JP6998240B2 - Ceramic decorative board and its manufacturing method - Google Patents

Description

The present invention relates to a ceramic decorative board having non-combustible performance and useful as an interior finishing material for a building, and a method for manufacturing the same.

Traditionally, the interior of a building has been required to have a space where you can feel calm and warmth, and wood grain materials are preferred to create that space. However, it is difficult to secure the non-combustible performance required for large buildings that are subject to the interior restrictions of the Building Standards Act with interior materials that are simply made of wood into a plate shape and finished with a wood grain finish. It can be said that it is difficult to mass-produce large-sized board materials with a grain pattern, which is preferred as an interior finishing material, from the viewpoint of wood resources. Therefore, from such a market, there is a demand for a highly productive decorative board that has the same appearance as a wood-based interior finishing material, is cheaper than a solid wood of natural wood, and has excellent non-combustible performance. ..

As a decorative board technology that expresses the texture of wood, a decorative low-gloss printing layer, a surface protective layer, etc. are laminated on the surface of the veneer to form a decorative sheet, which is used as a base material for the decorative board (base material) via an adhesive layer. ), Or a decorative sheet having a design layer on a laminated sheet having a paper quality layer and a resin film layer, and a surface of a nonflammable base material (substrate) having a metal thin film layer. A decorative sheet is bonded to a substrate, such as a non-combustible veneer (Patent Document 2), which has an uneven shape on the surface after being attached to the substrate via an adhesive layer, and non-combustible materials and quasi-non-combustible materials. Disclosed are those that are directly coated on the surface of the substrate, such as a veneer (Patent Document 3), which is applied with a sealer, an undercoat, a wood grain pattern printing, and a topcoat paint after the surface of the substrate is subjected to a base treatment.

The decorative board of Patent Document 1 provided with a pattern printing that expresses a feeling of unevenness using a veneer and a surface protective layer has a decorative sheet that contains a large amount of flammable substances because it emphasizes the texture of wood, and also adheres to the substrate. Therefore, since an adhesive containing a resin is required, it is difficult to secure the non-combustible performance of the veneer as a whole even if the substrate has the non-combustible performance. Further, in Patent Document 2, a decorative sheet in which the total amount of organic substances is limited is used, but since an adhesive containing organic substances is required for adhesion to the substrate, a metal thin film layer is provided in order to secure nonflammable performance. It is required to use a special nonflammable substrate. In the technology using a decorative sheet as described above, it is necessary to make a decorative sheet in which multiple layers are laminated in order to obtain high designability, and further, this is attached to the substrate using an adhesive, so that it is incombustible. There is a problem that it is difficult to secure the performance and the process is complicated, so that the production efficiency is low and the cost is high.

On the other hand, Patent Document 3 uses a non-combustible material such as a cotton board, a magnesium carbonate board, and a calcium silicate board, and a quasi-non-combustible material as a substrate, and after applying a wood-like base treatment to the surface thereof, printing a wood grain pattern and topcoating. It is a technology to apply paint, it is easy to secure nonflammability by controlling the amount of paint applied, and it is easy to perform base processing, printing and painting as a series of steps, so efficient production. Can be expected. However, this was a technology when non-combustible materials using asbestos were common, and it cannot be applied as it is today when asbestos was made non-asbestos.
That is, at present, fiber-reinforced cement boards such as calcium silicate board, which is the main substrate of ceramic non-combustible decorative boards, generally use organic fibers such as pulp as reinforcing fibers instead of asbestos. A fiber-reinforced cement board containing a large amount of pulp or the like tends to have more fluffing than a product using asbestos when the surface is polished with a belt sander. Therefore, when the surface is polished with a coarse belt sander as in Patent Document 3, fluff such as pulp becomes conspicuous, and the surface cannot be a surface imitating a wood grain-like conduit groove. Further, since it is difficult to suppress the fluffing caused by this pulp or the like even if a paint is applied on the pulp or the like, it becomes an unsuitable base for a decorative board whose purpose is to give a wood texture. In addition, simply applying a transparent topcoat paint on wood grain printing is only a cheap imitation board, and it is not possible to obtain the calm and warm wood texture that is required today. Therefore, in addition to overcoming fluffing, it is necessary to improve the texture of wood.

Japanese Unexamined Patent Publication No. 2012-183834 Japanese Unexamined Patent Publication No. 2012-210794 Special Publication No. 58-39678

The present invention has been made in view of the above problems, and an object of the present invention is to provide a streak-processed undercoat layer that suppresses fluffing of the substrate and a topcoat layer that improves the wood texture. It is an object of the present invention to provide a ceramic decorative board having excellent non-combustible performance and a method for manufacturing the same.

Therefore, as a result of various studies on the processing method of the undercoat layer of the ceramic decorative board and the clear paint of the topcoat layer, the present inventor uses a UV curable paint having a high coating hardness as the undercoat paint and is usually smooth. The surface of the undercoat layer, which is required to have properties, is polished with a coarse belt sander to create a surface that imitates a conduit groove that suppresses fluffing, and the clear paint of the topcoat layer has an amorphous synthetic silica particle that has a matte effect. It is possible to improve the wood texture by adding resin beads that give an expression to the surface of the topcoat layer, and by optimizing the amount of organic matter contained in the decorative layer, it is sufficiently non-combustible as a decorative board. We have found that a ceramic-based decorative board having both performance can be obtained, and completed the present invention.

That is, the present invention provides the following [1] to [3].

[1] A method for manufacturing a ceramic-based decorative board in which a sealer layer, an undercoat layer, a coloring layer, a printing layer, and a topcoat layer are formed in this order on the surface of at least one side of a ceramic-based substrate, wherein the undercoat layer is an undercoat. The surface coated and cured with the paint is roughly polished and formed so that innumerable streaks are formed along the longitudinal direction of the ceramic substrate, and the topcoat layer is formed by flowing a clear paint containing resin beads and synthetic silica. A method for manufacturing a ceramic decorative board, which is characterized by being applied and formed with a coater.
[2] The surface roughness after the formation of the undercoat layer is 0.5 to 4 μm for Ra in the direction parallel to the longitudinal direction of the ceramic substrate and 5 to 30 μm for Rz, which are orthogonal to each other. The method for manufacturing a ceramic decorative board according to [1], wherein the Ra value is 5 to 15 μm and the Rz value is 35 to 70 μm.
[3] At least two types of large beads having an average particle size of 20 to 40 μm and small beads having an average particle size of 5 to 10 μm are mixed and used as the resin beads, and the ratio of the small beads to the large beads is the mass ratio. [1] or [2], wherein the resin beads are contained in an amount of 1.1 to 1.6 times, and the resin beads are contained in an amount of 5 to 15% by mass based on the total solid content of the clear paint. How to make ceramic beads.

By using the method for manufacturing a decorative board of the present invention, fluffing of pulp and the like on a ceramic substrate can be suppressed, and by adding beads to the topcoat layer, a smooth, soft, calm and warm wood texture can be effectively obtained. It is possible to manufacture the expressed ceramic decorative board.

It is an image diagram of the cross section which showed the structure of the ceramic decorative board which concerns on this invention. It is a figure which showed the measured waveform of the surface roughness of Example 1. FIG. It is a figure which showed the measured waveform of the surface roughness of the comparative example 1. FIG. It is a figure which showed the measured waveform of the surface roughness of Reference Example 1. FIG. It is a figure which showed the measured waveform of the surface roughness of Reference Example 2.

FIG. 1 is an image diagram of a cross section orthogonal to the longitudinal direction of the substrate showing the configuration of the decorative board according to the present invention. The method for manufacturing a ceramic decorative board of the present invention is a step of applying an impregnated sealer to the surface of a substrate 1 to form a sealer layer 2, a step of applying an undercoat paint and then polishing to imitate a conduit groove along one direction. A step of forming an undercoat layer 3 on the surface, a step of forming a colored layer 4 which is a base of a wood grain pattern, a step of printing a wood grain pattern to form a print layer 5, and a top coat containing large and small resin beads 7 and 8. It is characterized by undergoing a step of forming the layer 6.

The present invention relates to a ceramic-based decorative board (hereinafter, also simply referred to as a decorative board), and has a decorative layer on at least one surface of a ceramic-based substrate. Here, as ceramic-based substrates (hereinafter, also simply referred to as substrates), fiber-reinforced cement boards, wood-based cement boards, wood wool cement laminated boards, extruded cement boards, fibers used for interior materials of buildings, etc. Examples include mixed gypsum plates, etc., and those having nonflammable performance corresponding to the exothermic first grade specified in JIS A 5430: 2013 Annex JA are used.

For these substrates, for example, hydraulic cement such as Portland cement is used as the main raw material for forming a matrix, fibers other than asbestos are used as the fiber raw material, and wallastnite, calcium carbonate powder, etc. are used as necessary. The admixture of the above is used as a raw material, water is added to these, and the mixture is molded into a plate shape and cured. More specifically, a substrate such as a fiber-reinforced cement plate specified in JIS A 5430: 2013. Is. In particular, 0.8 calcium silicate board or 1.0 silicate board, which is a kind of fiber-reinforced cement board that uses calcareous raw material and silicate raw material as raw materials for forming a matrix and performs autoclave curing in the curing process. The calcium silicate plate is a substrate having excellent flexibility, has high strength, and has a small rate of change in length due to water absorption, and is therefore suitable as the substrate used in the present invention.

Examples of the fiber raw material include organic fibers such as pulp, synthetic pulp, polypropylene fiber, rayon fiber, acrylic fiber, vinylon fiber, nylon fiber and polyester fiber, and metal fiber such as steel fiber (steel wire fiber) and amorphous metal fiber. Examples thereof include glass fiber, carbon fiber (carbon fiber), rock wool fiber, inorganic fiber such as whisker, etc., but in the present invention, even when the above-mentioned autoclave curing is adopted, the reinforcing property and toughness of the decorative board are maintained. From the viewpoint of improvement, it is preferable to use pulp. The pulp referred to here is a state in which cellulose is taken out by mechanically or chemically treating a plant raw material such as wood, and refers to so-called cellulose pulp.
The content ratio of fibers, especially organic fibers such as pulp, in the fiber-reinforced cement board varies depending on the matrix, but is preferably 5 to 9% by mass, preferably 6 to 8% by mass, from the viewpoint of ensuring strength and nonflammability. % Is more preferable. When the content ratio of organic fibers such as pulp is low, the mechanical strength of the decorative board is lowered, and cracks due to heat load, drying, carbonation and impact are likely to occur. On the contrary, if the content of organic fibers such as pulp is high, it becomes difficult to maintain nonflammability.

The hydraulic cement may be any cement generally used in the art, and examples thereof include Portland cement.
Examples of various admixtures used as needed include those commonly used in the art, and are not particularly limited, but for example, powders such as wallastnite, mica, and calcium carbonate, and fiber-reinforced cement plates are thin. Examples include waste material powder of calcium carbonate board. In the case of autoclave curing, silicic acid raw materials such as crystalline silica such as powdered silica stone and amorphous silica such as fly ash are used from the viewpoint of further increasing the strength by hydrothermal reaction curing with lime in cement. Is preferably mixed and used as needed.

In the present invention, the thickness of the substrate is preferably 3 to 12 mm. If the thickness is too thin, the impact resistance deteriorates, and the smoothness is impaired by strain after construction, which makes it particularly unsuitable as a decorative board. On the other hand, if it is too thick, the mass will increase, the workability will decrease, and the cost will increase. The thickness of the substrate is more preferably 4 to 8 mm. Further, it is preferable to polish at least the surface to which the substrate is to be applied with a wide belt sander or the like in advance in order to ensure smoothness before use.

Further, in the present invention, the bulk density of the substrate is preferably 0.6 to 1.8 g / cm ³ . If the bulk density is too small, the surface of the substrate becomes porous, and uneven suction of the impregnated sealer occurs, resulting in deterioration of the appearance after painting. In addition, the frost damage resistance is lowered, and the mechanical properties such as rigidity and breaking load are also lowered. If the bulk density is too large, the mass will increase and workability and workability will decrease. The bulk density of the substrate is more preferably 0.6 to 1.2 g / cm ³ .

In the present invention, the thickness is a value measured according to JIS A 5430: 2013, 9.2.2 item b), and the bulk density is a value measured according to JIS A 5430: 2013, item 9.5. be. The total calorific value is a value measured according to JIS A 5430: 2013 Annex JA.

The decorative board of the present invention has a sealer layer, an undercoat layer, a coloring layer, a printing layer, and a topcoat layer on the surface of at least one side of the substrate in this order. These organic coating film layers may be provided on only one surface (one side) of the substrate, or may be provided on both sides.

In the decorative board of the present invention, a sealer layer with an impregnated sealer is provided between the substrate and the undercoat layer, that is, at least one surface of the substrate. By providing the sealer layer, the surface layer of the substrate is strengthened, the elution of alkali on the surface can be prevented, and the adhesion to the undercoat layer, which is the upper layer thereof, is improved.

The sealer layer can be formed by using a known impregnated sealer. For example, the sealer layer is formed by using a curable resin such as a moisture-curable urethane resin or an epoxy resin and applying it to the surface of a substrate to cure it. The impregnated sealer has good impregnation property on the substrate, has a high non-volatile content, reacts with the moisture in the substrate and the moisture of the atmosphere, crosslinks three-dimensionally, and has good water resistance, etc. Prepolymers having a free isocyanate group, which are reaction products, and moisture-curable urethane-based ones containing a solvent such as butyl acetate as a main component are suitable. If yellowing as a decorative plate becomes a problem, aliphatic isocyanates such as HDI (hexamethylene diisocyanate), alicyclic isocyanates such as IPDI (isophorone diisocyanate), and MDI (methylenebis (4,1-phenylene)) = It is preferable to use an aromatic isocyanate such as diisocyanate). From the viewpoint of recent measures against volatile organic compounds (VOC), use a solvent-free sealer or water-based sealer that does not contain a solvent, or use an inorganic sealer such as a silicate-based sealer such as lithium silicate or sodium silicate. Alternatively, a silane compound-based sealer containing tetraethoxysilane or tetramethoxysilane as a main component can also be used.

The sealer layer can be formed, for example, by heating the surface temperature of the fiber-reinforced cement board to 50 to 60 ° C., applying the impregnated sealer by a known roll coater, spray, or the like, and then curing the impregnated sealer. The viscosity of the impregnated sealer can be appropriately determined in consideration of the type of the impregnated sealer to be used and the coating method, and the curing can be performed by, for example, heating and drying.

Further, in the present invention, it is preferable that the back surface of the substrate is also treated with an impregnated sealer to reinforce it. This is because the adhesive method is often used as the method of constructing the decorative board, and if the back surface of the substrate is reinforced, the workability is improved. When the impregnation sealer treatment is also performed on the back surface of the substrate, it is common to perform the impregnation sealer treatment on the back surface before forming the undercoat layer described later, but it may be performed after the undercoat layer is formed.

In the present invention, it is preferable to set the amount of the organic solid content in the components of the impregnated sealer to be 3 to 50 g per unit area (m ² ) of the substrate. If the amount of organic solids is too small, the surface layer of the substrate may not be strengthened so much. In addition, the adhesion to the undercoat layer, which is the upper layer thereof, may decrease. If the amount of organic solids is too large, excess organic solids will remain on the surface layer of the substrate, and this organic solids may cause coagulation peeling in the sealer layer, foaming in the subsequent process, and defects such as flanks. There is sex. In addition, the armpit is a minute hole formed by the gas in the foam breaking the coating film in foaming, and is caused by a local thick film at the time of painting, and is mainly generated by a rapid temperature rise at the time of drying. .. It is more preferable that the amount of the organic solid content in the components of the impregnated sealer is set to be 10 to 40 g per unit area (m ² ) of the substrate. Further, when the back surface of the substrate is subjected to the impregnation sealer treatment, it is preferable to set the amount of the organic solid content in the components of the impregnation sealer to be 3 to 30 g per unit area (m ² ) of the substrate.

In the present invention, the organic solid content can be easily calculated from the composition of the paint stock solution, the amount of the diluting solvent used, and the actual coating amount.

The decorative board of the present invention has an undercoat layer on the upper layer of the impregnated sealer layer, and the surface of the undercoat layer is a coarse-grained abrasive with fine streaks imitating conduit grooves along one direction. It is important that it is polished to. By polishing the undercoat paint after curing it, it is possible to suppress fluffing that occurs when the surface of the substrate is polished. This is because the fluff of organic fibers such as pulp on the surface of the substrate is firmly hardened with the resin of the undercoat paint, and the fluff is scraped together with the resin of the undercoat paint by the subsequent polishing, so that it does not remain on the surface after polishing. Conceivable. In addition, due to the formation of the undercoat layer, large and small uneven portions and voids existing on the surface of the substrate are filled with the undercoat paint, and the feeling of variation in gloss and color due to uneven suction of the paint applied to the upper layer than the undercoat layer is suppressed. Will be done. It also reduces the possibility of pinhole-like defects in the veneer. In the present invention, the undercoat paint is cured to form a coating film, and then the surface of the coating film is polished. First, at least once, the smoothness of the surface of the undercoat layer is adjusted with a relatively fine-grained abrasive, and finally, by polishing with a coarse-grained abrasive, it is possible to process the surface to imitate a conduit groove. This surface makes it possible to effectively express a natural, calm and warm wood texture.

The thickness of the undercoat layer is 10 to 120 μm, which is the surface smoothness of the decorative board, the adhesion of the topcoat layer to the coating film, the substrate hiding property, the waterproof property, the precipitation prevention property of the substrate component, and the coating film pinhole. It is important in terms of prevention of coating film curability, embedding of foreign matter on the surface, and ease of film thickness control. If it is less than 10 μm, the adhesion to the coating film of the upper layer and the lower layer may be lowered. On the other hand, if it exceeds 120 μm, the total calorific value increases, which may lead to deterioration of nonflammability, and when used in an extremely low humidity environment, the decorative board warps due to the drying shrinkage of the coating film. It will be easier. The preferred coating film is 10 to 80 μm, more preferably 15 to 60 μm.

The paint for forming the undercoat layer is a radical oligomer-based paint from the viewpoints of substrate hiding property, surface smoothness, chemical resistance, coating adhesion, polishing processability, coating hardness, coating ease, and crack prevention. And monomer radical-based paints, such as epoxy-based acrylates, urethane-based acrylates, ester-based acrylates, acrylic-based acrylates, silicon-based acrylates, and unsaturated polyester-based paints are preferable, and specifically, epoxy acrylates, urethane acrylates, phthalic acid diallyl esters, and the like. Allyl-based unsaturated polyester, maleic acid-based unsaturated polyester by polycondensation of unsaturated dibasic acid such as maleic anhydride and fumaric acid with glycols, polyester monoacrylate having carboxyl group and hydroxyl group as functional group, acrylic acid Polyester diacrylate obtained from dibasic acid and divalent alcohol, polyester acrylate such as polyester polyacrylate obtained from trivalent or higher polyhydric alcohol and dibasic acid and acrylic acid, and oligomers such as epoxy acrylate oligomer and epoxy oligomer. , Acrylic polyether, polyether acrylate and the like. In addition, the paint for forming the undercoat layer should be an ultraviolet curable paint, which is easy to apply, has a high curing speed of the paint film, grindability and durability of the paint film, and is different from the substrate and top coat paint. It is preferable because it has excellent adhesion. In addition, the UV curable paint has a high curing speed and can take in the fluff on the surface of the substrate and harden it firmly, so there is an advantage that the fluff is also scraped when polishing and no fluff remains on the surface after polishing. ..

After applying the paint, the paint is cured by irradiating it with ultraviolet rays, and then the surface is polished. Further, the paint for forming the undercoat layer is preferably one to which an inorganic pigment such as calcium carbonate is added for the purpose of ensuring the substrate hiding property and reducing the content of combustibles to reduce the calorific value.
As a method of applying the undercoat paint, a method using a roll coater, a flow coater, or the like can be mentioned. Among them, the roll coater is suitable in consideration of the effect of filling the large and small uneven portions and voids existing on the substrate surface with the paint. There is. Further, from the viewpoint of uniformly applying the paint, a flow coater is suitable.

In the present invention, the amount of the organic solid content contained in the undercoat layer is preferably set to 3 to 70 g, preferably 3 to 45 g, and more preferably 5 to 35 g per unit area (m ² ) of the substrate.
Further, the undercoat layer needs to have a property of firmly hardening the fluff from the substrate surface so as not to appear on the surface after polishing, and as a guideline, the surface hardness of the undercoat layer is H to 3H in pencil hardness. It is preferable to have. If the surface hardness is less than H, the fluff on the surface may remain during polishing, and the hardness of the entire decorative layer is insufficient, resulting in fragility. On the other hand, if the surface hardness exceeds 3H, the undercoat layer is too hard to follow the movement of the substrate, which causes cracks in the decorative layer. Here, the pencil hardness indicates the scratch hardness by the pencil method based on JIS K 5600-5-4: 1999.

The undercoating for forming the undercoat layer may be performed once to form an undercoat layer having a predetermined film thickness, or may be performed twice or more to form an undercoat layer having a predetermined film thickness. For example, when the undercoat coating is performed twice to form an undercoat layer having a predetermined film thickness, the amount of ultraviolet rays irradiated when the undercoat paint is cured by irradiating with ultraviolet rays after the first undercoat coating is performed. It is adjusted so that it does not completely cure, and after a second undercoat coating is applied, ultraviolet rays are irradiated again to completely cure the entire undercoat paint. Further, when the undercoat coating is applied three times or more, the entire undercoat paint is completely cured by ultraviolet irradiation after the final undercoat coating, as in the case of the two times. In the decorative board of the present invention, it is important to suppress the conduit groove pattern and fluffing, and to secure nonflammability. From this point of view, in order to efficiently obtain the effect of filling the large and small uneven parts and voids existing on the substrate surface with the paint and the effect of suppressing the conduit groove pattern and fluffing, the undercoat layer is coated twice. It is good to form a coating film.

Next, the surface of the undercoat layer is polished. Examples of the grinding machine to be used include a wide belt sander, a polisher grinding machine, a felt grinding machine, a buff grinding machine, a brush grinding machine, etc. Machine is preferred. A platen polishing machine is a kind of wide belt sander, and the polishing target is advanced in a state where an endless belt-shaped polishing paper driven around is pressed against the polishing target using a flat plate (push plate) called a platen. It is to be polished. For the final polishing of the undercoat layer, it is preferable to polish with an abrasive having a count (grain size of the abrasive) of 40 to 100. This makes it possible to effectively form the conduit groove pattern. Coarse abrasives with a count of 40 or less are not suitable for interior materials because the surface after polishing becomes too rough, and fine abrasives with a count of 100 or more make the surface after polishing too smooth, resulting in a good wood texture. The conduit groove pattern for obtaining is not obtained. The final polishing of the undercoat layer is more preferably performed using a No. 40 to 80 abrasive.

Further, by performing polishing a plurality of times, a more designable appearance can be obtained. When polishing is performed multiple times, the polishing is performed in order from the finest abrasive material. By polishing in order from the finest abrasive material, the surface becomes smooth once, so the conduit groove pattern when polishing with the coarser abrasive material at the end is further emphasized, and it is possible to ensure a good appearance. Become. Further, once the surface is smooth, the design of each coating film formed on the surface is improved.
Further, when the undercoat layer is formed in a plurality of times, the undercoat layer may be polished only on the surface after all the undercoat coatings are finished, or the surface may be polished each time the undercoat is applied and cured (semi-cured). Polishing can also be performed.

The surface roughness of the undercoat layer after polishing needs to be a streak-shaped polished surface along the longitudinal direction of the substrate from the viewpoint of forming a conduit groove pattern, and is in a direction parallel to the longitudinal direction of the substrate (hereinafter, parallel direction). It is preferable that each value of Ra (arithmetic average roughness) and Rz (maximum height) is in the following range in each of the directions orthogonal to the longitudinal direction of the substrate (hereinafter, orthogonal direction).
Ra in the parallel direction is preferably 0.5 to 4 μm, more preferably 1 to 3 μm, and Rz in the parallel direction is preferably 5 to 30 μm, preferably 10 to 25 μm. Is more preferable. Further, Ra in the orthogonal direction is preferably 5 to 15 μm, more preferably 5 to 10 μm, and Rz in the orthogonal direction is preferably 35 to 70 μm, more preferably 40 to 60 μm. preferable.

In the present invention, the surface roughness measurement is a value measured using a stylus type surface roughness measuring instrument compliant with JIS B 0651: 2001.

The decorative board of the present invention has a colored layer having a film thickness of 5 to 50 μm on the upper layer of the undercoat layer. By forming the colored layer, the decorative board of the present invention has good appearance, cosmeticity (design), and substrate hiding property (the color of the substrate itself hides the decorative board so as not to affect the appearance of the decorative board). Can be granted. The film thickness of the colored layer needs to be 5 to 50 μm in order to impart the above-mentioned characteristics, and is more preferably 10 to 40 μm. If the film thickness is less than 5 μm, good appearance, cosmeticity (design), and substrate hiding property cannot be imparted, and if it exceeds 50 μm, the amount of paint applied increases, so the paint is applied to the painted surface in the process of forming the colored layer. The surface of the decorative board is different from the conduit groove pattern formed by polishing the undercoat layer, because unevenness occurs and unevenness occurs in the colored layer, and bubble traces tend to remain inside or on the surface of the colored layer. In the present invention, the appearance tends to be deteriorated due to unintended unevenness, which is not preferable.

The paint used to form the colored layer is from the viewpoints of coating workability, coating dryness after coating, safety, durability after coating, coating surface hardness, and chemical resistance and stain resistance of the coating. , Acrylic resin paint, urethane resin paint, acrylic urethane resin paint and the like are preferable, among which acrylic urethane resin paint is preferable, and two-component curable acrylic urethane resin paint is more preferable.
Further, a paint containing a relatively high concentration of pigment is preferable. The pigment is preferably contained in an amount of 30 to 60% by mass based on the total solid content in the coating material, whereby good coloring property can be obtained, and it can be said that it is also preferable from the viewpoint of base material hiding property. As a method for forming the colored layer, coating with a roll coater or a flow coater is suitable, and in the case of recoating in two or more times, these may be appropriately combined and used.
Further, after the colored layer is formed, the surface thereof can be polished by buffing or the like. By buffing, it is possible to improve the formability, cosmetic properties, etc. of the print layer and the topcoat layer provided on the upper layer.

In the present invention, the amount of the organic solid content in the components of the colored layer is preferably set to be 5 to 35 g per unit area (m ² ) of the substrate, and more preferably 10 to 30 g.

In the decorative board of the present invention, a printing layer is provided between the colored layer and the topcoat layer. This printing layer gives a wood grain pattern to the decorative board. When the wood grain pattern is imparted by the print layer, it can be formed by one printing or two or more times. By repeating printing a plurality of times, it becomes possible to express the shadow of the wood grain pattern in more detail, and the appearance becomes better.

The paint for forming the print layer may be any paint that can form shapes such as patterns and letters, and contains, for example, pigments, acrylic resins, urethane resins, resins such as acrylic urethane resins, solvents, and additives. Paint can be mentioned. As the coating means, gravure printing, gravure offset printing, inkjet printing, screen printing, rotary screen printing, letterpress printing, and pad printing are preferable. The amount of the organic solid content in the printed layer is preferably 0.03 to 10 g, more preferably 0.1 to 7 g per unit area (m ² ) of the substrate from the viewpoint of ensuring the formability of patterns and the like and nonflammability. Further, it is preferable not to perform polishing after forming the print layer.

By combining the colored layer and the printed layer, the difference in tree species can be expressed. By combining the shades of the colored layer and the printed layer, it is possible to express a good wood surface and grain appearance that resembles the board material of some characteristic tree species. Furthermore, in the wood grain pattern on the printing layer, the same pattern is continuous even when the decorative board is continuously applied as an interior finishing material for buildings such as walls or ceilings by making the pattern without knots. It is hard to notice that it is being constructed, and it is hard to get a monotonous and cheesy wood grain pattern.

The top coat layer of the decorative board of the present invention is preferably a clear paint from the viewpoint of making the wood grain of the lower layer easy to see. The clear paint is not particularly limited, but is acrylic urethane resin-based, polyester resin-based, alkyd resin-based, polyether resin-based, acrylic resin-based, epoxy resin-based, urethane resin-based, silicon resin-based transparent resin paint, and polybutadiene. A transparent resin paint made of a UV curable resin such as a mixture of an ultraviolet polymerizable compound having a radically polymerizable unsaturated double bond and a photoinitiator such as a resin or a mixture of a cationic ring-opening polymerization type compound and a photoinitiator. Further, a transparent resin paint made of a heat-curable resin such as acrylic urethane resin-based, acrylic silicone resin-based, acrylic resin-based, epoxy resin-based, urethane resin-based, silicon resin-based, and fluororesin-based resin is preferable.
Further, a matting agent is added to the clear paint used for the topcoat layer in order to suppress the gloss on the surface and improve the texture. As the matting agent, fine powder of amorphous synthetic silica is preferred from the viewpoint of ensuring chemical stability and transparency, and it is particularly preferable to use fine powder silica synthesized by a wet method. The amount of the matting agent added is preferably 1 to 6% by mass, more preferably 1 to 3% by mass, based on the solid content in the clear paint. The average particle size of the matting agent is preferably 1 to 10 μm.

Further, by incorporating the resin beads in the clear paint used for the topcoat layer, the surface of the formed topcoat layer can be given an expression due to fine irregularities, and the conduit groove pattern formed by polishing the undercoat layer can be made more wood. It is possible to have a textured appearance. As the resin beads to be used, spherical particles made of acrylic resin, silicon resin, nylon resin, polyethylene resin, urethane resin and the like are preferable, and acrylic resin beads are particularly preferable because they have transparency and appropriate elasticity, and particularly crosslinked polymethacrylic. Methyl acid acid resin beads are preferred.
The average particle size of the resin beads is preferably 5 to 40 μm, and more preferably, a more natural uneven surface can be obtained by using two or more kinds of resin beads having a relatively large particle size and resin beads having a relatively small particle size. It is possible to form a topcoat layer having. For example, two types of large beads having an average particle size of 20 to 40 μm and small beads having an average particle size of 5 to 10 μm are mixed and used, and the ratio of small beads to large beads is 1.1 to 1.6 times the mass ratio. By doing so, it becomes a natural uneven surface. It can be expected that a slightly higher proportion of small beads will result in a more natural uneven surface.
The content of the resin beads is preferably 5 to 20% by mass, more preferably 5 to 15% by mass, based on the total solid content of the clear paint. If the content of the resin beads is less than 5% by mass, a sufficient unevenness cannot be obtained, and if it exceeds 20% by mass, an unnatural roughness appears, so that a good wood texture cannot be obtained.

Examples of the clear paint include those containing, for example, a wetting dispersant, a settling inhibitor, an antifoaming agent, a leveling agent, etc. as other additives, and, for example, butyl acetate, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, etc. as a solvent. As a method of applying the paint, the flow coater method is preferable from the viewpoint that it is easy to express a natural wood texture, but in addition, existing methods such as a roll coater method and a spray method may be used.

The amount of organic solids in the topcoat layer is preferably 10 to 50 g, more preferably 10 to 40 g, and the film thickness per unit area (m ² ) of the substrate, from the viewpoint of ensuring the appearance such as a pattern and ensuring nonflammability. It is preferably 10 to 50 μm, more preferably 10 to 40 μm. If the film thickness exceeds 50 μm, the amount of topcoat paint applied becomes too large, so leveling progresses in the coating process and the unevenness is diminished. If the film thickness is less than 10 μm, sufficient coating film performance and good appearance are ensured. It will be difficult.

Further, by adding various functional additives to the clear paint used for the topcoat layer, it is possible to impart various properties to the topcoat layer, for example, various antibacterial properties, antiviral properties, scratch resistance and the like. It can be a decorative board with an added function.

The decorative board of the present invention has a total calorific value of 8 MJ / m ² or less in the heat generation test. By satisfying this requirement, the exothermic first grade (heating time 20 minutes) specified in JIS A 5430: 2013 is satisfied, and high nonflammability is exhibited. A more preferable total calorific value is 7.2 MJ / m ² or less.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples.

(1) Calcium silicate board (board)
As a substrate, A & A Material Co., Ltd., which is a calcium silicate plate having a bulk density of 0.8 g / cm ³ in accordance with "Calcium silicate plate type 2 0.8 calcium silicate plate" in Table 1 of JIS A 5430: 2013. A high rack (size: 1820 mm × 910 mm × 6 mm) was used. The substrate used was one in which the surface (hereinafter referred to as the surface) on which the decorative layer was formed was smoothed in advance by polishing with a polishing paper having a count of 100 using a platen polishing machine. The polished substrate surface had a pencil hardness of 5B.

(2) Paint Each painting was performed using the following paint.
Impregnated sealer: V-selan # 100NS sealer manufactured by Dai Nippon Toryo Co., Ltd.
(Polyurethane resin sealer)
Undercoat layer paint: Modified epoxy resin paint (ultraviolet curable type)
The composition of the paint is 50% organic and 50% inorganic.
Colored layer paint: Ubi Mild 54F walnut manufactured by NATCO
(Two-component curable acrylic urethane resin paint)
Printing layer paint: NT ink M walnut manufactured by NATCO
(Acrylic resin gravure ink)
Topcoat layer paint: Two-component curable acrylic urethane resin-based clear paint
Of the total solid content in the paint, wet method silica: average particle size of about 4 μm is about 1.5% by mass, resin beads: average particle size of 30 μm is about 4% by mass, resin beads: average particle size of 8 μm is about 5% by mass. %, Each is contained. All of these average particle sizes are values obtained by the Coulter counter method (AP tube 50 μm).

Example 1
Example 1
An impregnated sealer of about 30 g / m ² was applied to the surface of the substrate using a roll coater to form an impregnated sealer layer having an organic solid content of about 30 g / m ² on the surface of the substrate.
Next, about 120 g / m ² of the undercoat paint was applied to the surface side of the substrate using a roll coater, the coating film was cured by ultraviolet irradiation, and the coating film was polished by a platen polishing machine. The surface hardness after curing of the undercoat paint was a pencil hardness of 2H. Polishing was first performed using a polishing paper having a count of 240, and then polishing using a polishing paper having a count of 60 to form an undercoat layer having a film thickness of about 40 μm. Further, as a coloring layer from above the undercoat layer, about 110 g / m ² of the coloring layer paint is applied using a flow coater, and after standing, the coating film is cured with a hot air dryer, and then a buffing machine is used. The surface of the colored layer was polished with a number 1000 baflor to form a colored layer having a film thickness of about 26 μm and an organic solid content of about 30 g / m ² .
Next, as a printing layer, a wood grain pattern printing layer having a thickness of about 1 μm or less and an organic solid content of about 5 g / m ² was formed on the surface of the colored layer by using a gravure offset printing machine. Furthermore, about 80 g / m ² of clear paint was applied to the surface after printing using a flow coater, and after standing, the coating film was cured in a hot air drying oven. The thickness of the coating film was about 21 μm and the organic solid content was about 28 g. A veneer was made by forming a / ^m2 topcoat layer.

Comparative Example 1
The undercoat layer was polished in the same manner as in Example 1 except that it was first polished with a polishing paper having a count of 240 and then polished using a polishing paper having a count of 400.

Reference example 1
An impregnated sealer of about 30 g / m ² was applied to the surface of the substrate using a roll coater to form an impregnated sealer layer having an organic solid content of about 30 g / m ² on the surface of the substrate.
Next, about 120 g / m ² of the undercoat paint was applied to the surface side of the substrate using a roll coater, the coating film was cured by ultraviolet irradiation, and the coating film was polished by a platen polishing machine. Polishing was performed first using a polishing paper having a count of 240, and then polishing using a polishing paper having a count of 60 to form an undercoat layer having a film thickness of about 40 μm, which was then polished in Example 1. It was up to the formation of the undercoat layer.

Reference example 2
In the polishing of the undercoat layer, the same as in Reference Example 1 except that first polishing is performed using a polishing paper having a count of 240 and then polishing is performed using a polishing paper having a count of 400. It was up to the formation of a polished undercoat layer.

About Example 1, Comparative Example 1 and Reference Example 1 and 2 Using a surface roughness measuring machine (SurfTest SJ-400 (manufactured by Mitutoyo Co., Ltd.)) compliant with JIS B 0651-2001, the surface roughness is as follows. Was measured. Each value of Ra and Rz is an average value calculated from the values measured three times in the polishing direction of the undercoat layer and the direction orthogonal to the (longitudinal direction of the substrate). The measured waveforms of the surface roughness are shown in FIGS. 1 to 4.
Measurement length: 15.0 mm
Cutoff: 2.5 mm
Measurement speed: 1.5 mm / s
Measurement range: 800 μm

The surface condition of the painted surface was visually and tactilely observed. The state of the conduit groove pattern and the presence or absence of fluffing were evaluated, and for the state of the conduit groove pattern, it was visually and tactilely observed whether the wood texture was expressed by an appropriate conduit groove pattern. Regarding the presence or absence of fluffing, the presence or absence of fluffing on the substrate was judged visually and by touch. For Example 1 and Comparative Example 1, the calorific value was measured according to JIS A 5430: 2013 Annex JA as an evaluation of nonflammability.

The obtained evaluation results are shown in Table 1.

As is clear from Table 1, in Example 1, a coloring layer, a printing layer, and a topcoat layer to which resin beads are added are provided on the upper layer of the fluff-free undercoat layer that imitates a conduit groove having a large roughness in the orthogonal direction. This made it possible to express a good wood texture. As can be seen from the roughness measurement waveform in FIG. 2, the groove pattern seen in the orthogonal direction is due to the rough polishing of the undercoat layer, and the large and small convex patterns seen in the parallel direction are brought about by the resin beads contained in the topcoat layer. By these synergistic effects, it was possible to impart a good wood texture to the surface of the decorative board.
However, if a coloring layer, a printing layer, and a topcoat layer to which resin beads are added are provided on the upper layer of the smooth undercoat layer as in Comparative Example 1, the surface is simply flat and rough, but is good. I couldn't express the texture of wood. As can be seen from the roughness measurement waveform in FIG. 3, although large and small convex patterns due to resin beads can be seen on the flat surface, there is no difference between the parallel direction and the orthogonal direction and it is monotonous, and it is not possible to express the wood texture. rice field.

Further, in Reference Example 1, fluffing is suppressed by applying an undercoat paint to the surface of the substrate and then polishing, and by finishing with a coarse polishing paper at the time of polishing, as can be seen from the roughness measurement waveform in FIG. The surface had a streak pattern with large irregularities only in the orthogonal direction. Therefore, it can be said that an undercoat layer suitable for expressing a wood texture imitating a conduit groove could be formed. On the other hand, in Reference Example 2, fluffing is suppressed, but as a result of finishing with fine abrasive paper, as can be seen from the roughness measurement waveform in FIG. 5, there is no difference in roughness in the parallel direction and the orthogonal direction, and it is simply The surface was highly smooth. Therefore, it can be said that the undercoat layer was not suitable for expressing the texture of wood.

Regarding nonflammability, in both Example 1 and Comparative Example 1, the total calorific value for 20 minutes was 8 MJ / m ² or less, which was equivalent to the exothermic first grade. This is because the substrate and the coating film composition are almost the same, so there is no difference.

As described above, according to the method for manufacturing a ceramic decorative board of the present invention, it is possible to improve the wood texture by the undercoat layer that suppresses fluffing of the substrate and the expressive decorative layer, and further excellent nonflammable performance is achieved. It is possible to manufacture a ceramic-based decorative board to have.

1: Substrate 2: Sealer layer 3: Undercoat layer 4: Colored layer 5: Printing layer 6: Topcoat layer 7: Resin beads (large beads)
8: Resin beads (small beads)

Claims (3)

A method for manufacturing a ceramic-based decorative board in which a sealer layer, an undercoat layer, a coloring layer, a printing layer, and a topcoat layer are formed in this order on at least one surface of a ceramic-based substrate, wherein the undercoat layer is coated with an undercoat paint. The surface cured by the process is roughly polished and formed along the longitudinal direction of the ceramic substrate so as to form innumerable streaks, and the topcoat layer is coated with a clear paint containing resin beads and synthetic silica using a flow coater. A method for manufacturing a ceramic decorative board, which is characterized in that it is formed in a ceramic manner. The surface roughness after the undercoat layer is formed is such that the Ra value in the direction parallel to the longitudinal direction of the ceramic substrate is 0.5 to 4 μm and the Rz value is 5 to 30 μm, and the Ra value in the orthogonal direction is the same. The method for producing a ceramic decorative board according to claim 1, wherein the value is 5 to 15 μm and the value of Rz is 35 to 70 μm. As the resin beads, at least two types of large beads having an average particle size of 20 to 40 μm and small beads having an average particle size of 5 to 10 μm are mixed and used, and the ratio of the small beads to the large beads is 1. The ceramic system according to any one of claims 1 or 2, wherein the resin beads are contained in an amount of 1 to 1.6 times and 5 to 15% by mass based on the total solid content of the clear paint. How to make a veneer.

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