| 摘要 |
<p>707,182. Incombustible felted-fibrous board &c. BJORKMAN, E. B. Jan. 30, 1952 [Feb. 12, 1951; May 29, 1951], No. 2511/52. Class 96 Incombustible building boards &c. are made from glass wool, rock wool, slag wool, or asbestos &c. optionally with some woodfibres, in a solution of up to 2 per cent. of gelatinized starch, which may include rosin, phenolic, cresolic, melamine, urea resins, or saponified resin acids, emulsified tall oil, blood albumin, cellulose derivatives, or inorganic binders, e.g. waterglass &c. The mineral fibre &c. is pulped in a dilute solution of the starch and sodium hydroxide, sulphuric acid or aluminium-, iron-, or zinc-sulphate being then added to precipitate the size, e.g. at pH = 5.8, and hard or porous board formed therefrom, with or without pressing. Board made from mineral wool may be placed on a thin sheet of wood pulp or asbestos fibres, and the two plies may be pressed and dried together.</p> |
