| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject board with improved surface accuracy and moisture absorbing/releasing characteristics by including gypsum, cement, inorganic powder, a fibrous material and moisture absorbing/releasing material. SOLUTION: This board comprises gypsum, cement, inorganic powder, a fibrous material and moisture absorbing/releasing material. The gypsum may be natural or synthetic one or the like, preferablyα-hemihydrate gypsum produced as the by-product by the wet process that produces phosphoric acid from phosphorus ore and sulfuric acid, more preferablyα-hemihydrate gypsum dried and incorporated with an inorganic alkali. The cement may be various types of Portland cement, Portland blast-furnace cement, fly ash cement or the like, used preferably at 30 to 0 pts.wt. per 70 to 100 pts.wt. of the gypsum. The inorganic powder is a light aggregate or the like, e.g. fly ashes, sirasu balloons or pearlite, its grain size being 20 to 500μm. The fibrous material may be natural or synthetic, e.g. fibers from pulp of a vegetable, needle-leaved tree or the like, or glass fibers. The moisture absorbing/releasing material includes inorganic one, e.g. zeolite or attapulgite, or organic one, e.g. poval, CMC or thermosetting resin. |
