| 摘要 |
<p>Glass fibre contains by wt. 37-48% SiO2, 17-25% Al2O3, 23-33% CaO, 0.1-7% MgO, 0.1-3% Fe2O3, 2-8% Na2O, 0.1-7% K2O, and less than 3% of impurities; where the total of alkaline earth oxides is max. 34% and the fibre contains more than 5% of alkali metal oxides. The ratio Al2O3/SiO2 is pref. above 0.4; and the ratio MgO/CaO is pref. below 0.2. The pref. fibre contains 38-44% SiO2, 17.5-22% Al2O3, 25-29% CaO, 0.1-5% MgO, 0.5-2.5% Fe2O3, 2-6% Na2O, and 0.1-6% K2O, where the total of alkaline earth oxides is max. 32%. An esp. pref. fibre has the compsn. (F1) 42.3% SiO2, 18.5% Al2O3, 27.7% CaO, 0.3% MgO, 1.7% Fe2O3, 4.3% Na2O, 4.3% K2O, and 0.9% impurities. Used esp. in the mfr. of tubes or shells used as thermally insulating lagging on pipes; panels; rigid- or semi-rigid prods.; fire barriers; sound insulation; or silencers carrying fluids at high temp. The glass compsn. given above is very suitable for mfg. discontinuous fibres by the plant described in FR 2223318. The fibres are used to make thermally insulating prods. which can be employed at up to 700 deg.C.</p> |
