Method for manufacturing printed matter

Abstract

To provide a method for manufacturing a printed matter which can form an excellent image even on a hydrophobic base material using aqueous ink without lowering productivity.SOLUTION: A method for manufacturing a printed matter includes a step of imparting a pretreatment liquid onto a base material of 45°C to 100°C, then imparting aqueous ink onto the base material of 45°C to 100°C by an inkjet method, and thereby forming an image, wherein the pretreatment liquid contains water, a water-soluble organic solvent, and a surface active agent, the surface active agent is an anionic surface active agent, a nonionic surface active agent or a combination thereof, the aqueous ink contains water, a coloring material, a water-soluble organic solvent, a water-dispersible resin, and a surface active agent, and at least one of the coloring material, the water dispersible resin and the surface active agent is anionic.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a printed matter.

Background Art

[0002] Since polyvinyl chloride, which is widely used in the signage market, is a hydrophobic substrate, non-aqueous inks such as solvent inks are suitable. Because solvent inks have a high affinity for polyvinyl chloride, the dot size after landing is large, and an image can be formed with a small number of dots, enabling high-speed printing. On the other hand, due to the increasing concern for the environment, in recent years, there has been a case where solvent inks are not used as the ink for producing printed matters in the signage market, and instead, aqueous inks are used.

[0003] When using an aqueous ink, from the viewpoints of ink permeability to the substrate, image density, image fixability, etc., there is a method of pretreating the substrate and then applying the aqueous ink to the substrate surface. At that time, there is a technique of including a cationic substance such as a polyvalent metal salt in the pretreatment liquid to aggregate the aqueous ink on the substrate surface to increase the image density. Patent Document 1 discloses that a white image with excellent concealability can be formed by a step of applying a pretreatment liquid to a substrate and applying a white resist inkjet ink to the substrate to which the pretreatment liquid has been applied.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since water-based ink has low affinity with polyvinyl chloride, when printing water-based ink on non-permeable substrates such as vinyl chloride, the dot size becomes smaller than that of solvent-based ink, and it is necessary to increase the number of dots to form an image. Therefore, the printing speed has to be reduced, which causes a problem in productivity.

[0006] An embodiment of the present invention aims to provide a method for manufacturing a printed matter that can use water-based ink on hydrophobic substrates such as polyvinyl chloride and form excellent images without reducing productivity.

Means for Solving the Problems

[0007] An embodiment of the present invention includes a step of forming an image by applying a pretreatment liquid to a substrate at 45°C to 100°C and then applying water-based ink to the substrate at 45°C to 100°C by an inkjet method. The pretreatment liquid includes water, a water-soluble organic solvent, and a surfactant. The surfactant is an anionic surfactant, a nonionic surfactant, or a combination thereof. The water-based ink includes water, a coloring material, a water-soluble organic solvent, a water-dispersible resin, and a surfactant. At least one of the coloring material, the water-dispersible resin, and the surfactant is anionic. The present invention relates to a method for manufacturing a printed matter.

Effects of the Invention

[0008] According to an embodiment of the present invention, it is possible to provide a method for manufacturing a printed matter that can use water-based ink on hydrophobic substrates such as polyvinyl chloride and form excellent images without reducing productivity.

Modes for Carrying Out the Invention

[0009] Hereinafter, the present invention will be described using one embodiment. The examples in the following embodiments do not limit the present invention.

[0010] One embodiment of the present invention includes a step of forming an image by applying a pretreatment liquid to a substrate at 45°C to 100°C and then applying an aqueous ink to the substrate at 45°C to 100°C by an inkjet method. The pretreatment liquid includes water, a water-soluble organic solvent, and a surfactant. The surfactant is an anionic surfactant, a nonionic surfactant, or a combination thereof. The aqueous ink includes water, a coloring material, a water-soluble organic solvent, a water-dispersible resin, and a surfactant. At least one of the coloring material, the water-dispersible resin, and the surfactant is anionic. The present invention relates to a method for manufacturing a printed matter.

[0011] When performing inkjet printing using a pretreatment liquid and an aqueous ink containing an anionic substance, a method is known in which a pretreatment liquid containing a cationic substance is used, and the ink is aggregated and fixed to a substrate by utilizing the electrostatic interaction between anions and cations. In one embodiment, the pretreatment liquid is characterized by containing a nonionic or anionic substance. By using these pretreatment liquid and aqueous ink, the aqueous ink can be prevented from aggregating and the dot size can be enlarged on the substrate surface. Further, by applying a pretreatment liquid containing water, a water-soluble organic solvent, and a surfactant to a substrate at 45°C to 100°C using an inkjet head or the like, the surface of the substrate can be modified to be hydrophilic, and the dot size of the aqueous ink can be increased. By the synergistic action of these two dot size enlargement effects, the dot size is significantly enlarged, and a high-quality image can be formed with a small number of dots. As a result, high-speed printing comparable to solvent ink can be achieved even on a water-repellent substrate such as polyvinyl chloride (PVC). By setting the substrate temperature to 45°C to 100°C, it becomes possible to uniformly apply the pretreatment liquid. Further, by setting the substrate temperature to 45°C to 100°C, it becomes possible to rapidly remove water and the water-soluble organic solvent from the applied pretreatment liquid. That is, a thin film of a nonionic or anionic surfactant can be uniformly formed on the substrate surface. Since this thin film exhibits hydrophilicity, the substrate is hydrophilized, and an enlargement of the dot size of the aqueous ink is realized. Further, since water and the water-soluble organic solvent are removed, unevenness due to liquid pooling disappears on the substrate surface, and a decrease in image quality due to the unevenness can also be avoided.

[0012] According to one embodiment, since the pretreatment liquid uses an anionic surfactant, a nonionic surfactant, or a combination thereof as the surfactant, the pretreatment liquid contains an anionic substance, a nonionic substance, or a combination thereof. It is preferable that the pretreatment liquid of this formulation substantially does not contain a cationic substance. Such a pretreatment liquid can contribute to the enlargement of the dot size of the aqueous ink on the substrate surface.

[0013] According to one embodiment, since at least one of the coloring material, the water-dispersible resin, and the surfactant in the aqueous ink is anionic, the aqueous ink contains an anionic substance. It is preferable that the aqueous ink of this formulation substantially does not contain a cationic substance. Such an aqueous ink can contribute to the enlargement of the dot size of the aqueous ink on the pretreated substrate surface. The aqueous ink only needs to have at least one component of the coloring material, the water-dispersible resin, and the surfactant being anionic, and two or three components may exhibit anionic properties. When at least one of the coloring material, the water-dispersible resin, and the surfactant exhibits anionic properties, the remaining components are preferably nonionic.

[0014] <Pretreatment Liquid> The pretreatment liquid of one embodiment contains water, a water-soluble organic solvent, and a surfactant, and the surfactant is an anionic surfactant, a nonionic surfactant, or a combination thereof.

[0015] The pretreatment liquid preferably contains water, and the main solvent may be water. Examples of the water include ion-exchanged water, distilled water, ultrapure water, and the like. Water is preferably contained in an amount of 10 to 99% by mass, more preferably 20 to 95% by mass, and even more preferably 30 to 90% by mass based on the total amount of the pretreatment liquid.

[0016] The pretreatment liquid preferably contains a water-soluble organic solvent. As the water-soluble organic solvent, an organic compound that is liquid at room temperature and soluble in water can be used, and it is preferable to use a water-soluble organic solvent that is uniformly mixed with the same volume of water at 20°C under 1 atm. In order to eliminate the unevenness of the substrate due to liquid pooling in a short time, it is preferable that the water-soluble organic solvent evaporates easily. The boiling point of the water-soluble organic solvent is preferably 245°C or lower, more preferably 220°C or lower, and even more preferably 200°C or lower. In particular, when the boiling point of the water-soluble organic solvent is 220°C or lower, after the pretreatment liquid lands on the substrate, the water-soluble organic solvent evaporates easily, and the unevenness of the substrate due to liquid pooling can be eliminated in a shorter time. As a result, the productivity can be further improved.

[0017] Examples of the water-soluble organic solvents include lower alcohols such as methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, 1,2-butanediol, isobutanol, and 2-methyl-2-propanol; glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, and 1,2-hexanediol; glycerols such as glycerin, diglycerin, triglycerin, and polyglycerin; acetins such as monoacetin and diacetin; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol dimethyl ether, and tetraethylene glycol diethyl ether; triethanolamine, 1-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, β-thiodiglycol, sulfolane, etc. can be used.

[0018] These water-soluble organic solvents may be used alone or in combination of two or more as long as they form a single phase with water. The content of the water-soluble organic solvent in the pretreatment liquid is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, and even more preferably 10 to 30% by mass.

[0019] The pretreatment liquid contains a surfactant. The surfactant is an anionic surfactant, a nonionic surfactant, or a combination thereof. It is more preferable to use a nonionic surfactant, and it is even more preferable to use the nonionic surfactant alone. The pretreatment liquid of this formulation can expand the dot size of the ink compared to the case of using a cationic surfactant. Also, either a low-molecular surfactant or a high-molecular surfactant may be used. The HLB value of the surfactant is preferably 5 to 20, and more preferably 10 to 18.

[0020] Examples of the nonionic surfactant include ester-type surfactants such as glycerin fatty acid ester and sorbitan fatty acid ester; ether-type surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxypropylene alkyl ether; ether ester-type surfactants such as polyoxyethylene sorbitan fatty acid ester; acetylene-based surfactants; silicone-based surfactants; and fluorine-based surfactants. Among them, silicone-based surfactants and fluorine-based surfactants can be preferably used. Since these surfactants can be hydrophilized in small amounts, it is difficult for the surfactant to inhibit the fixing of the ink to the substrate, and excellent fixing properties can be obtained.

[0021] Examples of the acetylene-based surfactant include acetylene glycol-based surfactants, acetylene alcohol-based surfactants, and surfactants having an acetylene group. The acetylene glycol-based surfactant is a glycol having an acetylene group, preferably a glycol having a symmetrical structure with the acetylene group located in the center, and may have a structure in which ethylene oxide is added to the acetylene glycol. Examples of commercially available acetylene surfactants include, for example, Surfynol series products manufactured by Evonik Industries, such as "Surfynol 104E", "Surfynol 104H", "Surfynol 420", "Surfynol 440", "Surfynol 465", "Surfynol 485", etc., and Orfin series products manufactured by Nissin Chemical Industry Co., Ltd., such as "Orfin E1004", "Orfin E1010", "Orfin E1020", etc. (all are trade names).

[0022] Examples of silicone surfactants include, for example, polyether-modified silicone surfactants, alkyl·aralkyl co-modified silicone surfactants, acrylic silicone surfactants, etc. Examples of commercially available silicone surfactants include, for example, "Silface SAG002", "Silface 503A", etc. manufactured by Nissin Chemical Industry Co., Ltd. (all are trade names).

[0023] Examples of other nonionic surfactants include, for example, polyoxyethylene alkyl ether surfactants such as the Emulgen series products manufactured by Kao Corporation, such as "Emulgen 102KG", "Emulgen 103", "Emulgen 104P", "Emulgen 105", "Emulgen 106", "Emulgen 108", "Emulgen 120", "Emulgen 147", "Emulgen 150", "Emulgen 220", "Emulgen 350", "Emulgen 404", "Emulgen 420", "Emulgen 705", "Emulgen 707", "Emulgen 709", "Emulgen 1108", "Emulgen 4085", "Emulgen 2025G", etc. (all are trade names).

[0024] Examples of anionic surfactants include the Emal series products manufactured by Kao Corporation, such as "Emal 0", "Emal 10", "Emal 2F", "Emal 40", "Emal 20C", etc., the Neoperex series products such as "Neoperex GS", "Neoperex G-15", "Neoperex G-25", "Neoperex G-65", etc., the Perex series products such as "Perex OT-P", "Perex TR", "Perex CS", "Perex TA", "Perex SS-L", "Perex SS-H", etc., and the Demol series products such as "Demol N, Demol NL", "Demol RN", "Demol MS", etc. (all are trade names). It is preferable to use the above-mentioned surfactant alone, but a combination of two or more kinds may also be used.

[0025] The content of the surfactant is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, and still more preferably 0.2 to 3% by mass, based on the total amount of the pretreatment liquid.

[0026] The pretreatment liquid may contain other components as necessary. Examples of other components include defoamers, pH adjusters, antioxidants, preservatives, etc. It is preferable that none of the other components is a cationic substance.

[0027] The method for producing the pretreatment liquid is not particularly limited, and it can be appropriately produced by a known method. For example, all components can be charged and dispersed into a stirrer such as a Three One motor all at once or in portions, and if desired, it can be obtained by passing through a filter such as a membrane filter.

[0028] The pH of the pretreatment liquid is preferably 3 to 9, and more preferably 4 to 8. The viscosity of the pretreatment liquid is preferably 1 to 30 mPa·s at 23°C. In the present disclosure, the viscosity of the pretreatment liquid is a value measured at 23°C using a rotational viscometer.

[0029] <Water-based ink> The aqueous ink of one embodiment contains water, a colorant, a water-soluble organic solvent, a water-dispersible resin, and a surfactant, and at least one of the colorant, the water-dispersible resin, and the surfactant is anionic.

[0030] The aqueous ink preferably contains water, and the main solvent may be water. Examples of the water include ion-exchanged water, distilled water, ultrapure water, and the like. From the viewpoint of adjusting the ink viscosity, the water is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass based on the total amount of the aqueous ink.

[0031] The colorant may be either a pigment or a dye, or a combination thereof. In the aqueous ink, the content of the colorant is preferably 0.5 to 20.0% by mass, more preferably 1.0 to 15.0% by mass, and even more preferably 2.0 to 10.0% by mass based on the total amount of the aqueous ink from the viewpoints of printing density and ink viscosity. Further, it is preferable that the colorant is contained in an amount of 2% by weight or more, more preferably 2.5% by weight or more, and even more preferably 3% by weight or more based on the total amount of the aqueous ink. In these ranges, when the colorant is 2% by mass or more, the color development per unit area is high, and the decrease in image density accompanying the dot size enlargement can be suppressed.

[0032] The pigment can be preferably blended into the ink as a pigment dispersion. The pigment dispersion may be one in which the pigment is dispersible in a solvent and the pigment is in a dispersed state in the ink. For example, a dispersion obtained by dispersing a pigment in water with a pigment dispersant, a dispersion obtained by dispersing a self-dispersible pigment in water, a dispersion obtained by dispersing a microencapsulated pigment in which the pigment is coated with a resin in water, or the like can be used. When the pigment has an ionic property, it is preferably anionic or nonionic.

[0033] As the pigment, organic pigments such as azo pigments, phthalocyanine pigments, polycyclic pigments, and lake pigments, and inorganic pigments such as carbon black and metal oxides can be used. Examples of azo pigments include soluble azo lake pigments, insoluble azo pigments, and condensed azo pigments. Examples of phthalocyanine pigments include metal phthalocyanine pigments and metal-free phthalocyanine pigments. Examples of polycyclic pigments include quinacridone pigments, perylene pigments, perinone pigments, isoindoline pigments, isoindolinone pigments, dioxazine pigments, thioindigo pigments, anthraquinone pigments, quinophthalone pigments, metal complex pigments, and diketopyrrolopyrrole (DPP). Examples of carbon black include furnace carbon black, lamp black, acetylene black, and channel black. These pigments may be used alone or in combination of two or more.

[0034] From the viewpoints of ejection stability and storage stability, the average particle diameter of the pigment particles in the ink is preferably 300 nm or less, more preferably 200 nm or less, and even more preferably 150 nm or less, as the volume-based average value in the particle size distribution measured by the dynamic light scattering method.

[0035] Self-dispersible pigments may be blended as the pigment. Self-dispersible pigments are pigments in which hydrophilic functional groups are introduced onto the surface of the pigment by chemical treatment or physical treatment. As the hydrophilic functional groups to be introduced into the self-dispersible pigments, those having ionic properties are preferred, and by charging the pigment surface anionic, the pigment particles can be stably dispersed in water by electrostatic repulsive force. Preferred examples of the anionic functional groups include carboxy group, sulfo group, sulfino group, sulfate ester group, phosphate group, phosphate ester group, phosphite group, and phosphite ester group.

[0036] These hydrophilic functional groups may be directly bonded to the pigment surface or may be bonded via other atomic groups. Examples of other atomic groups include, but are not limited to, alkylene groups, phenylene groups, naphthylene groups, etc. Examples of the treatment method for the pigment surface include diazotization treatment, sulfonation treatment, hypochlorous acid treatment, humic acid treatment, vacuum plasma treatment, etc.

[0037] As the self-dispersible pigment, for example, CAB-O-JET series products such as "CAB-O-JET200", "CAB-O-JET300", "CAB-O-JET250C", "CAB-O-JET260M", "CAB-O-JET270", "CAB-O-JET450C" manufactured by Cabot Corporation, and "BONJET BLACK CW-1", "BONJET BLACK CW-2", "BONJET BLACK CW-3", "BONJET BLACK CW-4" manufactured by Orient Chemical Industries Co., Ltd. (all are trade names) can be preferably used. As the pigment, a microencapsulated pigment in which the pigment is coated with a resin may be used.

[0038] A pigment dispersion in which the pigment is pre-dispersed with a pigment dispersant may be used. Examples of commercially available products of the pigment dispersion dispersed with a pigment dispersant include, for example, the HOSTAJET series manufactured by Clariant, the FUJI SP series manufactured by Fuji Pigment Co., Ltd., etc. A pigment dispersion dispersed with a pigment dispersant described later may also be used.

[0039] In order to stably disperse the pigment in the aqueous ink, a pigment dispersant can be used together with the pigment. The pigment dispersant is not particularly limited as long as it can stably disperse the pigment in an aqueous medium. For example, a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high-molecular-weight acid ester, a salt of a high-molecular-weight polycarboxylic acid, a salt of a long-chain polyaminoamide and a polar acid ester, a high-molecular-weight unsaturated acid ester, a copolymer of vinylpyrrolidone and a long-chain alkene, a modified polyurethane, a modified polyacrylate, a polyether ester type anionic surfactant, a polyoxyethylene alkyl phosphate ester, a polyester polyamine, etc. are preferably used.

[0040] As the dye, water-soluble dyes and water-soluble dyes made water-soluble by reduction or the like among acid dyes, direct dyes, soluble vat dyes, acid mordant dyes, mordant dyes, reactive dyes, vat dyes, sulfur dyes, etc. can be preferably used. Also, disperse dyes such as azo-based, anthraquinone-based, azomethine-based, nitro-based dyes can be preferably used. These may be used alone or in combination of multiple types. When the dye has ionic properties, it is preferably anionic or nonionic.

[0041] The aqueous ink preferably contains a water-soluble organic solvent. As the water-soluble organic solvent, an organic compound that is liquid at room temperature and soluble in water can be used, and it is preferable to use a water-soluble organic solvent that is uniformly mixed with the same volume of water at 1 atm and 20°C. The boiling point of the water-soluble organic solvent is preferably 245°C or lower, more preferably 220°C or lower, and even more preferably 200°C or lower. In particular, when the boiling point of the water-soluble organic solvent is 220°C or lower, after the aqueous ink lands on the substrate, the water-soluble organic solvent evaporates easily, and the unevenness of the substrate due to liquid pooling can be eliminated in a shorter time. As a result, productivity can be further improved. As the water-soluble organic solvent, for example, those described in the above pretreatment liquid can be used.

[0042] The aqueous ink can contain a water-dispersible resin.

[0043] The water-dispersible resin may be one in which the functional groups of the resin are present on the surface of the resin particles, such as a self-emulsifying type resin, or one that has been surface-treated such as attaching a dispersant to the surface of the resin particles. The resin may be, for example, either anionic or nonionic, but is more preferably anionic.

[0044] The anionic water-dispersible resin may be one in which the anionic functional groups possessed by the resin are present on the surface of the resin particles, like a self-emulsifying resin, or may be one that has been surface-treated such as by attaching an anionic dispersant to the surface of the resin particles. Representative examples of the anionic functional groups include a carboxy group, a sulfo group, a sulfino group, a sulfate ester group, a phosphate group, a phosphate ester group, a phosphite group, a phosphite ester group, and the like. Examples of the anionic dispersant include an anionic surfactant and the like. The nonionic water-dispersible resin may be one in which the nonionic functional groups possessed by the resin are present on the surface of the resin particles, like a self-emulsifying resin, or may be one that has been surface-treated such as by attaching a nonionic dispersant to the surface of the resin particles. Representative examples of the nonionic functional groups include a polyoxyalkylene glycol group, a hydroxy group, and the like. Examples of the nonionic dispersant include a nonionic surfactant and the like.

[0045] Examples of the resin include a urethane resin, a polyester resin, an acrylic resin, a vinyl acetate resin, a styrene resin, a butadiene resin, a styrene-butadiene resin, a vinyl chloride resin, an acrylic-styrene resin, an acrylic-silicone resin, and the like. These may be used alone or as a composite resin of two or more. The water-dispersible resin may be blended into the aqueous ink as a resin emulsion. For example, it is possible to obtain an aqueous ink by mixing materials such as a colorant and a water-soluble organic solvent in a state of a resin emulsion in which resin particles are dispersed using water as a dispersion medium.

[0046] As the water-dispersible resin, it may be synthesized or a commercially available product. Examples of commercially available products include "Microgel E-1002", "Microgel E-5002" manufactured by Nippon Paint Co., Ltd., "Boncoat 4001", "Boncoat 5454" manufactured by DIC Corporation, "SAE-1014" manufactured by Nippon Zeon Co., Ltd., "Cybinol SK-200" manufactured by Siden Chemical Co., Ltd., "Superflex 130", "Superflex 150", "Superflex 210", "Superflex 420" manufactured by Daiichi Kogyo Seiyaku Co., Ltd., "NeoRez R-4000", "NeoCryl XK12" manufactured by Covestro Coating Resins, etc.

[0047] In a state where the water-dispersible resin is dispersed in an aqueous medium, from the viewpoint of inkjet ejection property, the average particle diameter of the resin particles is preferably 600 nm or less, more preferably 300 nm or less, and even more preferably 200 nm or less. For example, the average particle diameter of the resin particles may be in the range of 10 nm to 600 nm, may be in the range of 50 nm to 300 nm, or may be in the range of 50 to 200 nm. Here, the average particle diameter of the resin particles is the volume-based particle diameter value (median diameter) in the particle size distribution measured by the dynamic light scattering method.

[0048] The content of the water-dispersible resin is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 0.5 to 20% by mass, more preferably 1 to 10% by mass, based on the total amount of the aqueous ink.

[0049] The aqueous ink can contain a surfactant.

[0050] As the surfactant, an anionic surfactant, a nonionic surfactant, or a combination thereof can be preferably used, and a nonionic surfactant is more preferable.

[0051] The HLB value of the surfactant is preferably 5 to 20, more preferably 10 to 18. As the surfactant, for example, it can be selected and used from those described in the above-described pretreatment liquid. Among them, nonionic surfactants are preferred, and silicone-based surfactants and fluorine-based surfactants can be more preferably used.

[0052] The surfactant may be used alone or in combination of two or more. The content of the surfactant is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, and even more preferably 0.2 to 3% by mass based on the total amount of the pretreatment liquid.

[0053] The aqueous ink may contain other components as necessary. Examples of other components include pH adjusters and preservatives. It is preferable that none of the other components is a cationic substance.

[0054] The method for producing the aqueous ink is not particularly limited and can be appropriately produced by a known method. For example, all components can be charged and dispersed into a stirrer such as a three-one motor all at once or dividedly, and if desired, the ink can be obtained by passing it through a filter such as a membrane filter.

[0055] The pH of the aqueous ink is preferably 7.0 to 10.0, more preferably 7.5 to 9.0, from the viewpoint of the storage stability of the ink. The viscosity of the aqueous ink is preferably 1 to 30 mPa·s at 23°C, for example, from the viewpoint of inkjet ejection property. In the present disclosure, the viscosity of the aqueous ink is a value measured at 23°C using a rotational viscometer.

[0056] <Method for manufacturing a printed matter> The manufacturing method of a printed matter according to an embodiment may include a step of applying a pretreatment liquid to a substrate (hereinafter, also referred to as "pretreatment liquid application step"), and a step of applying an aqueous ink to the substrate to which the pretreatment liquid has been applied by an inkjet method (hereinafter, also referred to as "aqueous ink application step"). As the pretreatment liquid, the pretreatment liquid described as the pretreatment liquid of the above-described embodiment can be used. Further, as the aqueous ink, the aqueous ink of the above-described embodiment can be used.

[0057] The pretreatment liquid application step will be described. The method of applying the pretreatment liquid to the substrate is not particularly limited. For example, any method such as a spray method using an airbrush or the like, a dipping method, a pad method, a coating method, etc. can be used, and further, various printing methods such as inkjet printing (inkjet method) and screen printing may be used.

[0058] The area to which the pretreatment liquid is applied may be an area having the same shape as the image formed by the aqueous ink, or a wider area including the shape of the image formed by the aqueous ink, or the entire surface of the substrate. The application area of the pretreatment liquid and the application area of the aqueous ink preferably at least partially overlap.

[0059] The transfer amount of the pretreatment liquid to the substrate is preferably 1 to 100 g / m 2 and more preferably 10 to 75 g / m 2 and even more preferably 30 to 50 g / m 2 is even more preferable.

[0060] The temperature of the substrate surface when applying the pretreatment liquid is preferably 45°C to 100°C, more preferably 55°C to 90°C, and even more preferably 60°C to 80°C. By applying while heating the substrate, it becomes possible to apply the pretreatment liquid uniformly. Also, the solvent is rapidly removed from the pretreatment liquid after application. As a result, unevenness due to liquid pooling on the substrate surface is eliminated, and thus deterioration of the image quality due to unevenness can also be avoided.

[0061] The aqueous ink application step will be described. The aqueous ink is preferably applied to the substrate by an inkjet method. The inkjet method is not particularly limited and may be any method such as a piezo method, an electrostatic method, or a thermal method. When using an inkjet printing apparatus, it is preferable to eject droplets of the pretreatment liquid or ink from the inkjet head based on a digital signal and attach the ejected droplets to the cloth. The application region of the pretreatment liquid and the application region of the aqueous ink preferably at least partially overlap.

[0062] The aqueous ink is preferably applied to the substrate to which the pretreatment liquid has been applied. Preferably, the aqueous ink can be applied to the substrate to which the pretreatment liquid has been applied in a state where a thin film of a surfactant is formed. As a result, the surface of the substrate becomes hydrophilic, so the aqueous ink is not repelled and the dot size becomes larger. When applying the aqueous ink to the substrate, it is preferable to apply it in a heated state. The temperature of the substrate surface when applying the aqueous ink is preferably 45°C to 100°C, more preferably 50°C to 90°C, and even more preferably 55°C to 80°C. The time from applying the pretreatment liquid to the substrate to applying the aqueous ink is preferably 0.1 to 200 seconds, more preferably 1 to 150 seconds, and even more preferably 10 to 100 seconds.

[0063] The heating of the substrate may be contact type or non-contact type. The heating device is not particularly limited, and for example, a heat press, a roll heater, a hot air device, an infrared lamp heater, etc. can be used. The heat treatment time may be appropriately set according to the type of the substrate, the heat treatment temperature, the heat treatment method, etc., together with the components and contents of the treatment liquid and the aqueous ink. For example, 1 second to 10 minutes is preferable, and it may be 5 seconds to 5 minutes.

[0064] The amount of the aqueous ink applied to the substrate is not particularly limited. For example, 10 to 500 g / m 2 is preferable, 50 to 400 g / m 2 is more preferable, and 100 to 200 g / m 2 is even more preferable.

[0065] The above-described method for manufacturing a printed matter can be suitably applied to a non-permeable substrate. A non-permeable substrate is a substrate into which liquid does not penetrate, specifically, a substrate on which most of the liquid in the treatment liquid or ink remains on the surface of the substrate. Examples of non-permeable substrates include metal substrates such as metal plates of aluminum, iron, copper, titanium, tin, chromium, cadmium, alloys (e.g., stainless steel, steel, etc.); glass substrates such as plate glass of borosilicate glass, quartz glass, soda-lime glass, etc.; resin sheets such as PET film, PP film, OHT sheet, polyester sheet, polypropylene sheet, resin substrates such as acrylic plate, polyvinyl chloride plate, etc.; ceramic substrates such as molded bodies of alumina, zirconia, steatite, silicon nitride, etc. These substrates may have a plating layer, a metal oxide layer, a resin layer, etc. formed thereon, or may be surface-treated using corona treatment or the like.

[0066] The method for manufacturing a printed matter according to one embodiment can perform printing with high image quality even on a non-permeable and non-hydrophilic substrate such as polyvinyl chloride. Specifically, since it is possible to increase the dot size on the substrate surface, high image quality can be obtained while reducing the number of dots, and the productivity of printing can be increased. For example, it is also suitable for printing on a large screen such as signage.

Examples

[0067] Hereinafter, the present invention will be described in detail with reference to examples. The present invention is not limited to the following examples. In the following description, unless otherwise specified, “%” indicates “mass%”. The contents shown in the table are indicated in mass%, and the raw materials formulated as a solution or dispersion, etc. are indicated by their total amounts.

[0068] 1. Preparation of pretreatment liquid Table 1 shows the formulation of the pretreatment liquid. According to the formulation shown in the table, the raw materials were put into a container so that the total amount became 100% by mass. After stirring, it was filtered through a cellulose acetate membrane filter with a pore size of 0.8 μm to obtain the pretreatment liquid.

[0069] 2. Preparation of Aqueous Ink Table 1 shows the formulation of the aqueous ink. According to the formulation shown in the table, the raw materials were put into a container so that the total amount became 100% by mass. After stirring, it was filtered through a cellulose acetate membrane filter with a pore size of 0.8 μm to obtain the aqueous ink.

[0070] The raw materials shown in Table 1 are as follows. (Water-soluble organic solvent) Ethylene glycol: FUJIFILM Wako Pure Chemical Corporation 1,2-Butanediol: FUJIFILM Wako Pure Chemical Corporation 1,2-Hexanediol: FUJIFILM Wako Pure Chemical Corporation (Colorant) CAB-O-JET 300 (trade name): Black pigment dispersion, manufactured by Cabot Corporation CAB-O-JET 250C (trade name): Cyan pigment dispersion, manufactured by Cabot Corporation CAB-O-JET 260M (trade name): Magenta pigment dispersion, manufactured by Cabot Corporation CAB-O-JET 270 (trade name): Yellow pigment dispersion, manufactured by Cabot Corporation (Resin) NeoRez R-4000 (trade name): Anionic urethane resin emulsion, manufactured by Sumika Covestro Urethane Co., Ltd. Superflex 130 (trade name): Anionic urethane resin emulsion, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (Surfactant) Silface SAG002 (trade name): Nonionic silicone-based surfactant, manufactured by Nissin Chemical Industry Co., Ltd.

[0071]

Table 1

[0072] 3. Production of Printed Matter Using the pretreatment liquid and the aqueous ink prepared above, printed matters of Examples 1 to 8 and Comparative Examples 1 to 4 were produced according to the following procedure. Table 2 shows the compositions of the pretreatment liquid and the aqueous ink used for the production of the printed matters of Examples 1 to 8 and Comparative Examples 1 to 4. As the substrate, a polyvinyl chloride film (product name MPI3022P WPE) manufactured by Avery Dennison was used and cut into a size of 74 mm × 210 mm. After heating the substrate to the temperature shown in Table 2, the pretreatment liquid was applied at a transfer amount of about 2 μm. After about 1 minute elapsed, after heating the substrate to the temperature shown in Table 2, the aqueous ink was applied onto the substrate by an inkjet method. As the printing apparatus, “MMP-8130” manufactured by Mastermind was used. The printing was performed at a printing speed of 4 or 8 according to the apparatus specifications. The printing speed of 4 is twice as fast as that of 8 in terms of the processing completion speed. The image was a solid image, and the printing area of the image was 50 mm × 200 mm. After printing, it was dried in a constant temperature bath at 90°C for 2 minutes to obtain a printed matter.

[0073]

Table 2

[0074] 4. Evaluation of Printed Matter The image quality of the printed matters of Examples 1 to 8 and Comparative Examples 1 to 4 was visually evaluated for the image quality of the solid image (image density, uniformity of solid) and judged according to the following criteria. A: Visually evaluated at a distance of 30 cm from the printed matter, and the image quality is excellent. B: Visually evaluated at a distance of 1 m from the printed matter, and the image quality is excellent. C: Visually evaluated at a distance of 1 m from the printed matter, and it is recognized that the image quality is at a level with problems in actual use.

[0075] As shown in Table 2, in Examples 1 to 8 in which the surfactant was contained in the pretreatment liquid and the temperature at the time of applying the pretreatment liquid and the aqueous ink was 45°C to 100°C, excellent image quality and productivity were shown as compared with Comparative Examples 1 to 4.

[0076] In Comparative Example 1 and Comparative Example 4, since the substrate temperature during printing was lower than 45°C, it was difficult to remove the solvent of the pretreatment liquid. In addition, since the unevenness due to the liquid pool of the pretreatment liquid was not eliminated, the dot shape of the ink was disturbed, resulting in an image lacking sharpness and not achieving good image quality. In Comparative Example 2, since the pretreatment liquid did not contain a surfactant, hydrophilicity of the substrate interface did not occur. For this reason, the dot size of the ink remained small, resulting in an image with poor solidity uniformity and not achieving good image quality. In Comparative Example 3, since the pretreatment liquid was not used, the compatibility between the substrate and the ink was poor, the dot size of the ink remained small, resulting in an image with poor solidity uniformity and not achieving good image quality. It was found that in order to obtain good image quality, it was necessary to set the printing speed to 8. Since the printing speed of 8 doubles the printing time compared to the printing speed of 4, it is considered that the productivity is inferior.

Claims

Claim 1 A method for manufacturing a printed matter, comprising the step of forming an image by applying a pretreatment liquid to a substrate at 45°C to 100°C and then applying an aqueous ink to the substrate at 45°C to 100°C by an inkjet method, wherein the pretreatment liquid contains water, a water-soluble organic solvent, and a surfactant, and the surfactant is an anionic surfactant, a nonionic surfactant, or a combination thereof, and the aqueous ink contains water, a coloring material, a water-soluble organic solvent, a water-dispersible resin, and a surfactant, and at least one of the coloring material, the water-dispersible resin, and the surfactant is anionic.

Images