JP7166104B2 - Inkjet ink set, printed matter and method for producing printed matter - Google Patents

Description

TECHNICAL FIELD The present invention relates to an inkjet ink set, a printed matter, and a method for producing a printed matter. More particularly, the present invention relates to an inkjet ink set capable of forming a coating film exhibiting excellent heat shielding properties and weather resistance, a printed matter, and a method for producing a printed matter.

2. Description of the Related Art Conventionally, studies have been made on imparting properties such as weather resistance by coating the surfaces of various members. For example, exterior members of building materials are required to have heat shielding properties and weather resistance because they are installed outdoors. Therefore, printing inks (coating compositions) have been developed for imparting heat shielding properties and weather resistance to exterior members of building materials and the like (Patent Document 1).

JP 2017-185782 A

However, the technique described in Patent Document 1 does not impart sufficient weather resistance to the resulting coating film. Therefore, it is insufficient as a coating composition applied to exterior members of building materials. By the way, in recent years, inkjet inks have been developed for forming a coating film by an inkjet method using an inkjet device. However, conventional inkjet inks also cannot form a coating film exhibiting excellent weather resistance while maintaining sufficient heat shielding properties.

The present invention has been made in view of such conventional inventions, and provides an inkjet ink set capable of forming a coating film exhibiting excellent heat shielding and weather resistance, a printed matter, and a method for producing a printed matter. With the goal.

The inkjet ink set, the printed matter, and the method for producing the printed matter of the present invention, which solve the above problems, mainly include the following configurations.

(1) A yellow ink containing a yellow colorant, a red ink containing a red colorant, and a blue ink containing a blue colorant are included, and the yellow colorant, the red colorant, and the blue colorant are inorganic pigments. wherein the yellow ink, the red ink, and the blue ink have an average reflectance of 40% or more at a wavelength of 780 to 2100 nm of a coating film formed when each ink is applied.

According to such a configuration, the inkjet ink set contains each color ink containing a predetermined color material so that the average reflectance at the time of coating film formation is 40% or more. As a result, the resulting coating film exhibits excellent heat shielding properties. Moreover, each colorant contains an inorganic pigment. By using each ink containing such an inorganic pigment, the resulting coating film exhibits excellent weather resistance.

(2) The inkjet ink set according to (1), wherein the yellow colorant, the red colorant, and the blue colorant have an average particle size of 100 to 1000 nm.

According to such a configuration, the inkjet ink set is less likely to clog nozzles when applying ink to the substrate. Also, the resulting coating film exhibits better weather resistance.

(3) further comprising a black ink containing a black colorant, wherein the black ink has an average reflectance of 40% or more at a wavelength of 780 to 2100 nm of a coating film formed by applying the black ink, and the black color The inkjet ink set according to (1) or (2), wherein the material includes at least one of a bismuth-manganese-based pigment and an yttrium-manganese-based pigment.

According to such a configuration, the resulting ink-jet ink set is less likely to be reddish and tends to exhibit the desired degree of blackness.

(4) The inkjet ink set according to any one of (1) to (3), wherein the yellow ink, the red ink, and the blue ink each contain a binder resin, and the binder resin is a fluororesin. .

According to such a configuration, the inkjet ink set provides a coating film with excellent heat resistance and weather resistance.

(5) An inkjet print to which the ink of the inkjet ink set according to any one of (1) to (4) is applied.

According to such a configuration, the printed matter obtained by using the inkjet ink set is formed with a coating film exhibiting excellent heat shielding properties and weather resistance. Therefore, the printed matter is suitable as, for example, an exterior member of a building material.

(6) Printing comprising a printing step of applying ink to a substrate by an inkjet method using the inkjet ink set according to any one of (1) to (4), and a drying step of drying the substrate. A method of making things.

According to such a configuration, by using the inkjet ink set, a printed matter having a coating film exhibiting excellent heat shielding properties and weather resistance is formed. The resulting printed matter is suitable, for example, as an exterior member for building materials.

ADVANTAGE OF THE INVENTION According to this invention, the inkjet ink set which can form the coating film which shows the heat-shielding property and weather resistance which were excellent, printed matter, and the manufacturing method of printed matter can be provided.

<Inkjet ink set>
An inkjet ink set (hereinafter also simply referred to as an ink set) of an embodiment of the present invention includes a yellow ink containing a yellow colorant, a red ink containing a red colorant, and a blue ink containing a blue colorant. Also, the ink set preferably further includes a black ink containing a black colorant. A yellow colorant, a red colorant, and a blue colorant are inorganic pigments. Yellow ink, red ink, and blue ink have an average reflectance of 40% or more at a wavelength of 780 to 2100 nm of the coating film formed when each ink is applied. As a result, the resulting coating film exhibits excellent heat shielding properties. Moreover, by using each ink containing an inorganic pigment, the resulting coating film exhibits excellent weather resistance. Each of these will be described below.

(Each color ink)
• Yellow ink Yellow ink contains a yellow colorant. The yellow colorant is not particularly limited as long as it contains an inorganic pigment. For example, inorganic pigments that make up the yellow colorant include iron oxide-based pigments, iron hydroxide-based pigments, chromic acid-based pigments, titanium-nickel-based pigments, titanium-chromium-based pigments, bismuth-based pigments, vanadium-based pigments, and praseodymium. Zircon pigments and the like. A yellow colorant may be used in combination. Among these, the yellow colorant tends to have an average reflectance of 40% or more for the coating film described later, and is easy to form a coating film with excellent heat shielding properties. Nickel-based pigments and titanium-chromium-based pigments are preferred, iron oxide-based pigments, iron hydroxide-based pigments, and titanium-nickel-based pigments are more preferred, and iron hydroxide-based pigments are even more preferred.

The content of the yellow coloring material in the yellow ink is not particularly limited. For example, the content of the yellow colorant in the yellow ink is preferably 0.5% by mass or more, more preferably 2% by mass or more. Also, the content of the yellow coloring material is preferably 40% by mass or less, more preferably 20% by mass or less, in the yellow ink. When the content of the yellow coloring material is within the above range, the resulting ink set can easily produce prints with excellent color developability, and also has excellent ejection stability during inkjet printing.

• Red ink Red ink contains a red coloring material. The red colorant is not particularly limited as long as it contains an inorganic pigment. Examples of inorganic pigments that constitute the red colorant include iron oxide-based pigments, zircon iron-based pigments, iron-aluminum-based pigments, iron-zinc-based pigments, and manganese-aluminum-based pigments. A red colorant may be used in combination. Among these, the red colorant is likely to have an average reflectance of 40% or more of the coating film described later, and it is easy to form a coating film with excellent heat shielding properties. is preferred, and iron oxide pigments are more preferred.

The content of the red coloring material in the red ink is not particularly limited. For example, the content of the red coloring material in the red ink is preferably 0.5% by mass or more, and more preferably 2% by mass or more. Also, the content of the red coloring material in the red ink is preferably 40% by mass or less, more preferably 20% by mass or less. When the content of the red colorant is within the above range, the resulting ink set can easily produce prints with excellent color development and also has excellent ejection stability during inkjet printing.

- Blue ink Blue ink contains a blue coloring material. The blue colorant is not particularly limited as long as it contains an inorganic pigment. Examples of inorganic pigments that constitute the blue colorant include cobalt-based pigments, cobalt-aluminum-based pigments, and cobalt-chromium-based pigments. A blue colorant may be used together. Among these, the blue colorant tends to have an average reflectance of 40% or more in the coating film described later, and is easy to form a coating film with excellent heat shielding properties. Pigments are preferred, and cobalt aluminum pigments are more preferred.

The content of the blue colorant in the blue ink is not particularly limited. For example, the content of the blue colorant in the blue ink is preferably 0.5% by mass or more, more preferably 2% by mass or more. Also, the content of the blue colorant in the blue ink is preferably 40% by mass or less, more preferably 20% by mass or less. When the content of the blue colorant is within the above range, the resulting ink set can easily produce prints with excellent color developability, and also has excellent ejection stability during inkjet printing.

- Black ink Black ink is preferably included in the ink set of the present embodiment. The black ink preferably contains a black colorant. Inorganic pigments are not particularly limited. Examples of inorganic pigments that make up the black colorant include bismuth manganese pigments, yttrium manganese pigments, copper chromium pigments, copper iron manganese pigments, cobalt iron chromium pigments, ruthenium oxide, cobalt manganese pigments, Titanium manganese pigments and the like. A black colorant may be used together. Among these, the black colorant tends to have an average reflectance of 40% or more for the coating film described later, and is easy to form a coating film with excellent heat shielding properties. It is preferable to include at least one of them. In addition, when at least one of bismuth-manganese-based pigments and yttrium-manganese-based pigments is used as the black colorant, compared with the case where other black colorants (iron-chromium-based pigments, etc.) are used. Thus, the ink jet ink set gives a coating film that is less likely to be reddish and tends to exhibit the desired degree of blackness.

The content of the black coloring material in the black ink is not particularly limited. For example, the content of the black colorant in the black ink is preferably 0.5% by mass or more, more preferably 2% by mass or more. Also, the content of the black colorant in the black ink is preferably 40% by mass or less, more preferably 20% by mass or less. When the content of the black colorant is within the above range, the resulting ink set can easily produce prints with excellent color development, and also has excellent ejection stability during inkjet printing.

Returning to the overall description of each color ink, the average particle size of the yellow colorant, red colorant, blue colorant, and black colorant contained in each color ink is preferably 100 nm or more, and is 120 nm or more. is more preferable, and 150 nm or more is even more preferable. Also, the average particle size is preferably 1000 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less. If the average particle size is less than 100 nm, the obtained coating film tends to have poor weather resistance. Especially when the average particle size of the black colorant is less than 100 nm, the resulting coating film tends to be reddish. On the other hand, if the average particle size exceeds 1000 nm, the coloring material of each color ink may settle, and the stability tends to decrease. In addition, when each color ink is applied to a base material by an inkjet method, nozzles and the like are likely to be clogged, and ejection stability is likely to decrease. In the ink set of the present embodiment, among the colorants contained in each color ink, the average particle size of at least one colorant is preferably within the above range. It is more preferable that the particle size is within the above range, and it is further preferable that the average particle size of all four colorants including the black colorant be within the above range. When the average particle size of all the four colorants is within the above range, clogging of nozzles during application of ink to a substrate is more likely to be improved, and weather resistance of the obtained coating film is further excellent. In addition, since the average particle size of the black colorant is within the above range, in addition to the effect of improving the nozzle clogging effect and the effect of improving the weather resistance of the coating film, the resulting coating film is less likely to be reddish, and the desired blackness can be reproduced. It is easy to obtain the effect of developing excellent colors. In addition, in this embodiment, the average particle size can be measured by a dynamic light scattering method using Zetasizer Nano series manufactured by Malvern Instruments.

In addition, each color ink (yellow ink, blue ink, and red ink) of the present embodiment has an average reflectance of 40% or more at a wavelength of 780 to 2100 nm of the coating film formed when each ink is applied. % or more, more preferably 45% or more. The upper limit of the average reflectance of each color ink is not particularly limited. The upper limit of the average reflectance is appropriately set based on the desired heat shielding properties and the like. If the average reflectance is less than 40%, the resulting coating film tends to have poor heat shielding properties. In the present embodiment, the average reflectance is about 150 g/m ² by air spraying a commercially available fluorine paint (Bonflon #1000SR overcoat, manufactured by AGC Coatec Co., Ltd.) on a substrate (aluminum steel plate subjected to chromate treatment). and dried for 3 minutes in an environment of 200 ° C.), the ink containing the above coloring material was applied so that the wet film thickness was 10 μm, and the average reflectance of the resulting coating film was Average reflection in the near-infrared region of 780 nm to 2100 nm measured when measured under conditions according to JIS K 5602 using an ultraviolet-visible near-infrared spectrophotometer (UV-3600plus, manufactured by Shimadzu Corporation) rate (%).

In addition, the black ink suitably contained in the ink set of the present embodiment preferably has an average reflectance of 40% or more, more preferably 42% or more. When the average reflectance of the black ink is within the above range, the resulting coating film exhibits excellent heat shielding properties.

(other ingredients)
Each color ink that constitutes the ink set of the present embodiment contains each of the above-mentioned colorants and has a composition such that the average reflectance at a wavelength of 780 to 2100 nm of the coating film formed when each ink is applied is 40% or more. As long as it satisfies this condition, it may contain other components as appropriate. Each color ink may contain, for example, a binder resin, a dispersant, a solvent and various optional components.

- Binder resin The binder resin is suitably included for adjusting the viscosity of the ink, adjusting the hardness of the obtained print, and controlling the shape, for example.

The type of binder resin is not particularly limited. Examples of binder resins include fluorine resins, epoxy resins, diallyl phthalate resins, silicone resins, phenol resins, unsaturated polyester resins, polyimide resins, polyurethane resins, melamine resins, urea resins, ionomer resins, ethylene ethyl acrylate resins, Acrylonitrile acrylate styrene copolymer resin, acrylonitrile styrene resin, acrylonitrile chloride polyethylene styrene copolymer resin, ethylene vinyl acetate resin, ethylene vinyl alcohol copolymer resin, acrylonitrile butadiene styrene copolymer resin, vinyl chloride resin, chlorinated polyethylene resin, polyvinylidene chloride Resin, cellulose acetate resin, polyoxymethylene resin, polyamide resin, polyarylate resin, thermoplastic polyurethane elastomer, polyether ether ketone resin, polyether sulfone resin, polyethylene, polypropylene, polycarbonate resin, polystyrene, polystyrene maleic acid copolymer resin, Polystyrene acrylic acid copolymer resin, polyphenylene ether resin, polyphenylene sulfide resin, polybutadiene resin, polybutylene terephthalate resin, acrylic resin, methylpentene resin, polylactic acid, polybutylene succinate resin, butyral resin, formal resin, polyvinyl alcohol, polyvinylpyrrolidone , ethyl cellulose, carboxymethyl cellulose, gelatin, and copolymer resins thereof. The binder resin may be appropriately selected in consideration of film strength, viscosity, residual viscosity of inkjet ink, dispersion stability of coloring material, thermal stability, non-coloring property, water resistance, and chemical resistance. A binder resin may be used in combination. Each color ink constituting the ink set of the present embodiment preferably contains a fluororesin as a binder resin. The fluororesin as the binder resin may be contained in any of the inks of each color. By using an ink containing a fluororesin, the ink set can improve the heat resistance and weather resistance of the resulting coating film. Above all, in the ink set of the present embodiment, it is preferable that the yellow ink, the red ink, and the blue ink among the respective color inks contain a fluororesin as a binder resin, and all the four color inks including the black ink contain a fluororesin. It is more preferable that a fluororesin is contained as the binder resin. Since all the color inks contain a fluororesin as a binder resin, the ink set further improves the heat resistance and weather resistance of the resulting coating film.

- Fluororesin The fluororesin is not particularly limited. For example, the fluororesin is preferably a copolymer of various fluorine-containing monomers and vinyl monomers. In addition, among vinyl monomers, the fluororesin is more preferably a copolymer with a vinyl ether monomer. Furthermore, the fluororesin is more preferably a copolymer of fluoroethylene and a vinyl ether monomer. In addition, the polymerization method is not particularly limited. Examples of the polymerization method include solution polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, and the like.

The obtained fluororesin may be an alternating copolymer, a block copolymer, a random copolymer or a graft copolymer. Among these, the fluororesin is preferably an alternating copolymer of fluoroethylene and a vinyl monomer. According to an ink set containing an ink containing such a fluororesin, it is easy to obtain a print having even better weather resistance. Therefore, by using such an ink set, the desired color can be maintained in the resulting prints for a longer period of time. In the present embodiment, the "alternating copolymer" means that the bond between the fluoroethylene unit and the vinyl monomer unit is the bond between the fluoroethylene unit and the fluoroethylene unit, and the bond between the vinyl monomer unit and the vinyl monomer unit. means a copolymer containing far more than the sum of the bonds of Specifically, the alternating copolymer of the present embodiment preferably contains 90 to 100 mol % of bonds between fluoroethylene units and vinyl monomer units. In addition, in this embodiment, the alternating copolymer may contain a small number of random bond moieties or block bond moieties. Also, the bonds can be distinguished by, for example, ¹ H NMR measurements and ²⁹ Si NMR measurements. Further, for the method of analyzing alternating copolymers, see, for example, Journal of Applied Polymer Science, Vol. 106, 1007-1013 (2007).

The weight average molecular weight (Mw) of the fluororesin is not particularly limited. For example, Mw is preferably 5000 or more, more preferably 8000 or more. Mw is preferably 50,000 or less, more preferably 40,000 or less. When Mw is within the above range, the fluororesin is easily dissolved in the solvent. In addition, the resulting ink has improved drying properties and excellent ejection stability during inkjet printing. If the Mw is less than 5,000, the resulting prints tend to be sticky and tend to have reduced antiblocking properties. On the other hand, when the Mw exceeds 50,000, the solubility of the fluororesin tends to decrease, and the ejection stability of the ink during inkjet printing tends to decrease. In the present specification, Mw and the number average molecular weight (Mn) to be described later are values measured by, for example, GPC (gel permeation chromatography), and a high-speed GPC device (manufactured by Tosoh Corporation, HLC-8120GPC). can be measured using

- Acrylic resin The acrylic resin is not particularly limited. As an example, the acrylic resin is exemplified by a polymer of acrylic acid ester (acrylate) or methacrylic acid ester (methacrylate). More specifically, acrylic resins include acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, and 2-ethylhexyl acrylate; Alkyl methacrylates such as ethyl acetate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, and 2-ethylhexyl methacrylate; 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, etc. Hydroxy group-containing acrylic acid esters; Polymers such as hydroxy group-containing methacrylic acid esters such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 4-hydroxybutyl methacrylate are exemplified. These may be used in combination.

The weight average molecular weight (Mw) of the acrylic resin is not particularly limited. For example, Mw is preferably 5,000 or more, more preferably 10,000 or more. Mw is preferably 100,000 or less, more preferably 50,000 or less. When Mw is within the above range, the ink containing such an acrylic resin has excellent ejection stability during inkjet printing.

- Vinyl chloride resin The vinyl chloride resin is not particularly limited. Examples of vinyl chloride resins include copolymers of vinyl chloride with other monomers such as vinyl acetate, vinylidene chloride, acrylic acid, maleic acid and vinyl alcohol. Among these, the vinyl chloride resin is preferably a copolymer (vinyl chloride-vinyl acetate copolymer) containing constitutional units derived from vinyl chloride and vinyl acetate.

A vinyl chloride-vinyl acetate copolymer can be obtained, for example, by suspension polymerization. The vinyl chloride-vinyl acetate copolymer preferably contains 70 to 90% by mass of vinyl chloride units. Within the above range, the vinyl chloride-vinyl acetate copolymer is stably dissolved in the ink, and therefore has excellent long-term storage stability. In addition, the obtained ink has excellent ejection stability.

The vinyl chloride-vinyl acetate copolymer may have other constitutional units in addition to vinyl chloride units and vinyl acetate units, if necessary. Examples of other structural units include carboxylic acid units, vinyl alcohol units, hydroxyalkyl acrylate units, and the like. Among these, other structural units are preferably vinyl alcohol units.

The number average molecular weight (Mn) of the vinyl chloride resin is not particularly limited. For example, Mn of the vinyl chloride resin is preferably 10,000 or more, more preferably 12,000 or more. Also, Mn is preferably 50,000 or less, more preferably 42,000 or less. In addition, Mn can be measured by GPC, and can be obtained as a relative value in terms of polystyrene.

- Silicone resin The silicone resin is not particularly limited. Examples of silicone resins include methyl-based straight silicone resin (polydimethylsiloxane), methylphenyl-based straight silicone resin (polydimethylsiloxane in which a portion of the methyl group is substituted with a phenyl group), acrylic resin-modified silicone resin, and polyester resin. Examples include resin-modified silicone resins, epoxy resin-modified silicone resins, alkyd resin-modified silicone resins, and rubber-based silicone resins. These may be used in combination. Among these, the silicone resin is preferably a methyl-based straight silicone resin, a methylphenyl-based straight silicone resin, or an acrylic resin-modified silicone resin.

The silicone resin may be dissolved in an organic solvent or the like. Examples of organic solvents include xylene and toluene.

The number average molecular weight (Mn) of the silicone resin is not particularly limited. For example, the Mn of the silicone resin is preferably 10,000 or more, more preferably 20,000 or more. Also, Mn is preferably 5,000,000 or less, more preferably 3,000,000 or less. In addition, Mn can be measured by GPC, and can be obtained as a relative value in terms of polystyrene.

Returning to the description of the binder resin as a whole, the content of the binder resin is not particularly limited. For example, the binder resin is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more in terms of solid content in each color ink. The binder resin content in the ink is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. When the content of the binder resin is less than 1% by mass, it is difficult to obtain the desired performance as a binder, and there is a tendency for the adhesion to the substrate to deteriorate. On the other hand, when the content of the binder resin exceeds 40% by mass, the viscosity of the ink tends to be high and the ejection stability during inkjet printing tends to be lowered.

(dispersant)
A dispersant is preferably included to disperse the colorant. Dispersants are not particularly limited. Examples of dispersants include anionic surfactants, nonionic surfactants, polymer dispersants, and the like. A dispersant may be used in combination.

Anionic surfactants include fatty acid salts, alkyl sulfate salts, alkyl benzene sulfonates, alkyl naphthalene sulfonates, lignin sulfonates, dialkyl sulfosuccinates, alkyl phosphate salts, naphthalene sulfonic acid formalin condensates, poly Examples include oxyethylene alkyl sulfate ester salts and substituted derivatives thereof.

Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylamines, glycerin fatty acid esters, oxyethyleneoxy Examples include propylene block polymers and substituted derivatives thereof.

Polymeric dispersants having both an acid value and a base value, and having a higher acid value than the base value are preferable from the viewpoint of obtaining more stable dispersion characteristics. Examples of polymer dispersants include the PB series manufactured by Ajinomoto Fine Techno Co., Ltd., the Hinoact series manufactured by Kawaken Fine Chemicals Co., Ltd., the Solsperse series manufactured by Nippon Lubrizol Co., Ltd., and the Kusumoto Kasei Co., Ltd. DISPARLON series manufactured by ) and Efka (registered trademark) series manufactured by BASF Japan Ltd. are exemplified.

When a dispersant is contained in the ink, the content of the dispersant is appropriately determined according to the type and content of the colorant to be dispersed. For example, the content of the dispersant is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, relative to 100 parts by mass of the colorant. Also, the content of the dispersant is preferably 150 parts by mass or less, more preferably 80 parts by mass or less, relative to 100 parts by mass of the coloring material. If the content of the dispersant is less than 5 parts by mass, the coloring material tends to be difficult to disperse. On the other hand, when the content of the dispersing agent exceeds 150 parts by mass, there is a tendency that the raw material cost increases and the dispersion of the coloring material is hindered.

(solvent)
The solvent is preferably contained in each color ink to dissolve the binder resin. The type of solvent is not particularly limited. Examples of solvents include water, glycol ether solvents, acetate solvents, alcohol solvents, ketone solvents, ester solvents, hydrocarbon solvents, fatty acid ester solvents, and aromatic solvents. A solvent may be used in combination. Among these, the solvent of the present embodiment preferably contains at least one of a glycol ether solvent and an acetate solvent. Glycol ether solvents and acetate solvents both have low viscosities and relatively high boiling points. Therefore, the ink containing these as a solvent is more improved in drying property, and is more excellent in ejection stability during inkjet printing.

Glycol ether solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono(iso)propyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, propylene glycol. Monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n -butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol mono-n-propyl ether, triethylene glycol mono-n-butyl ether, tripropylene glycol monoethyl ether, tripropylene glycol mono-n-propyl Ether, tripropylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol ethyl methyl ether, diethylene glycol isopropyl methyl ether, diethylene glycol butyl methyl ether , triethylene glycol butyl methyl ether, dipropylene glycol dimethyl ether, tripropylene glycol dimethyl ether, and the like.

Acetate solvents include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monoisopropyl ether acetate, ethylene glycol mono-n-butyl ether acetate, ethylene glycol mono-sec-butyl ether acetate, Ethylene glycol monoisobutyl ether acetate, ethylene glycol mono-tert-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monoisopropyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol mono-n-butyl ether Acetate, propylene glycol mono-sec-butyl ether acetate, propylene glycol monoisobutyl ether acetate, propylene glycol mono-tert-butyl ether acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-ethoxybutyl acetate, 3-methyl -3-propoxybutyl acetate, 3-methyl-3-isopropoxybutyl acetate, 3-methyl-3-n-butoxyethyl acetate, 3-methyl-3-isobutoxybutyl acetate, 3-methyl-3-sec- Alkylene glycol monoalkyl ether acetates such as butoxybutyl acetate and 3-methyl-3-tert-butoxybutyl acetate, ethylene glycol diacetate, diethylene glycol diacetate, triethylene glycol diacetate, propylene glycol diacetate, dipropylene glycol Examples include diacetate, tripropylene glycol diacetate, and the like.

The solvent of the present embodiment preferably has a boiling point of 150° C. or higher, more preferably 180° C. or higher. The solvent preferably has a boiling point of 300° C. or lower, more preferably 280° C. or lower. When the boiling point is within the above range, the resulting ink has more improved drying properties and more excellent ejection stability during inkjet printing. In addition, the ink tends to form clear prints with less bleeding. If the boiling point of the solvent is less than 150° C., the ink tends to dry in the vicinity of the head nozzle, resulting in a decrease in ejection stability. On the other hand, if the boiling point of the solvent exceeds 300° C., the ink becomes difficult to dry, and the drying process during the formation of the printed matter tends to take a long time. In addition, the printed matter obtained tends to blur the image.

The content of the solvent is not particularly limited. For example, the solvent content in each color ink is preferably 50% by mass or more, more preferably 60% by mass or more. The solvent content in each color ink is preferably 99% by mass or less, more preferably 80% by mass or less. If the solvent content is less than 50% by mass, the viscosity of the ink tends to be high and the ejection stability during inkjet printing tends to be low. On the other hand, when the content of the solvent exceeds 99% by mass, the ratio of the coloring material and the binder resin that can be added to the ink becomes low, and it tends to be difficult to obtain the desired color developability and performance.

(Optional component)
Each color ink constituting the ink set of the present embodiment may contain optional components in addition to the components described above. To give an example, optional ingredients include heat stabilizers, antioxidants, preservatives, antifoaming agents, penetrants, reduction inhibitors, leveling agents, pH adjusters, polymerization inhibitors, ultraviolet absorbers, light stabilizers, and the like. is.

Returning to the description of the ink as a whole, the viscosity of the ink is not particularly limited. For example, the viscosity of the ink is preferably 2 mPa·s or more, more preferably 5 mPa·s or more. Also, the viscosity is preferably 50 mPa·s or less, more preferably 30 mPa·s or less. When the viscosity is within the above range, the ink is less likely to cause ejection failure from the inkjet head and has excellent ejection stability. In this embodiment, the viscosity of the ink can be measured using a Brookfield viscometer (TVB-20LT manufactured by Toki Sangyo Co., Ltd., rotor speed 60 rpm). The method for adjusting the viscosity within the above range is not particularly limited. For example, the viscosity can be adjusted by the amount of each component added and the type and amount of solvent added. The viscosity may be adjusted by using a viscosity modifier such as a thickener as needed.

The surface tension of ink is not particularly limited. The surface tension of the ink is preferably 20 dyne/cm or more, more preferably 22 dyne/cm or more at 25°C. Also, the surface tension of the ink at 25° C. is preferably 40 dyne/cm or less, more preferably 35 dyne/cm or less. When the surface tension is within the above range, the ink has excellent ejection stability. In this embodiment, the surface tension can be measured using a static surface tensiometer (plate method) (CBVP-A3, manufactured by Kyowa Interface Science Co., Ltd.).

The ink set of the present embodiment can be used to form an ink image on a base material by ejecting the ink onto the base material using an ink jet device employing an ink jet method, thereby producing a print. The ink set contains ink containing a predetermined coloring material so that the average reflectance at the time of coating film formation is 40% or more. As a result, the resulting coating film exhibits excellent heat shielding properties. Moreover, each colorant contains the inorganic pigment. By using each color ink containing such an inorganic pigment, the resulting coating film exhibits excellent weather resistance. Therefore, the ink set of this embodiment is suitable for various uses that require heat shielding and weather resistance. That is, the ink set is suitably used for exterior applications of building materials, outdoor sign advertisements, and the like.

<Manufacturing method of printed matter>
A method for producing a printed matter according to one embodiment of the present invention includes a printing step of applying ink to a substrate by an inkjet method using the inkjet ink set described above, and a drying step of drying the substrate. The method for producing a printed matter according to the present embodiment only needs to include these printing process and drying process, and the other processes are not particularly limited. In addition, the conditions of the drying process can be appropriately optimized depending on the type of inkjet ink (whether it is an ultraviolet curable inkjet ink, etc.). Each of these will be described below.

(Other than UV curable inkjet ink)
Application step The method of applying the inks constituting the ink set to the base material by an inkjet recording method is not particularly limited. Examples of such methods include continuous methods such as charge modulation method, microdot method, charging jet control method, and ink mist method; A demand system or the like is exemplified.

An ink-jet device for applying ink supplies ink from an ink tank to a pressure chamber through an ink supply path, and applies an electric signal corresponding to image data to a piezoelectric element to drive the piezoelectric element. This is a device that reduces the volume of a pressure chamber by deforming a vibration plate that forms part of the chamber, and ejects ink in the pressure chamber as droplets from ejection openings of nozzles (heads).

There are two types of heads: shuttle type (multi-pass type) and line type (single-pass type). The multi-pass method is a method in which a short serial head is used and recording is performed while the head is scanned in the width direction of the substrate. On the other hand, the single-pass method uses a full-line head that covers the entire area of the base material, and moves the full-line head and the base material relative to each other only once to form an image on the entire surface of the base material. is.

The substrate to which the ink is applied is not particularly limited. Examples of the substrate include steel plates, metal plates such as aluminum and stainless steel, plastic plates or films such as acrylic, polycarbonate, ABS, polypropylene, polyester, and vinyl chloride, ceramic plates, concrete, wood, and glass. These substrates are preferably treated with a pretreatment agent prior to printing. Examples of the pretreatment agent include fluorine-based paints, silicone-based paints, acryl-silicone-based paints, acrylic-based paints, epoxy-based paints, urethane-based paints, and the like. Examples of methods for applying these pretreatment agents to the base material include a spray method, a roll coater method, a curtain flow coater method, a brush coating method, a spatula coating method, an immersion method, and an inkjet method. According to this embodiment, as described above, a printed matter having excellent heat shielding properties and weather resistance can be obtained. Therefore, the method for producing a printed matter according to the present embodiment can obtain a printed matter that is suitably used for the exterior of building materials, especially when the base material is a fluorine-based paint, a silicone-based paint, or an acryl-silicone-based paint. .

- Drying process The substrate to which the ink has been applied is then dried. Drying conditions are not particularly limited. For example, the drying temperature is preferably 50° C. or higher, more preferably 80° C. or higher, and even more preferably 100° C. or higher. Also, the drying temperature is preferably 400° C. or lower, more preferably 300° C. or lower, and even more preferably 200° C. or lower. The drying time is preferably 1 minute or longer, more preferably 2 minutes or longer, and even more preferably 3 minutes or longer. Also, the drying time is preferably 60 minutes or less, more preferably 30 minutes or less, and even more preferably 10 minutes or less. Such drying makes it difficult for the colorant in the ink to cause discoloration or the like, and the solvent can be removed. Drying is preferably performed at the same time or immediately after the ink is applied to the substrate in order to prevent bleeding of the ink.

The resulting print is an inkjet print to which the inkjet ink is applied. Such prints are formed with coating films exhibiting excellent heat-shielding properties and weather resistance due to the use of the ink set described above. Therefore, the printed matter is particularly suitable as, for example, an exterior member of a building material.

・Method for producing printed matter (in the case of UV-curable inkjet ink)>
The method for producing an inkjet print according to one embodiment of the present invention (hereinafter also simply referred to as the method for producing a printed object) is an inkjet method, particularly when producing an inkjet print using the above-mentioned ultraviolet curable ink. It includes a step of applying onto a base material, and a step of drying the applied ink by irradiating it with ultraviolet light (curing step). Each of these will be described below.

- Applying step The applying step is a step of applying the above-described ink onto a substrate by an inkjet method. The base material is not particularly limited. Substrates similar to those described above can be used. Also, the same inkjet device as described above can be used for applying ink.

・Drying process (curing process)
The drying process (curing process) is a process of curing the applied ink by irradiating it with ultraviolet rays. The ink ejected onto the substrate is cured by being irradiated with ultraviolet rays from an ultraviolet irradiation lamp attached to the inkjet device. A mercury lamp, a gas/solid-state laser, and the like are exemplified as the ultraviolet irradiation lamp. Among these, the ultraviolet irradiation lamp is preferably a mercury lamp or a metal halide lamp. Alternatively, the ultraviolet irradiation lamp may be an ultraviolet light emitting diode (UV-LED) or an ultraviolet laser diode (UV-LD).

There is no particular limitation on the cumulative amount of UV light during curing. The integrated amount of light is preferably 40 mJ/cm ² or more, more preferably 60 mJ/cm ² or more. Also, the integrated amount of light is preferably 500 mJ/cm ² or less, more preferably 400 mJ/cm ² or less. The integrated amount of light can be measured using, for example, an ultraviolet illuminometer/photometer (UV-351-25 manufactured by ORC Manufacturing Co., Ltd.) under the conditions of a measurement wavelength range of 240 to 275 nm and a measurement wavelength center of 254 nm.

As described above, according to the printed matter manufacturing method of the present embodiment, the obtained printed matter is an inkjet printed matter to which the inkjet ink is applied. Such prints are formed with coating films exhibiting excellent heat-shielding properties and weather resistance due to the use of the ink set described above. Therefore, the printed matter is particularly suitable as, for example, an exterior member of a building material.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples. The present invention is by no means limited to these examples. Unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass".

The raw materials used are shown below.
(colorant)
Yellow colorant 1: HY-100, iron oxide inorganic pigment, manufactured by Titan Kogyo Co., Ltd. Yellow colorant 2: NF-5850, Ti-Ni inorganic pigment, manufactured by Nikken Co., Ltd. Yellow colorant 3: Cromophtal Yellow D1085, azonickel-based organic pigment, BASF red colorant 1: R-516P, iron oxide-based inorganic pigment, Titan Kogyo Co., Ltd. red colorant 2: M-663, Zr-Fe-based inorganic pigment, Nitto Pigment Co., Ltd. red colorant 3: Ink Jet Red E5B02, quinacridone-based organic pigment, Clariant Japan Co., Ltd. blue colorant 1: #9410, Co-Al inorganic pigment, Dainichiseika Kogyo Co., Ltd. blue color Material 2: NF-2500, Co-Cr inorganic pigment, Nikken Co., Ltd. Blue color material 3: Hostaperm Blue P-BFS, copper phthalocyanine organic pigment, Clariant Japan Co., Ltd. Black color material 1: Black L 0095, Fe—Cr inorganic pigment, BASF black colorant 2: NF-550, Y—Mn inorganic pigment, Nikken Co., Ltd. black colorant 3: Black 6301, Bi—Mn inorganic pigment, Asahi Kasei Kogyo Co., Ltd. Black color material 4: NiPex35, carbon black, Orion Engineered Carbons Co., Ltd. (resin)
Resin 1: LF-200F, fluororesin, manufactured by Asahi Glass Co., Ltd., ethylene trifluoride/vinyl monomer alternating copolymer Resin 2: urethane acrylate, manufactured by Arkema, CN991, aliphatic urethane acrylate Resin 3: acryloyl morpholine , KJ Chemicals Co., Ltd., ACMO, acrylamide-based monomer Resin 4: acrylic monomer, Osaka Organic Chemical Industry Co., Ltd., MEDOL-10, monofunctional acrylic monomer (dispersant)
Dispersant 1: polymer dispersant, Solsperse 33000, manufactured by Lubrizol (solvent)
Solvent 1: Diethylene glycol diethyl ether (DEDG), glycol ether solvent, manufactured by Nippon Nyukazai Co., Ltd., boiling point: 189°C

<Inkjet ink set>
Ink sets consisting of the color inks of Examples 1 to 6 and Comparative Examples 1 and 2 were prepared according to the formulations (unit: parts by mass) shown in Tables 1 to 8 below. Specifically, each component was mixed with a resin in a mixer and filtered to prepare each color ink, which was then combined to produce each ink set. Using the obtained ink set, approximately 150 g/liter of commercially available fluorine paint (Bonflon #1000SR top coat, manufactured by AGC Coatec Co., Ltd.) was applied to a base material (chromate-treated aluminum steel sheet) by air spray under the following inkjet conditions. m ² was applied and dried for 3 minutes in an environment of 200° C.) was printed by inkjet printing to prepare a print.

<Inkjet condition>
Single pass method Dot size: 30pl
Nozzle diameter: 40 μm
Drive voltage: 80V
Pulse width: 10 μm
Frequency: 10kHz
Resolution: 400 x 600dpi
Application amount: 10 g/m ²
Base material temperature: 50°C (heating)
Pattern: Solid pattern of each color ink

<Drying conditions>
Examples 1 to 4, Example 6, and Comparative Examples 1 and 2, which are solvent-based inkjet inks, were dried in an environment of 200° C. for 1 minute after printing. Example 5, which is an ultraviolet curable inkjet ink, was dried under the following conditions immediately after printing.
Ultraviolet irradiation lamp: Metal halide lamp Irradiation intensity: 0.5 mW/cm ²
Accumulated amount of light: 400 mJ/cm ²
Irradiation height: 40mm

In preparing the printed matter, the initial viscosity, ink stability, ejection stability, infrared reflectance, and blackness (black ink only) of each ink were evaluated according to the following evaluation criteria. In addition, the weather resistance of the prints was measured. Table 1 shows the results.

<Initial viscosity of ink>
The prepared ink was adjusted to 50° C., and the viscosity was measured using a Brookfield viscometer (TVB-20LT manufactured by Toki Sangyo Co., Ltd., rotor speed 60 rpm).

<Infrared reflectance>
About 150 g/m ² of commercially available fluorine paint (Bonflon #1000SR overcoat, manufactured by AGC Coatec Co., Ltd.) was applied to the base material (chromate-treated aluminum steel plate) with each color ink by air spray, and the ink was applied in an environment of 200°C for 3 times. After drying for 1 minute), ink-jet printing was performed under the same conditions as the printed matter to form a coating film. The dry film thickness of the obtained coating film was about 10 μm. When the obtained coating film is measured under conditions according to JIS K 5602 using a device called an ultraviolet-visible-near-infrared spectrophotometer (model number: UV-3600plus, vendor name: manufactured by Shimadzu Corporation). The average reflectance was measured in the near-infrared region of 780 nm to 2100 nm.
(Evaluation criteria)
◯: Average reflectance was 40% or more for all color inks.
Δ: The average reflectance of any color ink was 30% or more and less than 40%.
x: Average reflectance was 30% or less for all color inks.

<Weather resistance>
Using a super UV tester (SUV-W161, manufactured by Iwasaki Electric Co., Ltd.), the printed matter is irradiated with ultraviolet rays for 6 hours (UV conditions: 100 mW/cm ² , temperature: 63°C, humidity: 50%) as a super-accelerated weather resistance test. After the application, a 30-second shower followed by 2 hours of dew condensation was defined as one cycle, and the color difference was measured after a total of 600 hours.
(Color difference measurement method)
The ΔE after the ultra-accelerated weathering test was taken as the color difference of the printed matter. The color difference was measured using a spectrophotometer (CM-3700, manufactured by Konica Minolta, Inc.).
(Evaluation criteria)
Good: The color difference was ΔE≦3.
Δ: The color difference was 3<ΔE≦5.
x: The color difference was ΔE>5.

<Blackness>
A coating film prepared under the same conditions as for infrared reflectance was measured using a spectrophotometer (CM-3700, manufactured by Konica Minolta Co., Ltd.), and the L* value was measured as a blackness.
(Evaluation criteria)
A: The degree of blackness was L*≦30.
○: Blackness was 30<L*≦40.
x: Blackness was L*>40.

As shown in Tables 1 to 8, the prints obtained using the ink sets of Examples 1 to 6 were excellent in shielding due to the use of each color ink having an infrared reflectance of 40% or more. showed febrile nature. These prints also exhibited excellent weatherability. On the other hand, the ink sets of Comparative Examples 1 and 2 contained an ink (blue ink 4 or 5) having an average reflectance of less than 40% among the respective color inks constituting the ink set, so that the heat shielding property was inferior. it was thought.

Claims (5)

Including a yellow ink containing a yellow colorant, a red ink containing a red colorant, and a blue ink containing a blue colorant,
The yellow colorant, the red colorant, and the blue colorant are inorganic pigments,
The yellow ink, the red ink, and the blue ink have an average reflectance of 40% or more at a wavelength of 780 to 2100 nm of the coating film formed when each ink is applied ,
further comprising a black ink containing a black colorant;
The black ink has an average reflectance of 40% or more at a wavelength of 780 to 2100 nm of a coating film formed by applying the black ink,
The inkjet ink set , wherein the black colorant includes at least one of a bismuth-manganese-based pigment and an yttrium-manganese-based pigment . The inkjet ink set according to claim 1, wherein the yellow colorant, the red colorant, and the blue colorant have an average particle size of 100 to 1000 nm. The yellow ink, the red ink, and the blue ink each contain a binder resin,
3. The inkjet ink set according to claim 1, wherein the binder resin is a fluororesin. An inkjet print to which the ink of the inkjet ink set according to any one of claims 1 to 3 is applied. a printing step of applying ink to a substrate by an inkjet method using the inkjet ink set according to any one of claims 1 to 3 ;
and a drying step of drying the substrate.