| 摘要 |
PURPOSE:To obtain the titled composition with hydraulic rate moderately made promotable, by incorporating proper amount of sulfamic acid or activated clay in a composition comprising hydrofluoric acid anhydrous gypsum and metal sulfate(s) as the curing promotor. CONSTITUTION:The objective composition can be obtained by incorporating (A) a composition prepared by incorporating (i) hydrofluoric acid anhydrous gypsum produced by adding, to a byproduct from hydrofluoric acid manufacturing processes, such amount of calcium hydroxide as to be more than that required for neutralizing the residual acid component with (ii) pref. 0.2-5.0wt.%, based on the gypsum, of at least one kind of curing promotor selected from potassium sulfate, sodium sulfate, aluminum sulfate and potash alum etc. with (B) such amount of sulfamic acid or activated clay as to be pH4-10 after kneading the composition A with water. This composition is suitable for gypsum board plaster etc. without using any setting retarder, also being able to made into self-leveling material by adding, furthermore, a fluidizing agent, viscosity regulator, antifoaming agent etc. |
