| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high quality gypsum board excellent in moisture absorbing/desorbing efficiency and water-repellence, good in dimensional stability when moisture is absorbed while excellent properties, convenience and economical efficiency are provided similarly to the conventional gypsum board by blending gypsum core with a water-repellence imparting agent and an inorganic moisture absorbing/desorbing material. SOLUTION: As the silicone-based water-repellence imparting agent, organosiloxane and organopolysiloxane are exemplified and, as the paraffin- based water-repellence imparting agent, such an emulsion can be used, as is obtained by incorporating polyvinyl alcohol in the emulsion of waxes having 40-90 deg.C melting point and a derivative of an olefin-maleic anhydride polymer. The amount of the water-repellence imparting agent to be added is 0.05-1 pts.wt. when the silicone-based water-repellence imparting agent is used and 0.5-5 pts.wt. when the paraffin-based water-repellence imparting agent is used respectively based on 100 pts.wt. gypsum. As the inorganic moisture absorbing/desorbing material, for example, zeolite group, diatomaceous earth, silicic shale, or the like, can be used.
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