JP5156605B2 - Decorative plate and manufacturing method thereof - Google Patents

Description

  The present invention relates to a decorative board and a method for producing the same, and more specifically, a thin inorganic papermaking board having a low degree of deflection due to its own weight, excellent workability and good nonflammability, even if it is a thin article. The present invention relates to a decorative board and a manufacturing method thereof.

  A decorative board with an inorganic board as a base material and a coating layer of acrylic urethane resin, acrylic resin, epoxy resin, etc. on its surface has weather resistance, water resistance, alkali resistance, and is widely used as a building material. It has been. For example, in Patent Document 1, at least one surface of an inorganic ceramic substrate subjected to sealing treatment is provided with one or more coating layers of resin paints such as acrylic urethane resin, acrylic resin, and epoxy resin, and further 10 μm on the surface. An inorganic ceramics decorative board having a protective coating layer characterized by providing a protective coating layer formed of a UV-curable high-hardness clear film having a thickness of ˜300 μm; After applying a resin paint such as acrylic urethane resin, acrylic resin, or epoxy resin to the surface of the inorganic ceramic substrate, and curing it, a solid plate attached to a gravure offset printing machine or a coating means such as a roll curtain coater After applying the UV curable high hardness clear so as to have a film thickness of 10 μm to 300 μm, A method for producing an inorganic ceramics decorative board having a protective layer characterized by curing a coated clear to form a protective coating layer formed from the clear (Section 2); The surface of the system substrate is heated using hot air or heat rays accumulated during drying after application of resin paint such as acrylic urethane resin, acrylic resin, epoxy resin, etc. After evaporating the solvent in the UV-curable high-hardness clear applied on the coating layer, the applied clear is cured by irradiating the UV light from the UV lamp to form a protective coating layer formed from the clear. The manufacturing method (3rd term | claim) of the inorganic ceramics type decorative board which has the protective coating layer characterized by the above is disclosed.

  Further, as a printing method for stones, bricks, wood grain, geometric patterns, etc. on a base material, for example, Patent Document 2 discloses a plate roll having a pattern on the surface, and an offset to which ink applied to the plate roll is transferred. A printing mechanism comprising a roll, a feeding roll for pressing the printing plate material against the offset roll, feeding means for feeding the printing plate material to the printing mechanism, the number of rotations of each roll of the printing mechanism and the feeding speed of the feeding means In a printing method for a plate material by a printing device comprising a control device for controlling the print, a printed pattern is detected to determine the amount of expansion / contraction of the printed pattern pitch with respect to the planned pattern pitch, and correction for this expansion / contraction amount is performed. And changing the peripheral speed of the plate roll to adjust the ratio of the peripheral speed of the plate roll to the peripheral speed of the offset roll. Printing method for plate material (claim 1) is disclosed.

  Furthermore, in Patent Document 3, an approximately square-shaped inorganic papermaking plate is used as a base material, and at least one surface of the base material is impregnated with an impregnation sealer, and the base material on which the impregnation sealer is applied is provided on one surface. And a decorative paper having a urethane-based reactive hot-melt adhesive layer and a printing surface are laminated in this order, and the surface opposite to the printing surface of the decorative paper is in contact with the urethane-based reactive hot-melt adhesive layer. And a decorative sheet in which the papermaking direction of the decorative paper coincides with the papermaking direction of the base material, and one end surface of the four sides of the base material parallel to the papermaking direction is opposite to the one surface Part of the surface is coated with the decorative paper and the urethane-based reactive hot melt adhesive layer (Claim 1); the base material and the urethane-based reactive hot melt Between the adhesive layer and the base The decorative board according to claim 1, wherein an outer-line curable resin layer is provided (claim 2); a clear layer made of a primer layer and a transparent or translucent curable resin on the printing surface of the decorative paper The decorative board according to claim 2, wherein the decorative board is provided in this order (Claim 3); a part of the opposite surface is covered with the decorative paper and the urethane-based reactive hot melt adhesive layer. The decorative board according to any one of claims 1 to 3, wherein the length from the end face is 5 to 10 mm (claim 4).

Examples of the inorganic board used as the base material of the decorative board as described above include materials of cement type, gypsum type, calcium silicate type and the like. These inorganic plates are usually produced by methods such as papermaking and press molding.
As raw materials for inorganic boards, cement-based, gypsum-based and calcium silicate-based materials usually use matrix forming raw materials and fiber raw materials as essential raw materials, and together with these essential raw materials, an inorganic filler for imparting necessary performance. Used together. Conventionally, asbestos has been used as a fiber raw material. Asbestos is a very suitable fiber for the production and performance of inorganic board, but it has been pointed out that its effects on health. Therefore, asbestos can be manufactured in various ways to produce inorganic board without using asbestos and obtain the required performance. Technology development has been carried out.

  For example, in Non-Patent Document 1, cellulose fiber such as wood pulp is used as a fiber raw material in decalcification of a calcium silicate plate, but using cellulose fiber makes the calcium silicate plate flexible. It is described that it is suitable for curved surface construction and the like.

Further, for example, with respect to a method for producing a fiber-reinforced inorganic plate by a papermaking method, Patent Document 4 discloses a hydrated raw material for forming a matrix of 20 to 60% by mass; an inorganic filler of 1 to 50% by mass; Inorganic fiber and / or synthetic fiber 0.5 in the range of natural fiber 3-11 mass% and fiber length 6.0-0.2 mm, fiber diameter 20-50 μm in the range of 150-450 ml with standard freeness Reinforcing fibers composed of ˜5% by mass (excluding asbestos) 3.5˜12% by mass; and an average particle diameter obtained by hydrothermal synthesis of a calcareous raw material and a siliceous raw material in advance within a range of 30 μm to 100 μm A slurry containing 10 to 50% by mass of calcium silicate hydrate is obtained by wet mixing to obtain a slurry, and the resulting slurry is subjected to a thin film dehydration rate of 5 on an endless felt. The apparent density of the green plate after separation from the making roll is set to 0.35 to 0.65 g by adjusting the moisture content of the thin film when wound on the making roll to 100 to 180% within the range of 30% / second. A green plate is obtained by papermaking within the range of / cm ^3, the green plate is pressure dehydrated, and the apparent density of the green plate after pressure dehydration is 1.3 of the apparent density of the green plate before pressure dehydration. A surface comprising an inorganic papermaking plate obtained by curing and curing after being within a range of ~ 2.0 times, and a moisture-permeable surface decorative layer provided on at least one surface of the substrate The decorative inorganic papermaking board (Claim 1); The surface decorative inorganic papermaking board (Claim 2) according to claim 1, comprising a permeable sealer layer between the base material and the permeable surface decorative layer. The paper making method of the inorganic paper making plate used as a material is the round net paper making method. , Surface decorative inorganic papermaking board according to claim 1, wherein (claim 3) is disclosed. The paragraph [0035] of Patent Document 1 states that “pressure dehydration of the green plate can be performed using a pressure dehydration apparatus such as a known press machine. , Holding pressure, holding time, etc.) must be determined so that the apparent density of the green plate after pressure dehydration is within a range of 1.3 to 2.0 times the apparent density of the green plate before pressure dehydration. As a method for determining the conditions for pressure dehydration, for example, prior to actual production, the raw slurry is dehydrated at 5 to 30% / second by a suction dehydration test simulating papermaking, and the apparent density is 0.35. A green plate of 0.65 g / cm ³ is prepared and subjected to a pressure dehydration test. The apparent density of the green plate after pressure dehydration is 1.3-2. The pressure dehydration conditions may be determined so that the pressure is within the range of 0. Therefore, the pressure dehydration conditions are defined as a specific range. But it is not limited to, holding pressure is generally a 5 to 30 N / mm ^2, the product of the holding pressure (N / mm ²⁾ and retention time (in seconds) is approximately at 1000~40000N / mm ² · sec There is also a statement to the effect.

In addition, the present applicant, in Japanese Patent Application No. 2008-78693, is 20 to 60% by mass of a hydratable raw material for forming a matrix; 3 to 11% by mass of a natural fiber having a freeness within a range of 150 to 450 ml in Canadian standard freeness. And / or a fiber length of 6.0 to 0.2 mm, and an inorganic fiber and / or synthetic fiber (excluding asbestos) in the range of a fiber diameter of 20 to 50 μm, 0.5 to 5% by mass, provided that the natural fiber and the inorganic fiber / Or total amount of synthetic fiber 3.5 to 12% by mass; calcium silicate hydrate 10 having an average particle diameter in the range of 30 μm to 100 μm obtained by hydrothermal synthesis of a calcareous raw material and a siliceous raw material in advance ~ 50% by mass; 1-50% by mass of an inorganic filler; and a composition containing 1-20% by mass of silica fume are wet mixed to obtain a slurry, and the resulting slurry is made. Providing a raw plate by, after pressurized圧脱water said biological plate to 40N / mm ² exceeding holding pressure 30 N / mm ² during pressure dehydration, the thickness 2~4mm by curing curable, apparent density 1.2 A method for producing a thin inorganic papermaking sheet characterized by obtaining a cured body of ˜1.5 g / cm ³ (Claim 1); the center in the longitudinal direction of the thin inorganic papermaking board having a width of 910 mm and a length of 2575 mm Deflection due to its own weight when it is supported by one line at the part is 500 mm or less in the difference between the center part and the edge part, and the fiber direction by the center one line support three-point bending test using No. 4 test piece of JIS A 1408 regulation A method for manufacturing a thin inorganic papermaking sheet according to claim 1 (Claim 2) has already been proposed, in which the maximum deflection is 15 mm or less and the bending strength in the fiber direction is 25 N / mm ² or more.

  However, the description of Non-Patent Document 1 suggests that the deflection of the calcium silicate plate using cellulose fibers increases, particularly when the thickness of the calcium silicate plate is thin. There was a problem that it was extremely large, warped during construction, and difficult to construct. Also for the surface-decorated inorganic papermaking plate disclosed in Patent Document 4, in the case of a thin object, the deflection due to its own weight is large, the handling property during transportation and construction is poor, and the problem that it is difficult to work has not been solved.

Therefore, the present applicant, in Japanese Patent Application No. 2008-30296, is a hydrated raw material for forming a matrix as a method for producing a thin inorganic papermaking sheet that has little deflection even in thin materials and has good handling properties during transportation and construction. 30 to 70% by mass; freeness of 3 to 9% by mass of natural fibers having a Canadian standard freeness in the range of 150 to 450 ml, fiber length of 6.0 to 0.2 mm, and fiber diameter of 10 to 50 μm Inorganic fiber and / or synthetic fiber (excluding asbestos) 0.5 to 5% by mass, provided that the total amount of natural fiber and inorganic fiber and / or synthetic fiber is 3.5 to 12% by mass; previously calcareous raw material and silicic acid raw material 5 to 30% by mass of calcium silicate hydrate having an average particle size of 30 to 100 μm obtained by hydrothermal synthesis of wollastonite; And a mixture containing 1 to 15% by mass of an inorganic filler is wet-mixed to obtain a slurry, and a green plate is obtained by paper-making the obtained slurry, and the green plate is held at pressure during pressure dehydration. A thin inorganic papermaking board characterized in that a cured product having a thickness of 2 to 5 mm and an apparent density of 1.2 to 1.5 g / cm ³ is obtained by pressure dehydration at 16 to 40 N / mm ² and then curing and curing. (Claim 1): Deflection due to its own weight when it is supported in a line at the center in the length direction of an air-dried thin inorganic paper sheet having a width of 910 mm and a length of 2575 mm The maximum deflection by a bending test based on JIS A 5430 10.3.3.2 is 20 to 50 mm using a No. 3 test piece defined in JIS A 1408 4.1. Bending strength is 28 N / mm ^The method for producing a thin inorganic paper-making board according to claim 1, which is ² or more (Claim 2); natural fiber is 3 to 6% by mass, and inorganic fiber and / or synthetic fiber is 0.5 to 3% by mass, but natural The total amount of fibers and inorganic fibers and / or synthetic fibers is in the range of 3.5 to 9% by mass, and the heating time is 20 minutes using the test apparatus specified in JA of JIS A 5430 Annex of thin inorganic papermaking board. The manufacturing method of the thin inorganic papermaking board of Claim 1 or 2 whose total calorific value in an exothermic test is 4.5 MJ / m < ² > or less is proposed.

Compositions, Vol. 13, no. 2 [April 1982] 123-128 "Developing asbestos-free calcium silicate building boards" Japanese Patent Publication No. 4-63037 Patent Claim JP, 2004-223906, A Claims JP, 2006-168255, A Claims JP, 2007-1043, A Claims [0035]

  Therefore, the object of the present invention is that even if it is a thin object, there is little deflection due to its own weight, the handling property during transportation and construction is good, the work is easy, and the nonflammability is excellent, that is, JIS A 5430 Annex JA. An object of the present invention is to provide a thin decorative board with a small total calorific value in a heat generation test in a heating time of 20 minutes using a specified test apparatus and a method for producing the same.

That is, the present invention relates to 30 to 70% by mass of a hydratable raw material for forming a matrix; 3 to 6% by mass of natural fibers having a freeness within the range of 150 to 450 ml in Canadian standard freeness, and a fiber length of 6.0 to 0.00. 0.5 to 3% by mass of inorganic fiber and / or synthetic fiber (excluding asbestos) in the range of 2 mm and fiber diameter of 10 to 50 μm, provided that the total amount of natural fiber and inorganic fiber and / or synthetic fiber is 3.5 to 9% by mass and 2% by mass or less of synthetic fiber (including zero); calcium silicate hydrate having an average particle diameter in the range of 30 μm to 100 μm obtained by hydrothermal synthesis of a calcareous raw material and a silicic acid raw material in advance 5-30% by mass; Wollastonite 5-20% by mass; and a mixture containing 1-15% by mass of an inorganic filler are wet mixed to obtain a slurry, and the resulting slurry is made by papermaking Obtain a plate, after pressurizing圧脱water biological plates at holding pressure 16~40N / mm ² during pressure dehydration, thickness 2~5mm obtained by curing curable, apparent density 1.2 to 1. 5g ^/ cm 3, JIS a 5430 gross calorific value of the heat generating resistance test Annex JA prescribed heating time of 20 minutes with the test device is 3.5 mJ / ^{m 2} Ri der hereinafter width 910 mm, length 2575mm 3. Deflection due to its own weight when it is supported in a line at the center in the length direction of an air-dried thin inorganic papermaking plate having dimensions is 500 mm or less due to the difference between the center and the edge, and JIS A 1408 using No. 3 specimen defined in 1, the maximum deflection der Ru thin inorganic papermaking plate and flexural strength of 28N / mm ² or more in 20~50mm by bending test based on 10.3.2 of JIS a 5430 As a base material, and The surface is provided with a decorative layer consisting of three layers of a base reinforcing layer, a decorative layer and a surface protective layer, and the total organic solid content of the decorative layer consisting of three layers of the base reinforcing layer, the decorative layer and the surface protective layer is 50. It is a decorative board within a range of ˜140 g / m ² and has a total calorific value of 8.0 MJ / m ² or less in a heat generation test in a heating time of 20 minutes using a test apparatus specified in JA of JIS A 5430 It is related with the decorative board characterized by being.

In the decorative board of the present invention, the other surface of the substrate is provided with a back surface protective layer, and the total of the decorative layer and the back surface protective layer composed of three layers of a base reinforcing layer, a decorative layer and a surface protective layer. The organic solid content is in the range of 50 to 140 g / m ² .

Further, the decorative board of the present invention comprises 30 to 70% by mass of a hydratable raw material for matrix formation; 3 to 6% by mass of natural fibers having a freeness within the range of 150 to 450 ml in Canadian standard freeness, and a fiber length of 6.0. 0.5 to 3% by mass of inorganic fiber and / or synthetic fiber (excluding asbestos) in the range of -0.2 mm and fiber diameter of 10 to 50 μm, provided that the total amount of natural fiber and inorganic fiber and / or synthetic fiber is 3 .5-9 mass% and synthetic fiber 2 mass% or less (including zero); calcium silicate having an average particle diameter in the range of 30 μm to 100 μm obtained by hydrothermal synthesis of a calcareous raw material and a siliceous raw material in advance Hydrate 5-30% by mass; Wollastonite 5-20% by mass; and a mixture containing 1-15% by mass of an inorganic filler are wet mixed to obtain a slurry, and the resulting slurry is made. This The resulting raw plate, after pressurizing圧脱water biological plates at holding pressure 16~40N / mm ² during pressure dehydration, the thickness 2~5mm by curing curable, apparent density 1.2~1.5g / ^cm 3, JIS a 5430 gross calorific value of the heat generating resistance test Annex JA prescribed heating time of 20 minutes with the test device is 3.5 mJ / ^{m 2} Ri der hereinafter width 910 mm, length dimension 2575mm Deflection due to its own weight when it is supported in a line at the center in the length direction of the thin inorganic papermaking sheet in an air-dried state having a thickness of 500 mm or less due to the difference between the center and the edge, is JIS A 1408 4.1. using No. 3 specimen defined in a maximum deflection due 10.3.2 based on the bending test of JIS a 5430 has a and flexural strength of 28N / mm ² or more der Ru thin inorganic papermaking plate in 20~50mm Obtained; Forming a base reinforcing layer on one surface of the plate; forming a decorative layer on the surface of the base reinforcing layer; and forming a surface protective layer on the surface of the decorative layer, wherein the base reinforcing layer, the decorative layer, and In the exothermicity test in which the total organic solid content of the surface protective layer is in the range of 50 to 140 g / m ² and the heating time is 20 minutes using the test apparatus defined in JIS A 5430 Annex JA of the obtained decorative board. The total calorific value is 8.0 MJ / m ² or less.

Furthermore, the method for producing a decorative board according to the present invention forms a back surface protective layer on the other surface of the thin inorganic papermaking board, wherein the base reinforcing layer, the decorative layer, the surface protective layer, and the back surface protective layer are combined. The organic solid content is in the range of 50 to 140 g / m ² .

  According to the decorative board of the present invention, even if it is a thin object, there is little deflection due to its own weight, the handling property during transportation and construction is good, the work is easy, and the nonflammability is excellent, that is, JIS A 5430 appendix. A decorative board having a small total calorific value in a heat generation test with a heating time of 20 minutes using a test apparatus specified by JA can be provided.

Hereinafter, the decorative board and the manufacturing method thereof according to the present invention will be described in more detail.
The thin inorganic papermaking board used as a base material in the decorative board of the present invention comprises 30 to 70% by mass of a hydratable raw material for matrix formation; natural fibers having a freeness within a range of 150 to 450 ml in Canadian standard freeness. 6 mass% and fiber length 6.0-0.2 mm, inorganic fiber and / or synthetic fiber (excluding asbestos) in the range of fiber diameter 10-50 μm 0.5-3 mass%, except natural fiber and inorganic fiber And / or a total amount of synthetic fibers of 3.5 to 9% by mass and synthetic fibers of 2% by mass or less (including zero); an average particle diameter obtained by hydrothermal synthesis of a calcareous raw material and a siliceous raw material in advance is 30 μm to A mixture containing calcium silicate hydrate 5 to 50% by mass within a range of 100 μm; 5 to 20% by mass of wollastonite; and 1 to 15% by mass of an inorganic filler is wet-mixed to form a slurry. Over the papermaking it can be produced by dehydration and curing curing pressure.

Here, the hydratable raw material for forming the matrix may be either hydraulic or pneumatic, and is not particularly limited, but a hydraulic cement is suitable because of its high strength expression power, for example, Examples include ordinary Portland cement, early-strength cement, blast furnace cement, low heat cement, and ecocement. Examples of the air-cement cement include gypsum-based materials such as hemihydrate gypsum and type II anhydrous gypsum. When a gypsum-based material is used, a predetermined amount of a curing retarder (citric acid, phthalic acid, tartaric acid, etc.) or a curing accelerator (alkali metal sulfate such as sodium sulfate) can be added as necessary. The specific surface area of the matrix-forming water-dispersible material in the case of hydraulic cement, 2500~5000cm ² / g, is preferably in the range of 3000~4000cm ² / g, when the air-hardening cement, 4000～8000Cm ² / G, preferably in the range of 4500 to 6500 cm ² / g.

  Reinforcing fibers include, for example, natural fibers such as wood pulp and various hemp, inorganic fibers such as glass fibers, rock wool, ceramic wool, and carbon fibers, artificial pulp, polyvinyl alcohol, polypropylene, polyethylene, polyester, acrylic, and rayon. Synthetic fibers such as Among these, from the viewpoint of further improving the bending strength and impact resistance performance, it is preferable to use cellulosic fibers such as wood pulp as the main component of the reinforcing fibers. In addition, the freeness of natural fibers is in the range of 150 to 450 ml, preferably 150 to 350 ml in terms of Canadian standard freeness (hereinafter referred to as “CSF”) defined in JIS P 8121. The CSF can be adjusted by beating a reinforcing fiber, such as wood pulp, with a refiner or the like wet. The beating treatment increases the branching of the fibers, so-called fibrillation, and as a result, it is possible to improve adhesion and flexibility with the matrix formed by hydrating the hydratable raw material for matrix formation. . Here, by setting the CSF to 450 ml or less, sufficient adhesion between the reinforcing fiber and the matrix is achieved, good dispersion of the reinforcing fiber is obtained, and high strength is imparted to the product (inorganic papermaking board). Can do. In addition, by increasing the CSF to 150 ml or more, the drainage of the slurry is increased, dehydration unevenness at the time of pressure dehydration, blistering, tearing, etc. are prevented, and good flexibility and consequently impact resistance performance is imparted to the product. Can do.

  In the papermaking method, the fiber lengths of the inorganic fibers and the synthetic fibers are 6.0 to 0.2 mm, preferably 4.0 to 0.00, in terms of papermaking suitability (formation of a thin film, formation of green board, etc.). It exists in the range of 5 mm, and a fiber diameter exists in the range of 10-50 micrometers. In the case of a synthetic fiber, the fiber diameter is preferably 20 to 50 μm, more preferably 20 to 40 μm.

In addition, calcium silicate hydrate can be produced by mixing a calcareous raw material and a silicic acid raw material with water and hydrothermal synthesis under high temperature and high pressure.
Examples of the calcareous raw material include quick lime and slaked lime, and examples of the siliceous raw material include silica, diatomaceous earth, and silica fume. Silica is particularly preferable.
The synthesis of calcium silicate hydrate can be performed, for example, as follows. The calcareous raw material and the siliceous raw material are mixed at, for example, a mixing ratio (CaO / SiO ₂ molar ratio) of 0.5 to 1.5, preferably 0.5 to 1.2. ~ 20 times, preferably 7-16 times water is added, mixed and dispersed to form a raw material slurry, and the raw material slurry is stirred at a temperature of 150 to 230 ° C, preferably 170 to 210 ° C, Hydrothermal synthesis is performed for 1 to 20 hours, preferably 3 to 12 hours. In this way, calcium silicate hydrate can be obtained as, for example, tobermorite, zonotrite and the like. The average particle diameter of calcium silicate hydrate is in the range of 30 μm to 100 μm, preferably 50 μm to 90 μm.

  The average particle diameter can be adjusted by the particle size of the siliceous raw material, the proportion of water used, the degree of stirring in the pressure vessel, and the like. For example, the particle size of the siliceous raw material is set to 80 μm or less, preferably 60 μm or less, and the amount of water used is 7 to 16 times by mass with respect to the mixture of the calcareous raw material and the siliceous raw material, and is provided in the pressure vessel. The average particle diameter of the obtained calcium silicate hydrate can be adjusted in the range of 30 μm to 100 μm as described above by setting the peripheral speed of the stirring rotary blade to 100 to 200 m / min. In addition, the average particle diameter of the calcium silicate hydrate prescribed | regulated by this specification is calculated | required with the particle size distribution measuring apparatus by the laser diffraction scattering method.

  Wollastonite is also used as an admixture.

  Further, the inorganic filler is not particularly limited as long as it is generally used for an inorganic board, but for example, a filler for improving heat resistance such as mica, fire resistance such as dihydrate gypsum and calcium carbonate. Non-hydratable raw materials such as fillers for improvement and fillers for preventing cracks such as silica can be used. In addition, these can also use 2 or more types together.

  The above-mentioned various raw materials are 30 to 70% by mass, preferably 40 to 60% by mass of a hydratable raw material for matrix formation as a mass ratio with respect to the obtained thin inorganic papermaking plate, (Total amount) 3.5-9% by mass, preferably 3.5-7% by mass, calcium silicate hydrate 5-30% by mass, preferably 8-20% by mass, wollastonite 5-20% by mass, It is preferable to blend so as to be 10 to 20% by mass and 1 to 15% by mass, preferably 3 to 10% by mass of the inorganic filler. The reinforcing fiber has a freeness of 3 to 6% by mass, preferably 3 to 5% by mass and a fiber length of 6.0 to 0.2 mm and a fiber diameter of 10 to CSF, with a freeness of CSF in the range of 150 to 450 ml. It is composed of 0.5 to 3% by mass, preferably 0.5 to 2% by mass of inorganic fiber and / or synthetic fiber in the range of ˜50 μm, and the total amount of natural fiber and inorganic fiber and / or synthetic fiber is the above It mix | blends so that it may become in the range. However, the synthetic fiber is 2% by mass or less (including zero), preferably 0.1 to 2% by mass, and more preferably 0.5 to 1.5% by mass. When the blending amount of the synthetic fiber exceeds 2% by mass, the total calorific value of the base material is increased, and the nonflammability of the resulting decorative board is lowered, which is not preferable. When the total organic solid content of the decorative layer is relatively large, it is preferable that the synthetic fiber content is 1.5% by mass or less. When the synthetic fiber is blended, the formability of the green plate when producing the base material by the papermaking method is improved, so it is preferable to blend 0.1% by mass or more, and if 0.5% by mass or more is blended, It is also suitable for increasing the strength of the thin inorganic papermaking plate that becomes the base material of the decorative plate. On the other hand, the inorganic fiber is effective in increasing the strength of the base material without increasing the total calorific value of the base material, that is, without impairing the incombustibility, but the reinforcing effect is often inferior to that of the synthetic fiber. Therefore, it is preferable that the inorganic fiber and the synthetic fiber have the above-described blending conditions.

  Here, when the blending amount of the hydratable raw material for matrix formation is less than 30% by mass, sufficient strength cannot be obtained, and when it exceeds 70% by mass, the apparent density becomes too high, which is not preferable. Further, if the blending amount of the fiber raw material (the total amount of natural fibers and inorganic fibers and / or synthetic fibers) is less than 3.5% by mass, it is not preferable because sufficient strength cannot be obtained and the material becomes brittle. If it exceeds mass%, the material becomes softer than necessary and the workability is lowered, which is not preferable. Furthermore, it is not preferable to increase the number of natural fibers or synthetic fibers, which are organic fibers, because the total calorific value exceeds a predetermined value in the exothermic test and a desired nonflammable performance cannot be obtained. In addition, since inorganic fibers are not very dispersible, many of them are difficult to use. If the blending amount of calcium silicate hydrate is less than 5% by mass, it is not preferable because sufficient strength cannot be obtained. If it exceeds 30% by mass, the apparent density of the product is lowered and sufficient strength is obtained. Since it disappears, it is not preferable. Moreover, when the compounding amount of wollastonite is less than 5% by mass, the rate of change in length due to water absorption specified in JIS A 5430 10.7 increases, which is not preferable. Is not preferable because it becomes brittle. Further, if the blending amount of the inorganic filler is less than 1% by mass, it is difficult to form a stable thin film at the time of forming the thin film by the papermaking method, and if it exceeds 15% by mass, sufficient strength can be obtained. It is not preferable because it disappears.

  The thin inorganic papermaking board used as the base material of the decorative board of the present invention contains the above-mentioned various materials, preferably in the above-mentioned mixing ratio, and 7-30 times (mass ratio) of the various materials, preferably 10 It can be manufactured by adding wet water to -20 times to make a slurry to make a slurry, papermaking the obtained slurry, obtaining a green plate, dehydrating the obtained green plate under pressure, followed by curing and curing it can.

  In addition, as the papermaking method referred to in this specification, any papermaking method known in the art can be applied, and examples thereof include a round net type papermaking method, a long net type papermaking method, and a flow-on type papermaking method. For example, in the round net making method, the raw slurry is made with a wire mesh cylinder to form a green film (thin film). The green sheet (raw board) is obtained by winding up to a thickness of 1 mm and separating from the making roll when the thickness reaches a predetermined thickness. In addition, the flow-on type papermaking method supplies raw slurry directly onto the endless felt, dehydrates it on the endless felt to form a green film (thin film), winds it up to a predetermined thickness on a making roll, When the thickness is reached, the green sheet (raw board) is obtained by separating from the making roll. Among them, the round net type papermaking method is preferable from the viewpoint that the production efficiency is high, the production of thin objects is possible, and the two-dimensional orientation of the fibers is good, so that the reinforcing performance can be sufficiently exhibited. In the present invention, a sheet-like molded product before pressure dehydration obtained after paper making of a slurry is defined as “green plate”.

The pressure plate can be dehydrated using a pressure dehydration apparatus such as a known press machine. The pressure dehydration condition of the green plate is a holding pressure of 16 to 40 N / mm ² , preferably 20 to 40 N / mm ² . Incidentally, when the holding pressure is less than 16N / mm ^2, not preferable since sufficient strength can not be obtained, also when more than 40N / mm ^2, or could not crack occurs and obtain a molded product The molded product obtained is not preferable because it becomes too hard and brittle.

The “apparent density” as used in the present specification means that the obtained material is dried to an absolutely dry state (a state dried at 105 ° C. until reaching a constant weight), and the mass (g) after drying is expressed as its volume (cm ^It can be calculated by the method of dividing by ³ ). The apparent density of the inorganic papermaking plate obtained by the production method of the present invention is 1.2 to 1.5 g / cm ³ , preferably 1.3 to 1.5 g / cm ³ . If the apparent density is less than 1.2 g / cm ^3, it is not preferable because sufficient strength cannot be obtained. If the apparent density exceeds 1.5 g / cm ³ , the material becomes hard and the thin inorganic papermaking plate is fixed to the ground. This is not preferable because the workability during the process is reduced.

  The curing and curing method is not particularly limited, and known means such as natural curing, steam curing, and cooling curing can be applied.

  The thickness of the inorganic paper-making board currently on the market is 3 to 4 mm, which is a thin material, and the thickness below that is the deflection due to its own weight, resulting in poor handling and handling during construction. Currently. However, the thin inorganic paper-making board used as the base material for the decorative board of the present invention does not cause deflection due to its own weight even at a thickness of 2 to 5 mm, and has good handling properties during transportation and construction. It has the advantage of being easy.

  Here, “deflection due to its own weight” is an air-dried plate having a width of 910 mm and a length of 2575 mm (commonly called 8.5-inch size), which is a long type of dimensions generally distributed in the building materials market. Is measured by measuring the difference in height between the support part and the end part in a state where it is hung down by its own weight. It is effective that the difference in height is 500 mm or less, preferably 400 mm or less. The thin inorganic papermaking board used as the base material for the decorative board of the present invention has a small amount of deflection due to its own weight, has good workability, and facilitates work during construction. The “air-dried state” described in the present specification is in accordance with JIS A 5430 10.1 Table 11 and indicates a state of being left for 7 days or more in a well-ventilated room.

In addition, the thin inorganic papermaking plate used as the base material of the decorative board of the present invention has a total calorific value of 3.5 MJ / in a heat generation test with a heating time of 20 minutes using a test apparatus specified in JA of JIS A 5430. m ² or less is preferable. In addition, the measurement of the total calorific value in the present specification is a result obtained by using “Cone Calorimeter III” C3 type (ISO5660 regulation device) manufactured by Toyo Seiki Seisakusho at a radiation amount of 50 kW / m ² .

  Furthermore, in the thin inorganic papermaking board used as the base material for the decorative board of the present invention, the maximum deflection in bending pressure during the bending test was the No. 3 test piece defined in JIS A 1408 4.1. Is 400 mm in length and 500 mm in length), the flow direction of the fiber is the length direction of the No. 3 test piece, and the bending test perpendicular to the length direction, that is, the bending specified in JIS A 5430 10.3.2 It can become the substitute characteristic which evaluates the said rigidity by being 20-50 mm in a test (air-dry state). The term “maximum deflection” as used herein refers to the elastic region and plasticity of the loaded part until the material breaks in the bending test, that is, the test according to the bisected one-line load method of JIS A 1408 5.1.1. The maximum amount of displacement combined with the area. In addition, when the maximum deflection exceeds 50 mm, the thin inorganic papermaking plate becomes too soft, which is not preferable because the workability of the decorative board obtained using the thin inorganic papermaking plate as a base material is deteriorated, and the maximum deflection is less than 20 mm. When it is, it is not preferable because the thin inorganic papermaking plate becomes too hard and may become brittle.

In the bending test (the dimensions of the specimen are 400 mm wide, 500 mm long, and the span is 400 mm), the bending strength when the fiber flow direction is the length direction of the specimen is 28 N / mm ² or more. When this bending strength is less than 28 N / mm ² , when the bending due to its own weight occurs, it cannot withstand the bending stress applied to the thin inorganic papermaking plate, and cracks and cracks are generated. However, by satisfying this bending strength, it can withstand bending stress due to deflection due to its own weight, and the workability of the decorative board is greatly improved.

  The decorative board of the present invention comprises the above-mentioned thin inorganic papermaking board as a base material, and a decorative layer comprising three layers of a base reinforcing layer, a decorative layer, and a surface protective layer on one surface thereof. By providing the decorative layer, it is possible to improve the design of the thin inorganic papermaking plate and to make a decorative plate with high added value.

  First, a base reinforcing layer can be formed on one surface of the substrate to reinforce the surface of the substrate and fill the voids in the substrate to improve the adhesion of the decorative layer. Moreover, the elution of the alkaline component from the base material is also prevented. The base reinforcing layer can be formed by a known impregnation sealer treatment, for example, a moisture curable urethane resin, an epoxy resin, a prepolymer having a free isocyanate group which is a reaction product of isocyanate or polyisocyanate and polyol, It can form by apply | coating well-known sealers, such as an aliphatic isocyanate, an alicyclic isocyanate, and a solvent-free sealer, for example by methods, such as a roll coater, a flow coater, and a spray. In addition, before forming a base reinforcement layer on a base material, it is preferable that the base material surface is surface-polished using the 80th-400th polishing paper with a platen type polishing machine, for example. By this surface polishing, the film thickness of the decorative layer can be controlled to ensure the surface accuracy.

  Next, a decorative layer is formed on the surface of the base reinforcing layer. The decorative layer can be formed using a known paint such as urethane, acrylic, acrylurethane, unsaturated polyester, urethane acrylate, or ultraviolet curable resin. For the formation of the decorative layer, a general method such as roll coater, flow coater, spray, transfer, screen printing, gravure printing, gravure offset printing, ink jet printing and the like can be used. In addition, even if a decoration layer is comprised from one layer, it may be comprised from two or more layers. For example, one layer can be formed by a roll coater, a flow coater, a spray or the like to form a base coat, and decoration can be performed on the base coat by transfer, screen printing, gravure printing, gravure offset printing, ink jet printing, or the like.

Moreover, a decoration layer can also be formed by adhere | attaching decorative paper on the surface of a base reinforcement layer. The decorative paper is based on the base paper, and the surface properties (increase the density to suppress the penetration of printing ink) are improved by using a known calendar process so that it is suitable for printing the base paper. The printed surface is provided with printing. Base paper includes architectural titanium paper with a basis weight of 30 to 120 g / m ² , architectural thin paper, print paper, pure white paper, bleached or unbleached kraft paper, mixed paper made by mixing so-called synthetic resins, titanium It is possible to use impregnated titanium paper impregnated with a resin such as latex, impregnated coated titanium paper coated with latex or the like. Among them, impregnated titanium paper not only has high strength between papers, but there are few air bubbles present between the papers, and when a surface protective layer is provided on the decorative paper, foaming, foaming, etc. caused by air bubbles escaping from between the papers It is more preferable for the reason that poor coating is prevented. The printed surface provided on one side of the decorative paper is printed with an arbitrary pattern such as an abstract pattern, stone pattern, wood pattern, geometric pattern for the purpose of design on a solid ink layer that has been printed on the entire surface. It is a formed surface. The pattern pattern printing method is not particularly specified, and can be formed by a known printing method such as gravure printing or ink jet printing. It is preferable to use a known gravure printing because it is highly productive, can be continuously printed, can be freely changed in color and density, and has high concealability. In addition, when heat resistance is requested | required of a decorative layer, it is preferable to use heat resistant ink for the ink which forms a solid ink layer and a pattern printing layer.

  When the decorative paper as described above is used as the decorative layer, it is preferable to use a urethane-based reactive hot melt adhesive to bond the base reinforcing layer and the decorative paper. As the urethane-based reactive hot melt adhesive, those having a viscosity of 1000 to 30000 mPa · s which are melted at 100 to 130 ° C. are preferable, and among them, the polyester polyol type urethane-based reactive hot is particularly excellent in initial adhesive strength. It is preferred to use a melt adhesive. In particular, such a urethane-based reactive hot melt adhesive is preferably obtained by using a polyester polyol in combination with a polyether polyol or other polyol, such as an acrylic polyol. In addition, the polyurethane reactive hot melt adhesive can use what is marketed, for example, Dainippon Ink & Chemicals Ltd. tie hose FH-100 etc. can be used.

  A surface protective layer is formed on the surface of the decorative layer formed as described above. The surface protective layer is for protecting the surface of the decorative layer, and can be formed by applying a colorless transparent or translucent resin. Examples of the colorless and transparent or translucent resin include urethane-based, acrylic-based, acrylic-urethane-based, unsaturated polyester-based, urethane acrylate-based, and ultraviolet curable resins. These resins can be applied by a method such as a roll coater, a flow coater, or a spray.

  Furthermore, on the other surface (back surface) of the base material, a back surface reinforcing layer can be formed to reinforce the base material surface and fill the voids in the base material. Moreover, the elution of the alkaline component from the base material is also prevented. The back reinforcing layer can be formed by a known impregnation sealer treatment, for example, a moisture curable urethane resin, an epoxy resin, a prepolymer having a free isocyanate group which is a reaction product of isocyanate or polyisocyanate and polyol, It can form by apply | coating well-known sealers, such as an aliphatic isocyanate, an alicyclic isocyanate, and a solvent-free sealer, for example by methods, such as a roll coater, a flow coater, and a spray. In addition, before forming a back surface reinforcement layer to a base material, it is preferable to carry out surface grinding | polishing of the base-material surface, for example using 80th-400th abrasive paper with a platen type grinder.

In the decorative board of the present invention, when there are a decorative layer and a back reinforcing layer composed of the base reinforcing layer, the decorative layer and the surface protective layer as described above, the total organic solid content of the decorative layer and the back reinforcing layer is 50 to 140 g / ^{m 2,} it is preferable that preferably a 50~130g / ^{m 2.} When the total organic solid content exceeds 140 g / m ² , it is not preferable because nonflammability deteriorates, and when it is less than 50 g / m ² , the designability and decorative film durability in decoration cannot be maintained. It is not preferable because there is.

The decorative board of the present invention has a total calorific value of 8.0 MJ / m ² or less, preferably 7.5 MJ / m ² in a heat generation test with a heating time of 20 minutes using a test apparatus specified in JA of JIS A 5430. It can be as follows. In addition, the measurement of the total calorific value in the present specification is a result obtained by using “Cone Calorimeter III” C3 type (ISO5660 regulation device) manufactured by Toyo Seiki Seisakusho at a radiation amount of 50 kW / m ² .

Example of production of thin inorganic paperboard:
Calcium silicate hydrate with an average particle size of 40 μm [tobermorite (slurry, solid content = 10% by mass)] 15% by mass, ordinary Portland cement (manufactured by Taiheiyo Cement Co., Ltd., specific surface area 3300 cm ² / g) 55% by mass; Wollastonite 15% by mass; wood pulp (fiber length 3.5 mm, fiber diameter 30 μm, CSF 280 ml) 6% by mass as natural fiber; polyvinyl alcohol fiber (fiber length 4.0 mm, fiber diameter 27 μm) 2% by mass as synthetic fiber; Water is added to and mixed with a compound having a composition of 7% by mass of calcium carbonate (inorganic filler) to form a slurry having a concentration of about 10% by mass. I got a raw board. The obtained green plate was subjected to pressure dehydration with a press at a pressure of 32 N / mm ² for 10 minutes, and then steam-cured at a temperature of 60 ° C. for 15 hours and cured to obtain a 3.2 mm thick inorganic paper plate. Obtained. The physical properties of the resulting inorganic paperboard are as follows:
Apparent density: 1.36 g / cm ³
Deflection by its own weight: 470mm in width 910mm, length 2572mm
Maximum deflection by bending test: 30.6 mm
Bending strength: 31 N / mm ²
Total calorific value: 2.9 MJ / m ²

Example 1
Using the thin inorganic papermaking board obtained as described above as a base material, and polishing the surface of the base material with a No. 120 polishing paper with a platen type polishing machine, a moisture curable isocyanate is then applied with a roll coater. A base reinforcing layer was formed by coating. In addition, the organic solid content application amount of the base reinforcing layer was 3.8 g / m ² .
Next, a decorative layer was formed on the surface of the base reinforcing layer obtained as described above by applying an acrylic urethane resin with a flow coater. In addition, the organic solid content application amount of the decoration layer was 33.0 g / m ² .
Furthermore, the surface protective layer was formed by apply | coating acrylic urethane type ultraviolet curable resin to the surface of the decoration layer obtained as mentioned above with a flow coater. In addition, the organic solid content application amount of the surface protective layer was 72.1 g / m ² .
The obtained decorative board had a total organic solid content of 108.9 g / m ² and a total calorific value of 7.0 MJ / m ² .

Example 2
Using the thin inorganic papermaking board obtained as described above as a base material, and polishing the surface of the base material with a No. 120 polishing paper with a platen type polishing machine, a moisture curable isocyanate is then applied with a roll coater. A base reinforcing layer was formed by coating. In addition, the organic solid content application amount of the base reinforcing layer was 3.5 g / m ² .
Next, an acrylic urethane resin is applied to the surface of the base reinforcing layer obtained as described above with a flow coater (organic solid content coating amount: 33.0 g / m ² ), and then the acrylic urethane resin is applied. A decorative layer was formed by applying the resin by gravure offset printing (application amount of organic solid content: 1.1 g / m ² ).
Furthermore, the surface protective layer was formed by apply | coating acrylic urethane type ultraviolet curable resin to the surface of the decoration layer obtained as mentioned above with a flow coater. In addition, the organic solid content application amount of the surface protective layer was 65.0 g / m ² .
The obtained decorative board had a total organic solid content of 116.2 g / m ² and a total calorific value of 7.5 MJ / m ² .

Example 3
Using the thin inorganic papermaking board obtained as described above as a base material, and polishing the surface of the base material with a No. 120 polishing paper with a platen type polishing machine, a moisture curable isocyanate is then applied with a roll coater. A base reinforcing layer was formed by coating. In addition, the organic solid content application amount of the base reinforcing layer was 3.0 g / m ² .
Next, a decorative layer was formed on the surface of the base reinforcing layer obtained as described above by applying an acrylic urethane resin with a flow coater. In addition, the organic solid content application amount of the decoration layer was 38.5 g / m ² .
Furthermore, the surface protective layer was formed by apply | coating acrylic urethane type ultraviolet curable resin to the surface of the decoration layer obtained as mentioned above with a flow coater. In addition, the organic solid content application amount of the surface protective layer was 69.3 g / m ² .
Further, after the other surface of the substrate was surface-polished using a No. 100 abrasive paper with a platen type grinder, moisture-curable isocyanate was applied with a roll coater to form a back surface reinforcing layer. In addition, the organic solid content application amount of the back reinforcing layer was 2.1 g / m ² .
The obtained decorative board had a total organic solid content of 112.9 g / m ² and a total calorific value of 7.3 MJ / m ² .

Comparative Example 1
Using the thin inorganic papermaking board obtained as described above as a base material, and polishing the surface of the base material with a No. 120 polishing paper with a platen type polishing machine, a moisture curable isocyanate is then applied with a roll coater. A base reinforcing layer was formed by coating. In addition, the organic solid content application amount of the base reinforcing layer was 4.8 g / m ² .
Next, a decorative layer was formed on the surface of the base reinforcing layer obtained as described above by applying an acrylic urethane resin with a flow coater. In addition, the organic solid content application amount of the decoration layer was 45.6 g / m ² .
Furthermore, the surface protective layer was formed by apply | coating acrylic urethane type ultraviolet curable resin to the surface of the decoration layer obtained as mentioned above with a flow coater. In addition, the organic solid content application amount of the surface protective layer was 96.2 g / m ² .
The obtained decorative board had a total organic solid content of 146.6 g / m ² and a total calorific value of 9.1 MJ / m ² .

  The decorative board of the present invention can be suitably used as a building material or the like.

Claims (4)

30-70% by mass of a hydratable raw material for matrix formation; 3-6% by mass of natural fibers having a freeness within the range of 150-450 ml in Canadian standard freeness, a fiber length of 6.0-0.2 mm, and a fiber diameter of 10-10 0.5 to 3% by mass of inorganic fiber and / or synthetic fiber (excluding asbestos) within the range of 50 μm, provided that the total amount of natural fiber and inorganic fiber and / or synthetic fiber is 3.5 to 9% by mass and synthetic fiber 2% by mass or less (including zero); 5-30% by mass of calcium silicate hydrate having an average particle diameter in the range of 30 μm to 100 μm obtained by hydrothermal synthesis of a calcareous raw material and a silicic acid raw material in advance; A mixture containing 5 to 20% by weight of wollastonite; and 1 to 15% by weight of an inorganic filler is wet-mixed to obtain a slurry, and the resulting slurry is made to obtain a green plate. Board After pressurizing圧脱water holding pressure 16~40N / mm ² during pressure dehydration, thickness 2~5mm obtained by curing curable, apparent density 1.2~1.5g ^/ cm 3, JIS A 5430 the total calorific value 3.5 mJ / ^{m 2} or less der in heating test at the heating time of 20 minutes with the test device Annex JA defined is, width 910 mm, thin the air dried state having dimensions of length 2575mm No. 3 test defined in JIS A 1408 4.1, where the deflection due to its own weight when it is supported at the central part in the longitudinal direction of the inorganic papermaking sheet is 500 mm or less due to the difference between the central part and the edge part. with single, maximum deflection and bending strength in 20~50mm by bending test based on 10.3.2 of JIS a 5430 has a 28N / mm ² or more der Ru thin inorganic papermaking plate substrate, the substrate Reinforcement of the base on one surface , Decorative layer and it becomes provided with a decorative layer consisting of three layers of the surface protective layer, the underlying reinforcing layer, decorative layer and three layers of the surface protective layer decorative layer total organic solid content 50~140g / m ² of The total calorific value in the exothermic test with a heating time of 20 minutes using a test apparatus defined in JIS A 5430 Annex JA is 8.0 MJ / m ² or less. A decorative board. The other surface of the substrate is provided with a back surface protective layer, and the total organic solid content of the decorative layer and the back surface protective layer consisting of three layers of the base reinforcing layer, the decorative layer and the surface protective layer is 50 to 140 g / m. The decorative board according to claim 1, which is in the range of ² . 30-70% by mass of a hydratable raw material for matrix formation; 3-6% by mass of natural fibers having a freeness within the range of 150-450 ml in Canadian standard freeness, a fiber length of 6.0-0.2 mm, and a fiber diameter of 10-10 0.5 to 3% by mass of inorganic fiber and / or synthetic fiber (excluding asbestos) within the range of 50 μm, provided that the total amount of natural fiber and inorganic fiber and / or synthetic fiber is 3.5 to 9% by mass and synthetic fiber 2% by mass or less (including zero); 5-30% by mass of calcium silicate hydrate having an average particle diameter in the range of 30 μm to 100 μm obtained by hydrothermal synthesis of a calcareous raw material and a silicic acid raw material in advance; A mixture containing 5 to 20% by weight of wollastonite; and 1 to 15% by weight of an inorganic filler is wet-mixed to obtain a slurry, and the resulting slurry is made to obtain a green plate. Board After pressurizing圧脱water holding pressure 16~40N / mm ² during pressure dehydration, the thickness 2~5mm by curing curable, apparent density 1.2~1.5g ^/ cm 3, JIS A 5430 Annex JA the total calorific value 3.5 mJ / ^{m 2} or less der in heating test at the heating time of 20 minutes with the test device defined is, width 910 mm, thin inorganic papermaking plates air dried state having dimensions of length 2575mm No. 3 test piece defined in JIS A 1408 4.1 is used, and the deflection due to its own weight when it is supported at the center in the longitudinal direction is 500 mm or less due to the difference between the center and the edge. , the maximum deflection give der Ru thin inorganic papermaking plate and flexural strength of 28N / mm ² or more in 20~50mm by bending test based on 10.3.2 of JIS a 5430; thin material one surface of the inorganic papermaking plate The ground reinforcement layer Forming a decorative layer on the surface of the base reinforcing layer; and forming a surface protective layer on the surface of the decorative layer, wherein the total organic solid content of the base reinforcing layer, the decorative layer, and the surface protective layer is The total calorific value in the exothermic test in a heating time of 20 minutes using a test apparatus defined in JIS A 5430 Annex JA of the obtained decorative plate is in the range of 50 to 140 g / m ² , and is 8.0 MJ / m. The manufacturing method of the decorative board characterized by being ² or less. A back surface protective layer is formed on the other surface of the thin inorganic papermaking plate, wherein the total organic solid content of the base reinforcing layer, the decorative layer, the surface protective layer, and the back surface protective layer is in the range of 50 to 140 g / m ² . The manufacturing method of the decorative board of Claim 3 which exists in a inside.