| 摘要 |
PURPOSE:To obtain glass requiring no excessive reduction of the slit width of a nozzle and causing no breaking of a glass layer due to the eccentricity of the nozzle by reducing the amount of BaO and specifying the amounts of SiO2, B2O3 and BaO, the total amount of them, and the total amount of one or more among Na2O, K2O and Li2O. CONSTITUTION:This glass consists of, by mole, 20.0%<SiO2<48.0%, 25.0%< B2O3<50.0%, 5.0%<=BaO<=6.0% and 7.0%<(one or more among Na2O, K2O and Li2O)<18.0% while satisfying 71.0%<(SiO2+B2O3+BaO)<80.0%. When sufficient water resistance is obtd. using less than the lower limit of BaO, the meltability is deteriorated in combination with other conditions, and in case of more than the upper limit of BaO, it is difficult to increase the viscosity of the glass at the spinning temp. |
