Manufacturing methods for printed materials

Abstract

To provide a method for producing a printed matter capable of preventing the peeling off of a printed layer having a desired quality from a substrate while effectively utilizing the substrate.SOLUTION: According to one aspect of the present invention, there is provided a method for producing a printed matter. This production method includes an underlayer forming step, a printed layer forming step, a print quality checking step, and a post-processing step. In the underlayer forming step, an underlayer peelable from a substrate is formed on the surface of the substrate. In the printed layer forming step, a printed layer is formed on the surface of the underlayer opposite to the substrate. In the print quality checking step, the quality of the printed layer is checked. In the post-processing step, depending on the quality of the printed layer, a covering layer is formed to cover the printed layer, or the printed layer is removed together with the underlayer from the substrate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing printed materials. [Background technology]

[0002] Conventionally, methods have been considered for reusing recording media by removing the image layer from a recording medium on which an image layer has been formed (see Patent Document 1). In such a method, a coating layer is formed on a recording medium using an inkjet method with a first ink containing a photocurable compound that hardens when exposed to light and dissolves in a solvent in the hardened state, an image layer is formed on the coating layer using an inkjet method with a second ink, the formed image layer is fixed by light irradiation, and then the coating layer is dissolved in a solvent to remove the image layer from the recording medium. However, the method described in Patent Document 1 only discloses how to remove the image layer from the recording medium, and does not disclose how to make the printed material with the image layer formed on the recording medium into a final product. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2016-65213 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] According to the inventors' research, since the coating layer is removable from the recording medium, its adhesion to the recording medium is inevitably low, and therefore, in the final printed product, the image layer (printed layer) tends to peel off easily from the recording medium (substrate). In view of the above circumstances, the present invention aims to provide a method for manufacturing printed materials that can prevent the peeling of a printed layer having the desired quality from the substrate while making effective use of the substrate. [Means for solving the problem]

[0005] According to one aspect of the present invention, a method for manufacturing printed materials is provided. This manufacturing method comprises a base layer formation step, a print layer formation step, a print quality confirmation step, and a post-processing step. In the base layer formation step, a base layer that can be removed from the substrate is formed on the surface of the substrate. In the print layer formation step, a print layer is formed on the side of the base layer opposite to the substrate. In the print quality confirmation step, the quality of the print layer is confirmed. In the post-processing step, depending on the quality of the print layer, a covering layer is formed to cover the print layer, or the print layer is removed from the substrate together with the base layer.

[0006] According to this embodiment, a printed material can be obtained that prevents the peeling of the printed layer, which has the desired quality, from the substrate while making effective use of the substrate. [Brief explanation of the drawing]

[0007] [Figure 1] This is a flowchart showing a first embodiment of the method for manufacturing printed materials according to the present invention. [Figure 2] These are a plan view (top) and a cross-sectional view (bottom) showing the state after the base layer and printed layer have been formed. [Figure 3] These are a plan view (top) and a cross-sectional view (bottom) showing the state after the base layer, printing layer, and coating layer have been formed. [Figure 4] This is a flowchart showing a second embodiment of the method for manufacturing printed materials according to the present invention. [Modes for carrying out the invention]

[0008] The method for manufacturing printed materials according to the present invention will be described in detail below based on preferred embodiments shown in the attached drawings. (First Embodiment) First, a first embodiment of the method for manufacturing printed materials according to the present invention will be described. Figure 1 is a flowchart showing a first embodiment of the method for manufacturing printed materials according to the present invention. Figure 2 is a plan view (top) and a cross-sectional view (bottom) showing the state in which the base layer and the printed layer have been formed. Figure 3 is a plan view (top) and a cross-sectional view (bottom) showing the state in which the base layer, the printed layer and the coating layer have been formed.

[0009] In the following description, the upper side in FIGS. 2 and 3 is defined as "upper" or "above", and the lower side is defined as "lower" or "below". The method for manufacturing a printed matter shown in FIG. 1 includes a base layer forming step S1, a printed layer forming step S2, a print quality confirmation step S3, a coating layer formation determination step S4, and a coating layer forming step S5 and a printed layer / base layer removing step S6 as post-treatment steps. Hereinafter, each step will be sequentially described.

[0010] <Base layer forming step S1> In the base layer forming step S1, a base layer 2 that can be removed from the base material (media) 1 is formed on the upper surface (surface) of the base material 1. First, the base material 1 is prepared. As the base material 1, a resin base material formed from polyester (such as polyethylene terephthalate), an olefin-based elastomer, etc. is preferable, but a paper base material, a ceramic base material, etc. may also be used. Also, the shape of the base material 1 may be any shape such as, for example, sheet-like, flat plate-like, or any three-dimensional shape. Note that the base material 1 may have a configuration having an ink receiving layer near its surface, that is, a configuration having a base material body and an ink receiving layer formed on the surface of the base material body.

[0011] Next, the base layer 2 is formed on the upper surface of the base material 1. This base layer 2 is formed by supplying a first ink (ink for forming the base layer) to the upper surface of the base material 1. The method for supplying the first ink is not particularly limited, and examples include a droplet ejection method (inkjet method), a bar coating method, a wire bar coating method, a spin coating method, a casting method, a microgravure coating method, a gravure coating method, a roll coating method, a dip coating method, a spray coating method, a screen printing method, a flexographic printing method, an offset printing method, etc. Among these methods, the droplet ejection method or the bar coating method is preferred as the first ink supply method. That is, the base layer 2 is suitably formed by the droplet ejection method or the bar coating method. The droplet ejection method makes it easy to accurately form the base layer 2 having a shape corresponding to the shape of the printed layer 3, which will be described later. Furthermore, the droplet ejection method also makes it possible to accurately form the base layer 2 having a fine shape. Furthermore, the bar coating method makes it easier to form a relatively large base layer 2 with a uniform thickness.

[0012] The underlayer 2 is configured to be removable from the substrate 1, and its removal is preferably carried out by at least one selected from contact with a solvent, ultraviolet irradiation, heating, and plasma treatment. When removing the underlayer 2 by contact with a solvent, suitable solvents include, for example, water, a weakly alkaline aqueous solution, and organic solvents (alcohols, esters, etc.). Therefore, the underlayer 2 that can be removed by contact with a solvent is composed of, for example, water-soluble compounds. Preferred water-soluble compounds include water-soluble resins such as polyvinyl alcohol (PVA), butenediol vinyl alcohol copolymer (BVOH), and polyallylamine (PAA). These water-soluble resins may be used individually or in combination of two or more.

[0013] Furthermore, the molecular weight (weight-average molecular weight) of the water-soluble resin is not particularly limited, but is preferably around 1000 to 7500, more preferably around 1250 to 5000, and even more preferably around 1500 to 3000. A water-soluble resin having such a molecular weight can maintain sufficiently high water solubility without causing a decrease in the strength of the base layer 2. The weight-average molecular weight of the resin is determined by gel permeation chromatography (GPC) as a converted value based on standard polystyrene.

[0014] When removing the base layer 2 by ultraviolet irradiation, the base layer 2 is composed of, for example, an ultraviolet-degradable compound. Preferred UV-degradable compounds include, for example, UV-degradable resins such as polyethylene, polypropylene, polyvinyl chloride, polylactic acid with a small amount of sugar polymer units introduced, acrylic resins, polyester resins, and urethane resins. These UV-degradable resins may be used individually or in combination of two or more.

[0015] When the base layer 2 is removed by heat, the base layer 2 is composed of, for example, a pyrolytic compound. Preferred thermally decomposable compounds include, for example, ethyl cellulose, alkylated, (meth)acrylated, or epoxidized polyalkylene glycols (such as polyethylene glycol and polypropylene glycol), polymers of (meth)acrylic acid esters having an alkyl group with 1 to 6 carbon atoms, poly(meth)acrylic acid, polystyrene, and cross-linked polystyrene. These thermally decomposable resins may be used individually or in combination of two or more.

[0016] Furthermore, the base layer 2 may be composed of, for example, a resin with a glass transition temperature (Tg) of about room temperature, and thermal expansion particles. In this case, the base layer 2 can be peeled off the substrate 1 by applying physical stress through the thermal expansion of the thermal expansion particles, either by the base layer 2 becoming highly softened at a temperature slightly higher than room temperature (25°C) or by the thermal expansion of the thermal expansion particles. Examples of resins with a Tg of approximately room temperature include polyethylene, polypropylene, polyurethane, ethyl polyacrylate, and butyl polyacrylate. These resins may be used individually or in combination of two or more. Examples of materials that make up the thermally expanding particles include acrylic resins such as acrylonitrile copolymers, amide resins, and styrene resins. These materials may be used individually or in combination of two or more. Thermally expanding particles may be hollow or solid, but hollow is preferable. Hollow thermally expanding particles contain gas, which allows for a greater volume change due to thermal expansion.

[0017] Examples of gases that can be contained within thermally expanding particles include low molecular weight hydrocarbons (low boiling point hydrocarbons) such as air, ethane, ethylene, propane, propene, n-butane, isobutane, butene, isobutene, n-pentane, isopentane, neopentane, n-hexane, heptane, and petroleum ether; chlorofluorocarbons such as CCl3F, CCl2F2, and CClF3; and tetraalkylsilanes such as tetramethylsilane, trimethylethylsilane, and trimethylisopropylsilane.

[0018] When the underlying layer 2 is removed by plasma treatment, the underlying layer 2 is composed of, for example, a plasma-degradable compound. Preferred plasma-degradable compounds include plasma-degradable resins such as polymers of (meth)acrylic acid esters having an alkyl group with 1 to 6 carbon atoms, polyvinyl alcohol, polyvinyl acetate, cellulose and its derivatives, and copolymers mainly composed of these. These plasma-degradable resins may be used individually or in combination of two or more.

[0019] A hydrophilic solvent is preferred as the solvent or dispersion medium used to dissolve or disperse the above components to prepare the first ink. Examples of such hydrophilic solvents include water, methanol, ethanol, alcohols with 3 or fewer carbon atoms such as 1-propanol and 2-propanol, glycol ethers such as ethylene glycol monomethyl ether and propylene glycol monomethyl ether, amides such as N,N-dimethylformamide and N-methylpyrrolidone, lactones such as γ-butyrolactone, γ-valerolactone and ε-caprolactone, ketones such as acetone, and dimethyl sulfoxide. These solvents may be used individually or in combination of two or more.

[0020] Various surfactants can be added to the first ink for purposes such as improving its wettability to the upper surface of the substrate 1. Cationic, anionic, amphoteric, and nonionic surfactants can all be used. Cationic surfactants are not particularly limited, but examples include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, and imidazolinium salts.

[0021] Anionic surfactants are not particularly limited, but examples include fatty acid soaps, N-acyl-N-methylglycine salts, N-acyl-N-methyl-β-alanine salts, N-acyl glutamate salts, alkyl ether carboxylate salts, acylated peptides, alkyl sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, dialkyl sulfosucrate salts, alkyl sulfoacetate salts, α-olefin sulfonates, N-acylmethyl taurine, sulfated oils, higher alcohol sulfate salts, secondary higher alcohol sulfate salts, alkyl ether sulfates, secondary higher alcohol ethoxysulfates, polyoxyethylene alkylphenyl ether sulfates, monoglyculfates, fatty acid alkylolamide sulfate salts, alkyl ether phosphate salts, and alkyl phosphate salts.

[0022] The amphoteric surfactants are not particularly limited, but examples include carboxybetaine type, sulfobetaine type, aminocarboxylate salts, and imidazolinium betaine.

[0023] Examples of nonionic surfactants are not particularly limited, but include polyoxyethylene alkyl ethers, polyoxyethylene secondary alcohol ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene sterol ethers, polyoxyethylene lanolin derivatives, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene glycerin fatty acid esters, polyoxyethylene castor oil, hydrogenated castor oil, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyethylene glycol fatty acid esters, fatty acid monoglycerides, polyglycerin fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, sucrose fatty acid esters, fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkylamines, alkylamine oxides, acetylene glycols, acetylene alcohols, polyether-modified polydimethylsiloxanes, polyester-modified polydimethylsiloxanes, and the like.

[0024] These surfactants may be used individually or in combination of two or more types. The surfactant content in the first ink is not particularly limited, but is preferably between 0.001% by mass and 5% by mass, more preferably between 0.01% by mass and 1% by mass, and even more preferably between 0.1% by mass and 0.5% by mass. By adjusting the surfactant content within this range, the surface tension of the first ink can be arbitrarily adjusted, particularly to a range suitable for droplet ejection.

[0025] The first ink may contain a photocurable compound. In this case, the first ink can be given photocurability (photopolymerization properties). When using the above-mentioned water-soluble compounds, water-soluble photocurable compounds are preferably used as the photocurable compounds. Examples of such water-soluble photocurable compounds include acrylamide compounds, monofunctional (meth)acrylate compounds, and polyfunctional (meth)acrylate compounds. Examples of acrylamide compounds include (meth)acrylamide derivatives having 3 to 15 carbon atoms, hydroxyl group-containing (meth)acrylates having 5 to 15 carbon atoms, hydroxyl group-containing (meth)acrylates with a number-average molecular weight (Mn) of 200 to 1000, and (meth)acryloylmorpholin.

[0026] Examples of (meth)acrylamide derivatives having 3 to 15 carbon atoms include (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-butyl(meth)acrylamide, N,N'-dimethyl(meth)acrylamide, N,N'-diethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide (HEAA), N-hydroxypropyl(meth)acrylamide, and N-hydroxybutyl(meth)acrylamide.

[0027] Examples of hydroxyl group-containing (meth)acrylates with 5 to 15 carbon atoms include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of hydroxyl group-containing (meth)acrylates with a number-average molecular weight (Mn) of 200 to 1000 include polyethylene glycol mono(meth)acrylate, monoalkoxy (1 to 4 carbon atoms) polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, monoalkoxy (1 to 4 carbon atoms) polypropylene glycol mono(meth)acrylate, and polyethylene glycol (PEG)-polypropylene glycol (PPG) block polymer mono(meth)acrylate.

[0028] As monofunctional (meth)acrylate compounds, monofunctional (meth)acrylate compounds with high polarity are preferred. Specific examples of these monofunctional (meth)acrylate compounds include, for example, vinyl group-containing lactams such as N-vinylpyrrolidone and N-vinylcaprolactam, acryloylmorpholine, dimethylaminoethyl (meth)acrylate, and N,N-dimethylaminopropyl (meth)acrylamide.

[0029] As for polyfunctional (meth)acrylate compounds, polyfunctional (meth)acrylate compounds having an aliphatic polyether structure or an aliphatic polyester structure are preferred. Specific examples of these polyfunctional (meth)acrylate compounds include, for example, tetramethylene glycol diacrylate, hexamethylene glycol diacrylate, polyethylene glycol diacrylate, polytetramethylene glycol diacrylate, polypropylene glycol diacrylate, and polyester diol diacrylate. Furthermore, as polyfunctional (meth)acrylate compounds, urethane (meth)acrylates having an aliphatic polyether structure or an aliphatic polyester structure are also suitably used. The number-average molecular weight (Mn) of the aliphatic polyether structure or aliphatic polyester structure of these polyfunctional (meth)acrylates is preferably 600 to 2000, and more preferably 800 to 1500.

[0030] When using a photocurable compound, it is preferable to add a photocuring initiator to the first ink. A photocuring initiator can be any compound that initiates the curing (polymerization) of a photocurable compound when irradiated with light; for example, a photopolymerization initiator is one such compound. The photopolymerization initiator may be used alone, in combination of two or more types, or in combination with a sensitizer. The selection, combination, and mixing ratio of the main photopolymerization initiator and sensitizer should be appropriately determined depending on the type of photocurable compound and substrate used.

[0031] Examples of photopolymerization initiators include 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthones, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, and 1-(4-isopropylphenyl)-2-hydroxy-2-methyl ester. Examples include ropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0032] Examples of sensitizers include amines (aliphatic amines, amines containing aromatic groups, piperidine, etc.), ureas (allylic ureas, o-tolylthiourea, etc.), sulfur compounds (sodium diethyldithiophosphate, soluble salts of aromatic sulfinic acid, etc.), nitrile compounds (N,N-disubstituted p-aminobenzonitrile, etc.), phosphorus compounds (tri-n-butylphosphine, netrium diethyldithiophosphate, etc.), nitrogen compounds (Michler ketone, N-nitrisohydroxylamine derivatives, oxazolidine compounds, tetrahydro-1,3-oxazine compounds, condensates of formaldehyde or acetaldehyde and diamines, etc.), chlorine compounds (carbon tetrachloride, hexachloroethane, etc.), polymerized amines which are reaction products of epoxy resins and amines, triethanolamine triacrylate, and the like.

[0033] Furthermore, preservatives, fungicides, pH adjusters, viscosity adjusters, dispersants, etc., may be added to the first ink as needed. By adding a preservative or antifungal agent, the long-term storage stability of the first ink can be maintained. Examples of preservatives or antifungal agents include aromatic halogen compounds, methylenedithiocyanates, halogenated nitrogen-sulfur compounds, and 1,2-benzisothiazolin-3-one.

[0034] The film (liquid film) of the first ink supplied to the upper surface of the substrate 1 is dried, causing the solid components contained in the first ink to solidify and a dried film to be obtained. For this drying, methods such as natural drying, vacuum drying, blow drying, and heat drying can be used. Alternatively, drying may be performed by combining two or more drying methods. This dried film can be used as a base layer as is, or, if a first ink that is less susceptible to heat is used, it may be subjected to heat treatment. The heat treatment temperature is not particularly limited, but is preferably between 40°C and 120°C, and more preferably between 60°C and 100°C. The heat treatment time is not particularly limited, but is preferably between 1 minute and 30 minutes, and more preferably between 5 minutes and 20 minutes.

[0035] Furthermore, if the first ink contains a photocurable compound, the liquid film or dried film can be irradiated with ultraviolet light (active energy rays). Examples of lamps that generate ultraviolet light include UV-LEDs (ultraviolet light-emitting diodes), metal halide lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and fluorescent tubes. Furthermore, the ultraviolet light used for irradiation is preferably ultraviolet light with a wavelength of approximately 300 nm to 400 nm, and it is even more preferable to cut out certain wavelengths as needed. The temperature when irradiating with ultraviolet light is preferably between 15°C and 100°C, and more preferably between 20°C and 50°C. Since UV curing is an exothermic reaction, the reaction is accelerated as the temperature increases, so the temperature may be adjusted considering the type of monomer contained in the first ink.

[0036] The intensity of the ultraviolet light being irradiated is 0.1 mW / cm². 2 More than 100W / cm 2 It is preferable that it be approximately 2 mW / cm². 2 More than 50W / cm 2 The following levels are more preferable. The intensity of the ultraviolet light may be varied. Furthermore, the ultraviolet light may be irradiated continuously or intermittently (pulsed). The amount of ultraviolet energy irradiated can be adjusted as needed, but it is 10 mJ / cm². 2 More than 500J / cm 2 Preferably, it should be around 100 mJ / cm². 2 More than 200J / cm 2 It is more preferable if it is at the following level.

[0037] The thickness of the liquid coating that forms the base layer 2 is not particularly limited, but is preferably about 0.05 μm to 20 μm, and more preferably about 0.1 μm to 25 μm. With a base layer 2 of such thickness, sufficient strength can be maintained while exhibiting an excellent removal effect (decomposition effect or peeling effect) from the substrate 1 when necessary. Furthermore, when using a first ink containing polyallylamine (PAA) as a water-soluble compound, the second ink (printing layer forming ink), described later, may be supplied onto the liquid film formed by the first ink supplied to the surface of the substrate (on the side opposite to the substrate 1). In other words, the printing layer 3 may be formed by a so-called wet-on-wet method.

[0038] The first ink to be used is appropriately selected based on the constituent materials, surface condition, surface treatment, chemical treatment, etc. of the substrate 1, taking into consideration the wettability to the upper surface of the substrate 1, the adhesion of the formed underlayer 2 to the substrate 1, etc. The viscosity of the first ink at room temperature (25°C) is preferably about 20 mPa·s or less, and more preferably about 3 mPa·s to 15 mPa·s. In this case, it is easy to form a homogeneous underlayer 2 with a uniform thickness.

[0039] The base layer 2 may be a single layer formed from only one type of first ink, or it may be a laminate having multiple layers formed from two or more types of first inks. In the latter case, the base layer 2 can consist of a first base layer on the substrate 1 side and a second base layer on the side of the first base layer opposite the substrate 1, which has higher adhesion to the printed layer 2 than the first base layer. This allows the printed layer 3 to be stably held on the base layer (second base layer) 2. In this case, it is preferable that the first base layer has higher adhesion to the substrate 1 than the second base layer. This allows the base layer 2 to be stably held on the substrate 1. Furthermore, an intermediate layer may be provided between the first and second substrate layers, for example, to improve their adhesion.

[0040] In this embodiment, as shown in Figure 2, the base layer 2 is formed by a circular central base layer 2a and a plurality of outer base layers 2b arranged along the outer circumference of the central base layer 2a. The size of the base layer 2 (central base layer 2a and outer base layer 2b) may be approximately equal to the size of the next printed layer 3, as shown in Figure 2(a), or slightly larger, as shown in Figure 2(b). With this configuration, a sufficient area can be secured that is exposed from the base layer 2 and the printed layer 3 of the substrate 1. Therefore, when the base layer 2 is removed by contact with a solvent, a sufficient contact area between the base layer 2 and the solvent can be secured, and the base layer 2 can be removed quickly. Furthermore, as will be described later, when forming the coating layer 4, a sufficient contact area can be secured between the substrate 1 and the coating layer 4, making it easier to prevent the coating layer 4 from peeling off from the substrate 1.

[0041] <Print layer formation process S2> In the printing layer formation process S2, the printing layer 3 is formed on the upper surface of the base layer 2 (the surface opposite to the substrate 1). This printed layer 3 is formed by supplying a second ink (printing layer forming ink) to the upper surface of the base layer 2. The method of supplying the second ink is not particularly limited, but examples include droplet ejection (inkjet method), bar coating method, wire bar coating method, spin coating method, casting method, microgravure coating method, gravure coating method, roll coating method, dip coating method, spray coating method, screen printing method, flexographic printing method, offset printing method, etc. Among these methods, the droplet ejection method is preferred as the second ink supply method. That is, the printed layer 3 is suitably formed by the droplet ejection method. The droplet ejection method makes it easy to accurately form a printed layer 3 having a shape corresponding to the shape of the base layer 2. Furthermore, the droplet ejection method also makes it possible to accurately form a printed layer 3 having a fine shape.

[0042] Examples of second inks that can be used to form the printed layer 3 include photocurable inks, water-based inks, and solvent-based inks. <<Photocuring Ink>> The photocurable ink preferably contains at least a photocurable compound and a colorant. Examples of photocurable compounds include unsaturated carboxylic acids (acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid) or their esters, styrene, styrene derivatives (vinyltoluene, dimethylstyrene, etc.), N-vinyl compounds (N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylformamide, N-vinylacetamide, etc.), N-substituted maleimides, acrylonitrile, acryloylmorpholine, polyester acrylate, polyurethane acrylate, epoxy acrylate, polyether acrylate, oligoacrylate, alkyd acrylate, polyol acrylate, polyester methacrylate, polyurethane methacrylate, epoxy methacrylate, polyether methacrylate, oligomethacrylate, alkyd methacrylate, polyol methacrylate, and the like.

[0043] Among these, the photocurable compound is preferably one of acrylic acid esters and N-vinyl compounds. These photocurable compounds are preferred because they exhibit excellent photopolymerization properties. Furthermore, a printed layer 3 with high adhesion to the substrate layer 2 can be formed. Examples of acrylic acid esters include monofunctional (meth)acrylates such as hexyl (meth)acrylate, 2-(2-methoxyethoxy)ethyl (meth)acrylate, glycidyl (meth)acrylate, glycidyloxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, and EO-modified phenol (meth)acrylate; and polyfunctional (meth)acrylates such as 1,6-hexanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, EO-modified bisphenol A di(meth)acrylate, bisphenol F polyethoxy di(meth)acrylate, trimethylolpropane tri(meth)acrylate, sorbitol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0044] The coloring agent is selected from pigments and dyes, but from the viewpoint of improving lightfastness, it is preferable to use pigments. Both inorganic pigments and organic pigments can be used as pigments. Examples of inorganic pigments include carbon blacks such as furnace black, lamp black, acetylene black, and channel black, as well as iron oxide and titanium dioxide. Examples of organic pigments include azo pigments such as insoluble azo pigments, condensed azo pigments, azo lakes, and chelate azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments; nitro pigments; and nitroso pigments. The pigments described above may be used individually or in combination of two or more types.

[0045] The colorant content in the light-curing ink (and the same applies to other second inks) is not particularly limited, but is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less. Furthermore, when the light-curing ink (and the same applies to other second inks) is an ink for droplet ejection, the average particle size of the colorant is preferably about 10 nm to 500 nm, more preferably about 25 nm to 200 nm, and even more preferably about 50 nm to 100 nm. In this case, the ejection stability and dispersion stability of the second ink can be improved, and a high-quality printed layer (image) 3 can also be formed. Here, the average particle size refers to the particle size (D50) at 50% of the volume integrated value in the particle size distribution determined by the laser diffraction-scattering method. Furthermore, the light-curing ink may also contain, in addition to the same solvents, photopolymerization initiators, surfactants, preservatives, fungicides, pH adjusters, viscosity adjusters, and dispersants as described for the first ink above, photopolymerization accelerators, photopolymerization inhibitors, and the like.

[0046] <<Water-based ink>> Water-based inks preferably contain at least a water-soluble compound, a colorant, and a solvent. For the water-soluble compound, the same compound as described for the first ink above can be used. In the case of a water-based ink, the content of the water-soluble compound in the water-based ink is preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 10% by mass or less. Furthermore, the same colorants described above for the light-curing inks can be used as the colorants. Furthermore, the solvent can be the same compound (solvent or dispersion medium) as described for the first ink above. Among these, it is preferable to use water and at least one of alcohols and glycol ethers as the solvent.

[0047] Furthermore, the pH of water-based inks may be adjusted by adding alkali. Both inorganic and organic alkalis can be used as the alkali. Examples of inorganic alkalis include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, and sodium metasilicate. Examples of organic alkalis include ammonia, ethylamine, n-propylamine, diethylamine, diethylaminoethanol, di-n-propylamine, triethylamine, N-methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, and tetraethylammonium hydroxide. The alkali content in water-based inks is preferably 0.05% by mass or more and 1% by mass or less, and more preferably 0.1% by mass or more and 0.5% by mass or less. The water-based ink may further contain surfactants, preservatives, fungicides, viscosity modifiers, dispersants, etc., similar to those described for the first ink above.

[0048] <<Solvent ink>> The solvent ink preferably contains at least a resin, a colorant, and a solvent. Examples of resins include vinyl resins (vinyl acetate resins, vinyl chloride resins, etc.), urethane resins, ester resins, acrylic resins, styrene resins, butadiene resins, styrene-butadiene resins, acrylic styrene resins, and acrylic silicone resins. Among these, vinyl resins are preferred as the resin. By using a solvent ink containing a vinyl resin, it is possible to sufficiently improve the adhesion between the formed printed layer 3 and the base layer 2 while maintaining high wettability of the second ink to the base layer 2. The resin content in the solvent ink is preferably about 0.1% by mass or more, more preferably about 0.5% by mass or more and 10% by mass or less, and even more preferably about 1% by mass or more and 5% by mass or less. By having the resin content in the solvent ink within the above range, a more aesthetically pleasing printed layer 3 can be formed.

[0049] For the coloring agent, the same coloring agent as described above for the light-curing ink can be used. Furthermore, the solvent can be the same compound (solvent or dispersion medium) as described for the first ink above. Among these, it is preferable to use at least one of glycol ethers and lactones as the solvent. The solvent ink may further contain surfactants, preservatives, fungicides, pH adjusters, viscosity adjusters, dispersants, etc., similar to those described for the first ink above.

[0050] The film (liquid film) of the second ink supplied to the upper surface of the base layer 2 is dried, causing the solid components contained in the second ink to solidify and a dried film to be obtained. For this drying, methods such as natural drying, vacuum drying, blow drying, and heat drying can be used. Alternatively, two or more drying methods may be combined. Furthermore, the same method used to dry the film of the first ink may also be used. By applying heat treatment to this dried film, the printed layer 3 is obtained. The heat treatment temperature is not particularly limited, but is preferably between 40°C and 120°C, and more preferably between 60°C and 100°C. The heat treatment time is not particularly limited, but it is preferably between 5 minutes and 24 hours, and more preferably between 10 minutes and 20 hours.

[0051] Furthermore, if the second ink is a photocurable ink, the liquid film or dried film can be irradiated with ultraviolet light (active energy rays). The conditions for ultraviolet irradiation can be set in the same way as the conditions for ultraviolet irradiation when forming the second base layer. The thickness of the liquid coating that forms the printed layer 3 is not particularly limited, but is preferably about 1 μm to 50 μm, and more preferably about 10 μm to 25 μm. A printed layer 3 having such a thickness can maintain sufficient strength.

[0052] The second ink to be used is appropriately selected based on the constituent materials and surface condition of the base layer 2 (first ink), taking into consideration factors such as its wettability to the upper surface of the base layer 2 and the adhesion of the formed printed layer 3 to the base layer 2. The viscosity of the second ink at room temperature (25°C) is preferably about 20 mPa·s or less, and more preferably about 3 mPa·s to 15 mPa·s. In this case, it is easy to form a homogeneous printed layer 3 with a uniform thickness.

[0053] When the substrate 1 is viewed from the direction normal to the top surface, it is preferable that the printed layer 3 is formed within the area of ​​the base layer 2, that is, that the base layer 2 has a size that encompasses the printed layer 3 (see Figures 2(a) and (b)). This allows the printed layer 3 to be stably held by the substrate 1 via the base layer 2. In Figure 2(b), the central printing layer 3a is formed inside the region of the central base layer 2a, and the outer printing layer 3b is formed inside the region of each outer base layer 2b. That is, the outer edge of the central base layer 2a is exposed from the central printing layer 3a, and the outer edge of each outer base layer 2b is exposed from the outer printing layer 3b.

[0054] <Print quality confirmation process S3> In the print quality verification process S3, the quality of print layer 3 is checked. The quality of the printed layer 3 is set appropriately according to the desired print quality and is not particularly limited, but it is preferably at least one selected from cracking, bleeding, clouding, and stickiness. The quality of the printed layer 3 can be checked by methods such as visual inspection, palpation, image analysis using an image sensor (CCD camera, etc.), surface roughness measurement, tape peel test, friction and abrasion test, scratch hardness test, and pencil hardness test. These methods may be used individually or in combination of two or more. <Coating layer formation judgment step S4> In the coating layer formation determination step S4, a decision is made to either form a coating layer 4 (YES in Figure 1) or remove the printing layer 3 together with the base layer 2 from the substrate 1 (NO in Figure 1), depending on the quality of the printed layer 3 confirmed in the printing quality confirmation step S3.

[0055] <Coating layer formation step S5> In the coating layer formation step S5, a coating layer 4 is formed to cover the printed layer 3. This coating layer 4 is formed by supplying a third ink (ink for forming the coating layer) so as to cover the printed layer 3. The method of supplying the third ink is not particularly limited, but examples include droplet ejection (inkjet method), bar coating method, wire bar coating method, spin coating method, casting method, microgravure coating method, gravure coating method, roll coating method, dip coating method, spray coating method, screen printing method, flexographic printing method, offset printing method, etc. Among these methods, the droplet ejection method is preferred as the third method of ink supply. That is, the coating layer 4 is suitably formed by the droplet ejection method. The droplet ejection method makes it easy to accurately form a coating layer 4 having a shape corresponding to the shape of the base layer 2 and the printed layer 3. Furthermore, the droplet ejection method also makes it possible to accurately form a coating layer 4 having a fine shape.

[0056] The third ink preferably contains at least a monofunctional (meth)acrylate, a polyfunctional (meth)acrylate, and a photopolymerization initiator. For monofunctional (meth)acrylates and polyfunctional (meth)acrylates, compounds similar to those described for the first or second ink can be used. Furthermore, the same compounds as those described for the first ink above can be used as photopolymerization initiators. The third ink may further contain solvents, surfactants, preservatives, fungicides, pH adjusters, viscosity adjusters, dispersants, etc., similar to those described for the first ink, as well as photopolymerization accelerators, photopolymerization inhibitors, etc. By using this third ink, a coating layer 4 with high adhesion to the substrate 1 can be formed.

[0057] The content of monofunctional (meth)acrylate in the third ink is preferably 30% by mass or more and 80% by mass or less, more preferably 40% by mass or more and 70% by mass or less, and even more preferably 50% by mass or more and 60% by mass or less. The polyfunctional (meth)acrylate content in the third ink is preferably 10% by mass or more and 55% by mass or less, more preferably 20% by mass or more and 45% by mass or less, and even more preferably 30% by mass or more and 35% by mass or less. The content of the photopolymerization initiator in the third ink is preferably 1% by mass or more and 35% by mass or less, more preferably 5% by mass or more and 25% by mass or less, and even more preferably 10% by mass or more and 15% by mass or less.

[0058] The third ink film (liquid film) supplied to cover the printing layer 3 is dried as needed, causing the solid components in the third ink to solidify and a dried film to be obtained. This drying can be performed by natural drying, vacuum drying, blow drying, heat drying, etc. Alternatively, two or more drying methods may be combined. Furthermore, the same method used to dry the first or second ink film may be used. Next, the dried film can be irradiated with ultraviolet light (active energy rays). The ultraviolet light may also be irradiated directly onto the liquid film. The conditions for ultraviolet irradiation can be set in the same way as the conditions for ultraviolet irradiation when forming the second base layer. The thickness of the liquid coating layer 4 is not particularly limited, but is preferably about 10 μm to 60 μm, and more preferably about 20 μm to 40 μm. A coating layer 4 having such a thickness can maintain sufficient strength.

[0059] The third ink to be used is appropriately selected based on the constituent materials and surface condition of the substrate 1 and the printed layer 3 (second ink), taking into consideration the wettability to the upper surface of the printed layer 3, the adhesion of the formed coating layer 4 to the substrate 1 and the printed layer 3, etc. The viscosity of the third ink at room temperature (25°C) is preferably about 20 mPa·s or less, and more preferably between 3 mPa·s and 15 mPa·s. In this case, it is easy to form a homogeneous coating layer 4 with a uniform thickness.

[0060] When the substrate 1 is viewed from the direction normal to the top surface, it is preferable that the coating layer 4 has a size that encompasses the underlayer 3 (see Figures 3(a) and (b)). This allows the underlayer 2 and the printed layer 3 to be stably held by the substrate 1. The coating layer 4 may be composed of individual coating layers, as shown in Figure 3(a), including a central coating layer 4a that covers the central base layer 2a and the central printed layer 3a, and an outer coating layer 4a that covers the outer base layer 2b and the outer printed layer 3b. Alternatively, as shown in Figure 3(b), it may be composed of a single coating layer that covers the central base layer 2a, the central printed layer 3a, the outer base layer 2b, and the outer printed layer 3b all at once. In this case, it is particularly preferable that the coating layer 4 be configured such that its adhesion to the substrate 1 is higher than that of the underlayment layer 2 by selecting its constituent materials. This makes it possible to further improve the retention force of the underlayment layer 2 and the printed layer 3 to the substrate 1. As described above, a printed material is obtained as a final product by sequentially forming the base layer 2, the printing layer 3, and the coating layer 4 on the substrate 1.

[0061] <Printing layer / base layer removal process S6> In the printing layer / underlayment removal process S6, the printing layer 3 is removed from the substrate 1 along with the underlayment layer 2. As described above, the removal of the underlayer 2 is preferably carried out by at least one selected from contact with a solvent, ultraviolet irradiation, heating, and plasma treatment.

[0062] <<Contact with solvent>> Contact between the base layer 2 and the solvent can be achieved, for example, by immersing the base layer 2 (or the substrate 1 on which the base layer 2 and the printed layer 3 are formed) in the solvent (immersion method), applying the solvent to the base layer 2 (application method), or spraying the solvent onto the base layer 2 (spray method). Among these methods, contact between the base layer 2 and the solvent is preferably achieved by the immersion method. The temperature of the solvent is not particularly limited, but is preferably 20°C to 70°C, more preferably 30°C to 60°C, and even more preferably 40°C to 50°C. Using a solvent at such a temperature allows the substrate layer 2 to be removed in a shorter time.

[0063] When immersing the base layer 2 (or the substrate 1 on which the base layer 2 and the printed layer 3 are formed) in a solvent, it is preferable to perform at least one of the following: ultrasonic irradiation, heating, and agitation. This can promote the removal of the base layer 2 by dissolution in the solvent. When irradiating with ultrasound, the frequency of the ultrasound is preferably between 10 kHz and 100 kHz, more preferably between 15 kHz and 80 Hz, and even more preferably between 30 kHz and 60 Hz. The ultrasonic irradiation time is preferably between 1 minute and 60 minutes, and more preferably between 5 minutes and 45 minutes. When heating, the temperature of the solvent (underlayer 2) is preferably between 30°C and 85°C, and more preferably between 40°C and 65°C. The oscillation can be performed by reciprocating the substrate 1 in relation to the solvent.

[0064] <<Ultraviolet irradiation>> The conditions for ultraviolet irradiation are not particularly limited because they are appropriately set according to the type of the ultraviolet-decomposable compound and the like. As an example of the conditions for ultraviolet irradiation, the intensity of ultraviolet light is preferably 10 mW / cm 2 or more and 3000 mW / cm 2 or less, more preferably 20 mW / cm 2 or more and 500 mW / cm 2 or less. Also, the energy amount of ultraviolet light is preferably 100 mJ / cm 2 or more and 20000 mJ / cm 2 or less, more preferably 200 mJ / cm 2 or more and 10000 mJ / cm 2 or less.

[0065] <<Heating>> The conditions for heating are not particularly limited because they are appropriately set according to the type of the thermally decomposable compound, the type of the resin having a Tg of about room temperature, the type of the gas encapsulated in the thermal expansion particles, and the like. As an example of the conditions for heating, the heating temperature is preferably about 110°C or more and 170°C or more, more preferably about 125°C or more and 150°C or less. Also, the heating time is preferably about 5 minutes or more and 100 minutes or less, more preferably about 10 minutes or more and 60 minutes or less. ;

[0066] <<Plasma treatment>> The conditions for plasma treatment are not particularly limited because they are appropriately set according to the type of the plasma-decomposable compound and the like. The treatment gas that can be used for generating plasma is not particularly limited. For example, a gas containing at least one of oxygen, nitrogen, argon, helium, and fluorocarbon as a main component can be mentioned. In particular, if a treatment gas containing argon or helium as a main component is used, plasma can be generated in an atmosphere with a relatively low degree of vacuum or under atmospheric pressure, so that the simplification of the device can be achieved. The flow rate of the processed gas is preferably between 10 sccm and 500 sccm, and more preferably between 50 sccm and 400 sccm.

[0067] The high-frequency output (RF power) is 0.005 W / cm². 2 More than 0.2W / cm 2 Preferably, it should be around 0.05 W / cm². 2 More than 0.1W / cm 2 It is more preferable if it is at the following level. The time (processing time) in plasma processing is preferably between 60 seconds and 600 seconds, and more preferably between 180 seconds and 360 seconds. The ambient temperature in plasma processing is preferably between 0°C and 100°C, and more preferably between 20°C and 50°C. The atmosphere used in plasma processing is preferably one with a relatively low vacuum or atmospheric pressure.

[0068] In this way, the printed layer 3 is removed from the substrate 1 along with the underlayer 2. Then, after the printed layer 3 is removed along with the base layer 2, the substrate 1 is returned to the base layer formation process S1 and subjected to the printed layer formation process S2, the print quality confirmation process S3, and the post-processing steps of the coating layer formation process S5 or the printed layer / base layer removal process S6. According to the printing method described above, even if a printed layer 3 of the desired quality cannot be formed, the printed layer 3 is removed together with the base layer 2, thus enabling effective utilization of the substrate 1. This is particularly advantageous when manufacturing printed materials using a valuable substrate 1 or a single substrate 1. Furthermore, the presence of the coating layer 4 in the resulting printed material prevents peeling of the printed layer 3 and suppresses a deterioration in the quality of the printed layer 3.

[0069] When the printed material as a final product is used for a long period of time and the quality of the printed layer or the performance of the coating layer 4 deteriorates, that is, when it is necessary to remove the printed layer 2 after the coating layer 4 covering the printed layer 3 has been formed, it is preferable to form a through-hole that penetrates the coating layer 4 in the thickness direction. In this case, for example, a solvent capable of dissolving the base layer 2 can be permeated through the through-hole, and the base layer 2, printed layer 3, and coating layer 4 can be removed from the substrate 1, allowing the substrate 1 to be reused. Furthermore, even when a method other than contact with a solvent is used to remove the underlayer 2, the strength of the coating layer 4 can be reduced by forming a penetration, making it easier to remove the underlayer 2, the printed layer 3, and the coating layer 4 from the substrate 1. Examples of such through-holes include continuously formed notches, intermittently formed notches (perforations), and through-holes (needle holes, punch holes, etc.).

[0070] (Second Embodiment) Next, a second embodiment of the method for manufacturing printed materials according to the present invention will be described. The following describes the method for manufacturing printed materials according to the second embodiment, focusing on the differences from the method for manufacturing printed materials according to the first embodiment described above, and omitting explanations of similar matters. Figure 4 is a flowchart showing a second embodiment of the method for manufacturing printed materials according to the present invention. As shown in Figure 4, the method for manufacturing printed materials of the second embodiment further includes a temporary coating layer formation determination step S7 and a temporary coating layer formation step S8 between the printing layer formation step S2 and the printing quality confirmation step S3, and otherwise is the same as the method for manufacturing printed materials of the first embodiment. The following explains each step in order.

[0071] <Temporary coating layer formation determination process S7> In the temporary coating layer formation determination step S7, it is determined whether or not to form a temporary coating layer that covers the printed layer 3. Whether or not to form a temporary coating layer is determined based on factors such as the degree of adhesion (affinity) between the printed layer 3 and the base layer 2, and the degree of susceptibility of the printed layer 3 to deterioration (oxidation, etc.). If it is determined that the formation of a temporary coating layer is necessary (indicated as "YES" in Figure 4), the process proceeds to the temporary coating layer formation step S8. If it is determined that the formation of a temporary coating layer is unnecessary (indicated as "NO" in Figure 4), the process proceeds to the print quality confirmation step S3.

[0072] <Temporary coating layer formation step S8> In the temporary coating layer formation step S8, a temporary coating layer is formed to cover the printed layer 3. This temporary coating layer may have the following functions: I: to maintain the shape of the printed layer 2 until the coating layer 4 is formed; II: to prevent the printed layer 2 from peeling off the substrate 1 until the coating layer 4 is formed; III: to prevent the quality of the printed layer 3 from deteriorating until the coating layer 4 is formed; IV: to assist in the removal process of the printed layer 3 and other components from the substrate 1 when the substrate 1 is reused after the final printed product has been used; and V: to check the level of completion or the state of the design when forming the coating layer 4.

[0073] This temporary coating layer is formed by supplying a fourth ink (temporary coating layer forming ink) so as to cover the printed layer 2. The method of supplying the fourth ink is not particularly limited, but examples include droplet ejection (inkjet method), bar coating method, wire bar coating method, spin coating method, casting method, microgravure coating method, gravure coating method, roll coating method, dip coating method, spray coating method, screen printing method, flexographic printing method, offset printing method, etc. Among these methods, the droplet ejection method is preferred as the fourth ink supply method. That is, the temporary coating layer is suitably formed by the droplet ejection method. The droplet ejection method makes it easy to accurately form a temporary coating layer having a shape corresponding to the shape of the printed layer 3. Furthermore, the droplet ejection method also makes it possible to accurately form a temporary coating layer having a fine shape.

[0074] The fourth ink can be at least one selected from the first ink, which can be used to form the underlayer 2, the third ink, which can be used to form the coating layer 4, and so on. The conditions for forming the temporary covering layer can be set, for example, on the same night as the conditions for forming the underlayment layer 2 and the conditions for forming the covering layer 4. The same effects and advantages as those of the first embodiment can be obtained with this second embodiment of the method for manufacturing printed materials. In particular, since a temporary covering layer is formed to cover the printing layer 3 as needed, it is possible to manufacture printed materials having a printing layer 3 of appropriate quality regardless of the constituent materials of the printing layer 3.

[0075] Furthermore, they may be provided in the following embodiments.

[0076] (1) A method for manufacturing a printed material, comprising a base layer formation step, a print layer formation step, a print quality confirmation step, and a post-processing step, wherein in the base layer formation step, a base layer that can be removed from the substrate is formed on the surface of the substrate; in the print layer formation step, a print layer is formed on the side of the base layer opposite to the substrate; in the print quality confirmation step, the quality of the print layer is confirmed; and in the post-processing step, a covering layer is formed to cover the print layer, or the print layer is removed from the substrate together with the base layer, depending on the quality of the print layer.

[0077] (2) A method for manufacturing a printed material as described in (1) above, wherein the base layer is a first base layer on the substrate side and a second base layer having higher adhesion to the printing layer than the first base layer is formed on the side of the first base layer opposite to the substrate.

[0078] (3) A method for manufacturing printed materials as described in (2) above, wherein the first underlay layer has higher adhesion to the substrate than the second underlay layer.

[0079] (4) A method for manufacturing printed materials according to any one of (1) to (3) above, wherein the underlayer is formed by a droplet ejection method or a bar coating method.

[0080] (5) A method for manufacturing a printed material according to any one of (1) to (4) above, wherein when the substrate is viewed from the direction normal to the surface, the underlayer has a size that encompasses the printed layer.

[0081] (6) A method for manufacturing a printed material according to any one of (1) to (5) above, wherein the printed layer is formed by a droplet ejection method.

[0082] (7) A method for manufacturing a printed material according to any one of (1) to (6) above, wherein the coating layer is formed by a droplet ejection method.

[0083] (8) A method for manufacturing a printed material according to any one of (1) to (7) above, wherein when the substrate is viewed from the direction normal to the surface, the coating layer has a size that includes the underlayment layer.

[0084] (9) A method for manufacturing a printed material according to any one of (1) to (8) above, wherein the coating layer has higher adhesion to the substrate than the underlayer.

[0085] (10) A method for manufacturing a printed material according to any one of (1) to (9) above, wherein the quality of the printed layer is at least one selected from cracking, bleeding, clouding and stickiness.

[0086] (11) A method for manufacturing a printed material according to any one of (1) to (10) above, wherein the removal of the underlay layer is carried out by at least one selected from contact with a solvent, ultraviolet irradiation, heating and plasma treatment.

[0087] (12) In the method for manufacturing a printed material as described in (11) above, the contact of the underlay layer with the solvent is carried out by immersing the underlay layer in the solvent.

[0088] (13) A method for manufacturing a printed material as described in (12) above, wherein when the underlayer is immersed in the solvent, at least one selected from ultrasonic irradiation, heating, and agitation is performed.

[0089] (14) A method for manufacturing a printed material according to any one of (1) to (13) above, further comprising a temporary covering layer formation step between the printing layer formation step and the printing quality confirmation step, wherein the temporary covering layer formation step forms a temporary covering layer that covers the printing layer.

[0090] (15) A method for manufacturing a printed material according to any one of (1) to (14) above, wherein the substrate after the printing layer has been removed together with the underlayment layer is subjected again to the underlayment layer formation step, the printing layer formation step, the printing quality confirmation step and the post-processing step.

[0091] (16) A method for manufacturing a printed material according to any one of (1) to (15) above, wherein, after forming the coating layer that covers the printed layer, if it is necessary to remove the printed layer, a through portion is formed that penetrates the coating layer in the thickness direction. Of course, this is not always the case.

[0092] As previously described, various embodiments of the present invention have been explained, but these are merely examples and do not limit the scope of the invention in any way. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Examples]

[0093] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. 1. Preparation of materials First, I prepared the following materials.

[0094] <Base material> • Substrate 1: PET film (manufactured by Toray Industries, Inc., "Lumirror S10") • Substrate 2: PET film (manufactured by Panac Co., Ltd., "Gelpoly 50UV-IJ") • Substrate 3: PET film (manufactured by Higashiyama Film Co., Ltd., "HK-31WF") • Substrate 4: PET film (manufactured by Toyobo Co., Ltd., "U292W")

[0095] <First ink (ink for forming the base layer)> • First ink 1: 3D support material (Mimaki Engineering Co., Ltd., "SW-100") • First ink 2: Polyallylamine-containing ink (manufactured by Nitto Boseki Medical Co., Ltd., "PPA-01 (molecular weight: 1600)") • First ink 3: Polyallylamine-containing ink (manufactured by Nitto Boseki Medical Co., Ltd., "PPA-03 (molecular weight: 3000)")

[0096] <Second ink (ink for forming the printing layer)> • Second ink 1: Water-based ink (manufactured by Mimaki Engineering Co., Ltd.) • Second ink: Light-curing ink (manufactured by Mimaki Engineering Co., Ltd., "LUS-170") • Second ink 3: Solvent ink (manufactured by Mimaki Engineering Co., Ltd., "SS21")

[0097] <Third ink (ink for forming a coating layer)> • Third ink 1: Photocurable ink (manufactured by Mimaki Engineering Co., Ltd., "TCU-100") • Third ink type 2: Light-curing ink (manufactured by Mimaki Engineering Co., Ltd., "LH-100 CL")

[0098] 2-1. Formation of the underlayer and printed layer The substrate size used below was set to 12mm x 12mm. (Sample No. 1A) <Underlayer formation process> First, a first ink 1 was supplied to the upper surface of the substrate 1 by a bar coating method to form a liquid coating with a thickness of 2 μm. Next, the liquid coating was irradiated with ultraviolet light at room temperature (25°C). This cured the liquid coating and formed a base layer. The ultraviolet intensity was set to 466 mW / cm². 2 The energy of ultraviolet light is 336 mJ / cm². 2 That's what I decided.

[0099] <Print layer formation process> First, a liquid film with a thickness of 14-42 μm was formed on the upper surface of the substrate by ejecting a second ink 1 in droplet form using an inkjet method (droplet ejection method). The platen heater temperature of the inkjet device was set to 60°C. Next, the liquid coating was heat-treated in air at 80°C for 10 minutes. This solidified the liquid coating and formed a printed layer. Furthermore, when the substrate 1 is viewed from the direction normal to the top surface, the shape and size of the base layer and the shape and size of the printed layer were set to match.

[0100] (Sample No. 2A) The underlayer and printed layer were formed in the same manner as in Sample No. 1A, except that the thickness of the liquid film made by the first ink 1 was changed to 10 μm. (Sample No. 3A) The underlayer and printed layer were formed in the same manner as in Sample No. 1A, except that base material 2 was used instead of base material 1. (Sample No. 4A) The underlayer and printed layer were formed in the same manner as in Sample No. 3A, except that the thickness of the liquid film made by the first ink 1 was changed to 10 μm.

[0101] (Sample No. 5A) <Underlayer formation process> First, the first ink 1 was supplied to the upper surface of the substrate 3 by the bar coating method to form a liquid coating with a thickness of 0.1 μm. Next, the liquid coating was irradiated with ultraviolet light at room temperature (25°C). This cured the liquid coating and formed a base layer. The ultraviolet intensity was set to 466 mW / cm². 2 The energy of ultraviolet light is 336 mJ / cm². 2 That's what I decided.

[0102] <Print layer formation process> First, a second ink 2 was ejected as droplets onto the upper surface of the substrate using an inkjet method (droplet ejection method) to form a liquid coating with a thickness of 23 to 69 μm. The platen heater of the inkjet device was not operated. Next, the liquid coating was irradiated with ultraviolet light at room temperature (25°C). This cured the liquid coating and formed a base layer. The ultraviolet light intensity was set to 370 mW / cm². 2 The energy level of ultraviolet radiation is 710 mJ / cm². 2 That's what I decided. Furthermore, when the substrate 3 is viewed from the direction normal to the top surface, the shape and size of the base layer and the shape and size of the printed layer were set to match.

[0103] (Sample No. 6A) The underlayer and printed layer were formed in the same manner as in Sample No. 5A, except that the thickness of the liquid coating made by the first ink 1 was changed to 13.7 μm. (Sample No. 7A) The underlayer and printed layer were formed in the same manner as in Sample No. 5A, except that base material 4 was used instead of base material 3. (Sample No. 8A) The underlayer and printed layer were formed in the same manner as in Sample No. 7A, except that the thickness of the liquid coating made by the first ink 1 was changed to 13.7 μm.

[0104] (Sample No. 9A) <Underlayer formation process> First, the first ink 1 was supplied to the upper surface of the substrate 3 by the bar coating method to form a liquid coating with a thickness of 0.1 μm. Next, the liquid coating was irradiated with ultraviolet light at room temperature (25°C). This cured the liquid coating and formed a base layer. The ultraviolet intensity was set to 466 mW / cm². 2 The energy of ultraviolet light is 366 mJ / cm². 2 That's what I decided.

[0105] <Print layer formation process> First, a liquid film with a thickness of 19-57 μm was formed on the upper surface of the substrate by ejecting a second ink 3 in droplet form using an inkjet method (droplet ejection method). The platen heater temperature of the inkjet device was set to 45°C. Next, the liquid coating was heat-treated in air at 60°C for 18 hours. This solidified the liquid coating and formed a printed layer. Furthermore, when the substrate 3 is viewed from the direction normal to the top surface, the shape and size of the base layer and the shape and size of the printed layer were set to match.

[0106] (Sample No. 10A) The underlayer and printed layer were formed in the same manner as in Sample No. 9A, except that the thickness of the liquid coating made by the first ink 1 was changed to 13.7 μm. (Sample No. 11A) The underlayer and printed layer were formed in the same manner as in Sample No. 9A, except that base material 2 was used instead of base material 3. (Sample No. 12A) The underlayer and printed layer were formed in the same manner as in Sample No. 11A, except that the thickness of the liquid coating made by the first ink 1 was changed to 13.7 μm.

[0107] (Sample No. 1B) <Underlayer formation process> First, the first ink 2 was supplied to the upper surface of the substrate 1 by the bar coating method to form a liquid coating with a thickness of 2 μm. <Print layer formation process> First, a second ink 1 was ejected as droplets onto the upper surface of the liquid coating using an inkjet method (droplet ejection method) to form (layer) a liquid coating with a thickness of 14 to 42 μm. The platen heater of the inkjet device was not operated. Next, the laminated liquid coating was heat-treated in air at 80°C for 10 minutes. This solidified the laminated liquid coating, forming the base layer and the printed layer. Furthermore, when the substrate 1 is viewed from the direction normal to the top surface, the shape and size of the base layer and the shape and size of the printed layer were set to match.

[0108] (Sample No. 2B) The underlayer and printed layer were formed in the same manner as in Sample No. 1B, except that the thickness of the liquid film made by the first ink 2 was changed to 10 μm. (Sample No. 3B) The underlayer and printed layer were formed in the same manner as in Sample No. 1B, except that base material 2 was used instead of base material 1. (Sample No. 4B) The underlayer and printed layer were formed in the same manner as in Sample No. 3B, except that the thickness of the liquid film made by the first ink 2 was changed to 10 μm.

[0109] (Sample No. 5B) <Underlayer formation process> First, a first ink 3 was supplied to the upper surface of the substrate 1 by a bar coating method to form a liquid coating with a thickness of 2 μm. <Print layer formation process> First, a second ink 1 was ejected as droplets onto the upper surface of the liquid coating using an inkjet method (droplet ejection method) to form (layer) a liquid coating with a thickness of 14 to 42 μm. The platen heater of the inkjet device was not operated. Next, the laminated liquid coating was heat-treated in air at 80°C for 10 minutes. This solidified the laminated liquid coating, forming the base layer and the printed layer. Furthermore, when the substrate 1 is viewed from the direction normal to the top surface, the shape and size of the base layer and the shape and size of the printed layer were set to match.

[0110] (Sample No. 6B) The underlayer and printed layer were formed in the same manner as in Sample No. 5B, except that the thickness of the liquid film made by the first ink 3 was changed to 10 μm. (Sample No. 7B) The underlayer and printed layer were formed in the same manner as in Sample No. 5B, except that base material 2 was used instead of base material 1. (Sample No. 8B) The underlayer and printed layer were formed in the same manner as in Sample No. 7B, except that the thickness of the liquid film made by the first ink 3 was changed to 10 μm.

[0111] (Sample No. 9B) <Underlayer formation process> First, the first ink 2 was supplied to the upper surface of the substrate 1 by the bar coating method to form a liquid coating with a thickness of 2 μm. Next, the liquid coating was heat-treated in air at 80°C for 10 minutes. This solidified the liquid coating and formed the base layer.

[0112] <Print layer formation process> First, a liquid film with a thickness of 14-42 μm was formed on the upper surface of the substrate by ejecting a second ink 1 in droplet form using an inkjet method (droplet ejection method). The platen heater temperature of the inkjet device was set to 60°C. Next, the laminated liquid coating was heat-treated in air at 80°C for 10 minutes. This solidified the laminated liquid coating, forming the base layer and the printed layer. Furthermore, when the substrate 1 is viewed from the direction normal to the top surface, the shape and size of the base layer and the shape and size of the printed layer were set to match.

[0113] (Sample No. 10B) The underlayer and printed layer were formed in the same manner as in Sample No. 9B, except that the thickness of the liquid film made by the first ink 2 was changed to 10 μm.

[0114] 2-2. Evaluation <Checking the quality of the printed layer> The state (image quality) of the upper surface of the printing layer was evaluated by visual observation and palpation. <X-Cut Test> After forming a plurality of compartments by making cuts in a grid pattern in the printing layer, a tape was adhered to the printing layer. Then, the tape was peeled off from the printing layer to check the state of the upper surface of the printing layer. In the table, the ratio of the compartments remaining on the substrate without peeling (assuming "10" when there is no peeling) is described. When there is stickiness in the printing layer and the X-cut test was not performed, it is described as "sticky".

[0115] <Claw Friction Test> The upper surface of the printing layer was rubbed 10 times with a claw and evaluated according to the following criteria. ○: Does not peel off. △: Peels off when rubbed strongly. ×: Peels off easily. <Water Immersion Test> After putting the sample and water (25 °C) in a vial and gently shaking it, the degree of peeling of the printing layer was observed. When applying ultrasonic waves, the frequency was set to 38 kHz.

[0116] These results are shown in Tables 1 and 2 below.

[0117]

Table 1

[0118] As shown in Table 1, it was found that when the underlayer was formed using the 3D support material, the compatibility with the printing layer formed of the photocurable ink was good. Also, when the underlayer was formed using the 3D support material, it was found that the printing layer (underlayer) could be easily peeled off by immersion in water regardless of the type of the second ink used for forming the printing layer. Furthermore, when the underlayer was formed using the 3D support material, it seemed that a thinner thickness was less likely to affect the strength of the printing layer. It was also confirmed that the ease of peeling by immersion in water did not depend on the thickness of the underlayer. Furthermore, in samples No. 1A-4A and 9A-12A, the printed layer was sticky and had low strength. In such cases, it is considered effective to form a temporary coating layer before forming the final coating layer.

[0119] [Table 2]

[0120] As shown in Table 2, when a base layer was formed using a polyallylamine-containing ink, the printed layer tended to become cloudy when a water-based ink was used to form the printed layer. This can be resolved by considering the type of solvent in the first ink, the type of second ink, etc., that is, by selecting the right combination of the first and second inks. Furthermore, the remaining printed layer (underlay) after 60 minutes of ultrasonic treatment could be easily peeled off by rubbing. Furthermore, it was found that when the printing layer is formed after the polyallylamine-containing ink has been cured or solidified, it is easier to peel off the printing layer (underlay) by immersion in water compared to when the printing layer is formed using the wet-on-wet method.

[0121] 3-1. Formation of the coating layer (Sample No. 1C) <Coating layer formation process> First, a third ink 1 was supplied in droplet form using the bar coating method to cover a portion of the printed layer and the underlayer of sample No. 5A, forming a liquid coating with a thickness of 22.9 μm. Next, the liquid coating was irradiated with ultraviolet light at room temperature (25°C). This cured the liquid coating and formed a protective layer. The ultraviolet light intensity was set to 466 mW / cm². 2 The energy of ultraviolet light is 336 mJ / cm². 2 That's what I decided.

[0122] (Sample No. 2C) The coating layer was formed in the same manner as in Sample No. 1C, except that the third ink 2 was used instead of the third ink 1. (Sample No. 3C) The coating layer was formed in the same manner as in Sample No. 1C, except that the coating layer was formed to cover the entire printed layer and the underlayer.

[0123] 3-2. Evaluation <Quality check of the coating layer> The presence or absence of image quality inconsistencies was evaluated by visually observing the coating layer. <Nail friction test> The procedure was carried out in the same manner as described above. <Water immersion test> The procedure was carried out in the same manner as described above.

[0124] These results are shown in Table 3 below.

[0125] [Table 3]

[0126] In Table 3, "*" indicates that no delamination of the printed layer was observed in the areas covered by the coating layer, but delamination of the printed layer was observed in the areas not covered by the coating layer. As shown in Table 3, it was revealed that forming a coating layer prevents peeling of the printed layer even in nail friction tests. Furthermore, it was confirmed that by forming a coating layer, the printed layer did not peel off even after 91 hours of immersion in water and 30 minutes of ultrasonic treatment.

[0127] 4. Effects of time progression under normal temperature and humidity conditions (Sample No. 1D) Except for using a 100mm x 160mm substrate 3, the underlayer and printed layer were formed in the same manner as in Sample No. 5A. (Sample No. 2D) Except for using a 100mm x 160mm substrate 3, the underlayer, printed layer, and coating layer were formed in the same manner as in Sample No. 3C.

[0128] Next, we examined the changes in the printed and coated layers of samples No. 1D and 2D immediately after formation and after being left in a normal temperature and humidity environment for 3 months. These results are shown in Table 4 below.

[0129] [Table 4]

[0130] As shown in Table 4, after 3 months of storage, the degree of bleeding tended to worsen in the printed layer (especially in lighter colored areas) when no coating layer was formed. Forming a coating layer did not change the degree of bleeding, but the gloss tended to decrease. Furthermore, after being left for three months, even with the formation of a protective coating, the printed layer appeared to be more prone to peeling during the fingernail friction test. No changes were observed in the water immersion test. The sample print layers (images) are printed with cyan, magenta, yellow, and black at print densities of 20-100% (in 20% increments) for each color. Furthermore, mixed colors of magenta and yellow, cyan and yellow, and cyan and magenta are printed at print densities of 40-200% (in 40% increments) for each color. In addition, mixed colors of cyan, magenta, and yellow are printed at print densities of 60-300% (in 60% increments). In Table 4, "Peeling only at 20% color density" means that cyan, magenta, yellow, and black at 20% print density will peel off.

[0131] 5. Effects of time progression in high temperature and high humidity environments Changes in the printed and coated layers of samples No. 1D and 2D were observed immediately after formation and after being left in a high-temperature, high-humidity environment (35°C, 90%RH) for 1 day and 3 months. These results are shown in Table 5 below.

[0132] [Table 5]

[0133] As shown in Table 5, under high temperature and high humidity conditions (harsh conditions), even if a coating layer is formed, the image quality and peel strength appear to deteriorate over time. In such cases, it is considered effective to remove the undercoat, printing layer, and coating layer from the substrate and reuse the substrate.

[0134] 6. Examination of abrasion resistance (Sample No. 1E) Except for using a 100mm x 160mm substrate 3, the underlayer and printed layer were formed in the same manner as in Sample No. 5A. (Sample No. 2E) Except for using a 100mm x 160mm substrate 3, the underlayer, printed layer, and coating layer were formed in the same manner as in Sample No. 3C.

[0135] Next, dry friction tests and wet friction tests were performed on the printed and coated layers of samples No. 1E and 2E as follows. • Dry friction test: Using a Japan Society for the Promotion of Science (JSPS) type friction tester, a dry cotton broadcloth was reciprocated against the sample at a height of 0 mm and a load of 1000 g. • Wet friction test: Using a Japan Society for the Promotion of Science (JSPS) type friction tester, a cotton broadcloth soaked in water was reciprocated against the sample at a height of 0 mm and a load of 1000 g.

[0136] As a result, in the dry friction test, peeling of the printed layer was observed after 100 reciprocating motions when the coating layer was not formed. In contrast, when the coating layer was formed, no damage occurred to the printed layer even after 2000 reciprocating motions. Furthermore, in the wet friction test, without the coating layer, slight scratches were observed on the surface of the printed layer after 2000 reciprocating motions. In contrast, with the coating layer, no scratches occurred on the printed layer even after 2000 reciprocating motions.

[0137] Based on the above, a high-quality printed layer can be formed by appropriately combining the constituent materials of the base layer and the constituent materials of the printed layer. If the quality of the printed layer does not meet the required standards, the printed layer can be peeled off (removed) along with the underlying layer, allowing the substrate to be reused. Furthermore, once a printed layer that satisfies the required quality is formed, it can be transformed into a final printed product by forming a coating layer. In such a printed product, the quality of the printed layer can be maintained over a long period of time. Furthermore, if the coating layer deteriorates over time, the substrate can be reused by removing the underlayer, printed layer, and coating layer. [Explanation of symbols]

[0138] 1: Base material 2: Base layer 2a: Central substratum 2b: Peripheral base layer 3: Printing layer 3a: Central printing layer 3b: Outer printing layer 4: Covering layer 4a: Central coating layer 4b: Outer coating layer S1: Base layer formation process S2: Printing layer formation process S3:Print quality confirmation process S4: Coating layer formation judgment process S5: Covering layer formation process S6: Base layer removal process S7: Temporary coating layer formation determination process S8: Temporary coating layer formation process

Claims

1. A method for manufacturing printed materials, The process comprises a base layer formation process, a print layer formation process, a print quality confirmation process, and a post-processing process. In the above-mentioned base layer formation step, a base layer that can be removed from the base material is formed on the surface of the base material. In the printing layer formation step, a printing layer is formed on the surface of the underlayer opposite to the substrate. In the print quality confirmation step, the quality of the print layer is confirmed, The post-processing step involves either forming a covering layer over the printed layer or removing the printed layer from the substrate together with the underlayment, depending on the quality of the printed layer.

2. In the method for manufacturing a printed article according to claim 1, A method comprising forming a first underlayer on the substrate side and a second underlayer on the side of the first underlayer opposite the substrate, the second underlayer having higher adhesion to the printing layer than the first underlayer.

3. In the method for manufacturing a printed material according to claim 2, A method wherein the first underlayer has higher adhesion to the substrate than the second underlayer.

4. In the method for manufacturing a printed article according to claim 1, The aforementioned underlayer is formed by a method such as droplet dispensing or bar coating.

5. In the method for manufacturing a printed article according to claim 1, A method wherein, when the substrate is viewed from the direction normal to the surface, the underlayer has a size that encompasses the printed layer.

6. In the method for manufacturing a printed article according to claim 1, The aforementioned printed layer is formed by a droplet ejection method.

7. In the method for manufacturing a printed article according to claim 1, The coating layer is formed by a droplet ejection method.

8. In the method for manufacturing a printed article according to claim 1, A method wherein, when the substrate is viewed from the direction normal to the surface, the coating layer has a size that encompasses the underlayer.

9. In the method for manufacturing a printed article according to claim 1, The method wherein the coating layer has higher adhesion to the substrate than the underlayer.

10. In the method for manufacturing a printed article according to claim 1, A method wherein the quality of the printed layer is at least one selected from cracking, bleeding, clouding, and stickiness.

11. In the method for manufacturing a printed article according to claim 1, The removal of the aforementioned substrate is carried out by at least one selected from contact with a solvent, ultraviolet irradiation, heating, and plasma treatment.

12. In the method for manufacturing a printed material according to claim 11, The method involves bringing the substrate layer into contact with the solvent by immersing the substrate layer in the solvent.

13. In the method for manufacturing a printed material according to claim 12, A method comprising immersing the aforementioned substrate layer in the aforementioned solvent, wherein at least one of ultrasonic irradiation, heating, and agitation is performed.

14. In the method for manufacturing a printed article according to claim 1, Furthermore, a temporary covering layer formation step is provided between the printing layer formation step and the printing quality confirmation step. The method for forming the temporary covering layer in the temporary covering layer formation step involves forming a temporary covering layer that covers the printed layer.

15. In the method for manufacturing a printed article according to claim 1, A method wherein the substrate, after the printing layer has been removed together with the underlayment layer, is subjected again to the underlayment layer formation step, the printing layer formation step, the print quality confirmation step, and the post-processing step.

16. In the method for manufacturing a printed article according to claim 1, A method for forming a coating layer that covers the printed layer, and then, if it is necessary to remove the printed layer, forming a through portion that penetrates the coating layer in the thickness direction.

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