摘要 |
<p>This specification describes a method for making a cellulosic material fire-resistant. The material is well dried and then impregnated with an aqueous solution containing phosphoric acid and ammonium sulphate and/or ammonium phosphate. The solution may also contain borax, trisodiumphosphate, ammonia, sodium carbonate, and sodium chloride. The method is particularly suited for treating sawdust in the manufacturing of chipboards. After impregnating the dry sawdust with the solution under stirring the material is dried once more and glue is applied whereupon chipboards are formed from the composite material.</p> |