Colored glass plate and method for manufacturing same
View Patent ↗To provide a colored glass plate of which the mass ratio of divalent iron as calculated as Fe 2 O 3 to total iron as calculated as Fe 2 O 3 can be stably maintained at a high level while amber coloring derived from salt cake (Na 2 SO 4 ) is suppressed by reducing the amount of salt cake used as a refining agent, and which has less bubbles regardless of a small amount of total sulfur as calculated as SO 3 . A colored glass plate which is made of alkali-containing silica glass containing iron, tin and sulfur, wherein, as represented by mass % based on oxides, the proportion of total sulfur as calculated as SO 3 is less than 0.025%, the proportion of divalent iron as calculated as Fe 2 O 3 to total iron as calculated as Fe 2 O 3 is at least 45%, the proportion of divalent tin as calculated as SnO 2 to total tin as calculated as SnO 2 is at least 0.1% as represented by mol %, and β-OH is at least 0.15 mm −1 .
1. A colored glass plate, comprising an alkali-containing silica glass comprising iron, tin and sulfur, wherein, as represented by mass % based on oxides:
the proportion of Na 2 O is from 0.5 to 50%,
the proportion of total sulfur as calculated as SO 3 is from 0.005 to less than 0.025%,
the proportion of divalent iron as calculated as Fe 2 O 3 to total iron as calculated as Fe 2 O 3 is at least 45%,
the proportion of divalent tin as calculated as SnO 2 to total tin as calculated as SnO 2 is at least 0.1% as represented by mol %, and
wherein β-OH is at least 0.15 mm −1 .
2. The colored glass plate according to claim 1 , wherein the proportion of divalent tin as calculated as SnO 2 to total tin as calculated as SnO 2 is at least 1% as represented by mol %.
3. The colored glass plate according to claim 1 , wherein the proportion of divalent tin as calculated as SnO 2 to total tin as calculated as SnO 2 is from 0.2 to 40% as represented by mol %.
4. The colored glass plate according to claim 1 , wherein the proportion of divalent iron as calculated as Fe 2 O 3 to total iron as calculated as Fe 2 O 3 is at least 55%.
5. The colored glass plate according to claim 1 , wherein the proportion of divalent iron as calculated as Fe 2 O 3 to total iron as calculated as Fe 2 O 3 is at least 60%.
6. The colored glass plate according to claim 1 , wherein the proportion of total sulfur as calculated as SO 3 as represented by mass % based on oxides is at least 0.01% and less than 0.02%.
7. The colored glass plate according to claim 1 , wherein the proportion of total sulfur as calculated as SO 3 as represented by mass % based on oxides is from 0.010% to less than 0.025%.
8. The colored glass plate according to claim 1 , which contains substantially no TiO 2 .
9. The colored glass plate according to claim 1 , comprising TiO 2 , and having a TiO 2 content of at most 3.0% as represented by mass % based on oxides.
10. The colored glass plate according to claim 1 , wherein the proportion of MgO as represented by mass % based on oxides is less than 2%.
11. The colored glass plate according to claim 1 , which contains, as represented by mass % based on oxides:
SiO 2
30 to 80%,
Al 2 O 3
0 to 30%
B 2 O 3
0 to 20%,
MgO
0 to 30%,
CaO
0 to 30%,
Na 2 O
0.5 to 50%,
K 2 O
0 to 50%,
total iron as calculated as Fe 2 O 3
0.001 to 5%, and
total tin as calculated as SnO 2
0.001 to 5%.
12. The colored glass plate according to claim 1 , which contains, as represented by mass % based on oxides:
SiO 2
65 to 73%,
Al 2 O 3
3 to 5%
B 2 O 3
0 to 1%,
MgO
at least 0% and less than 2%,
CaO
7 to 10%,
Na 2 O
12 to 16%,
K 2 O
1 to 5%,
total iron as calculated as Fe 2 O 3
0.1 to 0.9%, and
total tin as calculated as SnO 2
0.02 to 0.3%.
13. The colored glass plate according to claim 1 , which contains substantially no B 2 O 3 and contains, as represented by mass % based on oxides:
SiO 2
65 to 73%,
Al 2 O 3
3 to 5%
MgO
at least 0% and less than 2%,
CaO
7 to 10%,
Na 2 O
12 to 16%,
K 2 O
1 to 5%,
total iron as calculated as Fe 2 O 3
0.3 to 0.9%, and
total tin as calculated as SnO 2
0.02 to 0.3%.
14. The colored glass plate according to claim 1 , which contains, as represented by mass % based on oxides:
SiO 2
65 to 75%,
Al 2 O 3
0 to 3%
B 2 O 3
0 to 1%,
MgO
2 to 5%,
CaO
7 to 10%,
Na 2 O
11 to 15%,
K 2 O
0 to 5%,
total iron as calculated as Fe 2 O 3
0.1 to 0.9%, and
total tin as calculated as SnO 2
0.02 to 0.3%.
15. The colored glass plate according to claim 1 , wherein 443−420×β-OH (mm −1 )−4.8×Fe-redox (%) is less than 100.
16. The colored glass plate according to claim 1 , wherein the ratio Tv/Te of the visible light transmittance Tv (by illuminant A, 2° visual field) as defined in JIS R3106 (1998) to the solar transmittance Te as defined in JIS R3106 (1998), calculated as 4 mm thickness of the glass plate, is at least 1.3.
17. The colored glass plate according to claim 1 , wherein the ratio Tv/Te of the visible light transmittance Tv (by illuminant A, 2° visual field) as defined in JIS R3106 (1998) to the solar transmittance Te as defined in JIS R3106 (1998), calculated as 4 mm thickness of the glass plate, is at least 1.85.
18. The colored glass plate according to claim 1 , wherein the solar transmittance Te is at most 65% calculated as 4 mm thickness of the glass plate as defined in JIS R3106 (1998), and the visible light transmittance Tv (by illuminant A, 2° visual field) is at least 60% calculated as 4 mm thickness of the glass plate as defined in JIS R3106 (1998).
19. The colored glass plate according to claim 1 , wherein the solar transmittance Te is at most 50% calculated as 4 mm thickness of the glass plate as defined in JIS R3106 (1998), and the visible light transmittance Tv (by illuminant A, 2° visual field) is at least 60% calculated as 4 mm thickness of the glass plate as defined in JIS R3106 (1998).
20. A process for producing a colored glass plate, which comprises melting a glass raw material, followed by forming to produce soda lime silica glass, wherein the glass after the forming is the colored glass plate as defined in claim 1 .