFKA": Product name "EFKA PX 4701" (manufactured by BASF Corporation) ... 4 parts by mass - Synthetic dispersant (manufacturing method will be described later) ... 12 parts by mass (solids) - Polymerizable compound B "PEA": Phenoxyethyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd. ... 63 parts by mass - Polymerization inhibitor "UV12": Product name "FLORSTAB UV12" (manufactured by Kromachem Corporation) (a mixture of the active ingredient N-nitroso-N-phenylhydroxylamine aluminum salt and PEA, with a mixing ratio of 1:9) ... 1 part by mass

[0114] <Method for producing synthetic dispersant> A monomer mixture of amine monomer 1 (8.0 g), oligomer 1 (16.0 g), and methyl ethyl ketone (30.0 g) is introduced into a nitrogen-purged three-necked flask and heated to 65°C while stirring with a stirrer and flowing nitrogen into the flask. Subsequently, the following two steps are carried out. Step 1: Add only 60 mg of V-65 to the above mixture and heat and stir at 65°C for 1 hour. Step 2: Add only 60 mg of V-65 and heat and stir at 65°C for another 1 hour. The resulting reaction solution is poured into 1,000 mL of hexane while stirring, the resulting precipitate is heated and dried, and then redissolved in PEA to obtain a synthetic dispersant solution (1) with a solid content concentration (i.e., concentration of synthetic dispersant) of 30% by mass. The weight-average molecular weight (polystyrene equivalent) of the polymer measured by GPC is 20,000. The compounds used as raw materials are as follows. Amine monomer 1: 3-dimethylaminopropylacrylamide (manufactured by KJ Chemicals Co., Ltd.) Oligomer 1: Poly(methyl methacrylate) macromonomer having a methacryloyl group at the terminal, trade name: AA-6 (manufactured by Toagosei Co., Ltd.) V-65: 2,2'-azobis(2,4-dimethylvaleronitrile) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0115] <Preparation of Polymer Additive 1 Solution> Weigh 1-propanol (203.7 g) and N-vinylcaprolactam (NVC) (127.5 g) into a 1 L three-necked flask equipped with a condenser, and heat and stir at 75°C under a nitrogen stream. Separately, a mixed solution prepared by mixing 1-propanol (135.8 g), hydroxyethyl methacrylate (HEMA) (7.5 g), X-22-174ASX (methacrylate-modified silicone) (manufactured by Shin-Etsu Chemical Co., Ltd.) (15.0 g), and V-601 (2,2'-azobis(isobutyrate)dimethyl; polymerization initiator manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (10.5 g) is added dropwise to the above flask over 3 hours. After the dropwise addition is complete, stir at 75°C for a further 1 hour, raise the temperature to 90°C and react for a further 3 hours. The mixture is allowed to cool to room temperature (25°C; the same applies hereafter). Then, phenoxyethyl acrylate (PEA) (350.0 g) and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyl-1-oxyl (TEMPOL) (3.5 g) are added, and 1-propanol is removed by distillation under reduced pressure conditions of 80°C / 50 hPa to obtain a 30% by mass phenoxyethyl acrylate (PEA) solution of polymer additive 1 (a copolymer of NVC / HEMA / one-terminated methacrylic-modified silicone = 85 / 5 / 10 (mass ratio)). The weight-average molecular weight of polymer additive 1 is 5000.

[0116] <Ink Preparation> The magenta pigment dispersion described above, the solution of polymer additive 1 described above, and the other components are mixed to prepare an ink having the composition shown in Tables 1 and 2. In Tables 1 and 2, the numbers in the column for each component represent the amount (parts by mass) of each component, and if each component is a solution or dispersion, it represents the amount (parts by mass) of the active ingredient or solid content. In Tables 1 and 2, blank spaces mean that the corresponding component is not contained. Tables 1 and 2 show the molecular weight, the number of (meth)acryloyl groups, and the molecular weight per (meth)acryloyl group for each of the polymerizable compounds (i.e., polymerizable compound A, polymerizable compound B, and N-vinyl compound).

[0117] -Polymerizable Compound A- ・1,6-HDDA … 1,6-hexanediol diacrylate ・PEGDA (n=4) … polyethylene glycol diacrylate (number of repeats n=4) ・Ebecryl 4101 … urethane acrylate manufactured by Daicel Ornex ・Genomer 4215 … urethane acrylate manufactured by Rahn AG ・UV3520EA … urethane acrylate manufactured by Mitsubishi Chemical Corporation -Polymerizable Compound B- ・EOEOEA … ethoxydiethylene glycol acrylate ・CHA … cyclohexyl acrylate ・TBCHA … 4-tert-butylcyclohexyl acrylate ・PEA … phenoxyethyl acrylate -N-Vinyl Compound- ・NVC … N-vinyl caprolactam -Pigment- ・PR254 … as indicated as a component in the magenta pigment dispersion. - Dispersant - Synthetic dispersant: As indicated as a component in the magenta pigment dispersion. EFKA: As indicated as a component in the magenta pigment dispersion. - Sensitizer - DETX: 2,4-diethylthioxanthone - Photopolymerization initiator - Omni. 819: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (product name "Omnirad 819", manufactured by IGM Resins B.V.) - Polymerization inhibitor - TEMPOL: 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (manufactured by Tokyo Chemical Industry Co., Ltd.) UV12: As indicated as a component in the magenta pigment dispersion. -Polymer Additives- • Polymer Additive 1... The solid content in the solution of Polymer Additive 1 (a copolymer of NVC / HEMA / one-terminated methacrylic modified silicone = 85 / 5 / 10 (mass ratio)). The amounts shown in Tables 1 and 2 are the amounts of Polymer Additive 1.

[0118] <Manufacturing of Laminated Materials> -Image Recording Process- A polyvinyl chloride substrate (product name "PVC35phr", manufactured by Okamoto Co., Ltd.) is prepared as the image recording substrate. An inkjet recording device is prepared, equipped with an inkjet head (product name "Samba G3L", manufactured by Fujifilm Corporation) and a UV-LED irradiator with a peak wavelength of 385 nm as an LED light source (product name "G5A", manufactured by Kyocera Corporation). Using the above inkjet recording device, ink is applied once to the image recording substrate to record an image. Specifically, first, on a rectangular area of ​​5 cm x 5 cm, an image with a resolution of 1200 dpi x 1200 dpi and an ink amount of 3.0 g / m² is recorded. ２ Under these conditions, ink is applied to create a 100% solid image. Next, this ink layer is exposed to the LED light source "G5A" at an exposure rate of 45 mJ / cm². ２ After irradiating with UV (ultraviolet) under these conditions, the exposure dose was 1200 mJ / cm². ２ The ink layer is cured by irradiating it with UV (ultraviolet) light under these conditions to obtain an image. In this way, an image is recorded on an image recording substrate, and an image recording object containing the image recording substrate and the image is obtained.

[0119] -Laminating Process- A polyvinyl chloride substrate (product name "SG800", manufactured by KN Trading Co., Ltd., 75 μm thick) is used as the laminating substrate. The laminating substrate is placed on the image in the image recording obtained above (i.e., on the image recorded on the image recording substrate). In this state, the image recording and the laminating substrate are heat-pressed together using a desktop automatic transfer press (product name "AF-54TEN", Asahi Textile Machinery Co., Ltd.). This obtains a laminated body having a layered structure of image recording substrate / image / laminating substrate. The lamination temperature (i.e., heat-pressure temperature) is 160°C. The lamination pressure (i.e., heat-pressure pressure) is 0.52 MPa, and the lamination time (i.e., heat-fusion time) is 160°C.

[0120] <Evaluation of Lamination Strength> A sample for evaluating the lamination strength is prepared using the following method. A 3.2 cm × 3.2 cm image recording sample is cut from the image recording obtained in the image recording process described above. Also, a 3.2 cm × 3.2 cm laminate substrate sample is cut from the laminate substrate described above. A 12 μm thick PET (polyethylene terephthalate) sheet is placed on the image recording surface of the image recording sample, in a 1.0 cm × 3.2 cm area including one side of the image recording sample. Next, a 3.2 cm × 3.2 cm laminate substrate sample is placed over the entire area on the image recording surface of the image recording sample, including the area where the PET sheet is placed (1.0 cm × 3.2 cm area) and the area where the PET sheet is not placed (2.2 cm × 3.2 cm area). In this state, the image recording sample and the laminate substrate sample are laminated under the same conditions as the lamination process described above. An evaluation sample is obtained by removing the PET sheet from the resulting laminate.

[0121] In the evaluation sample, the area where the PET sheet was not placed before the lamination process adheres to the image recording sample and the lamination substrate sample. On the other hand, in the evaluation sample, the area where the PET sheet was placed before the lamination process does not adhere to the image recording sample and the lamination substrate sample. Next, in the area where the image recording sample and the lamination substrate sample do not adhere, a tensile test is performed by pulling the image recording sample and the lamination substrate sample in opposite directions to measure the peel strength. The tensile test is performed using a tensile testing machine (product name "Autograph AGS-X 5KN", manufactured by Shimadzu Corporation). Two evaluation samples are prepared, and the tensile test is performed twice. The average value of the peel strength from the two tests is calculated as the "lamination strength," and the lamination strength of the laminate is evaluated based on the evaluation criteria below. The results are shown in Tables 1 and 2. In the evaluation criteria below, the rank that is best for lamination strength is "5."

[0122] - Evaluation Criteria for Laminate Strength - 5: Laminate strength is 4 N / cm or higher. 4: Laminate strength is 3 N / cm or higher but less than 4 N / cm. 3: Laminate strength is 2 N / cm or higher but less than 3 N / cm. 2: Laminate strength is 1 N / cm or higher but less than 2 N / cm. 1: Laminate strength is 0.1 N / cm or higher but less than 1 N / cm.

[0123] <Evaluation of Image Distortion Due to Lamination> Samples for evaluating image distortion due to lamination are prepared using the following method. Except for changing the ink application area from a solid image area to an area of ​​character image group with character images arranged in two dimensions as shown in Figure 1, the character image group is recorded on the image recording substrate in the same manner as the image recording process in the manufacturing of the laminate, and an image recording object including the image recording substrate and the image (specifically the character image group) is obtained. A 3.2 cm × 3.2 cm image recording sample is cut from the area of ​​the image recording object obtained above on which the character image group is recorded. Also, a 3.2 cm × 3.2 cm laminate substrate sample is cut from the laminate substrate mentioned above. The 3.2 cm × 3.2 cm laminate substrate sample is placed on the image recording surface of the image recording sample. In this state, the image recording sample and the laminate substrate sample are laminated under the same conditions as the lamination process described above. This obtains a sample for evaluating image distortion due to lamination. The above evaluation samples will be created for character images of each size: 5pt, 6pt, 7pt, 8pt, 9pt, 10pt, 11pt, 12pt, 13pt, 14pt, and 15pt.

[0124] The character images in each evaluation sample were visually observed, and the image distortion caused by lamination was evaluated according to the evaluation criteria below. The results are shown in Tables 1 and 2. In the evaluation criteria below, rank "5" indicates the best suppression of image distortion caused by lamination.

[0125] - Criteria for evaluating image distortion due to lamination - 5: 5pt text images are visible. 4: 6-7pt text images are visible, but 5pt text images are not. 3: 8-10pt text images are visible, but 5-7pt text images are not. 2: 11-15pt text images are visible, but 5-10pt text images are not. 1: 15pt text images are not visible.

[0126]

[0127]

[0128] As shown in Tables 1 and 2, in Examples 1 to 12, where an ink containing polymerizable compound A, which is a compound containing two or more (meth)acryloyl groups, and polymerizable compound B, which is a compound containing one (meth)acryloyl group, with a mass ratio of polymerizable compound A / polymerizable compound B of 0.001 to 0.120, is used to record images and produce laminates, image distortion due to lamination is suppressed and the laminate strength is excellent. In contrast, in Comparative Examples 1 and 2, where the mass ratio of polymerizable compound A / polymerizable compound B is less than 0.001, the effect of suppressing image distortion due to lamination is inferior. Furthermore, in Comparative Example 3, where the mass ratio of polymerizable compound A / polymerizable compound B is greater than 0.120, the laminate strength is insufficient.

[0129] As shown in Examples 1 to 12, when the molecular weight per (meth)acryloyl group of polymerizable compound A is 2700 or less (Examples 1 to 11), image distortion due to lamination is further suppressed. The reason why image distortion due to lamination is further suppressed when the molecular weight per (meth)acryloyl group of polymerizable compound A is 2700 or less is thought to be that in the cured film image, the distance between crosslinking points becomes smaller, which further improves the image intensity, and as a result, the heat and pressure resistance of the laminate is improved. As shown in Examples 1, 4, 5, and 11, when the molecular weight per (meth)acryloyl group of polymerizable compound A is 145 or more (Examples 1, 4, and 5), the laminate strength is further improved. The reason why the laminate strength is further improved when the molecular weight per (meth)acryloyl group of polymerizable compound A is 145 or more is thought to be that, in the cured film image, the distance between crosslinking points is increased, which suppresses the image from becoming too hard, and as a result, the mixability between the image and the laminating substrate is improved.

[0130] As shown in Examples 1 and 10, when the proportion of compounds with a molecular weight of 190 or less in polymerizable compound B is 80% by mass or more (Example 1), the lamination strength of the image is further improved.

[0131] As shown in Examples 6 to 9, when the mass ratio of the content [(polymerizable compound A and polymerizable compound B) / N-vinyl compound] is 1.1 to 7.0 (Examples 6 and 7), image distortion due to lamination is further suppressed. This is thought to be because when the mass ratio of the content [(polymerizable compound A and polymerizable compound B) / N-vinyl compound] is 1.1 to 7.0, the curability of the ink is further improved, and as a result, the strength of the image in the cured film is further improved.

[0132] The above examples (Examples 1 to 12) show the use of magenta ink. However, the same results as those obtained in the examples using magenta ink can be obtained when cyan ink, yellow ink, and black ink are used instead of magenta ink. For cyan ink, for example, PB15:4 (Pigment Blue 15:4) (product name "HELIOGEN BLUE D 7110F", manufactured by DIC Corporation) is used as the cyan pigment, and product name "Solsperse 32000" (manufactured by Lubrizol) is used as the dispersant. For yellow ink, for example, PY155 (Pigment Yellow 155) (product name "INKJET YELLOW 4GC", manufactured by Heubach Corporation) is used as the yellow pigment, and product name "Solsperse 32000" (manufactured by Lubrizol) is used as the dispersant. For black ink, for example, the product name "Special Black 250" (manufactured by Orion) is used as the black pigment, and the product name "Solsperse 32000" (manufactured by Lubrizol) is used as the dispersant.

[0133] Furthermore, the above-described Examples 1 to 12 are examples in which, in the image recording process, ink is applied once to the image recording substrate to record a single-layer image. As a variation of Examples 1 to 12, ink may be applied multiple times (for example, 2 to 4 times) to record a multilayer (for example, 2 to 4-layer) image. When recording a multilayer image, for example, the application of ink and UV irradiation are repeated for the number of layers.

[0134] The disclosure of Japanese Patent Application No. 2024-190050, filed on 29 October 2024, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. A method for producing a laminate, comprising the steps of:

1. Recording an image on an image recording substrate containing a polymer containing vinyl chloride as a constituent unit by applying an inkjet ink containing a pigment using an inkjet recording method; and 2. Laminating a laminate substrate containing a polymer containing vinyl chloride as a constituent unit onto the image without any other layers, wherein the inkjet ink contains polymerizable compound A, which is a compound containing two or more (meth)acryloyl groups, and polymerizable compound B, which is a compound containing one (meth)acryloyl group, and the ratio of the mass content of polymerizable compound A to the mass content of polymerizable compound B in the inkjet ink is 0.001 to 0.

120.

2. The method for producing a laminate according to claim 1, wherein the polymerizable compound A has a molecular weight of 145 to 2700 per (meth)acryloyl group.

3. The method for producing a laminate according to claim 1, wherein the total content of polymerizable compound A and polymerizable compound B is 45% by mass or more with respect to the total amount of the inkjet ink.

4. The method for producing a laminate according to claim 1, wherein the polymerizable compound B includes a compound with a molecular weight of 190 or less, and the proportion of the compound with a molecular weight of 190 or less in the polymerizable compound B is 80% by mass or more.

5. The method for producing a laminate according to claim 1, wherein the inkjet ink further contains an N-vinyl compound.

6. The method for producing a laminate according to claim 5, wherein in the inkjet ink, the ratio of the total content mass of polymerizable compound A and polymerizable compound B to the content mass of the N-vinyl compound is 1.1 to 7.

0.

7. An inkjet ink comprising: polymerizable compound A, which is a compound containing two or more (meth)acryloyl groups; polymerizable compound B, which is a compound containing one (meth)acryloyl group; and an N-vinyl compound, wherein polymerizable compound A has a molecular weight of 145 to 2700 per (meth)acryloyl group; polymerizable compound B contains compound B1, which is a compound with a molecular weight of 190 or less and contains one (meth)acryloyl group, and the proportion of compound B1 in polymerizable compound B is 80% by mass or more; the ratio of the mass content of polymerizable compound A to the mass content of polymerizable compound B is 0.001 to 0.120; and the ratio of the total mass content of polymerizable compound A and polymerizable compound B to the mass content of the N-vinyl compound is 1.1 to 7.

0.

8. The inkjet ink according to claim 7, wherein the total content of polymerizable compound A and polymerizable compound B is 45% by mass or more of the total amount of inkjet ink.

Images