Tempered glass, tempered glass plate, and glass for tempering

Abstract

A tempered glass has a compressive stress layer in a surface thereof, includes as a glass composition, in terms of mass %, 50 to 80% of SiO 2 , 10 to 30% of Al 2 O 3 , 0 to 6% of B 2 O 3 , 0 to 2% of Li 2 O, and 5 to 25% of Na 2 O, and is substantially free of As 2 O 3 , Sb 2 O 3 , PbO, and F.

1 . A tempered glass having a compressive stress layer in a surface thereof, comprising as a glass composition, in terms of mass %, 50 to 80% of SiO 2 , 10 to 30% of Al 2 O 3 , 0 to 6% of B 2 O 3 , 0 to 2% of Li 2 O, and 5 to 25% of Na 2 O, and being substantially free of As 2 O 3 , Sb 2 O 3 , PbO, and F. 
     
     
         2 . The tempered glass according to  claim 1 , wherein the tempered glass comprises as a glass composition, in terms of mass %, 50 to 80% of SiO 2 , 10 to 30% of Al 2 O 3 , 0 to 6% of B 2 O 3 , 0 to 1.7% of Li 2 O, more than 7.0 to 25% of Na 2 O, and 0 to 2% of SrO. 
     
     
         3 . The tempered glass according to  claim 1 , wherein the tempered glass comprises as a glass composition, in terms of mass %, 50 to 76% of SiO 2 , more than 16.0 to 30% of Al 2 O 3 , 0 to 6% of B 2 O 3 , 0 to 1.7% of Li 2 O, more than 7.0 to 25% of Na 2 O, 0 to 2% of SrO, and 0 to 4.5% of TiO 2 . 
     
     
         4 . The tempered glass according to  claim 1 , wherein the tempered glass comprises as a glass composition, in terms of mass %, 50 to 76% of SiO 2 , more than 16.0 to 30% of Al 2 O 3 , 0 to 6% of B 2 O 3 , 0 to 1.7% of Li 2 O, more than 7.0 to 25% of Na 2 O, 0 to 2% of SrO, 0 to 0.5% of TiO 2 , and 0 to 4% of ZrO 2 . 
     
     
         5 . The tempered glass according to  claim 1 , wherein the tempered glass comprises as a glass composition, in terms of mass %, 50 to 76% of SiO 2 , more than 16.0 to 30% of Al 2 O 3 , 0 to 6% of B 2 O 3 , 0 to 1.7% of Li 2 O, more than 7.0 to 25% of Na 2 O, 0 to 2% of SrO, 0 to 0.5% of TiO 2 , 0 to 4% of ZrO 2 , and 0 to 1% of P 2 O 5 , and has a molar ratio (MgO+CaO+SrO+BaO)/(Al 2 O 3 +B 2 O 3 ) of from 0 to 0.60. 
     
     
         6 . The tempered glass according to  claim 1 , wherein the tempered glass comprises as a glass composition, in terms of mass %, 50 to 76% of SiO 2 , more than 16.0 to 30% of Al 2 O 3 , 0 to 6% of B 2 O 3 , O to less than 1.0% of Li 2 O, more than 7.0 to 25% of Na 2 O, 0 to 2% of SrO, 0 to 0.5% of TiO 2 , 0 to 2% of ZrO 2 , 0.2 to 3% of SnO 2 , and 0 to 1% of P 2 O 5 , and has a molar ratio (MgO+CaO+SrO+BaO)/(Al 2 O 3 +B 2 O 3 ) of from 0 to 0.55. 
     
     
         7 . The tempered glass according to  claim 1 , wherein the tempered glass comprises as a glass composition, in terms of mass %, 50 to 73% of SiO 2 , more than 16.0 to 30% of Al 2 O 3 , 0 to 6% of B 2 O 3 , O to less than 1.0% of Li 2 O, more than 7.0 to 25% of Na 2 O, 10 to 30% of Li 2 O+Na 2 O+K 2 O, 0 to 4% of CaO, 0 to 2% of SrO, 0 to 0.5% of TiO 2 , 0 to 2% of ZrO 2 , 0.2 to 3% of SnO 2 , and 0 to 1% of P 2 O 5 , and has a molar ratio (MgO+CaO+SrO+BaO)/(Al 2 O 3 +B 2 O 3 ) of from 0 to 0.55. 
     
     
         8 . The tempered glass according to  claim 1 , wherein a compression stress value of the compression stress layer is 300 MPa or more and 1,200 MPa or less, and a thickness of the compression stress layer is 10 μm or more and 60 μm or less. 
     
     
         9 . The tempered glass according to  claim 1 , wherein the tempered glass has a liquidus temperature of 1,200° C. or less. 
     
     
         10 . The tempered glass according to  claim 1 , wherein the tempered glass has a liquidus viscosity of 10 4.0  dPa·s or more. 
     
     
         11 . The tempered glass according to  claim 1 , wherein the tempered glass has a temperature at 10 4.0  dPa·s of 1,300° C. or less. 
     
     
         12 . The tempered glass according to  claim 1 , wherein the tempered glass has a thermal expansion coefficient in a temperature range of from 25 to 380° C. of 100×10 −7 /° C. or less. 
     
     
         13 . A tempered glass sheet, comprising the tempered glass according to  claim 1 . 
     
     
         14 . A tempered glass sheet having a length dimension of 500 mm or more, a width dimension of 300 mm or more, and a thickness of from 0.5 to 2.0 mm, having a compression stress value of a compression stress layer of 300 MPa or more and 1,200 MPa or less and a thickness of the compression stress layer of 10 μm or more and 60 μm or less, and being subjected to tempering treatment so as to have a dimensional change rate S between before and after tempering treatment of from −1,000 ppm to +1,000 ppm. 
     
     
         15 . The tempered glass sheet according to  claim 13 , wherein the tempered glass sheet has a Young's modulus of 65 GPa or more. 
     
     
         16 . The tempered glass sheet according to  claim 13 , wherein the tempered glass sheet has a fictive temperature Tf of 500° C. or more. 
     
     
         17 . The tempered glass sheet according to  claim 13 , wherein the tempered glass sheet is formed by an overflow down-draw method. 
     
     
         18 . The tempered glass sheet according to  claim 17 , wherein the tempered glass sheet is cut at a position spaced apart downwardly by 1,000 mm or more from a lower end of a forming trough used in the overflow down-draw method. 
     
     
         19 . The tempered glass sheet according to  claim 13 , wherein the tempered glass sheet is used for a touch panel display. 
     
     
         20 . The tempered glass sheet according to  claim 13 , wherein the tempered glass sheet is used for a cover glass for a cellular phone. 
     
     
         21 . The tempered glass sheet according to  claim 13 , wherein the tempered glass sheet is used for a cover glass for a solar battery. 
     
     
         22 . The tempered glass sheet according to  claim 13 , wherein the tempered glass sheet is used for a protective member for a display. 
     
     
         23 . A tempered glass sheet having a length dimension of 500 mm or more, a width dimension of 300 mm or more, and a thickness of from 0.3 to 2.0 mm, comprising as a glass composition, in terms of mass %, 50 to 80% of SiO 2 , 10 to 30% of Al 2 O 3 , 0 to 6% of B 2 O 3 , 0 to 2% of Li 2 O, 5 to 25% of Na 2 O, 10 to 30% of Li 2 O+Na 2 O+K 2 O, 0 to 2% of SrO, 0 to less than 0.50% of TiO 2 , 0 to 4% of ZrO 2 , 0.2 to 3% of SnO 2 , and 0 to 1% of P 2 O 5 , having a molar ratio (MgO+CaO+SrO+BaO)/(Al 2 O 3 +B 2 O 3 ) of from 0 to 0.60, being substantially free of As 2 O 3 , Sb 2 O 3 , PbO, and F, having a compression stress value of a compression stress layer of 300 MPa or more and 1,200 MPa or less, a thickness of the compression stress layer of 10 μm or more and 60 μm or less, a liquidus temperature of 1,200° C. or less, a thermal expansion coefficient in a temperature range of from 25 to 380° C. of 100×10 −7  or less, a Young's modulus of 65 GPa or more, and a fictive temperature Tf of 500° C. or more, and being subjected to tempering treatment so as to have a dimensional change rate S between before and after tempering treatment of from −1,000 ppm to +1,000 ppm. 
     
     
         24 . A glass to be tempered, comprising as a glass composition, in terms of mass %, 50 to 80% of SiO 2 , 10 to 30% of Al 2 O 3 , 0 to 6% of B 2 O 3 , 0 to 2% of Li 2 O, and 5 to 25% of Na 2 O, and being substantially free of As 2 O 3 , Sb 2 O 3 , PbO, and F. 
     
     
         25 . A glass to be tempered having a dimensional change rate S between before and after tempering treatment of from −1,000 ppm to +1,000 ppm, the tempering treatment comprising immersion in a KNO 3  molten salt at 440° C. for 6 hours. 
     
     
         26 . The glass to be tempered according to  claim 25 , wherein the glass to be tempered has a fictive temperature Tf of 500° C. or more.