SHEET GLASS (VERSIONS) AND SHEET GLASS PRODUCTION METHODS Russian patent published in 1998 - IPC

FIELD: glass-making. SUBSTANCE: invention provides sheet glass manufactured preferably in float process, reinforced by prolonged surface ion exchange at temperature ensuring exchange depth to exceed 200 mcm for surface compressive stresses above 400 MPa and to exceed 50 mcm for surface compressive stresses above 700 MPa, whose matrix meets following makeup, wt % oxides of: silicon 65-76, aluminum 1.5-5, magnesium 4-8, calcium up to 4.5, sodium 10-18, potassium 1-7, and boron up to 4, all components constituting at least 96% of glass weight and meeting following inequalities: 0 < CaO/(CaO+MgO) ≪ 0.45 and 0.05 ≪ K₂O/(Na₂O+K₂O) < 0.35. Glass is molded on float-type installation and subjected to potassium ion exchange at 350-475 C for more than 72 h. EFFECT: increased thickness of reinforced layer. 14 cl, 4 dwg