JP2022153820A - Decorative laminate - Google Patents

Abstract

To provide a decorative laminate that has sufficiently enhanced surface hardness and maintains incombustibility without any special operation, such as baking finish to stick a special decorative sheet.SOLUTION: A decorative laminate includes two or more decorative layers on at least one surface of a base plate. An outermost decorative layer of the plurality of decorative layers and/or a decorative layer immediately below the outermost decorative layer is formed by a coating composition containing 35-90 mass% of glass beads in terms of a solid content.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a decorative board used for interiors and the like.

BACKGROUND ART Conventionally, various decorative panels have been used for interior finishing of buildings. Decorative boards include decorative boards having substrate surfaces coated with various types of paint such as urethane resin-based paints, acrylic resin-based paints, and epoxy resin-based paints, and decorative boards having sheets or films adhered to substrates. These veneers are subject to scratches and dents when struck by hard objects, which are often difficult to repair. Therefore, a high surface hardness is required to maintain the design for a long period of time.
On the other hand, these veneers are required to meet the standard of noncombustible certification under the Building Standards Law in order to ensure safety in the event of a fire or the like.

As a method for improving the surface hardness of a decorative board, there is a method of providing a sealer layer on a substrate (Patent Document 1). However, it was difficult to obtain sufficient surface hardness only by providing the sealer layer. In order to obtain a higher surface hardness, there is also a method of applying a top coat containing glass beads to a high-density base paper and a coating film (Patent Document 2). In addition, depending on the type of base material to which the sheet is attached and the type of adhesive used when bonding the base material and the sheet, there is a problem that the non-combustibility of the laminated decorative board cannot be ensured.
There is also a method of obtaining a high-hardness coating film surface with only a top coat (Patent Document 3), but this method requires a baking treatment, and the substrate temperature at that time reaches 200 to 300 ° C., so pulp or the like is used. However, it was difficult to apply it to a ceramic-based decorative board containing organic fibers.

JP 2012-210742 A JP-A-2000-218735 JP-A-08-183926

Accordingly, an object of the present invention is to provide a decorative board having a sufficiently high surface hardness and ensuring noncombustibility without performing special operations such as bonding a special decorative sheet or baking treatment.

Therefore, the present inventors have made various studies to increase the surface hardness while ensuring nonflammability. The present inventors have found that by forming a decorative board with a coating composition that is capable of improving the surface hardness remarkably and ensuring noncombustibility, the present invention has been completed.

That is, the present invention provides the following inventions [1] to [5].
[1] A decorative board having two or more decorative layers on at least one surface of a substrate, wherein the outermost decorative layer of the plurality of decorative layers and/or the decorative layer immediately below the decorative layer contains 35 mass of glass beads per solid content. % or more and 90% or less by mass of a coating composition.
[2] The decorative board according to [1], wherein the glass beads have an average particle size of 5 μm or more and 60 μm or less.
[3] The decorative board according to [1] or [2], wherein the shape of the glass beads is spherical or irregular.
[4] The decorative board according to any one of [1] to [3], which is a decorative board for interior use.
[5] The decorative board according to any one of [1] to [4], which is a ceramic-based decorative board.

The decorative board of the present invention is useful as a decorative board for interior decoration because it has sufficiently high surface hardness to prevent scratches and dents and has noncombustibility.

The decorative board of the present invention is a decorative board having two or more decorative layers on at least one surface of a substrate, wherein the outermost decorative layer of the plurality of decorative layers and/or the decorative layer immediately below solidifies glass beads. It is characterized by being formed from a coating composition containing 35% by mass or more and 90% by mass or less per minute.

As the substrate of the decorative board of the present invention, the substrate of the decorative board for interior use, particularly the substrate of the ceramic-based decorative board is preferable because of its noncombustibility.
Substrates for ceramic-based decorative boards include fiber-reinforced cement boards (including calcium silicate boards) that form the walls of houses, wood-based cement boards, wood wool cement laminates, volcanic vitreous double-layer boards, and extrusion molding. Examples include cement plates, slag gypsum plates, lightweight cellular concrete plates, glass plates, and ceramic plates.
Of these substrates, fiber reinforced cement boards are more preferred.

These substrates, for example, use hydraulic cement such as Portland cement as the main raw material for forming the matrix, use fibers other than asbestos as the fiber raw material, and if necessary, wollastonite, calcium carbonate powder, etc. It is preferable that the substrate uses the admixture of (1) as a raw material. In particular, 0.8 calcium silicate board and 1.0 silicate board, which are a kind of fiber reinforced cement board obtained by using a lime raw material and a silicic raw material as raw materials for forming a matrix, and performing autoclave curing in the curing process. A calcium acid plate is a substrate having excellent flexibility, high strength, and a small rate of change in length due to water absorption.

Examples of the fiber raw material include pulp, synthetic pulp, polypropylene fiber, rayon fiber, acrylic fiber, vinylon fiber, nylon fiber, organic fiber such as polyester fiber, steel fiber (steel wire fiber), metal fiber such as amorphous metal fiber, Inorganic fibers such as glass fiber, carbon fiber (carbon fiber), rock wool fiber, and whiskers can be used. It is preferable to use pulp from the viewpoint that it can be improved. The pulp referred to here is a state in which cellulose is extracted by mechanically or chemically treating plant raw materials such as wood, and refers to so-called cellulose pulp.
The content ratio of fibers, particularly organic fibers such as pulp, in the fiber-reinforced cement board varies depending on the matrix, but from the viewpoint of ensuring strength and noncombustibility, it is preferably 5 to 9% by mass, and 6 to 8% by mass. % is more preferred. If the content ratio of organic fibers such as pulp is small, the mechanical strength of the decorative board is lowered, and cracks due to heat load, drying, carbonation, and impact are likely to occur. Conversely, if the content of organic fibers such as pulp is high, it becomes difficult to maintain noncombustibility.

As the hydraulic cement, any one commonly used in the industry may be used, and examples thereof include Portland cement.
Various additives that are used as necessary include those commonly used in the industry, and are not particularly limited. Examples include powdered scraps of cucumber boards. In the case of autoclave curing, silicic raw materials such as crystalline silica such as powdered silica, amorphous silica such as fly ash, etc. are used because the strength is further increased by hydrothermal reaction hardening with lime in cement. is added, and if necessary, a calcareous raw material such as quicklime, slaked lime, etc. is added to adjust the CaO/SiO ₂ molar ratio of the matrix component to 0.7 to 1.2. preferable.

In the present invention, the thickness of the substrate is preferably 3 to 12 mm, more preferably 4 to 8 mm, from the viewpoints of impact resistance, lightness and workability.

In the present invention, the bulk density of the substrate is preferably 0.6 to 1.8 g/cm ³ and more preferably 0.6 to 1.2 g/cm ³ from the viewpoints of lightness, mechanical strength and workability. is more preferred.

In the present invention, the total calorific value of the substrate is preferably 5 MJ/m ² or less, more preferably 4.7 MJ/m ² or less, from the viewpoint of noncombustibility.

In the present invention, the thickness of the substrate or decorative plate is a value measured according to JIS A 5430:2013, Section 9.2.2 b). Bulk density is a value measured according to JIS A 5430:2013, Section 9.5.
The total calorific value of the substrate is a value measured according to JIS A 5430:2013, Annex JA.

The decorative sheet of the present invention has two or more decorative layers on at least one surface of the substrate.
In the case of an interior decorative board, particularly a ceramic decorative board, a sealer layer, an undercoat layer, a colored layer, a clear layer and the like are usually applied from the surface of the substrate as the decorative layer. In some cases, a clear layer is provided on the colored layer, but in some cases, an enamel paint containing a pigment is used as the colored layer, and the clear layer is not provided on the surface thereof.
In the present invention, the outermost decorative layer of the plurality of decorative layers and/or the decorative layer immediately below it is formed of a coating composition containing 35% by mass or more and 90% by mass or less of glass beads based on the solid content. Therefore, the outermost decorative layer of the present invention usually corresponds to the colored layer or the clear layer. In addition, the decorative layer immediately below it usually corresponds to a colored layer or an undercoat layer. Specifically, when the undercoat layer and/or the colored layer is formed with a coating composition containing the glass beads, the colored layer and/or the clear layer may be formed with a coating composition containing the glass beads. . However, when a printed layer is provided between the colored layer and the clear layer to be described later, the printed layer does not touch the decorative layer immediately below.
Furthermore, a colored layer can be overcoated on the colored layer. In this case, either the colored layer on the substrate side or the colored layer on the surface side, or the colored layer on the substrate side A coating composition containing the glass beads may be used for both of the colored layers on the surface side. Furthermore, it is possible to provide a clear layer formed of a coating composition containing or not containing the glass beads on the colored layer formed of the coating composition containing the glass beads.
The content of glass beads in the coating composition is the content of glass beads per solid content of the coating composition used for forming each layer.

Next, the sealer layer, the undercoat layer, the colored layer, and the clear layer, which are decorative layers, will be described.
A sealer layer is preferably provided between the substrate of the decorative sheet and the undercoat layer. By providing the sealer layer, the surface layer of the substrate can be strengthened, the elution of alkali to the surface can be prevented, and the adhesion with the undercoat layer which is the upper layer can be improved.
The sealer layer can be formed using a known sealer, for example, by using a curable resin such as a moisture-curable urethane resin or an epoxy resin, applying it to the surface of the substrate and curing it. The sealer has good impregnation to the substrate, high non-volatile content, three-dimensional cross-linking by reacting with moisture in the substrate and atmospheric moisture, and good water resistance etc. Polyisocyanate or reaction of polyisocyanate and polyol Moisture-curable urethane systems based on prepolymers with free isocyanate groups and solvents such as butyl acetate are preferred. Moreover, when yellowing as a decorative board becomes a problem, it is preferable to use aliphatic isocyanates, such as HDI (hexamethylene diisocyanate), and alicyclic isocyanates, such as IPDI (isophorone diisocyanate). In addition, from the viewpoint of recent VOC countermeasures, it is recommended to use solvent-free sealers or water-based sealers that do not contain solvents, inorganic sealers such as silicate-based sealers such as lithium silicate or sodium silicate, tetraethoxysilane, etc. A silane compound sealer containing tetramethoxysilane or the like 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 sealer by a known roll coater, spraying method or the like, and then curing. The viscosity of the impregnating sealer can be appropriately determined in consideration of the type of impregnating sealer to be used and the coating method, and curing can be performed, for example, by heating and drying.
The amount of organic solids in the impregnation sealer component is preferably set to 3 to 50 g per unit area (m ² ) of the substrate.

A decorative board usually has an undercoat layer on the surface of the sealer layer. By forming the undercoat layer, large and small irregularities and gaps existing on the surface of the substrate are filled with the paint, and unevenness and variation in gloss and color due to uneven absorption of the paint are suppressed. It also reduces the possibility of defects such as pinholes in the decorative laminate.

The film thickness of the undercoat layer is 5 to 100 μm. prevention, coating film curability, surface foreign matter burying property, and ease of film thickness control. A more preferable film thickness is 20 to 90 μm, more preferably 25 to 70 μm.
As used herein, the film thickness of a coating layer formed from a coating composition containing glass beads is the thickness of a region with a flat surface that is not affected by projections formed by glass bead particles. be.

From the viewpoint of surface smoothness, chemical resistance, coating adhesion, polishing workability, coating hardness, ease of coating, and crack prevention, the coating composition for forming the undercoat layer is an unsaturated polyester-based coating and / Or acrylate-based paints are preferred, specifically epoxy acrylate, urethane acrylate, allyl-based unsaturated polyester such as diallyl phthalate, polycondensation of unsaturated dibasic acid such as maleic anhydride and fumaric acid, and glycols. Maleic acid-based unsaturated polyester by, polyester monoacrylate having a carboxyl group or hydroxyl group as a functional group, polyester diacrylate obtained from acrylic acid, dibasic acid and dihydric alcohol, polyhydric alcohol of 3 or more valences and dibasic acid Examples include polyester acrylates such as polyester polyacrylates obtained from acrylic acid, epoxy acrylate oligomers, oligomers such as epoxy oligomers, acrylic polyethers, polyether acrylates, and the like. In addition, the coating composition for forming the undercoat layer is an ultraviolet curable coating, because of the ease of coating, the fast curing speed of the coating film, the grindability and durability of the coating film, the substrate and the top coating It is preferable because it has excellent adhesion with.

Examples of the method of applying the undercoat paint composition include a method using a roll coater, a flow coater, etc. Among them, considering the effect of filling the large and small irregularities and voids on the substrate surface with the paint, the roll coater is preferred. Are suitable. A flow coater is suitable from the viewpoint of uniform application of paint.

In the present invention, the amount of organic solids contained in the undercoat layer is preferably 3 to 70 g, more preferably 10 to 65 g, and still more preferably 13 to 60 g per unit area (m ² ) of the substrate.
In this specification, the amount of organic solids contained in the coating film layer is obtained by coating amount (g/m ² ) × solid content of coating composition (%) × amount of organic component in solid content of coating composition (%). can be done.

The undercoat coating for forming the undercoat layer can be applied once to form an undercoat layer having a predetermined thickness, or can be applied twice or more to form an undercoat layer having a predetermined thickness. For example, when forming an undercoat layer of a predetermined thickness by applying the undercoat twice, first apply the first undercoat with a slightly high-viscosity undercoat (200 to 600 dPa s), and then reduce the amount of UV irradiation. Apply UV light so that it does not harden completely, then apply a second primer coat with a slightly less viscous primer (20-60 dPa・s), then irradiate again with UV light to completely cure the entire primer coat. It is best to let it harden completely. By doing so, the first undercoat has the effect of filling large and small irregularities and voids on the substrate surface with the paint, and the second undercoat has a self-leveling effect that smoothes the coating surface of the undercoat layer. is obtained, a good undercoat layer can be efficiently formed. Further, the undercoat layer can be made to have a smoother surface by polishing with a belt sander or the like after completely curing the undercoat paint.

A colored layer is provided on the surface of the undercoat layer. The thickness of the colored layer is preferably 5 to 70 μm, more preferably 10 to 65 μm, even more preferably 15 to 60 μm.

Examples of inorganic coloring pigments contained in the coating composition forming the colored layer include titanium oxide, zinc white, red iron oxide, ocher, chromium oxide green, Prussian blue, carbon black, and iron black. It is more preferable to use one or a combination of two or more. Moreover, an organic pigment can also be used together as needed.
As the coating composition for forming the colored layer, an organic solvent-based coating or a water-based coating can be used. Among them, acrylic urethane resin paint is preferable, and it is more preferable to use two-liquid curable acrylic urethane resin paint. Moreover, paints such as epoxy resin paint, polyurethane resin paint, vinyl chloride resin paint, vinylidene chloride resin paint, acrylic silicone resin paint, and fluorine resin paint may be used.

The method of forming the colored layer is not particularly limited, and can be selected from known methods used in ordinary coating such as spray method, roll coater method and flow coater method. These may be used in combination as appropriate when two or more separate coatings are applied.

In the present invention, the organic solid content in the components of the colored layer is preferably set to 5 to 40 g per unit area (m ² ) of the substrate, more preferably 10 to 35 g, more preferably 10 to 30 g. is more preferred.

The decorative board may provide a clear layer on the surface of the colored layer. The thickness of the clear layer is preferably 1 to 70 μm, more preferably 1 to 65 μm, even more preferably 3 to 60 μm.

The coating composition for forming the clear layer can be an organic solvent-based coating or a water-based coating. Colorless transparent resins such as mold resins, other additives such as wetting and dispersing agents, anti-settling agents, antifoaming agents and leveling agents, and solvents such as butyl acetate and ethyl acetate can be used. Among them, it is preferable to use a clear paint using an acrylic silicone-based or acrylic urethane-based resin, which is excellent in weather resistance and stain resistance.

Existing methods such as flow coater, roll coater and spray coater can be applied to the coating method for forming the clear layer. The dry coating amount of the clear layer is preferably 1 to 160 g, more preferably 2 to 140 g per unit area (m ² ) of the substrate. The amount of organic solids in the clear layer is preferably 1 to 45 g, more preferably 2 to 35 g, even more preferably 3 to 30 g per unit area (m ² ) of the substrate from the viewpoint of ensuring noncombustibility.

In the present invention, the outermost decorative layer of the plurality of decorative layers and/or the decorative layer immediately below it is formed of a coating composition containing 35% by mass or more and 90% by mass or less of glass beads based on the solid content. and Specifically, as described above, when the undercoat layer and/or the colored layer are formed from a coating composition containing glass beads, the colored layer and/or the clear layer are formed from a coating composition containing glass beads. Sometimes.
Among these, in order to maintain the superior hardness of the decorative board coating film, it is more preferable to form the colored layer and/or the clear layer with a coating composition containing glass beads. More preferably, it is formed from a coating composition containing beads.
In addition, by forming a colored layer and a clear layer with a coating composition containing glass beads on a colored layer formed with a coating composition that does not contain existing glass beads, a coating composition that does not contain existing glass beads Surface hardness can be improved more than a colored layer formed of a material.

The glass beads to be contained in the coating composition used for forming these decorative layers may be silicate glass beads, and the shape may be spherical or irregular. These glass beads can be used not only for fillers, but also for road marking paints, blasting, crushing/dispersing, etc., and two or more of them can be used in combination.
Commercially available glass beads include CF0002, CF0003, CF00017, CF0018, CF0027, CF00033, CF0093 (manufactured by Takara Standard Co., Ltd.), GB301S, GB731, GB210, EGB063Z, EGB731, EGB210, EMB-20, EMB-10. (manufactured by Potters Barrotini Co., Ltd.), UBS-0020L, UBS-0030L, UBS-02L, UBS-0010E, UBS-0020E, UBS-0030E, UB-02E (manufactured by Unitika Ltd.), etc. and the surface of these glass beads may be treated with a silane coupling agent such as aminosilane, glycidoxysilane, acrylsilane, or the like.
The average particle size of the glass beads is preferably 5 μm or more and 60 μm or less, more preferably 5 μm or more and 50 μm or less, even more preferably 5 μm or more and 45 μm or less, and 10 μm or more and 40 μm or less, from the viewpoint of improving the hardness of the decorative board coating film. Even more preferable.
Here, the average particle size of the glass beads is measured by employing, for example, a measurement method utilizing image analysis using an electron microscope image, a sieving method, a Coulter counter method, an electrical detection zone method, a sedimentation method, or the like. Average particle size.
In this specification, the average particle size (primary particle size) of the glass beads is specified by observation with a scanning electron microscope (SEM). Specifically, 50 randomly selected glass beads were observed with a scanning electron microscope, the maximum diameter was taken as the particle diameter of the glass beads, and the average value of these was taken as the average particle diameter. The maximum diameter is obtained by drawing a straight line connecting any two points on the outer periphery of the glass bead in the SEM image, identifying the point where the length of the straight line is the maximum, and measuring the length of the straight line at the point. and

The content per solid content of the glass beads in the coating composition forming the outermost decorative layer or the decorative layer immediately below it is 35% by mass or more and 90% by mass or less from the viewpoint of improving the coating film hardness of the decorative board. do. If it is less than 35% by mass, a sufficient effect of improving the coating film hardness cannot be obtained, and if it exceeds 90% by mass, it becomes difficult to form a decorative layer. The content per solid content of the glass beads in the coating composition forming each decorative layer is preferably 37% by mass or more and 85% by mass or less, more preferably 40% by mass or more and 85% by mass or less, and still more preferably It is 45% by mass or more and 85% by mass or less, and more preferably 50% by mass or more and 80% by mass or less.
More specifically, the preferred amount of the glass beads when the coating composition for forming the colored layer contains the glass beads is 35% by mass or more and 70% by mass or less, more preferably 35% by mass or more and 70% by mass or less, based on the solid content. is 45% by mass or more and 60% by mass or less, and more preferably 50% by mass or more and 55% by mass or less. When glass beads are contained in a coating composition for forming a clear layer, the content of glass beads per solid content is preferably 50% by mass or more and 90% by mass or less, more preferably 60% by mass or more and 85% by mass. or less, and more preferably 65% by mass or more and 80% by mass or less.
In addition, the total content per solid content of the glass beads in the coating composition that forms both the outermost decorative layer and the decorative layer immediately below it is 30% by mass from the viewpoint of improving the coating film hardness of the decorative board. 85% by mass or less is preferable, 30% by mass or more and 80% by mass or less is more preferable, 30% by mass or more and 75% by mass or less is even more preferable, and 30% by mass or more and 70% by mass or less is even more preferable.

Further, in the decorative board of the present invention, a printed layer may be provided between the colored layer and the clear layer. By providing the printed layer, it is possible to give the decorative board a pattern such as wood grain or stone grain. As a printing method, existing methods such as gravure printing, gravure offset printing, inkjet printing, screen printing, rotary screen printing, letterpress printing, and pad printing can be applied.

The decorative laminate of the present invention preferably has a total calorific value of 8 MJ/m ² or less as measured by a cone calorimeter heat build-up test. By satisfying this requirement, it satisfies the exothermic class 1 (heating time 20 minutes) specified in JIS A 5430:2013, Annex JA, and exhibits high nonflammability. A more preferable total calorific value is 7.2 MJ/m ² or less.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[Materials used]
(1) Glass beads (silicate glass) Average particle size 10 μm, 20 μm and 40 μm
(2) Glass beads (silicic acid glass, aminosilane surface treatment) average particle size 10 μm
(3) Substrate 0.8 calcium silicate plate

(4) Paint a. Urethane sealer (impregnation sealer)
stomach. Acrylic epoxy UV curable paint (UV undercoat)
hare. Enamel paint (forms a colored layer)
Enamel paint is a two-liquid curing type acrylic urethane paint.
workman. Clear paint (forms a clear layer)
The clear paint is a two-liquid curable acrylic urethane paint.

[Method for Forming Cosmetic Layer]
Example 1
After smoothing the surface of the substrate by polishing with a belt sander, about 30 g/m ² of an impregnation sealer was applied using a roll coater.
On the impregnated sealer layer, about 120 g/m ² of the undercoat paint was applied in two portions using a roll coater, cured by ultraviolet irradiation, and then sanded using a belt sander to form a smooth undercoat layer. .
After applying about 100 g/m ² of an enamel paint containing glass beads using a flow coater on the undercoat layer, it is dried for 20 minutes in a drier at 90 ° C and cured to form a colored layer, and a decorative board is formed. Obtained.

Example 2
After forming an undercoat layer by the same process as in Example 1, about 100 g/m ² of an enamel paint containing no glass beads was applied to the undercoat layer using a flow coater, and then dried in a dryer at 90°C. was dried and cured for 20 minutes to form a colored layer, and a colored layer containing glass beads was formed in the same process as the colored layer to obtain a decorative board.

Example 4
After forming an undercoat layer in the same process as in Example 1, about 100 g/m ² of an enamel paint containing glass beads was applied to the undercoat layer using a flow coater, and dried in a dryer at 90°C for 20 minutes. After drying and curing for 1 minute to form a colored layer, apply about 75 g/m ² of clear paint that does not contain glass beads using a flow coater, and dry and cure for 20 minutes in a dryer at 90 ° C to form a clear layer. formed to obtain a decorative board.

Example 11
After forming an undercoat layer in the same process as in Example 1, about 100 g/m ² of an enamel paint containing glass beads was applied to the undercoat layer using a flow coater, and dried in a dryer at 90°C for 20 minutes. After drying and curing for a minute to form a colored layer, apply about 10 g/m ² of a clear paint that does not contain glass beads using a roll coater, and dry and harden for 20 minutes in a dryer at 90 ° C to form a clear layer. formed to obtain a decorative board.

Examples 3, 5-10, 12-17 and Comparative Example 1
By the same steps as in Examples 1, 2 and 4 described above, a decorative board was obtained by adjusting the type and content of glass beads and the presence/absence of content, and the type and coating amount of paint.

[Test method]
The hardness of the coating film surface was measured according to "JIS K 5400 Pencil Scratch Test". Note that a hardness of 7H or more was regarded as acceptable.
According to the exothermicity test (cone calorimeter exothermicity test) stipulated in "JIS A 5430:2013, Annex JA", the total calorific value after 20 minutes of heating was measured.
The external appearance was observed with the naked eye by facing the outermost decorative layer at a distance of 1 m and checking for unevenness, streaks, and the like. A good case was evaluated as ◯, and a case where there was no problem in use but was a little worrisome was evaluated as △.

[result]
Tables 1 and 2 show the measurement results. The glass bead content in the table indicates the glass bead content (mass %) per solid content in the coating composition forming each coating film.

From Table 1, when a coating composition without glass beads added as in Comparative Example 1 was used, the hardness of the coating film of the decorative board was 3H, whereas the outermost decorative layer (clear layer) and / or When the decorative layer (colored layer) immediately below is formed with a coating composition containing 35 to 90% by mass of glass beads (average particle size: 20 μm), the hardness of the coated film of the decorative board becomes 7H or more, which is significantly improved. I understand.
Further, from Table 2, similar effects can be obtained if the average particle size of the glass beads contained is 10 to 40 μm. If the average particle size of the glass beads is 40 μm, the coating film of the decorative board will have a hardness of 9H, but the appearance will be somewhat lacking due to the large particle size.
Furthermore, when both the colored layer and the clear layer are formed with a coating composition containing glass beads, the hardness of the coating film of the decorative board is improved, and in the example in which the coating film is more significantly improved, a hardness of 9H is obtained. I know there is.
Regarding the exothermic test results, even in Example 8, which has the highest organic solid content, it is about 6.6 MJ/m ² . ing.

Claims (5)

A decorative board having two or more decorative layers on at least one surface of a substrate, wherein the outermost decorative layer of the plurality of decorative layers and/or the decorative layer immediately below the decorative layer contains glass beads in an amount of 35% by mass or more per solid content of 90 A decorative board characterized by being formed from a coating composition containing at most % by mass. 2. The decorative board according to claim 1, wherein said glass beads have an average particle size of 5 [mu]m or more and 60 [mu]m or less. 3. The decorative board according to claim 1, wherein said glass beads are spherical or irregular in shape. The decorative board according to any one of claims 1 to 3, which is a decorative board for interior use. The decorative board according to any one of claims 1 to 4, which is a ceramic-based decorative board.