High strength glass fibre for reinforcing plastic - has low alkali content and low softening point

摘要

Glass fibre prods. contg. 52-57.3 wt.% SiO2, 16.3-18.5 wt.% Al2O3, 6.6-10.5 wt.% MgO, 8,5-12.7 wt.% CaO, 0.6-0.8 wt.% TiO2, 2.0-4.1 wt.% B2O3 and 0.8-3.3 wt.% Na2O having a tensile strength of 570,000 psi (pounds/inch2), are formed from a glass with a softening point of 900 degrees C and a temp. at which the glass is molten of 1210 degrees C.