JP2015051549A - Coated plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated plate having high designability which suppresses the permeation of ink into an ink receiving layer to stably fixes ink and cause no color unevenness and no color difference.SOLUTION: A coated plate is provided with a coating film M on the surface of a substrate 1. The coating film M includes an ink receiving layer 3 and an ink jet print layer 4. The ink receiving layer 3 is formed of a coating material comprising a material not having a glass transition point in a range of 0-200°C. The ink receiving layer 3 may be transparent. The ink receiving layer 3 is preferably formed of a polysiloxane-based inorganic coating material.

Description

  The present invention relates to a painted board used for a building board or the like.

  As a building board used as an exterior material such as an outer wall material, a roofing material, and a roofing material, a coated plate obtained by coating a cement-based base material is widely used. Since such a coated plate is responsible for forming the exterior of a building, technical studies have been made on surface makeup that realizes various designs. For example, a wet sheet obtained by molding a cement-based molding material by papermaking, extrusion molding, cast molding, etc. is cured and cured, and the resulting inorganic plate is used as a base material, and this is generally coated. ing.

  As a method of painting, inkjet coating has recently been developed and put into practical use by spraying paint from an inkjet nozzle head in synchronization with the substrate conveyance speed toward the surface of the substrate conveyed on a conveyor. Yes. Such ink-jet coating enables local and position-controlled coating as compared with a coating roll or the like that has been generally used so far. Therefore, there is an advantage that a building board coated with a high design with a natural texture can be manufactured by expressing dark and light.

  By inkjet coating, for example, a brick-like or tile-like building board can be obtained by, for example, painting a place where joints are formed and a place where joints are not formed in different colors.

JP 2008-253942 A

  When performing ink jet coating, for example, an ink receiving layer (ink receiving layer) is formed on a substrate such as an inorganic plate, and ink jet printing is performed on the ink receiving layer (see, for example, Patent Document 1). By printing on the ink receiving layer, it is possible to fix the ink applied during ink jet printing without bleeding. Known paints for forming the ink receiving layer include acrylic emulsion paints and acrylic silicon emulsion paints. These paints are easy to handle and advantageous in terms of cost. In these paints, white enamel is usually applied.

  Here, in the ink receiving layer, baking is performed after coating to stabilize the coating film. However, the state of the ink receiving layer may not be sufficiently stabilized depending on baking conditions and a temperature environment after baking. For example, when the resin in the ink receiving layer is softened at the baking temperature of the ink receiving layer, the state of the coating film is not uniform. And if the state of the ink receiving layer is different for each substrate, or if the state of the ink receiving layer is partially different in the substrate, etc., the ink for ink jet printing may partially penetrate. There was a risk of color unevenness and color differences.

  The present invention has been made in view of the above circumstances, suppresses ink permeation into the ink receiving layer, stably fixes the ink, has no color unevenness and color difference, and has high design properties. The object is to provide a painted plate.

  The coated plate according to the present invention is a coated plate provided with a coated film on the surface of a substrate, and the coated film has an ink receiving layer and an ink jet printing layer, and the ink receiving layer is at least 0. It is formed with the coating material comprised with the material which does not have a glass transition point in the range of -200 degreeC.

  The ink receiving layer is preferably transparent.

  The ink receiving layer is preferably formed of a polysiloxane inorganic coating.

  The coating film preferably has a white paint layer as a lower layer of the ink receiving layer.

  According to the present invention, since the ink receiving layer is formed of a paint made of a material that does not have a glass transition point in at least the above temperature range, the ink receiving layer is stabilized, and ink to the ink receiving layer is obtained. Soaking can be suppressed. Therefore, it is possible to stably obtain a coated plate having high design properties without color unevenness and color difference.

It is sectional drawing which shows an example of embodiment of a coating board.

  FIG. 1 is an example of an embodiment of a painted plate according to the present invention. This coating plate is provided with a coating film M on the surface of the substrate 1. The coating film M has an ink receiving layer 3 and an ink jet printing layer 4. In this embodiment, the coating film M includes the base layer 2, the ink receiving layer 3, the inkjet printing layer 4, the clear layer 5, the inorganic coating layer 6, and the functional coating layer 7 in this order from the substrate 1 side. Yes.

  As the base material 1 of the coated plate, an appropriate material such as an inorganic base material or a metal siding material can be used.

  When an inorganic base material is used as the base material 1, a wet sheet (green sheet) formed from a cement-based molding material mainly composed of cement and reinforcing fibers can be used for the production. This wet sheet is obtained by making paper by various types of paper making methods such as a long mesh type and a round net type, using a cement-based aqueous slurry as a cement-based molding material, or by extrusion molding. Examples of the cement-based molding material include hydraulic cement components of 30 to 95% by mass, fillers such as silica, silica powder, and fly ash 2 to 60% by mass, and reinforcing fibers such as pulp 3 to 10% by mass. A slurry having a solid content of about 20 to 2000 parts by mass of water with respect to 100 parts by mass of the solid content can be used. In addition, as a cement component, what adjusted composition suitably, such as normal Portland cement and blast furnace cement, can be used. As the reinforcing fiber pulp, softwood pulp, hardwood pulp, or a mixture thereof can be used. An inorganic base material can be obtained by curing and curing the wet sheet.

  Curing and curing of the inorganic base material can be performed by an appropriate method, but it is desirable to perform autoclave curing, and the temperature at that time is preferably 140 ° C. or higher. In practice, it is desirable that the curing is a two-stage curing of an autoclave curing and a pre-acceleration curing preceding this, that is, a pre-curing in which steam is added for heating. Thereby, the strength of the inorganic base material is improved, and the structure and performance are made uniform.

  During this curing, it is desirable to apply a sealer to the surface of the wet sheet before curing. By applying the sealer, it is possible to prevent the occurrence of efflorescence during curing, and further, the coating film of the sealer exhibits water resistance, so that the water resistance of the coated plate can be improved.

  The sealer is not particularly limited, and for example, an aqueous resin emulsion such as acrylic, vinyl acetate, epoxy, chlorinated rubber, urethane, silicon, or fluorine can be used.

  In addition, inorganic particles such as heavy calcium carbonate, precipitated calcium carbonate, kaolin, bentonite, sericite, dolomite, talc, clay, aluminum oxide, magnesium oxide, and diatomaceous earth can be mixed in the sealer.

  And, such a sealer can be applied to the surface of the wet sheet and heated to form a film of the sealer. Although not shown in FIG. 1, a sealer layer may be formed by applying a sealer. The sealer layer is disposed between the base material 1 and the base layer 2.

  The sealer is usually applied before curing, but when performing pre-acceleration curing as described above, it is preferable to apply the sealer after pre-acceleration curing and then perform autoclave curing. Can improve frost resistance and dimensional stability.

  The base material 1 (inorganic base material) obtained by such curing is subjected to a drying process or a cutting process as necessary.

  Further, when a metal siding material is used as the base material 1, an appropriate primer, enamel paint, or the like can be applied to one surface of the base material 1.

  The coating film M is provided on the surface of the surface of the base material 1 thus obtained, such as a sealer coating film. The coating film M has a multilayer structure formed by coating a plurality of coating films.

  The underlayer 2 is preferably provided on the surface of the substrate 1 such as a sealer coating. The underlayer 2 is a lower layer (layer on the base material 1 side) of the coating film M. By forming the underlayer 2, the ink receiving layer 3 can be formed more stably. Moreover, when the ink receiving layer 3 is transparent, the color below the inkjet printing layer 4 can be provided, and the design property can be improved. The underlayer 2 is configured as an undercoat coating film.

  The underlayer 2 is preferably not transparent. That is, the underlayer 2 is preferably colored. The color in this case includes white. When the underlayer 2 is colored, the ink-jet coating ink can be colored more clearly, and the design can be improved.

  The underlayer 2 is preferably white. In this case, the coating film M has the white paint layer 2 a as the lower layer of the ink receiving layer 3. In this embodiment, the base layer 2 is composed of a white paint layer 2a. Since the foundation layer 2 is white, it is possible to more clearly color the ink-jet printing, so that the design can be further improved.

  The underlayer 2 may be a colored coating other than white. The colored coatings are preferably the same color. Thereby, the coating color of inkjet printing can be stabilized. The underlayer 2 may be a monochrome paint. The underlayer 2 may be multicolored. The underlayer 2 can be set to, for example, black, blue, green, yellow, red, etc. other than white. However, in order to improve the design, it is advantageous that the base layer 2 is white.

  The underlayer 2 can be formed of a coating material (underlayer forming composition) for forming the underlayer 2.

  As the underlayer-forming composition, an acrylic resin paint based on an acrylic emulsion or an acrylic silicon resin paint based on an acrylic silicon emulsion can be used. The underlayer forming composition may contain at least one of extender pigments and hygroscopic resins. Thereby, the coloring property of the ink by inkjet coating can be improved. Here, silica, alumina, aluminum hydroxide, barium sulfate, porous silica, diatomaceous earth, or the like can be used as the extender pigment. Further, as the hygroscopic resin, an absorbent polymer such as vinyl acetate, urethane polymer, acrylic polymer, polyvinyl alcohol, or the like can be used.

  The underlayer forming composition preferably contains a coloring pigment in addition to the above-described extender pigment. By containing a coloring pigment, the underlayer 2 can be colored in a desired color such as white. As coloring pigments, use inorganic pigments such as titanium oxide, bengara, ocher, calcium carbonate, and composite metal oxides, and organic pigments such as carbon black, quinacridone, naphthol red, cyanine blue, cyanine green, Hansa yellow, and ultramarine blue. Can do. Only one type of pigment can be used, or two or more types can be used in combination. Of the pigments, inorganic pigments are preferably used. In that case, the weather resistance of the coated plate can be improved. The particle size of the pigment is not particularly limited, but an average particle size of about 0.01 to 4 μm is preferable. The pigment can be dispersed by a usual method, and a dispersant, a dispersion aid, a thickener, a coupling agent, and the like can be used at that time.

  The pigment content (PWC) when the above-mentioned extender pigment or colored pigment is contained in the underlayer-forming composition is appropriately set, but can be in the range of 40 to 80% by mass. Here, the pigment content is determined when the content of the pigment component including the extender pigment and the color pigment in the composition is A (parts by mass) and the content of the resin component is B (parts by mass). It is a value defined by the formula {A / (A + B)} × 100 (%).

  In one preferred embodiment, the underlayer-forming composition is aqueous. When an aqueous underlayer-forming composition is used, the color developability of a coating pattern is increased when an aqueous ink is used in ink jet printing. Moreover, the load on the environment can be reduced by using a water-based paint.

The underlayer 2 can be formed by applying the above-described underlayer-forming composition onto the surface of the substrate 1 provided with a sealer or the like by an appropriate method and heat-curing. In forming the underlayer 2 with the underlayer-forming composition, it is preferable to apply the underlayer-forming composition to the surface of the substrate 1 at a coating amount of 30 to 200 g / m ² · wet. The underlayer-forming composition can be applied by an appropriate method such as spray coating, curtain coating, dipping, wire bar coating, applicator coating, spin coating, roll coating, electrodeposition coating, or brush coating. In that case, coating apparatuses, such as a spray gun, a roll coater, a flow coater, and a curtain coater, can be used. The thickness of the underlayer 2 is not particularly limited, but can be in the range of 1 to 100 μm, for example.

  The ink receiving layer 3 is provided on the surface of the base layer 2. The ink receiving layer 3 can be formed on the surface of the base layer 2 on the surface of the substrate 1. The ink receiving layer 3 is also called an ink receiving layer. By providing the ink receiving layer 3, coating by ink jet printing is stabilized.

  The ink receiving layer 3 is formed of a paint made of a material having no glass transition point (Tg) in the range of at least 0 to 200 ° C. Thereby, even when heat is applied by baking, the ink receiving layer 3 is formed stably without becoming unstable, and therefore, ink permeation into the ink receiving layer 3 can be suppressed. Therefore, it is possible to stably obtain a highly-designed coated plate having no color unevenness and different colors with high productivity.

  Conventionally, acrylic emulsion paints, acrylic silicon emulsion paints, and the like are used as the paint for forming the ink receiving layer 3. In the ink receiving layer 3, baking is performed after coating to stabilize the coating film, but the state of the ink receiving layer 3 may not be sufficiently stabilized depending on baking conditions and the temperature environment after baking. For example, when the resin in the ink receiving layer 3 is softened at the baking temperature of the ink receiving layer 3, the state of the coating film is not uniform. Then, when the state of the ink receiving layer 3 is different for each substrate 1 or the state of the ink receiving layer 3 is partially different in the substrate 1, the ink for ink jet coating partially penetrates. As a result, color irregularities and color differences may occur. The cause of this is considered to be that the temperature in baking is higher than the glass transition point (Tg) of the resin, so that the ink is printed in a state where the resin is softened and the coating film is not sufficiently stabilized. When the softening of the resin is not uniform due to the baking conditions or the state of the residual heat after the baking process, when ink jet printing is performed in such a coating state, the ink receiving layer 3 is soaked and uniform. The degree of penetration is not uniform due to softening of the resin. In particular, when ink-jet printing is performed using a UV curable ink, the uncured UV ink has a large amount of monomer components, so that the ink receiving layer 3 is likely to penetrate. As a result, the fixing property of the ink becomes non-uniform, and color unevenness and color difference occur. In order to stably perform ink-jet printing without color unevenness, it is conceivable that the substrate 1 and the surroundings are sufficiently cooled after the ink receiving layer 3 is baked. However, if an attempt is made to lower the temperature of the substrate 1 once heated or the ambient temperature, the productivity is lowered and the coated plate cannot be produced efficiently.

  Therefore, in this embodiment, the ink receiving layer 3 is formed of a paint made of a material having no glass transition point in the above temperature range. Therefore, the ink receiving layer 3 is hardly affected by the ambient temperature and the substrate temperature. As a result, it is possible to prevent the state of the coating film from becoming non-uniform depending on the temperature conditions after baking, so that it is possible to suppress ink penetration and to cause color unevenness and color differences. Can be suppressed. In addition, the substrate 1 and the ambient temperature after the ink receiving layer 3 is formed can be easily set, and ink jet printing can be performed even when the temperature is not sufficiently lowered. Therefore, productivity can be improved.

  The ink receiving layer 3 is preferably formed of a paint composed of a material having no glass transition point (Tg) in the range of at least −50 to 500 ° C. Thereby, the ink receiving layer 3 is further stabilized.

  The ink receiving layer 3 is more preferably formed of a paint composed of a material that does not have a glass transition point (Tg). Thereby, the ink receiving layer 3 is further stabilized, and the ink permeation into the ink receiving layer 3 can be highly suppressed. Here, the material having no glass transition point (Tg) means having no glass transition point (Tg) in the entire temperature range. That is, it is a material whose glass transition point (Tg) is not measured. The glass transition point (Tg) can be measured by, for example, DSC (differential scanning calorimetry). Therefore, it is confirmed by DSC etc. that it does not have a glass transition point (Tg).

  The ink receiving layer 3 is formed of a paint for forming an ink receiving layer. Therefore, the coating material for forming the ink receiving layer is composed of a material having no glass transition point in the above temperature range. Examples of the material having no glass transition point include inorganic paints.

  The ink receiving layer 3 is preferably formed of a polysiloxane inorganic coating. Since the polysiloxane-based inorganic coating does not have a glass transition point (the glass transition point is not measured), it is possible to suppress uneven penetration of the ink into the ink receiving layer 3. In addition, since the polysiloxane-based inorganic paint has high solvent resistance, the influence of temperature in the process of forming the coating film M can be reduced. Therefore, since the stable ink receiving layer 3 can be formed, stable color development can be realized by ink jet printing. Furthermore, since the polysiloxane-based inorganic coating material can also exhibit the function of protecting the underlayer 2, durability and weather resistance can be improved.

  The polysiloxane-based inorganic paint preferably contains polyalkylsiloxane. Thereby, ink fixability is good, nonuniform penetration can be suppressed, and high-design ink-jet coating can be performed. As the polyalkylsiloxane, those which are hydrolyzed from a silicate having an alkyl group and crosslinked by dehydration and / or dealcoholization reaction are useful.

  Specific examples of polysiloxane-based inorganic paints are shown below.

  As the polysiloxane-based inorganic paint, a paint containing the following component (A) and component (B) can be preferably used.

(A): General formula R ¹ _n SiX _4-n (Formula 1)
A hydrolyzable organosilane and / or a partial hydrolyzate thereof.

(B): Average composition formula R ² _a Si (OH) _b O _{(4-ab) / 2} (Formula 2)
Polyorganosilane represented by

In the above (formula 1), R ¹ is the same or different alkyl group, cycloalkyl group, alkenyl group, halogen-substituted hydrocarbon group, γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4- A monovalent hydrocarbon group having 1 to 8 carbon atoms selected from the group consisting of an epoxycyclohexylethyl group and a γ-mercaptopropyl group. In said (Formula 1), n shows the integer of 0-3. In the above (Formula 1), X represents a hydrolyzable group selected from the group consisting of an alkoxy group, an acetoxy group, an oxime group, an enoxy group, an amino group, an aminoxy group, and an amide group.

In the above (formula 2), R ² is the same or different, alkyl group, cycloalkyl group, alkenyl group, halogen-substituted hydrocarbon group, γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4- A monovalent hydrocarbon group having 1 to 8 carbon atoms selected from the group consisting of an epoxycyclohexylethyl group and a γ-mercaptopropyl group. In the above (Formula 2), a and b are numbers satisfying the relations 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, and a + b <4, respectively.

R ¹ in the above (Formula 1) is preferably an alkyl group. For example, a methyl group, an ethyl group, a propyl group, a butyl group and the like are exemplified. X in the above (formula 1) is preferably an alkoxy group. For example, a methoxy group, an ethoxy group, etc. are illustrated.

R ² in the above (Formula 2) is preferably an alkyl group. For example, a methyl group, an ethyl group, a propyl group, a butyl group and the like are exemplified.

  The polysiloxane inorganic paint preferably contains colloidal silica. When colloidal silica is contained, the coating film height can be increased. More preferably, the colloidal silica is contained in the component (A). More preferably, the component (A) is obtained by partially hydrolyzing the compound of the above (formula 1) in colloidal silica.

  More preferably, the polysiloxane-based inorganic coating material contains a catalyst that promotes the condensation reaction between the component (A) and the component (B). Examples of such catalysts include metal salts of carboxylic acids such as alkyl titanates, tin octylate and dibutyltin dilaurate, dioctyltin dimaleate; amine salts; amine-based silane coupling agents; p-toluenesulfonic acid, phthalic acid, Examples include acids such as hydrochloric acid; alkali catalysts such as potassium hydroxide; halogenated silanes such as methyltrichlorosilane, dimethyldichlorosilane, and trimethylmonochlorosilane.

  The above-described polysiloxane inorganic coating material may further contain the following component (C).

(C): General formula OH (R ³ ₂ SiO) _m H (Formula 3)
A silicone diol represented by

In the above (Formula 3), R ³ is the same or different alkyl group, cycloalkyl group, alkenyl group, halogen-substituted hydrocarbon group, γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4- A monovalent hydrocarbon group having 1 to 8 carbon atoms selected from the group consisting of an epoxycyclohexylethyl group and a γ-mercaptopropyl group. In the above (Formula 3), m represents an integer of 1 or more.

R ³ in the above (formula 3) is preferably an alkyl group. For example, a methyl group, an ethyl group, a propyl group, a butyl group and the like are exemplified. In the above (Formula 3), there is no particular upper limit on m, but for example, m may be 1000 or less.

  By using the polysiloxane inorganic coating material as described above, it is possible to highly suppress non-uniform ink penetration during ink jet coating. Of course, the ink receiving layer 3 may be formed of a polysiloxane inorganic paint other than the above.

  The polysiloxane-based inorganic paint is preferably an aqueous paint. Thereby, application becomes easy and ink receptivity can be improved. Further, it is possible to form the ink receiving layer 3 with less penetration. In addition, the load on the environment can be reduced.

  The surface tension of the ink receiving layer 3 is preferably 40 [mN / m] or less. When UV ink is used for inkjet coating, the UV ink has a lower surface tension, and therefore, the ink receiving layer 3 having a lower surface tension can improve compatibility with the ink. The lower limit of the surface tension of the ink receiving layer 3 is not particularly limited, but the surface tension of the ink receiving layer 3 may be, for example, 10 [mN / m] or more.

  The ink receiving layer 3 is preferably transparent. If the ink receiving layer 3 is transparent, the color of the lower layer of the ink receiving layer 3 can be developed, so that the design can be improved. Here, in ink jet printing, the ink is usually coated in a dot shape, and when observed finely, portions other than the ink coating can be visually recognized. At that time, if the ink receiving layer 3 is transparent, the color of the ink is confirmed in the portion where the ink is applied (dot portion), and the portion other than the portion where the ink is applied (around the dot) is transparent. The lower color is confirmed through the ink receiving layer 3. Then, at the lower side of the ink receiving layer 3, the color is developed from the lower side at least by the thickness of the ink receiving layer 3, and as a whole, ink jet dots emerge and a deep color is developed. Therefore, the designability is enhanced. Further, when the ink receiving layer 3 is transparent and the undercoat layer 2 is the white paint layer 2a, the entire color is produced by the white color of the undercoat layer 2 and the dots of the ink jet paint, so that the ink is more vivid. Paint color is developed. Therefore, it is possible to perform coating with high design properties.

  The ink receiving layer 3 preferably has a function of fixing ink applied during ink jet printing without bleeding. Thereby, the color developability of the ink can be stabilized. The ink receiving layer 3 preferably has a property of absorbing ink. Thereby, the ink can be fixed. However, the ink receiving layer 3 preferably absorbs ink without spreading the printed dots as much as possible. Thereby, the color unevenness of inkjet printing can be suppressed. The ink receiving layer 3 may be formed of, for example, a porous layer having water absorption.

The ink receiving layer 3 can be formed by applying a coating material for forming an ink receiving layer to the surface of the underlayer 2 by an appropriate method and curing by heating. In forming the ink receiving layer 3, it is preferable to apply a coating for forming the ink receiving layer to the surface of the substrate 1 at a coating amount of 30 to 200 g / m ² · wet.

  Application of the coating for forming the ink receiving layer can be performed by an appropriate method such as spray coating, curtain coating, dipping, wire bar coating, applicator coating, spin coating, roll coating, electrodeposition coating, brush coating, and the like. . In that case, coating apparatuses, such as a spray gun, a roll coater, a flow coater, and a curtain coater, can be used. The ink receiving layer 3 can also be applied by electrostatic coating or the like.

  Baking is preferably performed after the coating material for forming the ink receiving layer is applied. Baking can be performed by setting the temperature to 60 to 180 ° C., for example. The temperature at this time may be the substrate temperature. By baking, the ink-receiving layer-forming paint is cured and dried, and the ink-receiving layer 3 is stabilized and formed. The thickness of the ink receiving layer 3 is not particularly limited, but can be in the range of 1 to 50 μm, for example. The thickness of the ink receiving layer 3 can be preferably in the range of 3 to 30 μm.

  The ink jet printing layer 4 is provided on the surface of the ink receiving layer 3. The inkjet printing layer 4 can be formed by performing inkjet printing (inkjet coating) on the surface of the ink receiving layer 3 formed as described above. Inkjet printing is performed on the surface of the ink receiving layer 3 after baking. Ink jet printing may be performed in a state in which the heat at the time of baking remains slightly. Thereby, productivity can be improved.

  UV ink can be used as the ink used for inkjet printing. Thereby, printing with high designability can be performed. The UV ink is a type of ink that is cured by UV (ultraviolet light). The UV ink is also called ultraviolet curable ink or UV curable ink. As the UV ink, a water-based ink can be used, and an oil-based ink can also be used. The UV ink may contain monomers and / or oligomers.

  A water-based ink may be used as the ink used for ink jet printing. As the water-based ink, a pigment ink in which a conventionally known pigment is dispersed with a dispersant can also be used. However, in this type of ink, it is difficult to increase the pigment concentration by ink jet printing and the amount of the binder resin is small, so that the color of the printed product tends to be dark and the quality as an exterior decoration material is likely to be significantly reduced. From such a viewpoint, an aqueous pigment type ink comprising an aqueous dispersion of colored resin particles in which pigment particles are coated with a film-forming resin having an acid group neutralized at least partially with a base is preferable. This type of ink has a wide color reproduction range as well as excellent weather resistance, and can achieve high print quality.

  The film-forming resin having an acid group is not particularly limited as long as it has a known acid group, but is preferably a resin having a carboxyl group having an acid value of 50 to 280. In the case of a self-water dispersible resin in which at least a part thereof is neutralized with a base, particularly excellent stability as a jet ink is exhibited.

  Examples of the film-forming resin include acrylic acid resin, maleic acid resin, and polyester resin. Particularly preferred is a styrene- (meth) acrylic acid resin. In addition, (meth) acryl includes both acryl and methacryl. The styrene- (meth) acrylic acid resin is a resin obtained by copolymerizing a (meth) acrylic acid monomer with a styrene monomer as an essential component. Examples of the (meth) acrylic acid monomer include (meth) acrylic acid and / or (meth) acrylic acid ester. The film-forming resin is more preferably UV curable.

  Examples of the resin include substituted styrene such as styrene or α-methylstyrene, acrylic acid ester such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate. At least one monomer unit selected from esters, methacrylic acid ethyl ester, methacrylic acid butyl ester, methacrylic acid esters such as 2-ethylhexyl methacrylate, and at least one monomer unit selected from acrylic acid and methacrylic acid The copolymer containing is illustrated. At least a part of these copolymers may be covalently crosslinked or ionically crosslinked with a polyvalent metal.

  When the resin is used as a self-water dispersible resin, at least a part of the carboxyl group may be neutralized with a base. Neutralization with a base, that is, an alkaline neutralizing agent, may be performed to such an extent that the obtained self-water dispersible resin does not dissolve in water. Examples of the base include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, basic substances such as ammonia, triethylamine and morpholine, in particular triethanolamine, diethanolamine, N-methyldiethanolamine and the like. The alcohol amine is preferable. Among these, triethanolamine is particularly preferable as the jet ink.

  When the pH of the ink in the presence of a base is in the range of 7 to 10, preferably 8 to 9, the resin containing the pigment is hardly dissolved in the ink and prevents nozzle clogging. In addition, a vivid color can be obtained and a clear pattern can be obtained.

  The pigment used in the above-mentioned water-based ink is not particularly limited. For example, inorganic pigments such as carbon black, titanium black, titanium white, zinc sulfide, bengara and yellow ocher, azo such as phthalocyanine pigment, monoazo, and disazo are used. There are organic pigments such as pigments, phthalocyanine pigments, and quinacridone pigments. The amount (content) of the pigment used is not particularly defined, but is preferably an amount that is 0.5 to 10% by mass in the finally obtained ink.

  A method for producing colored resin particles in which a pigment is included by the resin is not particularly limited. The colored resin particles can be produced, for example, by a method of obtaining an aqueous dispersion of colored resin particles by a process having a resin coloring process, a suspension process, and a reprecipitation process. The resin coloring step is a step of obtaining a solid coloring compound by dispersing or dissolving at least a colorant in a film-forming resin having an acid value. The suspending step mixes at least water, an organic solvent that dissolves the film-forming resin, a base, and the solid coloring compound obtained in the resin coloring step, and a colorant in which at least a part of the resin is dissolved by dispersion. This is a step of obtaining a suspension. The reprecipitation step is a step of depositing a dissolved resin component on the colorant surface in the colorant suspension obtained in the suspension step.

  Ink for inkjet printing is obtained as a pigment dispersion. Additives can be added to this dispersion as needed. Examples of the additive include a drying inhibitor, a penetrant, a water-soluble resin, a preservative, and a chelating agent.

  It is preferable that an anti-drying agent is added to the ink. Anti-drying agents are often added to water-based inks, and give an effect of preventing ink from drying at the jet nozzle opening of an ink jet. As the drying inhibitor, a water-soluble organic solvent having a boiling point higher than that of water is usually used. Such an anti-drying agent is not particularly limited, and conventionally known polyhydric alcohols such as ethylene glycol, diethylene glycol, polyethylene glycol, glycerin, N-methyl-2-pyrrolidone, 2-pyrrolidone, etc. Pyrrolidones, amides, dimethyl sulfoxide, imidazolidinone and the like can be used. The usage-amount of a drying inhibitor changes with kinds, and is normally selected from the range of 1-150 mass parts with respect to 100 mass parts of water normally.

  A penetrant is preferably added to the ink. By adding the penetrant, it is possible to improve the penetration of the ink into the ink receiving layer 3. The penetrant can be used in an appropriate amount. Examples of penetrants include water-soluble organic solvents such as lower alcohols such as ethanol and isopropyl alcohol, glycol ethers such as diethylene glycol-N-butyl ether, propylene glycol derivatives, and pyrrolidone compounds that exhibit the effect of imparting permeability to the ink receiving layer 3. Nonionic, anionic, and amphoteric surfactants can be used.

  Note that the inkjet printing layer 4 is not limited to water-based ink, and may be formed using oil-based ink.

  As a coating apparatus used for performing inkjet printing, an appropriate inkjet coating machine that performs inkjet printing for each color on the conveyed substrate 1 from a plurality of nozzles can be used.

  The clear layer 5 is formed on the surface of the inkjet printing layer 4. By providing the clear layer 5, the coating film can be highly protected, and the design can be enhanced by imparting clearness to the printed surface. The clear layer 5 is a layer for protecting the surface of the colored coating. The clear layer 5 can be formed by applying and forming a water-based clear paint after inkjet coating. The clear layer 5 is preferably formed of a water-based clear paint. As the water-based clear paint, for example, an appropriate paint such as acrylic, acrylic silicon, or acrylic urethane can be used.

  The clear layer 5 can be formed, for example, by applying a water-based clear paint by spraying or the like on the surface of the substrate 1 after ink jet printing, followed by baking and drying at 80 to 150 ° C. it can. Although the thickness in particular of the clear layer 5 is not restrict | limited, For example, it can be set as the range of 1-50 micrometers.

  The inorganic coating layer 6 is formed on the surface of the clear layer 5. By providing the inorganic coating layer 6, durability can be improved. Since the clear layer 5 that is often composed of resin can be covered with the inorganic coating layer 6 composed of an inorganic film, durability can be improved. The inorganic coating layer 6 can be formed by applying and coating an inorganic paint on the surface of the clear layer 5. As the inorganic coating material, an appropriate silicon alkoxide coating agent or the like can be used. For example, a silicon alkoxide paint in which a condensation reaction catalyst such as polyorganosiloxane or an alkyl titanate is added to a silica-dispersed oligomer solution of organosilane or silica is further added can be used.

  The inorganic coating layer 6 is preferably formed of a polysiloxane inorganic coating. As the polysiloxane-based inorganic coating material, the same materials as those described for the ink receiving layer 3 can be used. When a polysiloxane inorganic coating is used in both the ink receiving layer 3 and the inorganic coating layer 6, the ink jet printing layer 4 can be sandwiched between the inorganic coatings. Thereby, while being able to protect inkjet coating highly, the coloring property of inkjet coating can be improved and the coating plate which was highly durable and excellent in the designability can be obtained.

  The inorganic coating layer 6 can be formed, for example, by applying a paint for forming the inorganic coating layer 6 by electrostatic coating or the like and then baking and drying at 60 to 120 ° C. to form a film. Although the thickness in particular of the inorganic coating layer 6 is not restrict | limited, For example, it can be set as the range of 1-30 micrometers.

  The functional coating layer 7 is formed on the surface of the inorganic coating layer 6. By providing the functional coating layer 7, an appropriate function can be imparted, and for example, the antifouling property can be enhanced.

  The functional coating layer 7 is a preferred embodiment that contains a photocatalyst. Accordingly, it is possible to suppress the adhesion of dirt by the photocatalytic action, and it is possible to remove the attached dirt. The functional coating layer 7 can be formed by, for example, an inorganic paint containing a photocatalyst. As the inorganic coating material containing a photocatalyst, an appropriate one can be used. For example, a material obtained by adding a photocatalyst such as titanium oxide to the above silicon alkoxide coating material can be used. Moreover, it is a preferable aspect that the functional coating layer 7 has hydrophilicity. In that case, the antifouling property can be enhanced by the hydrophilic action. The functional coating layer 7 is a preferred embodiment having water repellency. In that case, the antifouling property can be increased by the action of water repellency. Moreover, it is a preferable aspect that the functional coating layer 7 has heat ray reflectivity. In that case, since a heat ray can be reflected, heat insulation can be improved. The functional coating layer 7 may have a plurality of functions exemplified above. Thereby, since high functionality is provided, the weather resistance and durability of a coating board improve.

  The functional coating layer 7 is formed by applying a paint for forming the functional coating layer 7 to the surface of the inorganic coating layer 6 by spray coating or the like and then baking and drying at 60 to 120 ° C. Can be formed. Although the thickness in particular of the functional coating layer 7 is not restrict | limited, For example, it can be set as the range of 0.1-5.0 micrometers.

  In the present embodiment, the coating film M has the base layer 2, the ink receiving layer 3, the inkjet printing layer 4, the clear layer 5, the inorganic coating layer 6, and the functional coating layer 7, Some or all of the underlayer 2, the clear layer 5, the inorganic coating layer 6, and the functional coating layer 7 may be omitted. Even in that case, the ink receiving layer 3 can perform ink-jet printing with high design. However, in order to obtain a coated plate having excellent design properties and high durability and weather resistance, it is preferable that at least a part of these layers is provided, and it is more preferable that all the layers are provided.

  The painted plate is useful as a building plate. The painted plate can be used as an exterior material such as an outer wall material, a roof material, and a roofing material.

Example 1
As the substrate 1, a cement-based inorganic substrate was used.

In producing this base material 1, a sealer made of an acrylic emulsion paint is applied on the surface of a wet sheet before curing and curing formed with a cement-based molding material by a roll coater, and dried by heating at 250 ° C. for 20 minutes. A base film 1 was obtained by forming a sealer coating of 40 g / m ² and curing the wet sheet.

  A surface layer-forming composition (pigment content ratio PWC = 50 mass%) in which calcium carbonate fine particles are contained as a pigment in an acrylic emulsion paint is spray-applied to the surface of the base material 1 provided with a sealer coating, and 130 The underlayer 2 having a thickness of 30 μm was formed by heating at 2 ° C. for 2 minutes. The underlayer 2 was configured as a white paint layer 2a.

  The base material 1 on which the underlayer 2 is formed is spray-coated with a polysiloxane-based inorganic paint (ink-receiving layer-forming paint) and heated at 160 ° C. for 5 minutes to form the ink-receiving layer 3 having a thickness of 10 μm. Formed. This polysiloxane inorganic coating does not have a glass transition point. Further, the surface tension of the ink receiving layer 3 was 29 [mN / m].

  The substrate 1 on which the ink receiving layer 3 was formed was subjected to ink jet printing on the surface of the ink receiving layer 3 using an ink jet coating apparatus. Here, coating was performed under two conditions of 40 ° C. and 70 ° C. as the temperature of the substrate 1 before inkjet printing.

  Water-based UV ink was used for inkjet printing. As the ink, an ink having a composition of 4% by mass of pigment, 35% by mass of ethylene glycol, 20% by mass of glycerin, 3% by mass of additive, and 38% by mass of water was used. The pigment used was yellow ocher in yellow ink, phthalocyanine in cyan ink, Bengala in magenta ink, and carbon black in black ink. Further, the amount of ink ejected from each ejection nozzle for one dot was set to 27 pl. The inkjet printing layer 4 was formed by inkjet printing.

  Next, a clear paint was spray-coated on the surface of the substrate 1 after inkjet printing, and heated at 130 ° C. for 2 minutes to form a clear layer 5 having a dry film thickness of 20 μm.

  Next, an inorganic coating layer containing polyorganosiloxane was spray-coated on the surface of the clear layer 5 and heated at 130 ° C. for 2 minutes to form an inorganic coating layer 6 having a dry film thickness of 5 μm.

Next, the surface of the inorganic coating layer 6 is spray-coated with an inorganic paint containing polyorganosiloxane and titanium oxide at a ratio of 50% by mass, and heated at 130 ° C. for 2 minutes to dry-coat. A photocatalyst layer was formed as a functional coating layer 7 in an amount of 3 g / m ² .

  Thus, a coated plate of Example 1 was obtained.

(Comparative Example 1)
A coated plate was obtained in the same manner as in Example 1 except that the ink receiving layer 3 was formed using a paint containing an acrylic emulsion resin. The glass transition point of this acrylic emulsion resin was 32 ° C. The surface tension of the ink receiving layer 3 was 42 [mN / m]. In addition, it apply | coated on two conditions, 40 degreeC and 70 degreeC, as temperature of the base material 1 before inkjet printing.

(Evaluation)
It confirmed about the color development (L ^* a ^* b ^* ) and the change of a dot diameter by the difference (2 conditions of 40 degreeC and 70 degreeC) of the temperature of the base material 1 before inkjet printing.

For color development property, the ^L * ^a * ^{b *} measured by a colorimeter, ^{a *} from the values and ^{b *} values, ^{c *} values in the following equation,
c ^* = (a ^* ^ 2 + b ^* ^ 2) ^ 0.5
The change rate of the c ^* value at 70 ° C. printing was calculated using the c ^* value at 40 ° C. printing as a reference (0% change rate). Here, “^” is a symbol indicating a multiplier. The case where the change rate of the c ^* value was less than 10% was evaluated as “◯”, and the case where the change rate of the c ^* value was 10% or more was determined as “x”.

  The dot diameter was measured by observing the surface of the coated plate with a microscope, and the dot diameter change rate at 70 ° C. printing was calculated using the dot diameter at 40 ° C. printing as a reference (change rate 0%). The case where the change rate of the dot diameter was less than 10% was indicated as “◯”, and the case where the change rate of the dot diameter was 10% or more was indicated as “X”.

  Table 1 shows the results.

  As shown in Table 1, Example 1 has less color developability and a change rate of dot diameter than Comparative Example 1, and is well coated even when printed under conditions of high temperature. This is presumably because the influence of temperature was suppressed because the material of the ink receiving layer 3 did not have a glass transition point. Therefore, in Example 1, it was confirmed that the ink permeation was suppressed, and a coated plate excellent in design properties by suppressing color unevenness and color difference could be obtained.

M coating film 1 base material 2 ground layer 2a white paint layer 3 ink receiving layer 4 inkjet printing layer 5 clear layer 6 inorganic coating layer 7 functional coating layer

Claims (4)

  A coating plate having a coating film provided on a surface of a substrate, wherein the coating film has an ink receiving layer and an ink jet printing layer, and the ink receiving layer has a glass transition in a range of at least 0 to 200 ° C. A painted plate characterized by being formed of a paint made of a material having no dots.   The painted plate according to claim 1, wherein the ink receiving layer is transparent.   The coated plate according to claim 1, wherein the ink receiving layer is formed of a polysiloxane-based inorganic paint.   The said coating film has a white paint layer as a lower layer of the said ink receiving layer, The coating board of any one of Claim 1 thru | or 3 characterized by the above-mentioned.

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