Clear glass composition with high visible transmittance
View Patent ↗A high transmittance fairly clear/neutral colored glass composition is provided. An oxidizing agent(s) such as cerium oxide (e.g., CeO 2 ) or the like is added to the glass batch in order to realize very oxidized conditions (i.e., to significantly lower the redox of the resulting glass). As a result of the oxidizing agent(s) used in the batch, the iron is oxidized to a very low FeO (ferrous state) content. For example, this may result in a glass having a glass redox value of no greater than 0.12 (more preferably <=0.10; even more preferably <=0.08; and most preferably <=0.05) and a % FeO (i.e., ferrous content) of from 0.0001 to 0.05%. In certain example embodiments, in order to compensate for yellow or yellow-green coloration a small amount of cobalt (Co) may be provided in the glass to enable it to realize a more neutral color.
1. A glass comprising:
a base glass portion comprising:
SiO 2
at least 67%
Na 2 O
10 to 20%
CaO
5 to 15%
MgO
0 to 8%
Al 2 O 3
0 to 5%
K 2 O
0 to 5%
a colorant portion comprising:
total iron (expressed Fe 2 O 3 ):
0.04 to 0.10%
cobalt oxide:
0.1 to 15 ppm
chromium oxide:
0 to 10 ppm
titanium oxide:
0 to 0.5%
glass redox:
<=0.10
wherein the glass has a visible transmission of at least about 85%, and wherein the glass contains 0% cerium oxide.
2. The glass of claim 1 , wherein the glass further comprises from 0 to 0.2% titanium oxide.
3. The glass of claim 1 , wherein the glass has a visible transmission of at least 88%.
4. The glass of claim 1 , wherein the glass has a visible transmission of at least 90%, and a UV % transmission of no greater than about 75%.
5. The glass of claim 1 , wherein the colorant portion comprises:
cobalt oxide:
0.3 to 10 ppm
glass redox:
<=0.08.
6. The glass of claim 1 , wherein the colorant portion comprises:
cobalt oxide:
0.5 to 5 ppm
glass redox:
<=0.08.
7. The glass of claim 1 , wherein the colorant portion comprises:
cobalt oxide:
0.3 to 5 ppm
glass redox:
<=0.05
titanium oxide:
0 to 0.2%.
8. The glass of claim 1 , wherein the glass has a UV % transmission no greater than about 75%.
9. The glass of claim 1 , wherein the glass has a UV % transmission no greater than about 72%.
10. The glass of claim 1 , wherein the glass is colored as follows:
a*
−1 to +1
b*
−1 to +1.
11. A glass comprising:
a base glass portion comprising:
SiO 2
at least 67%
Na 2 O
10 to 20%
CaO
5 to 15%
MgO
0 to 8%
Al 2 O 3
0 to 5%
K 2 O
0 to 5%
a colorant portion consisting essentially of:
total iron (expressed Fe 2 O 3 ):
0.04 to 0.10%
cobalt oxide:
0.1 to 15 ppm
chromium oxide:
0 to 10 ppm
titanium oxide:
0 to 0.5%
wherein the glass has a visible transmission of at least about 85%, a glass redox of no greater than 0.10, and 0% cerium oxide.
12. The glass of claim 11 , wherein the glass has a visible transmission of at least 88%.
13. The glass of claim 11 , wherein the glass has a visible transmission of at least 90%, and a UV % transmission of no greater than about 75%.
14. The glass of claim 11 , wherein the glass has a glass redox of no greater than 0.08.
15. The glass of claim 11 , wherein the glass is colored as follows:
a*
−1 to +1
b*
−1 to +1.
16. A glass comprising:
total iron (expressed Fe 2 O 3 ):
0.014to 0.10%
cobalt oxide:
0.1 to 15 ppm
chromium oxide:
0 to 10 ppm
titanium oxide:
0 to 0.5%
glass redox:
<=0.10.
wherein the glass has a visible transmission of at least about 85% and contains 0% cerium oxide.
17. The glass of claim 16 , wherein the glass is colored as follows:
a*
−1 to +1
b*
−1 to +1.
18. The glass of claim 16 , wherein the glass is colored as follows:
a*
−0.5 to +0.5
b*
−0.5 to +0.5.
19. The glass of claim 16 , comprising:
cobalt oxide:
0.3 to 10 ppm
glass redox:
<=0.08.
20. The glass of claim 16 , comprising:
cobalt oxide:
0.5 to 5 ppm
glass redox:
<=0.08.
21. The glass of claim 16 , wherein the glass has a visible transmission of at least 88%.
22. The glass of claim 16 , wherein the glass has a visible transmission of at least 90%, and a UV % transmission of no greater than about 75%.
23. A glass comprising a base portion, and a colorant portion consisting essentially of:
total iron (expressed Fe 2 O 3 ):
0.04 to 0.10%
cobalt oxide:
0.1 to 15 ppm
chromium oxide:
0 to 10 ppm
titanium oxide:
0 to 0.5%
wherein the glass has a visible transmission of at least about 85%, 0% cerium oxide, and a glass redox of no greater than 0.12.
24. The glass of claim 23 , wherein the glass is colored as follows:
a*
−1 to +1
b*
−1 to +1.
25. The glass of claim 23 , wherein the glass is colored as follows:
a*
−0.5 to +0.5
b*
−0.5 to +0.5.
26. The glass of claim 23 , wherein the glass has a glass redox no greater than 0.05.
27. The glass of claim 23 , wherein the glass has a visible transmission of at least 88%.