Sound absorption panels or mouldings for outdoor use - made from perlite or obsidian plus sodium silicate and -fluorosilicate

摘要

In addn. to good sound absorption esp. at low frequencies the matl. has good fire- and weather-resistance, 100 pts. wt. dry, burnt or sintered granular perlite or obsidian is mixed with 50-100 pts. wt. sodium silicate, and 7-12 wt. % sodium fluorosilicate w.r.t. the wt. of sodium silicate, then moulded to the required shape using a press. of 1.5-3 kg/cm2. The sodium silicate functions as binder and the fluorosilicate as a fixing, setting or bedding matl.; fillers, e.g. CaO, alumina, ZnO, china clay or diatomite can be added and multi-layer panels can be made with air cavities etc.