Tempered glass sheet and method for manufacturing same

Abstract

The present invention provides a tempered glass sheet having a compressive stress layer in a surface thereof, the tempered glass sheet including as a glass composition, in terms of mol %, 50% to 80% of SiO2, 8% to 25% of Al2O3, 0% to 10% of B2O3, 3% to 15% of Li2O, 3% to 21% of Na2O, 0% to 10% of K2O, 0% to 10% of MgO, 0% to 10% of ZnO, and 0% to 15% of P2O5.

1 - 19 . (canceled) 
     
     
         20 . A tempered glass sheet having a compressive stress layer in a surface thereof,
 the tempered glass sheet comprising as a glass composition, in terms of mol %, 50% to 80% of SiO 2 , 8% to 25% of Al 2 O 3 , 0% to 10% of B 2 O 3 , 3% to 10% of Li 2 O, 3% to 21% of Na 2 O, 0% to 10% of K 2 O, 10% to 18% of [Li 2 O]+[Na 2 O]+[K 2 O], 0% to 10% of MgO, 0% to 10% of ZnO, and 0.1 to 15% of P 2 O 5 .   
     
     
         21 . The tempered glass sheet according to  claim 20 , wherein the tempered glass sheet has a content of Li 2 O of from 3 mol % to 7 mol %. 
     
     
         22 . The tempered glass sheet according to  claim 20 , wherein the tempered glass sheet has a content of [Li 2 O]+[Na 2 O]+[K 2 O] of from 10 mol % to 16.99 mol %. 
     
     
         23 . The tempered glass sheet according to  claim 20 , wherein the tempered glass sheet has a content of Al 2 O 3  of from 16.25 mol % to 25 mol %. 
     
     
         24 . The tempered glass sheet according to  claim 20 , wherein the tempered glass sheet satisfies the following relationship: a molar ratio ([Na 2 O]−[Li 2 O])/([Al 2 O 3 ]+[B 2 O 3 ]+[P 2 O 5 ])≤0.23. 
     
     
         25 . The tempered glass sheet according to  claim 20 , wherein the tempered glass sheet has a liquidus viscosity of 10 3.74  dPa·s or more. 
     
     
         26 . The tempered glass sheet according to  claim 20 , wherein the compressive stress layer has a depth of layer of 140 μm or more. 
     
     
         27 . The tempered glass sheet according to  claim 20 , wherein the compressive stress layer has a compressive stress value of 900 MPa or more on an outermost surface. 
     
     
         28 . A glass sheet to be tempered, comprising as a glass composition, in terms of mol %, 50% to 80% of SiO 2 , 8% to 25% of Al 2 O 3 , 0% to 10% of B 2 O 3 , 3% to 10% of Li 2 O, 3% to 21% of Na 2 O, 0% to 10% of K 2 O, 10% to 18% of [Li 2 O]+[Na 2 O]+[K 2 O], 0% to 10% of MgO, 0% to 10% of ZnO, and 0.1% to 15% of P 2 O 5 . 
     
     
         29 . The tempered glass sheet according to  claim 21 , wherein the tempered glass sheet has a content of [Li 2 O]+[Na 2 O]+[K 2 O] of from 10 mol % to 16.99 mol %. 
     
     
         30 . The tempered glass sheet according to  claim 21 , wherein the tempered glass sheet has a content of Al 2 O 3  of from 16.25 mol % to 25 mol %. 
     
     
         31 . The tempered glass sheet according to  claim 21 , wherein the tempered glass sheet satisfies the following relationship: a molar ratio ([Na 2 O]−[Li 2 O])/([Al 2 O 3 ]+[B 2 O 3 ]+[P 2 O 5 ])≤0.23. 
     
     
         32 . The tempered glass sheet according to  claim 21 , wherein the tempered glass sheet has a liquidus viscosity of 10 3.74  dPa·s or more. 
     
     
         33 . The tempered glass sheet according to  claim 21 , wherein the compressive stress layer has a depth of layer of 140 μm or more. 
     
     
         34 . The tempered glass sheet according to  claim 21 , wherein the compressive stress layer has a compressive stress value of 900 MPa or more on an outermost surface.