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AssigneeAGC Inc.
InventorsJun Endo, Shusaku Akiba, Kazutaka Ono, Tetsuya Nakashima
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To provide glass to be used for chemically tempered glass, of which the strength is less likely to be reduced even when indentations are formed thereon. Glass for chemical tempering, which comprises, as represented by mole percentage based on oxides, from 62 to 68% of SiO2, from 6 to 12% of Al2O3, from 7 to 13% of MgO, from 9 to 17% of Na2O, and from 0 to 7% of K2O, wherein the difference obtained by subtracting the content of Al2O3 from the total content of Na2O and K2O is less than 10%, and when ZrO2 is contained, its content is at most 0.8%. Chemically tempered glass obtained by chemically tempering such glass for chemical tempering. Such chemically tempered glass has a compressive stress layer formed on the glass surface, which has a thickness of at least 30 μm and a surface compressive stress of at least 550 MPa.
A plate glass which comprises, as represented by mole percentage based on oxides, from 62 to 66% of SiO2, from 7.5 to 9% of Al2O3, from 8 to 13% of MgO, from 9 to 16% of Na2O, from 0.5 to 7% of K2O, 0% B2O3, 0% ZnO, and from 0 to 1% of CaO, wherein the difference obtained by subtracting the content of Al2O3 from the total content of Na2O and K2O is at most 9%, and optionally ZrO2 in an amount of at most 0.6%, wherein the plate glass has a glass transition point of at least 570° C. and a specific gravity of at most 2.55.
Dependencies are inferred from the claim text.