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AssigneePilkington plc
InventorsAshley Carl Torr, Louise Sara Butcher, Kevin Jones, Alan Charles Woodward
Estimating the term…
Glazing, thermally tempered to required standards, are produced more readily by tempering panes having a high coefficient of thermal expansion (greater than 93×10−7 per degree Centigrade) and for a low Fracture Toughness (less than 0.72 MPam½). Use of glasses selected according to the invention enables thin glazings (especially glazings less than 3 mm thick) to be tempered to automotive standard with improved yields using conventional tempering methods, and thicker glazings to be tempered at lower quench pressure than required hitherto. Suitable glasses include glasses comprising, in percentages by weight, 64 to 75% SiO2, 0 to 5% Al2O3, 0 to 5% B2O3, 9 to 16% alkaline earth metal oxide other than MgO, 0 to 2% MgO, 15 to 18% alkali mental oxide and at least 0.05% total iron (calculated as Fe2O3)
A thermally tempered glazing of soda lime silica glass produced by tempering a pane of glass having an alkali metal oxide content in the range 15 to 18% by weight, a coefficient of thermal expansion greater than 93×10−7 per degree Centigrade and a Fracture Toughness of less than 0.72 MPam½.
A thermally tempered glazing of soda lime silica glass having a thickness of less than 3 mm, the glass being green glass containing at least 14.5% by weight Na2O, at least 10.5% by weight CaO, at least 0.5% by weight total iron (measured as Fe2O3) and being substantially magnesium-free, the glass having a ferrous value (% ferrous) of at least 30%.
A laminated automotive comprising at least one semi tempered glass pane having a thickness in the range 1.5 mm to 2.5 mm, and being of green glass having a composition comprising at least 14.5% by weight Na2O, at least 10.5% by weight CaO, at least 0.5% by weight total iron (measured as Fe2O3) and being substantially magnesium-free, the glass having a ferrous value (% ferrous) of at least 30%.
Dependencies are inferred from the claim text.