Glass for chemical strengthening

Abstract

The present invention relates to a glass for chemical strengthening including, in mole percentage on an oxide basis: 60 to 72% of SiO2; 9 to 20% of Al2O3; 1 to 15% of Li2O; 0.1 to 5% of Y2O3; 0 to 1.5% of ZrO2; and 0 to 1% of TiO2, having a total content of one or more kinds of MgO, CaO, SrO, BaO and ZnO of 1 to 10%, having a total content of Na2O and K2O of 1.5 to 10%, having a total content of B2O3 and P2O5 of 0 to 10%, wherein a ratio ([Al2O3]+[Li2O])/([Na2O]+[K2O]+[MgO]+[CaO]+[SrO]+[BaO]+[ZnO]+[ZrO2]+[Y2O3]) is from 0.7 to 3, wherein a ratio [MgO])/([CaO]+[SrO]+[BaO]+[ZnO]) is from 10 to 45, and having a value M expressed by the following expression of 1,100 or more: M=−5×[SiO2]+121×[Al2O3]+50×[Li2O]−35×[Na2O]+32×[K2O]+85×[MgO]+54×[CaO]−41×[SrO]−4×[P2O5]+218×[Y2O3]+436×[ZrO2]−1180, wherein each of [SiO2], [Al2O3], [Li2O], [Na2O], [K2O], [MgO], [CaO], [SrO], [P2O5], [Y2O3], and [ZrO2] designates a content of each component in mole percentage on an oxide basis.

Dependencies are inferred from the claim text.