Strengthened glass plate and glass plate for strengthening
A tempered glass sheet of the present invention is a tempered glass sheet having a compressive stress layer in a surface thereof, wherein the tempered glass sheet comprises as a glass composition, in terms of mol %, 50% to 75% of SiO 2 , 1% to 20% of Al 2 O 3 , 5% to 30% of B 2 O 3 , 0% to 15% of Li 2 O, 1% to 25% of Na 2 O, 0% to 10% of K 2 O, and 0% to 15% of P 2 O 5 , wherein the tempered glass sheet has a molar ratio [Al 2 O 3 ]/[Na 2 O] of from 0.1 to 2.5, and wherein the tempered glass sheet satisfies the following relationship: [SiO 2 ]−3×[Al 2 O 3 ]−[B 2 O 3 ]−2×[Li 2 O]−1.5×[Na 2 O]−[K 2 O]+1.2×[P 2 O 5 ]≥−20%.
1 . A tempered glass sheet having a compressive stress layer in a surface thereof,
wherein the tempered glass sheet comprises as a glass composition, in terms of mol %, 50% to 75% of SiO 2 , 1% to 20% of Al 2 O 3 , 16% to 13% to 30% of B 2 O 3 , 0% to 1% of Li 2 O, 1% to 25% of Na 2 O, 0% to 10% of K 2 O, and 0% to 15% of P 2 O 5 ,
wherein the tempered glass sheet has a sheet thickness of 80 μm or less,
wherein the tempered glass sheet has an internal tensile stress value that is 60 MPa or more,
wherein the tempered glass sheet has a Young's modulus of 67 GPa or less,
wherein the tempered glass sheet has a molar ratio [Al 2 O 3 ]/[Na 2 O] of from 0.1 to 2.5, and
wherein the tempered glass sheet satisfies the following molar relationship:
[SiO 2 ]−3×[Al 2 O 3 ]−[B 2 O 3 ]−2×[Li 2 O]−1.5×[Na 2 O]−[K 2 O]+1.2×[P 2 O 5 ]≥−20%.
2 . The tempered glass sheet according to claim 1 , the tempered glass sheet having a compressive stress layer in a surface thereof,
wherein the tempered glass sheet comprises as a glass composition, in terms of mol %, 50% to 75% of SiO 2 , 11.7% to 13.5% of Al 2 O 3 , 16% to 30% of B 2 O 3 , 0% to 1% of Li 2 O, 13% to 16% of Na 2 O, 0% to 10% of K 2 O, and 0% to 15% of P 2 O 5 ,
wherein the tempered glass sheet has a molar ratio [Al 2 O 3 ]/[Na 2 O] of from 0.8 to 1.2, and
wherein the tempered glass sheet satisfies the following molar relationship:
[SiO 2 ]−3×[Al 2 O 3 ]−[B 2 O 3 ]−2×[Li 2 O]−1.5×[Na 2 O]−[K 2 O]+1.2×[P 2 O 5 ]≥−2.5%.
3 . The tempered glass sheet according to claim 1 , wherein the tempered glass sheet has a content of P 2 O 5 of from 0.1 mol % to 15 mol %.
4 . The tempered glass sheet according to claim 1 , wherein the tempered glass sheet has a content of Li 2 O of from 0.1 mol % to 1 mol %.
5 . The tempered glass sheet according to claim 1 , wherein the tempered glass sheet has a softening point of 950° C. or less.
6 . The tempered glass sheet according to claim 1 , wherein the tempered glass sheet has a temperature at a viscosity at high temperature of 102.5 dPa's of less than 1,650° C.
7 . The tempered glass sheet according to claim 1 , wherein the tempered glass sheet has dimensions of rectangular shape with a side of 100 mm or more.
8 . The tempered glass sheet according to claim 1 , wherein the compressive stress layer has a compressive stress value of from 200 MPa to 1,100 MPa on an outermost surface.
9 . The tempered glass sheet according to claim 1 , wherein the compressive stress layer has a depth of layer of from 10% to 15% of a sheet thickness.
10 . The tempered glass sheet according to claim 1 , wherein the tempered glass sheet comprises overflow-merged surfaces in a middle portion thereof in a sheet thickness direction.
11 . The tempered glass sheet according to claim 1 , wherein the tempered glass sheet is used as a cover glass for a flexible display.
12 . The tempered glass sheet according to claim 1 , wherein the tempered glass sheet has a content of B 2 O 3 of from 19 mol % to 30 mol %.
13 . The tempered glass sheet according to claim 2 , wherein the tempered glass sheet has a content of B 2 O 3 of from 19 mol % to 30 mol %.
14 . The tempered glass sheet according to claim 1 , wherein the tempered glass sheet has a content of B 2 O 3 of from 22 mol % to 30 mol %.
15 . The tempered glass sheet according to claim 2 , wherein the tempered glass sheet has a content of B 2 O 3 of from 22 mol % to 30 mol %.