Heat-ray-absorbing glass plate and method for producing same
A heat-absorbing glass plate containing iron, tin and sulfur, where, as represented by mass % based on oxides, the amount of total iron as calculated as Fe 2 O 3 is at least 0.3%, the amount of total tin as calculated as SnO 2 is less than 0.4%, and the ratio (SnO 2 /SO 3 ) of the amount of total tin to the amount of total sulfur as calculated as SO 3 is from 0.2 to 100.
1. A heat-absorbing glass plate, comprising iron, tin and sulfur,
wherein, as represented by mass % based on oxides;
the amount of total iron as calculated as Fe 2 O 3 is at least 0.3%,
the amount of Na 2 O is from 5 to 18%,
the amount of CeO 2 is from 0 to less than 0.8%,
the amount of total tin as calculated as SnO 2 is less than 0.4%,
the amount of total sulfur as calculated as SO 3 is from 0.005 to 0.1%, and
the ratio (SnO 2 /SO 3 ) of the amount of total tin to the amount of total sulfur as calculated as SO 3 is from 0.2 to 100.
2. The heat-absorbing glass plate according to claim 1 , which comprises soda lime silica glass having the following composition, as represented by mass % based on oxides:
SiO 2 : 65 to 75%,
Al 2 O 3 : more than 3% and at most 6%,
MgO: 0% to less than 2%,
CaO: 7 to 10%,
Na 2 O: 5 to 18%,
K 2 O: 0 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%.
3. The heat-absorbing glass plate according to claim 1 , wherein the amount of total tin as calculated as SnO 2 as represented by mass % based on oxides is at least 0.09%.
4. The heat-absorbing glass plate according to claim 1 , wherein the amount of total tin as calculated as SnO 2 as represented by mass % based on oxides is at least 0.15%.
5. The heat-absorbing glass plate according to claim 1 , wherein the amount of total sulfur as calculated as SO 3 as represented by mass % based on oxides is at least 0.005% and less than 0.02%.
6. The heat-absorbing glass plate according to claim 1 , wherein the ratio of SnO 2 /SO 3 to Fe-redox i.e. (SnO 2 /SO 3 )/Fe-redox is from 0.0025 to 5.
7. The heat-absorbing glass plate according to claim 1 , wherein the proportion of divalent iron as calculated as Fe 2 O 3 to the total iron as calculated as Fe 2 O 3 is at least 55%.
8. The heat-absorbing glass plate according to claim 1 , wherein the proportion of divalent iron as calculated as Fe 2 O 3 to the total iron as calculated as Fe 2 O 3 is at least 61%.
9. The heat-absorbing glass plate according to claim 1 , wherein the proportion of divalent iron as calculated as Fe 2 O 3 to the total iron as calculated as Fe 2 O 3 is at least 63%.
10. The heat-absorbing glass plate according to claim 1 , which contains substantially no TiO 2 .
11. The heat-absorbing glass plate according to claim 1 , which contains TiO 2 and has a TiO 2 content of at most 3% as represented by mass % based on oxides.
12. The heat-absorbing glass plate according to claim 1 , wherein as represented by mass % based on oxides, the content of CeO 2 is less than 0.6%.
13. The heat-absorbing 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), and the amount of total iron t-Fe 2 O 3 as calculated as Fe 2 O 3 as represented by mass % based on oxides, calculated as 4 mm thickness of the glass plate, are in a relation of the following formulae:
Tv/Te> 1.70 when t - Fe 2 O 3 is at least 0.30% and less than 0.351%;
Tv/Te> 1.252×( t - Fe 2 O 3 )+1.260 when t - Fe 2 O 3 is at least 0.351% and less than 0.559%; and
Tv/Te> 1.960 when t - Fe 2 O 3 is at least 0.559%.
14. The heat-absorbing 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), and the amount of total iron t-Fe 2 O 3 as calculated as Fe 2 O 3 as represented by mass % based on oxides, calculated as 4 mm thickness of the glass plate, are in a relation of the following formulae:
Tv/Te> 1.70 when t - Fe 2 O 3 is at least 0.30% and less than 0.351%;
Tv/Te> 1.252×( t - Fe 2 O 3 )+1.260 when t - Fe 2 O 3 is at least 0.351% and less than 0.575%; and
Tv/Te> 1.980 when t - Fe 2 O 3 is at least 0.575%.
15. The heat-absorbing 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), and the amount of total iron t-Fe 2 O 3 as calculated as Fe 2 O 3 as represented by mass % based on oxides, calculated as 4 mm thickness of the glass plate, are in a relation of the following formulae:
Tv/Te> 1.70 when t - Fe 2 O 3 is at least 0.30% and less than 0.351%; and
Tv/Te> 1.252×( t - Fe 2 O 3 )+1.260 when t - Fe 2 O 3 is at least 0.351%.
16. The heat-absorbing glass plate according to claim 1 , which provides a transmitted light having a dominant wavelength Dw of less than 492 nm calculated as 4 mm thickness of the glass plate as defined in JIS Z8701 (1982).
17. The heat-absorbing glass plate according to claim 1 , which provides a transmitted light having a dominant wavelength Dw of at least 492 nm calculated as 4 mm thickness of the glass plate as defined in JIS Z8701 (1982).
18. The heat-absorbing 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 2.0.
19. The heat-absorbing 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. The heat-absorbing glass plate according to claim 1 , wherein β-OH is at least 0.15 mm −1 .
21. A process for producing a heat-absorbing 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 heat-absorbing glass plate as defined in claim 1 .