| 摘要 |
<p><PICT:1037351/C1/1> A lightweight gypsum board comprises a paper cover sheet and a gypsum core of density 38-45 lb./ft.3 containing boric acid in an amount defined by the area ABCDE of the Figure. The gypsum core may be prepared from a mixture of gypsum hemihydrate, paper fibre accelerator, lignin dispersant, starch, rosin soap foaming agent, water and boric acid.</p> |
