# US 2016/0355430 A1 · Glass for chemical strengthening, chemically-strengthened glass, and method for producing chemically-strengthened glass > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2016/0355430 A1 - Document ID: US20160355430A1 - Status: Published application - Kind: A1 - Application number: 15/179,067 - Filed: 2016-06-10 - Published: 2016-12-08 - Earliest claimed: 2013-12-13 - Assignees: Asahi Glass Company, Limited - Applicants: Asahi Glass Company, Limited - Inventors: Shuji YAMAZAKI; Akio Koike; Junichiro Kase; Shusaku Akiba; Junko Miyasaka; Seiki Ohara - Web page: https://patentgrep.com/patent/US20160355430A1 ## CPC - C03C 3/087: containing calcium oxide, e.g. common sheet or container glass - C03C 4/18: for ion-sensitive glass - C03C 21/002: {to perform ion-exchange between alkali ions (C03C21/005 takes precedence)} - C03C 2204/00: Glasses, glazes or enamels with special properties - C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS ## Abstract A glass is a glass sheet containing, as expressed by mass percentage based on oxides, 63 to 75% of SiO2, 3 to 12% of Al2O3, 3 to 10% of MgO, 0.5 to 10% of CaO, 0 to 3% of SrO, 0 to 3% of BaO, 10 to 18% of Na2O, 0 to 8% of K2O, 0 to 3% of ZrO2, and 0.005 to 0.25% of Fe2O3. The glass has a temperature (T2) at which a viscosity thereof reaches 102 dPa·s of 1525° C. or lower. In the glass, R2O/Al2O3 is 2.0 or more and 4.6 or less (in the formula, the R2O is Na2O+K2O). ## Claims ### Claim 1 A glass that is a glass sheet comprising, as expressed by mass percentage based on oxides, 63 to 75% of SiO2, 3 to 12% of Al2O3, 3 to 10% of MgO, 0.5 to 10% of CaO, 0 to 3% of SrO, 0 to 3% of BaO, 10 to 18% of Na2O, 0 to 8% of K2O, 0 to 3% of ZrO2, and 0.005 to 0.25% of Fe2O3, having a temperature (T2) at which a viscosity thereof reaches 102 dPa·s of 1525° C. or lower, wherein R2O/Al2O3 is 2.0 or more and 4.6 or less (in the formula, the R2O is Na2O+K2O). ### Claim 2 (depends on 1) The glass according to claim 1, comprising 1% or more of CaO. ### Claim 3 (depends on 1) The glass according to claim 1, wherein the R2O/Al2O3 is 2.4 or more. ### Claim 4 (depends on 1) The glass according to claim 1, wherein the R2O is 10 to 18%. ### Claim 5 (depends on 1) The glass according to claim 1, wherein Al2O3 is 4% or more, MgO is 3.5% or more, CaO is 5% or more, and BaO is 1% or less. ### Claim 6 (depends on 1) The glass according to claim 1, wherein CaO is less than 5%, BaO is 1% or less and the R2O/Al2O3 is 3.2 or less. ### Claim 7 (depends on 1) The glass according to claim 1, wherein K2O is 2% or less. ### Claim 8 (depends on 1) The glass according to claim 1, further comprising, as expressed by mass percentage based on an oxide, 1% or less of B2O3. ### Claim 9 (depends on 1) The glass according to claim 1, wherein the T2 is 1510° C. or lower. ### Claim 10 (depends on 1) The glass according to claim 1, having a devitrification temperature of not higher than a temperature (T4) at which the viscosity thereof reaches 104 dPa·s. ### Claim 11 (depends on 1) The glass according to claim 1, further comprising, as expressed by mass percentage based on an oxide, 0.2% or less of TiO2. ### Claim 12 (depends on 1) The glass according to claim 1, having a glass transition point (Tg) of 530° C. or higher. ### Claim 13 (depends on 1) The glass according to claim 1, having a mean linear thermal expansion coefficient at 50 to 350° C. of 100×10−7° C.−1 or less. ### Claim 14 (depends on 1) The glass according to claim 1, formed according to a float process. ### Claim 15 (depends on 1) The glass according to claim 1, which is applicable to a chemical strengthening treatment. ### Claim 16 (depends on 15) A chemically strengthened glass obtained by chemically strengthening the glass of claim 15. ### Claim 17 (depends on 16) The chemically strengthened glass according to claim 16, having a surface compressive stress of 580 MPa or more and a depth of compressive stress of 5 μm or more and 30 μm or less. ### Claim 18 (depends on 1) A method for producing a chemically strengthened glass, comprising a chemical strengthening step of subjecting the glass of claim 1 to an ion-exchange treatment.