JP5308170B2 - Building board manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a building board having a sufficient weatherability resistant to outdoor use in the method for manufacturing the building board, on which an image is formed by inkjet printing. <P>SOLUTION: The method for manufacturing the building board comprises: a process (1) of applying an inkjet coating with UV ink onto a base material where priming coating is applied; a process (2) of curing the UV ink with UV rays after the process (1); and a process (3) of applying a clear coating onto a surface where the inkjet coating is applied after the process (2). The UV ink comprises a photopolymerization initiator, a reactive oligomer and/or a reactive monomer and pigment. A curing ratio of the UV ink after curing at the process (2) is 50 to 90% and a clear coating material contains a cross-linking component. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing a building board. More specifically, the present invention relates to a method for manufacturing a building board on which an image is formed with UV ink using an inkjet printer.

  In recent years, application of inkjet printing to various materials has been studied, and one example is a building board for outdoor use. This building board is required to have excellent weather resistance that can cope with all natural conditions. The term “weather resistance” as used herein means that an image printed on a substrate is held without cracking or peeling even when exposed to heat, light, water, or the like. Specifically, the quality is required such that it hardly deteriorates after being exposed to heat, light, water, etc., usually for 5 to 10 years outdoors.

  As a building board on which images have been formed by inkjet printing that has been proposed so far, the base material is first coated with an undercoat, then inkjet printed on it, and finally a clear coating is applied. (For example, Patent Document 1). Further, a receiving layer is first formed on a base material, and then ink jet printing is performed thereon with water-based ink, water-based paint is applied with a clear coating, and finally an inorganic paint is applied (for example, Patent Document 2). There is also.

  As a major feature of the methods described in Patent Documents 1 and 2, when ink-jet printing is performed using a volatile ink such as a solvent-based or water-based ink, the surface of the substrate on which the printing is performed is made liquid-absorbing There are times when you have to leave. Otherwise, there is a risk of causing a problem that the quality of the image is greatly impaired, such as blurring and uneven coloring due to the amount of ink applied.

JP 2004-60241 A JP 2007-152595 A

  However, making the substrate surface liquid-absorbing is not very preferable from the viewpoint of weather resistance. That is, the clear paint applied on the portion where ink is applied (image is formed by ink jet) and the portion where ink is not applied (image is not formed by ink jet) in a later step A difference occurs in the liquid absorbency. As a result, a uniform clear paint layer is not formed, resulting in coating unevenness, which may adversely affect the above-described weather resistance and even the appearance.

  On the other hand, there is a method called UV inkjet printing. Since the UV ink is an ink that is cured by irradiation with ultraviolet rays, it is not necessary to perform a liquid-absorbing treatment on the surface of the base material like a solvent or water-based ink. However, when a clear paint or the like is applied on a cured product of UV ink, the adhesion is poor and there is a risk of peeling. The reason is that the UV ink forms a UV ink image layer by crosslinking a reactive oligomer or a reactive monomer having an acrylic group in the molecule by radical polymerization. The UV ink image layer crosslinked by this radical polymerization has a dense two-dimensional and three-dimensional molecular structure and is difficult to adhere to a clear paint.

  Therefore, in the manufacturing method of the building board in which the image was formed by inkjet printing, the thing provided with sufficient weather resistance which can be used outdoors is not proposed yet.

  The present invention has been made in view of the above problems, and in a method for manufacturing a building board on which an image is formed by inkjet printing, a method for manufacturing a building board having sufficient weather resistance that can withstand outdoor use is provided. The purpose is to provide.

The manufacturing method of the building board of the present invention includes (1) a step of performing inkjet coating with UV ink on a base material that has undergone undercoating, and
(2) After the step (1), a step of curing the UV ink with ultraviolet rays;
(3) After the process of (2), it is a manufacturing method of the building board which consists of the process of performing clear coating on the surface on which ink-jet coating was applied,
The UV ink includes a photopolymerization initiator, a reactive oligomer and / or a reactive monomer, and a pigment.
The curing rate of the UV ink after curing in the step (2) is 50 to 90%, and the clear coating contains a crosslinking component.

  It is preferable to adjust the curing rate of the UV ink by changing the UV lamp irradiation conditions.

  The reactive oligomer and / or reactive monomer is preferably bifunctional and / or trifunctional.

  The photopolymerization initiator is preferably a hydroxy ketone or an acyl phosphine oxide.

  The concentration of the pigment is preferably 0.5 to 20% by weight in the UV ink.

  According to the method for producing a building board of the present invention, in the method for producing a building board on which an image is formed by ink jet printing, a method for producing a building board having sufficient weather resistance capable of withstanding outdoor use is provided. be able to.

  The present invention has found that the adhesion between the clear coating and the UV ink image is strengthened by crosslinking and / or interaction between a crosslinking component contained in the clear coating and a polar group such as an acrylic group of the UV ink. is there.

  In the present invention, it is important that the curing rate of the UV ink after being cured with ultraviolet rays before the clear coating is 50 to 90%. Originally, a UV ink image having excellent weather resistance can be obtained by setting the curing rate of the UV ink to 100%. However, in the present invention, the polymerization reaction is still achieved by setting the curing rate of the UV ink to 50 to 90%. The adhesion is improved by crosslinking and / or interaction between the reactive oligomer in the UV ink and the acrylic group or other polar group of the reactive monomer and the crosslinking component contained in the clear coating. When the curing rate of the UV ink is less than 50%, the curing of the UV ink is insufficient, so that the UV ink image may be peeled off and the weather resistance may be deteriorated. When the curing rate exceeds 90% There is a problem that the adhesion between the UV ink image and the clear coating is deteriorated.

Here, the curing rate of the UV ink refers to the degree of polymerization of the reactive oligomer and the acrylic group of the reactive monomer, which are the main components of the UV ink, in a Fourier transform infrared spectrum (hereinafter referred to as FT-IR), 800 to 820 cm. It can be calculated by measuring the peak intensity of ^-1 . That is, the reactive oligomer which is the main component of the UV ink and the acrylic group of the reactive monomer have a peak at 800 to 820 cm ⁻¹ in FT-IR. Since the acrylic group will be polymerized when the UV ink is cured, the peak at 800 to 820 cm ⁻¹ will become smaller. This decrease in peak intensity is a polymerization of acrylic groups and can be calculated as the cure rate.

  Means for adjusting the curing rate of the desired UV ink include (1) UV lamp irradiation conditions when curing the UV ink, (2) reactive oligomer and / or reactive monomer components in the UV ink, (3) Components of the photopolymerization initiator in the UV ink, (4) Pigment concentration in the UV ink, and the like. Among them, the means (1) is preferable because adjustment can be easily performed. Specifically, the UV ink can be adjusted to a desired curing rate by varying the intensity of the UV lamp and the irradiation time. Furthermore, it is possible to combine (1) with other means (2) to (4).

  The other means will be specifically described. In (2), the reactive oligomer and / or reactive monomer of the UV ink is preferably bifunctional and / or trifunctional. If it is smaller than bifunctional, it is difficult to adjust the curing rate, and adhesion with the undercoat may not be obtained. If it is larger than trifunctional, it is difficult to adjust the curing rate because the curing speed is high, and the crosslinking density Therefore, there is a possibility that adhesion with clear coating cannot be obtained.

  Furthermore, in (3), the photopolymerization initiator of the UV ink is preferably a hydroxyketone and an acylphosphine oxide, and the blending ratio is preferably 5: 1 to 1: 1. There is a possibility that a sufficient curing rate cannot be obtained only with hydroxy ketones, and when there are many acylphosphine oxides, there is a possibility that the curing rate cannot be adjusted because the curing rate is high.

  Furthermore, in (4), the pigment concentration of the UV ink is preferably 0.5 to 20% by weight in the UV ink. When the pigment concentration exceeds 20% by weight, the light from the UV lamp does not pass through the UV ink, and the curing rate of the UV ink may not be obtained.

  In the present invention, the reason for paying attention to the curing rate of the UV ink is that the cured film of the UV ink is hardly adhesive in each adhesion of the base material, the undercoat coating, the UV ink image, and the clear coating. This is because adhesion of clear paint is particularly difficult. Actually, when exposed to heat, light, water, etc. for a long time, compared with the boundary between the primer coating and the clear coating, the boundary between the primer coating and the UV ink coating and between the clear coating and the UV ink image. A lot of peeling occurs at the boundary.

  Therefore, by combining a UV ink image with a specific curing rate and a clear coating containing a crosslinking component, strong adhesion that does not peel even when exposed to heat, light, water, etc. for a long time can be obtained, resulting in weather resistance. Sexuality is improved.

  The advantages of forming an image with UV ink in the present invention are as follows.

  The UV ink has a property that the resin instantly cures when irradiated with ultraviolet rays, and does not require liquid absorbency on the substrate surface. Further, most of the UV ink images obtained by curing the UV ink are hydrophobic and can be said to have excellent water resistance.

  Further, the UV ink can be designed with a larger amount of resin solids than volatile inks such as solvent-based and water-based inks, so that high-density image expression is possible.

  Further, since the pigment is wrapped and protected by the cured resin of UV ink, the pigment is less likely to be discolored or faded.

  Furthermore, it is possible to adjust the film thicknesses of undercoating, UV ink image, and clear coating, and the overall film thickness can be designed to be thick. The advantage of being able to design this thick film is that even if deterioration or erosion occurs from the surface of the clear coating, which is the outermost layer, it immediately affects the underlying coating and UV ink images. As a result, the weather resistance is good.

  The substrate is preferably a metal plate or a ceramic board.

  Examples of the metal plate include plated steel plates such as ordinary steel plates and galvalume steel plates, steel plates such as painted steel plates and stainless steel plates, aluminum plates, and copper plates. Furthermore, the PCM steel plate which gave various resin coatings as a base coating layer to these metal plates is mention | raise | lifted. Moreover, it is also possible to give unevenness, such as a tile tone, a brick tone, and a wood grain tone, to these metal plates by embossing or drawing. Furthermore, for the purpose of improving heat insulation and soundproofing, it is also possible to cover the back surface of the metal plate with aluminum laminated kraft paper or the like using an inorganic material such as a resin foam or gypsum board as a core material.

  Examples of ceramic plates include unglazed ceramic plates, glazed and fired ceramic plates, and cement plates. Furthermore, the thing shape | molded in plate shape using a cement-like raw material, a fiber raw material, etc. is mention | raise | lifted. Moreover, it is also possible to give unevenness, such as a tile tone, a brick tone, and a wood grain tone, by embossing etc. to these ceramic boards.

  Moreover, sealer coating can be applied to the above-mentioned base material for the purpose of durability and sealing. The sealer paint used may be either water-based or solvent-based, but water-based paints are preferred from the viewpoint of workability and safety.

  Next, the undercoat used in the undercoat is for constituting the base of the ink jet print, that is, it is prepared in white with a pigment or a light color similar to the image to be printed. By preparing with a light color similar to the image to be printed, the printed part and the part that is not printed become familiar, and the image can appear naturally as a whole. The undercoat paint may be either water-based or solvent-based, but is preferably a water-based paint from the viewpoint of workability and safety. The undercoat paint is composed of a pigment, a resin, and, if necessary, an additive such as a thickener.

  Examples of the pigment include organic or inorganic pigments. Examples of the organic pigment include nitroso, dyed lake, azo lake, insoluble azo, monoazo, disazo, condensed azo, benzimidazolone, phthalocyanine, Anthraquinones, perylenes, quinacridones, dioxazines, isoindolines, azomethines, pyrrolopyrroles and the like. Examples of inorganic pigments include oxides, hydroxides, sulfides, ferrocyanides, chromates, carbonates, silicates, phosphates, carbons (carbon black) and metal powders. Etc.

  The pigment weight concentration of the undercoat paint is preferably 10 to 50% by weight in the undercoat paint. When the pigment weight concentration of the undercoat paint is less than 10% by weight, the amount of the pigment is small, the color of the base material cannot be concealed, and the target “undercoat” may not be achieved. When the weight concentration exceeds 50% by weight, the water resistance of the undercoat paint layer may be deteriorated. The pigment weight concentration referred to here is the pigment concentration relative to the non-volatile component of the paint.

  Examples of the resin include an acrylic resin, an acrylic styrene resin, an acrylic silicon resin, a polyester resin, a urethane resin, and a fluororesin. From the viewpoints of adhesion with a UV ink image layer and a clear paint layer, versatility, and economical efficiency, An acrylic resin, an acrylic styrene resin, and an acrylic silicon resin are preferable. In the case of a solvent-based paint, the resin is dissolved in a solvent to obtain a paint. In the case of a water-based paint, the resin is dissolved or emulsified in water to obtain a paint.

  Additives include heat stabilizers, antioxidants, preservatives, antifoaming agents, penetrants, reduction inhibitors, leveling agents, pH adjusters, pigment derivatives, polymerization inhibitors, UV absorbers, light stabilizers and resins Examples include beads. In the case of water-based emulsion paints, solvents such as ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and benzyl alcohol may be appropriately added as a film-forming aid. Is possible.

The coating amount of the undercoat paint is preferably 10 to ²⁰⁰ g / m ² (dry state). If the coating amount is less than 10 g / m ² , the entire substrate may not be completely covered. If the coating amount is more than 200 g / m ² , the film thickness of the undercoat becomes too thick and cracks occur in the undercoat. It becomes easy to do.

  The film thickness of the undercoat is preferably 10 to 150 μm. If the film thickness is less than 10 μm, the entire substrate may not be completely covered. If the film thickness is more than 150 μm, cracks are likely to occur in the undercoat paint layer.

  The undercoat paint can be applied with a spray gun, a curtain coater, a flow coater or the like, and is not particularly limited.

  Moreover, about drying of undercoat, it can carry out by hot-air drying, ventilation drying, drying with a heater, drying with a hot plate, etc., and it does not specifically limit. The temperature and time can be appropriately determined, but the drying temperature is preferably 60 to 150 ° C. and the drying time is preferably 1 to 30 minutes.

  Next, the UV ink used for UV ink image formation comprises a pigment, a reactive monomer and / or a reactive oligomer, a photopolymerization initiator, and, if necessary, an additive such as a thickener. Since the same pigment as the pigment in the undercoat paint can be used, description thereof is omitted.

  The pigment concentration of the UV ink is preferably 0.5 to 20% by weight in the UV ink. When the pigment concentration of the UV ink is less than 0.5% by weight, coloring may be insufficient, and the target “image” may not be formed. When the pigment concentration exceeds 20% by weight, There is a possibility that the viscosity of the UV ink becomes too high and the UV ink cannot be ejected from the nozzles of the inkjet printer.

  Examples of reactive monomers include hexafunctional acrylates such as dipentaerythritol hexaacrylate and modified products thereof; pentafunctional acrylates such as dipentaerythritol hydroxypentaacrylate; tetrafunctionals such as pentaditrimethylolpropane tetraacrylate and pentaerythritol tetraacrylate. Acrylates; trifunctional acrylates such as trimethylolpropane triacrylate, pentaerythritol triacrylate, tris (2-hydroxyethyl) isocyanurate triacrylate, glyceryl triacrylate; hydroxypivalic acid neopentyl glycol diacrylate, polytetramethylene glycol diacrylate, Trimethylolpropane acrylate benzoate, diethyleneglycol Diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol (200) diacrylate, polyethylene glycol (400) diacrylate, polyethylene glycol (600) diacrylate, neopentyl glycol diacrylate, 1,3-butane Bifunctional acrylates such as diol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, dimethylol-tricyclodecane diacrylate, bisphenol A diacrylate; and , Caprolactone acrylate, tridecyl acrylate, isodecyl acrylate, isooctyl acrylate, isomyristyl acrylate , Isostearyl acrylate, 2-ethylhexyl-diglycol diacrylate, 2-hydroxybutyl acrylate, 2-acryloyloxyethyl hexahydrophthalic acid, neopentyl flycol acrylate benzoate, isoamyl acrylate, lauryl acrylate, stearyl acrylate , Butoxyethyl acrylate, ethoxy-diethylene glycol acrylate, methoxy-triethylene glycol acrylate, methoxy-polyethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxy-polyethylene glycol acrylate, nonylphenol acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate 2-Hido Roxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl-succinic acid, 2-acryloyloxyethyl-phthalic acid, 2-acryloyloxyethyl-2-hydroxy And monofunctional acrylates such as ethyl-phthalic acid. Among these, a bifunctional monomer is preferable in terms of excellent toughness and flexibility. Among the bifunctional monomers, aliphatic reactive monomers composed of hydrocarbons, specifically 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, 1,3-butanediol, are hardly yellowing. Diacrylate, 1,4-butanediol diacrylate, 1,9-nonanediol diacrylate and the like are preferable.

  Examples of the reactive monomer further include a reactive monomer in which a functional group of phosphorus, fluorine, ethylene oxide or propylene oxide is added to the reactive monomer. Moreover, these reactive monomers can be used individually or in combination of 2 or more types.

  The reactive monomer is preferably contained in the UV ink in an amount of 50 to 85% by weight. If the amount is less than 50% by weight, the viscosity of the UV ink is increased, which may result in ejection failure. If the amount exceeds 85% by weight, other components necessary for curing may be insufficient, resulting in a curing failure.

  Examples of the reactive oligomer include urethane acrylate, polyester acrylate, epoxy acrylate, silicon acrylate, and polybutadiene acrylate, and these can be used alone or in combination of two or more. Of these, urethane acrylate is preferable in terms of excellent toughness, flexibility, and adhesion. Among urethane acrylates, aliphatic urethane acrylates composed of hydrocarbons are more preferable in that they are hardly yellowing.

  It is also possible to use a reactive monomer mixed in advance with the reactive oligomer. The reactive monomer to be mixed is preferably bifunctional and / or trifunctional. In the mixing of the reactive oligomer and the reactive monomer, the reactive monomer can be appropriately added to such an extent that the performance of the reactive oligomer is not impaired.

  The reactive oligomer is preferably contained in the UV ink in an amount of 1 to 40% by weight, more preferably 5 to 40% by weight, and further preferably 10 to 30% by weight. When the reactive oligomer is in the range of 1 to 40% by weight, the cured film of the UV ink has better toughness, flexibility and adhesion.

  Examples of the photopolymerization initiator include benzoins, benzyl ketals, aminoketones, titanocenes, bisimidazoles, hydroxyketones and acylphosphine oxides, which can be used alone or in combination of two or more.

  Among the photopolymerization initiators, hydroxyketones and acylphosphine oxides are preferable because they are highly reactive and hardly yellow-modified.

  The addition amount of the photopolymerization initiator is preferably 1 to 15% by weight in the UV ink, and more preferably 3 to 10% by weight. If it is less than 1% by weight, the polymerization may be incomplete and the film may be uncured. On the other hand, even if it is added in excess of 15% by weight, no further improvement in the curing rate or curing speed efficiency can be expected. Become high.

  Moreover, you may add a dispersing agent to the UV ink for the purpose of disperse | distributing a pigment as needed. Examples of the dispersant include anionic surfactants, cationic surfactants, nonionic surfactants, zwitterionic surfactants, and polymeric dispersants, which may be used alone or in combination of two or more. Can do.

  Further, if necessary, the UV ink includes a sensitizer, a heat stabilizer, an antioxidant, an antiseptic, an antifoaming agent, a penetrating agent, a resin binder, and a resin emulsion to accelerate the initiation reaction of the photopolymerization initiator. Additives such as a reduction inhibitor, a leveling agent, a pH adjuster, a pigment derivative, a polymerization inhibitor, an ultraviolet absorber and a light stabilizer can also be added.

  The UV ink can be obtained by mixing the raw materials to be used, further dispersing the mixture using a dispersing machine such as a roll mill, a ball mill, a colloid mill, a jet mill, or a bead mill, and then performing filtration. Among these, a bead mill is preferable because it can be dispersed in a large amount in a short time.

  The viscosity of the UV ink is preferably 1 to 20 mPa · s at 50 ° C., and more preferably 2 to 15 mPa · s. When the viscosity is less than 1 mPa · s, it is difficult to adjust the ejection amount, and there is a possibility that the ink ejection becomes unstable, and when it exceeds 20 mPa · s, there is a possibility that the ink cannot be ejected.

  The surface tension of the UV ink at the time of ejection is preferably 15 to 40 dyne / cm, and more preferably 20 to 30 dyne / cm. If it is less than 15 dyne / cm, the wettability will be too good and the image may be blurred, and it will be difficult to supply ink to the printer head. If it exceeds 40 dyne / cm, the ink may be repelled on the substrate and the image may become unclear.

The amount of UV ink applied is preferably 1 to 100 g / m ² . More preferably, it is 1-50 g / m < ² >. If it is less than 1 g / m ² , it may be difficult to express a sufficient image and water resistance may be deteriorated. If it exceeds 100 g / m ² , ink curing failure may occur.

  Furthermore, the film thickness of the UV ink image is preferably 1 to 150 μm. If the thickness is less than 1 μm, it is difficult to obtain a sufficient image expression, and the water resistance tends to deteriorate. If the thickness exceeds 150 μm, the ink may be cracked or peeled off.

  The ink jet recording apparatus that discharges UV ink is not particularly limited. For example, continuous methods such as charge modulation method, micro dot method, charge jet control method and ink mist method, on-demand method such as stemme method, pulse jet method, bubble jet (registered trademark) method and electrostatic suction method, etc. Can be used. Further, as a specific ink jet recording apparatus, a serial type, a line type and the like can be mentioned and any of them can be used.

  The serial type scans the serial type print head in the main scanning direction (carriage movement direction) by driving the carriage, and intermittently conveys the ink in the conveyance direction (sub scanning direction) orthogonal to the main scanning direction. Discharge to form an image. In the print head, for example, ink cartridges of black (Bk), yellow (Y), magenta (M), cyan (C), and the like are mounted. Each color cartridge has a plurality of ink discharge nozzles. They are provided along both the scanning direction and the sub-scanning direction. An ultraviolet irradiation device may be provided in the print head.

  When a serial type print head is used, the step of applying ink droplets to the substrate and the step of irradiating ultraviolet rays are repeated for each main scan. Here, main scanning means that the serial type print head moves on the same line, and the print head does not move in the sub-scanning direction but moves once from left to right. A mode of moving once, a mode of moving once from right to left, a mode of moving multiple times from right to left, a mode of reciprocating, a mode of reciprocating multiple times, and the like are included. “Every main scan” means every time the serial type print head moves from one line to another (every time the sub-scan direction moves). For each main scan of the print head, the ink is cured by ultraviolet irradiation after the ink application process is completed or in parallel with the ink application process.

  In the line type, ink discharge nozzles for each color are provided in a line shape in the width direction of the printer (direction orthogonal to the conveyance direction of the printing substrate). For example, black (Bk), yellow (Y), magenta ( M) and cyan (C) discharge nozzles are provided in a line. It is possible to cure the ink by ultraviolet irradiation after completion of the ink application process in the line type head, or an ultraviolet irradiation device may be provided in the line type print head. When such a line-type print head is used, color change is performed for each line of printing, and ultraviolet rays are irradiated for each color change to cure ink droplets applied to the substrate.

  When UV ink is ejected in the ink jet recording apparatus, the head equipped in the ink jet recording apparatus may be equipped with a heating device, and the ink may be heated to lower the ink viscosity. The heating temperature of the ink is preferably 25 to 150 ° C, more preferably 30 to 70 ° C. If it is lower than 25 ° C, the viscosity of the ink may not be lowered, and if it exceeds 150 ° C, the ink may be cured. The heating temperature of the ink is determined in consideration of the curability of the reactive monomer and / or reactive oligomer with respect to heat, and is set lower than the temperature at which curing is started by heat.

  As a condition of ultraviolet irradiation for curing the reactive monomer and / or reactive oligomer contained in the UV ink, the output of the ultraviolet lamp is preferably 50 to 280 W / cm, more preferably 80 to 200 W / cm. When the output of the ultraviolet lamp is less than 50 W / cm, the ink tends not to be cured sufficiently due to the peak intensity of ultraviolet rays and insufficient accumulated light amount. When the output exceeds 280 W / cm, the colored medium is deformed or melted by the heat of the ultraviolet lamp. In addition, the cured film of the ink tends to deteriorate.

  The irradiation time of ultraviolet rays is preferably 0.1 to 20 seconds, and more preferably 0.5 to 10 seconds. When the irradiation time of the ultraviolet lamp is longer than 20 seconds, the coloring medium tends to be deformed or melted by the heat of the ultraviolet lamp, and the cured film of the ink tends to be deteriorated. The UV curable ink tends to be insufficiently cured.

  Next, the clear paint used in clear coating is applied after inkjet printing in order to adjust appearance such as gloss and improve weather resistance. The clear paint may be either water-based or solvent-based, but is preferably a water-based paint from the viewpoint of workability and safety. The clear paint is composed of pigments, resins, and additives as necessary. As the resin and additives, the same resins and additives as those described for the undercoat paint can be used. The pigment used in the clear paint is a so-called matting agent, and specific examples thereof include silica and resin beads. When it is desired to have a glossy clear coating, the matting agent is not included, or even if it is included, the amount is very small. Conversely, when it is desired to have a clear coating with a matte feeling, it is designed to contain a lot of matting agent. However, if too much is added, the quality and physical properties of the building board deteriorate, so the pigment weight concentration of the clear paint is preferably 15 parts by weight or less in 100 parts by weight of the clear paint. When the pigment weight concentration of the clear paint exceeds 15 parts by weight, the UV ink image located in the lower layer may not be clearly seen, and the water resistance of the clear paint may be deteriorated.

  In the present invention, clear coating includes a crosslinking component (1) a system including at least one crosslinking component (functional group capable of crosslinking reaction) in at least one resin of a clear paint, and (2) a crosslinking agent is added. (3) means a system in which (1) and (2) are used in combination.

  Specific examples of the crosslinking system (1) include a system for forming a siloxane bond, a system containing an acetoacetoxy group, a system containing an epoxy group and a carboxyl group, a system containing a tertiary isocyanate group, a sulfonic acid group or A system containing a phosphate group and an acetoacetoxy group, a system containing a carbonyl group and a hydrazino group, a system containing a carboxyl group and an oxazoline group, a system containing a carboxyl group and a carbodiimide, and the like (2) Examples of the crosslinking agent include oxazoline-based, carbodiimide-based, isocyanate-based, hydrazide-based, epoxy-based, siloxane-based, and amine-based. Further, the crosslinking system (3) includes carboxyl group-containing resin-hydrhydrin group-containing 4. Quaternary ammonium salt polymer system, epoxy group-containing resin-aminosilane , Carboxyl group-containing resin-carbodiimide type, carboxyl group-containing resin-oxazoline type, sulfonic acid group- or phosphate group-containing resin-carbodiimide type, acetoacetate group-containing resin-polyamine type, enamine-containing resin-polyacrylate type, phosphate group-containing resin -Epoxysilane compound system, carboxyl group-containing resin (amine neutralization)-silicon compound system, thiocarbonate group-containing resin-polyamine system, hydroxyl group-containing resin-isocyanate system, system that forms siloxane bond, acetal group-containing resin-acid catalyst And carbonyl group-containing resin-hydrazino compound system. These crosslinking systems can be used alone or in combination.

The application amount of the clear paint is preferably 3 to 150 g / m ² (dry state). If the amount is less than 3 g / m ² , the substrate may not be completely covered. If the amount is more than 150 g / m ² , the clear coating may be easily cracked.

  The film thickness of the clear coating is preferably 3 to 100 μm. If the thickness is less than 3 μm, the substrate may not be completely covered. If the thickness is more than 100 μm, the clear coating may be easily cracked.

  As the clear coating application method and the drying method, the same methods as those described for the undercoat coating can be applied. In particular, the drying temperature is preferably 80 ° C. or higher, and more preferably 100 ° C. or higher, in order to obtain close adhesion by clear coating and UV ink image and / or interaction.

  EXAMPLES Next, although an Example is given and this invention is demonstrated, this invention is not necessarily limited to these Examples.

  First, the composition of the undercoat used in the examples is shown below.

<Undercoat paint>
Acrylic emulsion 100 parts by weight (AD176, manufactured by Henkel Technologies Japan, solid content 50%)
Film-forming aid 10 parts by weight (ethylene glycol monobutyl ether, manufactured by Nippon Emulsifier Co., Ltd.)
Titanium oxide dispersion (60% pigment content) 15 parts by weight (CR-90, titanium oxide, manufactured by Ishihara Sangyo Co., Ltd.)
Calcium carbonate dispersion (pigment content 60%) 40 parts by weight (Homocal D, calcium carbonate, manufactured by Shiroishi Kogyo Co., Ltd.)
Antifoam 0.3 parts by weight (FS Antifoam 013A, manufactured by Toray Dow Corning Co., Ltd.)
Thickener 0.1 parts by weight (SN thickener 627N, manufactured by San Nopco)
10 parts by weight of water

  The above raw materials were mixed, stirred with a hand mixer and filtered to prepare an undercoat paint. The pigment weight concentration of the undercoat paint is 37.5% by weight.

  Next, the formulation of the UV ink used in the examples is shown below.

<Yellow UV ink 1>
Pigment dispersion (pigment content 20%) 20 parts by weight (pigment: TSY-1, yellow iron oxide, manufactured by Toda Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan Co., Ltd. )
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
47 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
5 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Yellow UV ink 2>
Pigment dispersion (pigment content 20%) 20 parts by weight (pigment: TSY-1, yellow iron oxide, manufactured by Toda Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan Co., Ltd. )
25 parts by weight of reactive oligomer (CN968, hexafunctional aliphatic urethane acrylate, manufactured by Sartomer Japan, Inc.)
47 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
5 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Yellow UV ink 3>
Pigment dispersion (pigment content 20%) 20 parts by weight (pigment: TSY-1, yellow iron oxide, manufactured by Toda Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan Co., Ltd. )
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
49 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
3 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Yellow UV ink 4>
Pigment dispersion (pigment content 20%) 20 parts by weight (pigment: TSY-1, yellow iron oxide, manufactured by Toda Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan Co., Ltd. )
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
47 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
3 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
5 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Magenta UV ink 1>
Pigment dispersion (pigment content: 20%) 20 parts by weight (pigment: 160ED, iron oxide, manufactured by Toda Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan Co., Ltd.)
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
47 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
5 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Magenta UV ink 2>
Pigment dispersion (pigment content: 20%) 20 parts by weight (pigment: 160ED, iron oxide, manufactured by Toda Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan Co., Ltd.)
25 parts by weight of reactive oligomer (CN968, hexafunctional aliphatic urethane acrylate, manufactured by Sartomer Japan, Inc.)
47 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
5 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Magenta UV ink 3>
Pigment dispersion (pigment content: 20%) 20 parts by weight (pigment: 160ED, iron oxide, manufactured by Toda Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan Co., Ltd.)
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
49 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
3 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Magenta UV ink 4>
Pigment dispersion (pigment content: 20%) 20 parts by weight (pigment: 160ED, iron oxide, manufactured by Toda Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan Co., Ltd.)
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
47 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
3 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
5 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Cyan UV ink 1>
25 parts by weight of pigment dispersion (pigment content: 40%) (pigment: dipyroxide side 9410, cobalt blue, manufactured by Dainichi Seika Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, Sartomer Japan (Made by Co., Ltd.)
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
Reactive monomer 42 parts by weight (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
5 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Cyan UV ink 2>
25 parts by weight of pigment dispersion (pigment content: 40%) (pigment: dipyroxide side 9410, cobalt blue, manufactured by Dainichi Seika Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, Sartomer Japan (Made by Co., Ltd.)
25 parts by weight of reactive oligomer (CN968, hexafunctional aliphatic urethane acrylate, manufactured by Sartomer Japan, Inc.)
Reactive monomer 42 parts by weight (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
5 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Cyan UV ink 3>
25 parts by weight of pigment dispersion (pigment content: 40%) (pigment: dipyroxide side 9410, cobalt blue, manufactured by Dainichi Seika Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, Sartomer Japan (Made by Co., Ltd.)
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
44 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
3 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Cyan UV ink 4>
25 parts by weight of pigment dispersion (pigment content: 40%) (pigment: dipyroxide blue 9410, cobalt blue, manufactured by Dainichi Seika Kogyo Co., Ltd., dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, Sartomer Japan (Made by Co., Ltd.)
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
Reactive monomer 42 parts by weight (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
3 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
5 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Black UV ink 1>
10 parts by weight of pigment dispersion (pigment content: 20%) (pigment: NIPex 35, carbon, manufactured by Degussa Japan, dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan)
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
57 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
5 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Black UV ink 2>
10 parts by weight of pigment dispersion (pigment content: 20%) (pigment: NIPex 35, carbon, manufactured by Degussa Japan, dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan)
25 parts by weight of reactive oligomer (CN968, hexafunctional aliphatic urethane acrylate, manufactured by Sartomer Japan, Inc.)
57 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
5 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Black UV ink 3>
10 parts by weight of pigment dispersion (pigment content: 20%) (pigment: NIPex 35, carbon, manufactured by Degussa Japan, dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan)
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
59 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
3 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
3 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

<Black UV ink 4>
10 parts by weight of pigment dispersion (pigment content: 20%) (pigment: NIPex 35, carbon, manufactured by Degussa Japan, dispersion medium: SR9003, PO-modified neopentyl glycol diacrylate, manufactured by Sartomer Japan)
25 parts by weight of reactive oligomer (CN985B88, bifunctional aliphatic urethane acrylate 88%, 1,6-hexanediol diacrylate 12%, manufactured by Sartomer Japan, Inc.)
57 parts by weight of reactive monomer (SR238F, 1,6-hexanediol diacrylate, manufactured by Sartomer Japan, Inc.)
3 parts by weight of photopolymerization initiator (Irgacure 184, hydroxy ketones, manufactured by Ciba Japan Co., Ltd.)
5 parts by weight of photopolymerization initiator (Irgacure 819, acylphosphine oxides, manufactured by Ciba Japan Co., Ltd.)

The above raw materials were mixed and filtered to prepare yellow, magenta, cyan, and black UV inks, respectively. The pigment concentration of each UV ink is as follows.
・ Yellow UV ink 14
・ Yellow UV ink 2 4% by weight
-Yellow UV ink 3 4% by weight
・ Yellow UV ink 4 4% by weight
・ Magenta UV ink 1 4% by weight
・ Magenta UV ink 2 4% by weight
・ Magenta UV ink 3 4% by weight
・ Magenta UV ink 4 4% by weight
Cyan UV ink 1 10% by weight
-Cyan UV ink 2 10% by weight
-Cyan UV ink 3 10% by weight
Cyan UV ink 4 10% by weight
・ Black UV ink 12% by weight
・ Black UV ink 2 2% by weight
Black UV ink 3 2% by weight
-Black UV ink 42% by weight

  Next, the formulation of the clear paint used in the examples is shown below.

<Clear paint 1>
100 parts by weight of acrylic silicon emulsion (Primal C-3668, manufactured by Rohm and Haas Co., Ltd., solid content 40.5%, siloxane bond forming system, acetoacetoxy group-containing system)
Film-forming aid 10 parts by weight (ethylene glycol monobutyl ether, manufactured by Nippon Emulsifier Co., Ltd.)
Matting agent 3 parts by weight (AZ-200, silica, manufactured by Tosoh Silica Co., Ltd.)
Antifoam 0.3 parts by weight (FS Antifoam 013A, manufactured by Toray Dow Corning Co., Ltd.)
Thickener 0.2 parts by weight (Primal RM-8W, manufactured by Rohm and Haas Co., Ltd.)
0.8 parts by weight of UV absorber (TINUVIN400, manufactured by Ciba Japan Co., Ltd.)
0.8 parts by weight of light stabilizer (TINUVIN123, manufactured by Ciba Japan Co., Ltd.)
10 parts by weight of water

  The above raw materials were mixed, stirred with a hand mixer, and filtered to prepare a clear paint. The pigment weight concentration of the clear paint is 6.6% by weight.

<Clear paint 2>
100 parts by weight of acrylic silicone emulsion (Polydurex G659, manufactured by Asahi Kasei Chemicals Corporation, solid content 40.5%, acid value 7, siloxane bond forming system, carboxyl group-containing resin-oxazoline system)
Cross-linking agent 6 parts by weight (Epocross WS-500, manufactured by Nippon Shokubai Co., Ltd., solid content 39%, oxazoline series)
Film-forming aid 10 parts by weight (ethylene glycol monobutyl ether, manufactured by Nippon Emulsifier Co., Ltd.)
Matting agent 3 parts by weight (AZ-200, silica, manufactured by Tosoh Silica Co., Ltd.)
Antifoam 0.3 parts by weight (FS Antifoam 013A, manufactured by Toray Dow Corning Co., Ltd.)
Thickener 0.2 parts by weight (Primal RM-8W, manufactured by Rohm and Haas Co., Ltd.)
0.8 parts by weight of UV absorber (TINUVIN400, manufactured by Ciba Japan Co., Ltd.)
0.8 parts by weight of light stabilizer (TINUVIN123, manufactured by Ciba Japan Co., Ltd.)
10 parts by weight of water

  The above raw materials were mixed, stirred with a hand mixer, and filtered to prepare a clear paint. The pigment weight concentration of the clear paint is 6.3% by weight.

<Clear paint 3>
100 parts by weight of acrylic emulsion (Primal E-357EF, manufactured by Rohm and Haas Co., Ltd., solid content 47.5%)
Film-forming aid 10 parts by weight (ethylene glycol monobutyl ether, manufactured by Nippon Emulsifier Co., Ltd.)
Matting agent 3 parts by weight (AZ-200, silica, manufactured by Tosoh Silica Co., Ltd.)
Antifoam 0.3 parts by weight (FS Antifoam 013A, manufactured by Toray Dow Corning Co., Ltd.)
Thickener 0.2 parts by weight (Primal RM-8W, manufactured by Rohm and Haas Co., Ltd.)
0.8 parts by weight of UV absorber (TINUVIN400, manufactured by Ciba Japan Co., Ltd.)
0.8 parts by weight of light stabilizer (TINUVIN123, manufactured by Ciba Japan Co., Ltd.)
10 parts by weight of water

  The above raw materials were mixed, stirred with a hand mixer, and filtered to prepare a clear paint. The pigment weight concentration of the clear paint is 5.7% by weight.

Example 1
After applying the undercoat paint prepared above to the ceramic board by spraying, it was dried with a hot air dryer (100 ° C. × 15 minutes) to give the undercoat paint. Next, using the yellow UV ink 1, the magenta UV ink 1, the cyan UV ink 1 and the black UV ink 1 produced as described above, a brick-like image is printed on the undercoat with an inkjet printer to cure the UV ink. The UV ink was cured with a UV lamp so that the rate was 80%, and a UV ink image was produced. In addition, about the cure rate, it measured by FT-IR. Furthermore, after apply | coating the clear coating material 1 produced above, it dried with the hot air dryer (100 degreeC x 15 minutes), and it applied clear coating, and obtained the building board of this invention.

◇ Application amount and film thickness (dry state)
・ Undercoat paint: 110 g / m ² 100 μm
UV ink: 10 g / m ² 12 μm
・ Clear paint: 30g / m ² 25μm

◇ UV ink curing conditions ・ Lamp output: 110 W / cm (Intensity: 0.65 W / cm ² )
・ Irradiation time: 0.3 seconds (light intensity: 0.195 J / cm ² )

Example 2
After applying the undercoat paint prepared above to the ceramic board by spraying, it was dried with a hot air dryer (100 ° C. × 15 minutes) to give the undercoat paint. Next, using the yellow UV ink 1, the magenta UV ink 1, the cyan UV ink 1 and the black UV ink 1 produced as described above, a brick-like image is printed on the undercoat with an inkjet printer to cure the UV ink. The UV ink was cured with a UV lamp so that the rate was 60%, and a UV ink image was produced. In addition, about the cure rate, it measured by FT-IR. Furthermore, after apply | coating the clear coating material 1 produced above, it dried with the hot air dryer (100 degreeC x 15 minutes), and it applied clear coating, and obtained the building board of this invention.

◇ Application amount and film thickness (dry state)
・ Undercoating paint: 95 g / m ² 85 μm
UV ink: 11 g / m ² 11 μm
・ Clear paint: 35g / m ² 28μm

◇ UV ink curing conditions ・ Lamp output: 110 W / cm (Intensity: 0.65 W / cm ² )
・ Irradiation time: 0.2 seconds (light intensity: 0.13 J / cm ² )

Example 3
After applying the undercoat paint prepared above to the ceramic board by spraying, it was dried with a hot air dryer (100 ° C. × 15 minutes) to give the undercoat paint. Next, using the yellow UV ink 1, the magenta UV ink 1, the cyan UV ink 1 and the black UV ink 1 produced as described above, a brick-like image is printed on the undercoat with an inkjet printer to cure the UV ink. The UV ink was cured with a UV lamp so that the rate was 80%, and a UV ink image was produced. In addition, about the cure rate, it measured by FT-IR. Furthermore, after apply | coating the clear coating material 2 produced above, it dried with the hot air dryer (100 degreeC x 15 minutes), and it applied clear coating, and obtained the building board of this invention.

◇ Application amount and film thickness (dry state)
・ Undercoat paint: 110 g / m ² 95 μm
UV ink: 10 g / m ² 10 μm
・ Clear paint: 38g / m ² 30μm

◇ UV ink curing conditions ・ Lamp output: 110 W / cm (Intensity: 0.65 W / cm ² )
・ Irradiation time: 0.3 seconds (light intensity: 0.195 J / cm ² )

Example 4
After applying the undercoat paint prepared above to the ceramic board by spraying, it was dried with a hot air dryer (100 ° C. for 15 minutes ×) to give the undercoat paint. Next, using the yellow UV ink 3, the magenta UV ink 3, the cyan UV ink 3 and the black UV ink 3 produced above, a brick-like image is printed on the undercoat with an inkjet printer, and the UV ink is cured. The UV ink was cured with a UV lamp so that the rate was 80%, and a UV ink image was produced. In addition, about the cure rate, it measured by FT-IR. Furthermore, after apply | coating the clear coating material 1 produced above, it dried with the hot air dryer (100 degreeC x 15 minutes), and it applied clear coating, and obtained the building board of this invention.

◇ Application amount and film thickness (dry state)
・ Undercoat paint: 100 g / m ² 90 μm
UV ink: 12 g / m ² 14 μm
・ Clear paint: 35g / m ² 27μm

◇ UV ink curing conditions ・ Lamp output: 110 W / cm (Intensity: 0.65 W / cm ² )
・ Irradiation time: 0.3 seconds (light intensity: 0.195 J / cm ² )

Comparative Example 1
After applying the undercoat paint prepared above to the ceramic board by spraying, it was dried with a hot air dryer (100 ° C. × 15 minutes) to give the undercoat paint. Next, using the yellow UV ink 2, magenta UV ink 2, cyan UV ink 2 and black UV ink 2 produced above, a brick-like image is printed on the undercoat with an ink jet printer, and the UV ink is cured. The UV ink was cured with a UV lamp so that the rate was 100%, and a UV ink image was produced. In addition, about the cure rate, it measured by FT-IR. Furthermore, after applying the clear paint 2 produced above, it was dried with a hot air drier (100 ° C. × 15 minutes) and clear-coated to obtain a building board.

◇ Application amount and film thickness (dry state)
・ Undercoat paint: 100 g / m ² 90 μm
UV ink: 10 g / m ² 12 μm
・ Clear paint: 30g / m ² 25μm

◇ UV ink curing conditions ・ Lamp output: 110 W / cm (Intensity: 0.65 W / cm ² )
・ Irradiation time: 0.3 seconds (light intensity: 0.195 J / cm ² )

Comparative Example 2
After applying the undercoat paint prepared above to the ceramic board by spraying, it was dried with a hot air dryer (100 ° C. × 15 minutes) to give the undercoat paint. Next, using the yellow UV ink 1, the magenta UV ink 1, the cyan UV ink 1 and the black UV ink 1 produced as described above, a brick-like image is printed on the undercoat with an inkjet printer to cure the UV ink. The UV ink was cured with a UV lamp so that the rate was 30%, and a UV ink image was produced. In addition, about the cure rate, it measured by FT-IR. Furthermore, after applying the clear paint 2 produced above, it was dried with a hot air drier (100 ° C. × 15 minutes) and clear-coated to obtain a building board.

◇ Application amount and film thickness (dry state)
・ Undercoat paint: 100 g / m ² 95 μm
UV ink: 11 g / m ² 11 μm
・ Clear paint: 35g / m ² 30μm

◇ UV ink curing conditions ・ Lamp output: 80 W / cm (Intensity: 0.45 W / cm ² )
・ Irradiation time: 0.2 seconds (light intensity: 0.09 J / cm ² )

Comparative Example 3
After applying the undercoat paint prepared above to the ceramic board by spraying, it was dried with a hot air dryer (100 ° C. × 15 minutes) to give the undercoat paint. Next, using the yellow UV ink 4, the magenta UV ink 4, the cyan UV ink 4 and the black UV ink 4 produced as described above, a brick-like image is printed on the undercoat with an inkjet printer to cure the UV ink. The UV ink was cured with a UV lamp so that the rate was 100%, and a UV ink image was produced. In addition, about the cure rate, it measured by FT-IR. Furthermore, after applying the clear paint 3 produced above, it was dried with a hot air drier (100 ° C. × 15 minutes) and clear painted to obtain a building board.

◇ Application amount and film thickness (dry state)
・ Undercoat paint: 105 g / m ² 95 μm
UV ink: 12 g / m ² 12 μm
・ Clear paint: 35g / m ² 30μm

◇ UV ink curing conditions ・ Lamp output: 110 W / cm (Intensity: 0.65 W / cm ² )
・ Irradiation time: 0.3 seconds (light intensity: 0.195 J / cm ² )

Comparative Example 4
After applying the undercoat paint prepared above to the ceramic board by spraying, it was dried with a hot air dryer (100 ° C. × 15 minutes) to give the undercoat paint. Next, using the yellow UV ink 1, the magenta UV ink 1, the cyan UV ink 1 and the black UV ink 1 produced as described above, a brick-like image is printed on the undercoat with an inkjet printer to cure the UV ink. The UV ink was cured with a UV lamp so that the rate was 80%, and a UV ink image was produced. In addition, about the cure rate, it measured by FT-IR. Furthermore, after applying the clear paint 3 produced above, it was dried with a hot air drier (100 ° C. × 15 minutes) and clear painted to obtain a building board.

◇ Application amount and film thickness (dry state)
・ Undercoat paint: 100 g / m ² 95 μm
UV ink: 10 g / m ² 12 μm
・ Clear paint: 35g / m ² 33μm

◇ UV ink curing conditions ・ Lamp output: 110 W / cm (Intensity: 0.65 W / cm ² )
・ Irradiation time: 0.3 seconds (light intensity: 0.195 J / cm ² )

  The building board obtained in each Example was evaluated by the following methods. The results are shown in Table 1.

(1) Adhesion test Adhesion (JIS K 5600 5-6) between each layer of the building board and the substrate was evaluated.

  In addition, the evaluation method of adhesiveness used the cutter knife to the building board, and drawn the line | wire which reaches | attains to a base material 6 pieces at intervals of 4 mm in length and breadth, and produced 25 grids. Next, cellophane tape was applied on the grid, and the cellophane tape was quickly peeled off to confirm the condition of the colored plate.

(2) Warm water test A test in which a building board is immersed in warm water at 50 ° C. for 10 days is performed to evaluate the swelling (JIS K 5600 8-2) and adhesion (JIS K 5600 5-6) of the building board after the test. did.

(3) Freeze-thaw test The building board was frozen in the air at -20 ° C x 8 hours, and the water-melted 20 ° C x 8 hours was taken as one cycle. JIS K 5600 8-2) and cracks (JIS K 5600 8-4) were evaluated.

(4) Weathering test The building board was tested with an accelerated weathering tester Super UV tester. The test conditions are as follows. The swelling (JIS K 5600 8-2) and cracking (JIS K 5600 8-4) of the building board after the test were evaluated.

<Weather resistance test conditions>
1) Light source: Water-cooled metal halide lamp 2) Illuminance: 100 mW / cm ²
3) Wavelength: 295-450 nm
4) Temperature: 60 ° C (irradiation), 30 ° C (condensation)
5) Humidity: 50% (irradiation), 90% (condensation)
6) Cycle: Irradiation 5 hours, condensation 5 hours 7) Shower: 10 seconds before and after condensation 8) Test time: 500 hours (equivalent to 10-year exposure)

  In addition, evaluation item adhesiveness represents peeling with each layer in a test body, and if it is 1, it means that there is no peeling and it is so large that a numerical value becomes large. In addition, the size of blisters and cracks represents the size of blisters and cracks in the specimen, meaning that there are no blisters or cracks if it is 0, and that larger blisters and cracks as the value increases. Yes. In addition, the density of blisters and cracks represents the density of blisters and cracks with respect to the test specimen. If 0, there is no blister or crack, and the larger the value, the greater the amount of blisters or cracks. doing.

  In the building board obtained in Examples 1-4, as can be seen from Table 1, it peels off on the building board surface after each evaluation test, and no swelling or cracking is observed, and it can be said that the building board is excellent in weather resistance. On the other hand, in the building boards obtained in Comparative Examples 1 to 4, the building board surface after each evaluation test was peeled off, swollen and cracked, and the weather resistance was inferior compared to those obtained in the examples. It can be said that.

Claims (5)

(1) A step of performing inkjet coating with UV ink on a base material that has undergone undercoating;
(2) After the step (1), a step of curing the UV ink with ultraviolet rays;
(3) After the process of (2), it is a manufacturing method of the building board which consists of the process of performing clear coating on the surface on which ink-jet coating was applied,
The UV ink includes a photopolymerization initiator, a reactive oligomer and / or a reactive monomer, and a pigment.
Wherein (2) curing rate of UV ink after curing in the process of a 50-90% and viewed contains a crosslinking component clear paint,
The method of manufacturing a building board according to the step (3), wherein the coated material is dried at a temperature of 80 ° C. or higher after the clear paint is applied . The method for manufacturing a building board according to claim 1, wherein the curing rate of the UV ink is adjusted by changing the UV lamp irradiation conditions. The said reactive oligomer and / or reactive monomer are bifunctional and / or trifunctional, The manufacturing method of the building board of Claim 1 or 2 characterized by the above-mentioned. The said photoinitiator is hydroxyketone or acylphosphine oxides, The manufacturing method of the building board of any one of Claims 1-3 characterized by the above-mentioned. The manufacturing method of the building board of any one of Claims 1-4 whose density | concentration of the said pigment is 0.5-20 weight% in UV ink.