Float glass composition adapted for chemical strengthening
Float glass compositions adapted for chemical strengthening, and methods of making the same. Certain example embodiments of this invention relate to such a glass composition having improved ion-exchanged, surface durability, and/or mechanical properties for use in applications where higher strength and improved durability of the glass are desired.
1. Float glass comprising:
a float glass composition that includes:
Ingredient
(wt. %)
SiO 2
67-69.5%
A1 2 O 3
2.5-4.5%
(SiO 2 + A1 2 O 3 )
<73%
Na 2 O
16.6-20%
K 2 O
0.5-2.0%
CaO
4.0-7.0%
MgO
2.5-3.5%
CaO + MgO
6.5-10.5%
wherein the float glass is chemically strengthened and has a depth of layer, which is depth of a compressive stress layer in the glass resulting from the chemical strengthening, with a 4 hour chemical strengthening process at 435 degrees C. being used as a reference, of at least 25 μm.
2. The glass of claim 1 , wherein the float glass is chemically strengthened and has a depth of layer, which is depth of a compressive stress layer in the glass resulting from the chemical strengthening, with a 4 hour chemical strengthening process at 435 degrees C. being used as a reference, of at least 26 μm.
3. The glass of claim 1 , wherein the compressive stress layer has a maximum surface stress of from 450-550 MPa.
4. The glass of claim 1 , wherein the glass has a Young's modulus of from 74-76.5 GPa.
5. The glass of claim 1 , wherein the glass has a Young's modulus of from 74.5-75.5 GPa.
6. The glass of claim 1 , wherein the glass comprises from 67.5-68.5 SiO 2 .
7. The glass of claim 1 , wherein the glass comprises from 2.7-3.4% Al 2 O 3 .
8. The glass of claim 1 , wherein the glass comprises from 18-19% Na 2 O.
9. The glass of claim 1 , wherein the glass comprises from 5.0-7.0% CaO.
10. The glass of claim 1 , wherein the glass comprises from 5.5-6.5% CaO.
11. The glass of claim 1 , wherein the glass comprises from 2.8-3.2% MgO.
12. The glass of claim 1 , wherein the glass comprises from 7.5-10.5% CaO +MgO.
13. The glass of claim 1 , wherein the glass comprises from 8.5-9.7% CaO +MgO.
14. The glass of claim 1 , wherein CaO %/MgO % is from 1.2-2.8.
15. The glass of claim 1 , wherein in the glass the ratio CaO %/MgO % is from 1.8 to 2.3.
16. The glass of claim 1 , wherein the glass comprises from 67.5-68.5 SiO 2 , from 2.7-3.4% Al 2 O 3 , from 18-19% Na 2 O, and from 5.5-6.5% CaO.
17. The glass of claim 1 , wherein the glass has a visible transmission Lta of at least about 60%.
18. Chemically strengthened float glass comprising:
a float glass composition that is chemically strengthened and includes:
Ingredient
(wt. %)
SiO 2
67-69.5%
A1 2 O 3
2.5-4.5%
(SiO 2 + A1 2 O 3 )
<73%
Na 2 O
16.6-20%
K 2 O
0.5-2.0%
CaO
4.0-7.0%
MgO
2.5-3.5%
CaO + MgO
6.5-10.5%
wherein the glass has a depth of layer, which is depth of a compressive stress layer in the glass resulting from the chemical strengthening, of at least 25 μm.
19. The glass of claim 18 , wherein the compressive stress layer has a maximum surface stress of from 450-550 MPa.
20. The glass of claim 18 , wherein the glass comprises from 67.5-68.5 SiO 2 .
21. The glass of claim 18 , wherein the glass comprises from 2.7-3.4% Al 2 O 3 .
22. The glass of claim 18 , wherein the glass comprises from 18-19% Na 2 O.
23. The glass of claim 18 , wherein the glass comprises from 5.0-7.0% CaO.
24. The glass of claim 18 , wherein the glass comprises from 5.5-6.5% CaO.
25. The glass of claim 18 , wherein the glass comprises from 67.5-68.5 SiO 2 , from 2.7-3.4% Al 2 O 3 , from 18-19% Na 2 O, and from 5.5-6.5% CaO.