Colored glass compositions and glazings produced therewith

Abstract

The invention relates to a colored glass composition for producing glazings for use, e.g., as automobile sunroofs. The colored glass according to the invention is a soda-lime-silica glass comprising, as coloring agents, 1.4 to 4% iron oxide expressed as Fe 2 O 3 and 0 to 0.05 % cobalt oxide, with the cobalt oxide exceeding about 0.02% when the Fe 2 O 3 is below about 2% and, optionally, selenium and chromium oxide, whereby the sum of the CoO+Se+Cr 2 O 3 is preferably less than about 0.24% by weight. The glass of the invention has a total light transmission factor under illuminant A equal to or below approximately 20% and a total energy transmission factor equal to or below approximately 12% for a thickness of 3.85 mm.

We claim:  
     
       1. A glass composition for forming colored glazings consisting essentially of, in percent by weight, 64 to 75% SiO 2 , 5 to 15% CaO, 10 to 18% Na 2 O, at least one of Al 2 O 3 , B 2 O 3 , MgO or K 2 O, each in an amount of up to 5% by weight and CoO as a coloring agents, CoO in an amount of up to 0.05% by weight, wherein the amount of CoO is greater than about 0.02% by weight when Fe 2 O 3  is present in said composition in an amount less than 2% by weight, and selenium in an amount up to about 0.005% by weight, and as a coloring agent, 1.4 to 4% by weight Fe 2 O 3 in an amount of about  1 . 4  to  4 %  by weight , wherein CoO is present in an amount greater than about  0 . 02 %  by weight when Fe   2   O   3    is present in an amount of less than  2   %  by weight, CoO is present in an amount of at least  0 . 014   %  by weight when Fe   2   O   3    is preset in an amount of  2  to  3   %  by weight , the amount of alkaline earth oxides is between about  6- to  16% by weight and the amount of alkali metal oxides is between about  10- to  20% by weight and wherein glazings formed of said composition when illuminated under Illuminant C, hashave a dominant percentage light transmission between about 485-570 nm, and which glazings have a total light transmission factor under illuminantIlluminant A of less than 20% a total energy transmission factor of less than 12% when said glazings have a thickness of about 3.85 mm. 
     
     
       2. The composition of  claim 1  which further comprises consists essentially of a color effective amount of chromium oxide as an additional coloring agent, wherein the total amount of CoO, selenium and Cr 2 O 3  is less than about 0.24% by weight of said composition. 
     
     
       3. The composition of  claim 2  which consists essentially of 2 to 3% by weight Fe 2 O 3 , 0.014 to 0.04 percent by weight CoO and up to 0.005% by weight selenium. 
     
     
       4. The composition of  claim 2  which consists essentially of 1.4 to 2% by weight Fe 2 O 3 , 0.015 to 0.003 0.033% by weight CoO and 0.0010 to 0.0035% by weight selenium. 
     
     
       5. The composition of  claim 2  which consists essentially of 1.5 to 2.5% by weight Fe 2 O 3 , 0015 to 0.030% by weight CoO and 0.07 to 0.2% by weight Cr 2 O 3 . 
     
     
       6. The composition of  claim 1  wherein said Fe 2 O 3  comprises between about 16 to 40% by weight of FeO. 
     
     
       7. The composition of  claim 6  wherein said Fe 2 O 3  is present in said composition in an amount between about 3-4% by weight. 
     
     
       8. A glazing comprising at least one colored glass sheet having the composition of  claim 3 . 
     
     
       9. A glazing comprising at least one colored glass sheet having the composition of  claim 4 . 
     
     
       10. A glazing comprising at least one colored glass sheet having the composition of  claim 5 . 
     
     
       11. A glazing comprising at least one colored glass sheet having the composition of  claim 8 . 
     
     
       12. The glazing of  claim 8 ,  9 ,  10  or  11  wherein the thickness of said glazing is between about 2 and 10 millimeters. 
     
     
       13. The glazing of  claim 12  wherein the thickness of said glazing is between about 3 and 6 millimeters. 
     
     
       14. The glazing of  claim 13  which further comprises at least one metal oxide layer coated upon at least a portion of said glazing. 
     
     
       15. A glass composition for forming colored glazings consisting essentially of, in percent by weight, about  64  to  75 %  SiO   2   , about  5  to  15   %  CaO, about  10  to  18   %  Na   2   O, at least one of Al   2   O   3   , B   2   O   3   , MgO, or K   2   O, each in an amount of up to about  5   %  by weight, a coloring agent of Fe   2   O   3    in an amount of about  1 . 4  to  4   %  by weight, an additional coloring agent of selenium in an amount effective to provide coloring to the composition, and, optionally, cobalt oxide or chromium oxide as additional coloring agents, wherein the amount of cobalt oxide, if present, is greater than about  0 . 02   %  by weight when Fe   2   O   3    is present in an amount of less than  2   %  by weight and is at least  0 . 014   %  by weight when Fe   2   O   3    is present in an amount of  2  to  3   %  by weight, the total amount of cobalt oxide, selenium and chromium oxide, if present in combination, is no greater than about  0 . 24   %  by weight, the amount of alkaline earth oxides is between about  6  to  16   %  by weight, the amount of alkali metal oxides is between about  10  to  20   %  by weight, and glazings formed of such compositions have a dominant percentage light transmission of between about  485  to  570  nm when illuminated under Illuminant C.   
     
     
       16. The composition of  claim 15  wherein glazings formed of such compositions have a total light transmission factor under Illuminant A of less than about  20 %  when such glazings have a thickness of about  3 . 85  mm.   
     
     
       17. The composition of  claim 15 , wherein glazings formed of such compositions have a total energy transmission factor of less than about  12 %  when such glazings have a thickness of about  3 . 85  mm.   
     
     
       18. The composition of  claim 15 , wherein at least about  15  to  40 %  by weight of the Fe   2   O   3    is present in the form of FeO.   
     
     
       19. The composition of  claim 15 , wherein additional coloring agents of cobalt oxide and chromium oxide are present. 
     
     
       20. The composition of  claim 19 , wherein the selenium is present in an amount of about  0 . 001  to  0 . 005 %  by weight, and the cobalt oxide is present in an amount of between about  0 . 014  to  0 . 04   %  by weight, and the chromium oxide is present in an amount of about  0 . 07  to  0 . 2   %  by weight.   
     
     
       21. A glazing comprising at least one colored glass sheet having the composition of  claim 1 . 
     
     
       22. A glazing comprising at least one colored glass sheet having the composition of  claim 15 . 
     
     
       23. The glazing of  claim 22  having a thickness of between about  2  to  10  mm. 
     
     
       24. The glazing of  claim 22  which further comprises at least one metal oxide layer coated upon at least a portion of said glazing. 
     
     
       25. A glass composition for forming colored glazings consisting essentially of, in percent by weight, about  64  to  75 %  SiO   2   , about  5  to  15   %  CaO, about  10  to  18   %  Na   2   O, at least one of Al   2   O   3   , B   2   O   3   , MgO, or K   2   O, each in an amount of up to about  5   %  by weight, a coloring agent of Fe   2   O   3    in an amount of about  1 . 4  to  4   %  by weight, at least two additional coloring agents of cobalt oxide and chromium oxide in amounts sufficient to provide additional coloring of the composition, and selenium as an optional additional coloring agent, wherein the amount of cobalt oxide is greater than about  0 . 02   %  by weight when Fe   2   O   3    is present in an amount of less than  2   %  by weight, the total amount of cobalt oxide, selenium and chromium oxide, if present in combination, is no greater than about  0 . 24   %  by weight, the amount of alkaline earth oxides is between about  6  to  16   %  by weight, the amount of alkali metal oxides is between about  10  to  20   %  by weight, and glazings formed of such compositions have a dominant percentage light transmission of between about  485  to  570  nm when illuminated under Illuminant C.   
     
     
       26. An automobile sunroof comprising at least one glazing according to  claim 22 . 
     
     
       27. An automobile sunroof comprising at least one colored glazing having a glass composition consisting essentially of, in percent by weight, about  64  to  75 %  SiO   2   , about  5  to  15   %  CaO, about  10  to  18   %  Na   2   O, at least one of Al   2   O   3   , B   2   O   3   , MgO, or K   2   O, each in an amount of up to about  5   %  by weight, a coloring agent of Fe   2   O   3    in an amount of about  1 . 4  to  4   %  by weight, and at least one additional coloring agent of selenium, optionally with cobalt oxide as an additional coloring agent, wherein the amount of cobalt oxide, if present, is greater than about  0 . 02   %  by weight when the Fe   2   O   3    is present in an amount of less than  2   %  by weight and is at least  0 . 014   %  by weight when Fe   2   O   3    is present in an amount of  2  to  3   %  by weight, the total amount of cobalt oxide, selenium and chromium oxide, if present in combination, is no greater than about  0 . 24   %  by weight, the amount of alkaline earth oxides is between about  6  to  16   %  by weight, the amount of alkali metal oxides is between about  10  to  20   %  by weight, and the glazing has a dominant percentage light transmission of between about  485  to  570  nm when illuminated under Illuminant C.   
     
     
       28. The sunroof of  claim 27  wherein the glazing has a total light transmission factor under Illuminant A of less than about  20 %  when such glazings have a thickness of about  3 . 85  mm.   
     
     
       29. The automobile sunroof of  claim 27 , having a total energy transmission factor of less than about  12 %  at a thickness of about  3 . 85  mm.   
     
     
       30. The automobile sunroof of  claim 27 , wherein at least about  15  to  40 %  by weight of the Fe   2   O   3    is present in the form of FeO.   
     
     
       31. The automobile sunroof of  claim 27 , wherein the two additional coloring agents of cobalt oxide and chromium oxide are present. 
     
     
       32. The automobile sunroof of  claim 31 , wherein the cobalt oxide is present in an amount of between about  0 . 014  to  0 . 04 %  by weight, the selenium is present in an amount of about  0 . 001  to  0 . 005   %  by weight, the chromium oxide is present in an amount of about  0 . 07  to  0 . 2   %  by weight or mixtures thereof.   
     
     
       33. The automobile sunroof of  claim 27  which further comprises at least one metal oxide layer coated upon at least a portion of said glazing. 
     
     
       34. An automobile sunroof comprising at least one glazing according to  claim 21 . 
     
     
       35. An automobile sunroof comprising at least one colored glazing having a glass composition consisting essentially of, in percent by weight, about  64  to  75 %  SiO   2   , about  5  to  15   %  CaO, about  10  to  18   %  Na   2   O, at least one of Al   2   O   3   , B   2   O   3   , MgO, or K   2   O, each in an amount of up to about  5   %  by weight, a coloring agent of Fe   2   O   3    in an amount of about  1 . 4  to  4   %  by weight, at least two additional coloring agents of cobalt oxide and chromium oxide in amounts sufficient to provide additional coloring of the glazing, and selenium as an optional additional coloring agent, wherein the cobalt oxide is present in an amount of greater than about  0 . 02   %  by weight when Fe   2   O   3    is present in an amount of less than  2   %  by weight, the total amount of cobalt oxide, selenium and chromium oxide, if present in combination, is no greater than about  0 . 24   %  by weight, the amount of alkaline earth oxides is between about  6  to  16   %  by weight, the amount of alkali metal oxides is between about  10  to  20   %  by weight, and the glazing has a dominant percentage light transmission of between about  485  to  570  nm when illuminated under Illuminant C.