Patent ID: 6881692
Filing Date: 2005-04-19
Classification: C03C

Abstract:
1. An alkali-free glass cons sting essentially of, in mass percent, 58-70% SiO 2 , 10-19% Al 2 O 3 , 6.5-15% B 2 O 3 , 0-2% MgO, greater than 8%-12% CaO, 0.1-2% BaO, 0-4% SrO, 0.1-6% BaO+SrO, 0-5% ZnO, 5-12% MgO+CaO+BaO+SrO+ZnO, 0-5% ZrO 2, 0-5% TiO 2 , and 0-5% P 2 O 5 , containing substantially no alkali metal oxide, being formed into a plate shape by the down-drawn process, and having a density of 2.40 g/cm 3 or less, an average coefficient of thermal expansion of 25×10 −7 /° C.-36×10 −7 /° C. within a temperature range between 30 and 380° C. and a strain point not lower than 640° C., in which the liquidus temperature is not higher than 1130° C., and the viscosity at the liquidus temperature being not lower than 10 5.4 dPa·s.