Glass for mfg. fibres, esp. for thermal insulation - contains silica, alumina, boric oxide, sodium oxide and lime, and has low softening pt. aiding spinning of thin fibres

摘要

The glass contains by wt. 53-63% SiO2, 3-7% Al2O3, 5-10% B2O3, 10-15.5% Na2O, 6-12% CaO, and all maxima, 2.5% K2O, 6% MgO, 6% BaO, 2% Li2O, 1.2% fluorine; and with all maxima, 16.4% Na2O + Li2O; 18% Na2O + K2O + Li2O. The glass contains 8-18% CaO + MgO + BaO in which at least 6/10ths consists of CaO; and also contains at least 0.4% Li2O + F. The glass pref. contains min. 0.4% or min. 0.6% F and min. 1% Li2O, plus min. 1% K2O. The glass pref. also contains ca. 4% of MgO and/or BaO. The glass has a low softening point of 621-666 deg.C, facilitating the mfr. of fibres by a rotary die described in US4058386.