Building board and method for producing the same

Abstract

A building board includes a base material, an insulating coating film for covering a surface of the base material, and a transparent clear coating film for covering the insulating coating film. The insulating coating film contains a coating film forming material, organic hollow particles, and a water-soluble solvent. The method for producing the building board includes a step of forming an insulating coating film in which an insulating paint is applied to a surface of the base material and then dried to form the insulating coating film, and a step of forming a clear coating film in which a clear paint is applied to a surface of the insulating coating film and then dried to form the clear coating film. The insulating paint contains a coating film forming material, organic hollow particles, and a water-soluble solvent.

What is claimed is: 
     
         1 . A building board comprising:
 a base material;   an insulating coating film for covering a surface of the base material; and   a transparent clear coating film for covering the insulating coating film,   wherein the insulating coating film contains a coating film forming material, organic hollow particles, and a water-soluble solvent,   the organic hollow particles have an average hollow ratio of 80% or more and an average particle diameter of 5 to 50 μm, and   the water-soluble solvent is at least one of a glycol-based solvent and a glycol ether-based solvent.   
     
     
         2 . The building board according to  claim 1 , wherein the organic hollow particles comprise at least one of acrylonitrile, methacrylonitrile, vinylidene chloride, acrylic ester, and styrene. 
     
     
         3 . The building board according to  claim 1 , wherein the insulating coating film contains 0.01 to 5.0 parts by mass of the organic hollow particles with respect to 100 parts by mass of solid content thereof. 
     
     
         4 . The building board according to  claim 1 , wherein the insulating coating film has an average film thickness of 5 to 500 μm. 
     
     
         5 . The building board according to  claim 1 , wherein a transparent hydrophilic coating film is formed as an outermost layer so as to cover the clear coating film. 
     
     
         6 . The building board according to  claim 5 , wherein the hydrophilic coating film is constituted by at least one of silica, colloidal silica, and fumed silica. 
     
     
         7 . The building board according to  claim 1 , wherein the base material is a ceramic siding board. 
     
     
         8 . A method for producing a building board comprising a base material, an insulating coating film for covering a surface of the base material, and a clear coating film for covering the insulating coating film, the method comprising:
 a step of forming an insulating coating film in which an insulating paint is applied to a surface of the base material and then dried to form the insulating coating film; and   a step of forming a clear coating film in which a clear paint is applied to a surface of the insulating coating film and then dried to form the clear coating film,   wherein a paint containing a coating film forming material, organic hollow particles, and a water-soluble solvent whose boiling point is higher than a temperature of the coating film when the coating film is dried in the step of forming an insulating coating film and the step of forming a clear coating film is used as the insulating paint,   the organic hollow particles have an average hollow ratio of 80% or more, and an average particle diameter of 5 to 50 μm, and   the water-soluble solvent is at least one of a glycol-based solvent and a glycol ether-based solvent.   
     
     
         9 . The method for producing a building board according to  claim 8 , wherein the temperature of the coating film is set to not more than 130° C.° when the coating film is dried in the step of forming an insulating coating film and the step of forming a clear coating film. 
     
     
         10 . The method for producing a building board according to  claim 8 , wherein the organic hollow particles comprise at least one of acrylonitrile, methacrylonitrile, vinylidene chloride, acrylic ester, and styrene. 
     
     
         11 . The method for producing a building board according to  claim 8 , wherein the insulating paint contains 0.01 to 5.0 parts by mass of the organic hollow particles with respect to 100 parts by mass of solid content thereof. 
     
     
         12 . The method for producing a building board according to  claim 8 , further comprising a step of forming a hydrophilic coating film in which a hydrophilic paint is applied to a surface of the clear coating film and then dried to form a transparent hydrophilic coating film as an outermost layer. 
     
     
         13 . The method for producing a building board according to  claim 12 , wherein the hydrophilic paint is a solution in which at least one of silica, colloidal silica, and fumed silica is dispersed. 
     
     
         14 . The method for producing a building board according to  claim 8 , wherein the base material is a ceramic siding.