HIGH-STRENGTH ALKALI-ALUMINOSILICATE GLASS

摘要

A high-strength alkali-aluminosilicate glass, characterized by excellent meltability, fineability. and processibility, exhibits the following formula: SiO2 60.5 to 69.0 weight percent Al2O3 7.0 to 11.8 weight percent B2O3 0 to 4.0 weight percent MgO 2.0 to 8.5 weight percent CaO 0 to 4.0 weight percent ZnO 0 to 5.0 weight percent ZrO2 0 to 3.0 weight percent Na2O 15.0 to 17.5 weight percent K2O 0 to 2.7 weight percent Li2O 0 to 2.0 weight percent and from 0 to 1.5 weight percent of a fining agents such as As2O3, Sb2O3 CeO2, SnO2, Cl-, F-, (SO4) 2- and combinations thereof. The glass allows for adequate conditions for an alkali ion exchange treatment in a short time period (4 to 8 hours) and can also be produced according to the established, continuous, vertically downward directed drawing process such as the overflow down-draw method or the fusion method, the die slot or the slot down-draw method, or combinations thereof. The viscosity temperature profile of these glasses allows the use of conventional fining agents in combination at the lowest amounts possible and additionally allows the production of glasses that are free of or contain only small amounts of either or both of antimony oxide and arsenic oxide.