Tempered glass and tempered glass sheet
A tempered glass has a compression stress layer in a surface thereof, and includes as a glass composition in terms of mol %, 50 to 75% of SiO 2 , 3 to 13% of Al 2 O 3 , 0 to 1.5% of B 2 O 3 , 0 to 4% of Li 2 O, 7 to 20 % of Na 2 O, 0 to 10 % of K 2 O, 0.5 to 13% of MgO, 0 to 6% of CaO, and 0 to 4.5% of SrO. The tempered glass is substantially free of As 2 O 3 , Sb 2 O 3 , PbO, and F. The tempered glass has a molar ratio MgO/(MgO+Al 2 O 3 ) of 0.05 to 0.30.
1. A glass sheet to be tempered by being subjected to a tempering treatment, comprising, as a glass composition in terms of mol %,
50 to 75% of SiO 2 ,
3 to 13% of Al 2 O 3 ,
0 to 1.5% of B 2 O 3 ,
0 to 4% of Li 2 O,
7 to 20% of Na 2 O,
0 to 10% of K 2 O,
0.5 to 13% of MgO,
0 to 6% of CaO, and
0 to 4.5% of SrO,
wherein the glass sheet is substantially free of As 2 O 3 , Sb 2 O 3 , PbO, and F, and
wherein the glass sheet has:
a length of 500 mm or more,
a width of 500 mm or more,
a thickness of 1.5 mm or less, and
an Fmax value of 5 MPa or less, wherein the Fmax value is a maximum value of residual stresses in a planar direction with respect to all planar portions of the glass sheet.
2. The glass sheet to be tempered according to claim 1 , wherein the glass sheet comprises, as a glass composition in terms of mol %,
50 to 75% of SiO 2 ,
4 to 13% of Al 2 O 3 ,
0 to 1.5% of B 2 O 3 ,
0 to 2% of Li 2 O,
9 to 18% of Na 2 O,
1 to 8% of K 2 O,
0.5 to 12% of MgO,
0 to 3.5% of CaO,
0 to 3% of SrO, and
0 to 0.5% of TiO 2 .
3. The glass sheet to be tempered according to claim 1 , wherein the glass sheet comprises, as a glass composition in terms of mol %,
50 to 75% of SiO 2 ,
4 to 12% of Al 2 O 3 ,
0 to 1% of B 2 O 3 ,
0 to 1% of Li 2 O,
10 to 17% of Na 2 O,
2 to 7% of K 2 O,
1.5 to 12% of MgO,
0 to 3% of CaO,
0 to 1% of SrO, and
0 to 0.5% of TiO 2 .
4. The glass sheet to be tempered according to claim 1 , wherein the glass sheet comprises, as a glass composition in terms of mol %,
55 to 75% of SiO 2 ,
4 to 11% of Al 2 O 3 ,
0 to 1% of B 2 O 3 ,
0 to 1% of Li 2 O,
10 to 16% of Na 2 O,
2 to 7% of K 2 O,
3 to 12% of MgO,
0 to 3% of CaO,
0 to 1% of SrO,
0.5 to 10% of ZrO 2 , and
0 to 0.5% of TiO 2 .
5. The glass sheet to be tempered according to claim 1 , wherein the glass sheet comprises, as a glass composition in terms of mol %,
55 to 69% of SiO 2 ,
4 to 11% of Al 2 O 3 ,
0 to 1% of B 2 O 3 ,
0 to 1% of Li 2 O,
11 to 16% of Na 2 O,
2 to 7% of K 2 O,
3 to 9% of MgO,
0 to 3% of CaO,
0 to 1% of SrO,
1 to 9% of ZrO 2 , and
0 to 0.1% of TiO 2 .
6. The glass sheet to be tempered according to claim 1 , which has a degradation coefficient D of 0.01 to 0.6.
7. The glass sheet to be tempered according to claim 1 , which has a liquidus temperature of 1,075° C. or less.
8. The glass sheet to be tempered according to claim 1 , which has a liquidus viscosity of 10 4.0 dPa·s or more.
9. The glass sheet to be tempered according to claim 1 , which has a temperature at 10 4.0 dPa·s of 1,250° C. or less.
10. The glass sheet to be tempered according to claim 1 , which has a density of 2.6 g/cm 3 or less.
11. The glass sheet to be tempered according to claim 1 , which has a Young's modulus of 65 GPa or more.
12. The glass sheet to be tempered according to claim 1 , which is formed by a float method.
13. A tempered glass sheet, which is formed by performing an ion exchange treatment to the glass sheet to be tempered according to claim 1 .
14. The tempered glass sheet according to claim 13 , comprising a compression stress layer having a compression stress value of 300 MPa or more and a thickness of 10 μm or more.
15. The tempered glass sheet according to claim 13 , which has a surface formed by polishing by 0.5 μm or more in a thickness direction.
16. The tempered glass sheet according to claim 13 , which has a ΔCS value of 50 MPa or less, wherein the ΔCS value is a difference in compression stress value between compression stress layers in surfaces opposite to each other.
17. The tempered glass sheet according to claim 13 , which has:
a molar ratio MgO/(MgO+Al 2 O 3 ) of 0.05 to 0.30,
a length of 500 mm or more,
a width of 500 mm or more,
a thickness of 0.5 to 1.5 mm,
a Young's modulus of 65 GPa or more,
a compression stress value of a compression stress layer of 200 MPa or more,
a thickness of the compression stress layer of 20 μm or more,
a degradation coefficient D of 0.6 or less, and
a ΔCS value of 50 MPa or less, wherein the ΔCS value is a difference in compression stress value between compression stress layers in surfaces opposite to each other.
18. The tempered glass sheet according to claim 13 , which has a compression stress in a surface thereof, wherein the tempered glass sheet comprises, as a glass composition in terms of mol %,
50 to 75% of SiO 2 ,
4 to 12% of Al 2 O 3 ,
0 to 1% of B 2 O 3 ,
0 to 1% of Li 2 O,
10 to 17% of Na 2 O,
0 to 7% of K 2 O,
1.5 to 12% of MgO,
0 to 3% of CaO,
0 to 1% of SrO, and
0 to 0.5% of TiO 2 ,
wherein the tempered glass has:
a molar ratio MgO/(MgO+CaO) of 0.5 or more,
a molar ratio MgO/(MgO+Al 2 O 3 ) of 0.05 to 0.30,
a length of 500 mm or more,
a width of 500 mm or more,
a thickness of 0.5 to 1.5 mm,
a Young's modulus of 65 GPa or more,
a compression stress value of a compression stress layer of 400 MPa or more,
a thickness of the compression stress layer of 30 μm or more, and
a degradation coefficient D of 0.4 or less.
19. A touch panel display comprising the tempered glass according to claim 13 .
20. A cellular phone comprising the tempered glass according to claim 13 as a cover glass.
21. A solar battery comprising the tempered glass according to claim 13 as a cover glass.
22. A display comprising the tempered glass according to claim 13 as a protective member.