Blue glass composition for making glass panes

Abstract

The invention relates to a glass composition of silica-soda-lime type colored blue which comprises the coloring agents below in a content varying within the following limits, by weight: Fe 2 O 3 (total iron) 0.2 to 0.51% CoO 10 to 50 ppm Cr 2 O 3 10 to 300 ppm CuO 0-400 ppm the glass exhibiting a redox factor of less than 0.35, a dominant wavelength XD Of between 485 and 489 nm, an excitation purity of less than 13% and a selectivity at least equal to 1.1 under a thickness of between 3 and 5 mm. It also relates to the glass sheet obtained from the above-mentioned composition, said sheet being intended in particular to form an automobile window or for the construction industry.

1 . A blue glass composition of silica-soda-lime, comprising: 
 the coloring agents below in a content varying within the following limits, by weight:                                                Fe 2 O 3  (total iron)   0.2 to 0.51         CoO    10 to 50 ppm         Cr 2 O 3     10 to 300 ppm         CuO    0 to 400 ppm                                                wherein the glass comprises a redox factor of less than or equal to 0.35, a dominant wavelength λ D  of between 485 and 489 nm, an excitation purity of less than 13% and a selectivity at least equal to 1.1 under a thickness of between 3 and 5 mm.    
     
     
         2 . The glass composition as claimed in  claim 1 , wherein the iron content is greater than 0.3%.  
     
     
         3 . The glass composition as claimed in  claim 1 , wherein the CoO content varies from 15 and 40 ppm.  
     
     
         4 . The glass composition as claimed in  claim 1 , whrein the Cr 2 O 3  content is greater than or equal to 20 ppm.  
     
     
         5 . The glass composition as claimed in  claim 4 , wherein the Cr 2 O 3  content is between 30 and 80 ppm.  
     
     
         6 . The glass composition as claimed in  claim 1 , wherein the CuO content is less than 250 ppm.  
     
     
         7 . The glass composition as claimed in  claim 1 , wherein the glass composition comprises a selectivity of at least equal to 1.3.  
     
     
         8 . The glass composition as claimed in  claim 1 , wherein the glass composition comprises a light transmission LTA at least equal to 60%.  
     
     
         9 . The glass composition as claimed in  claim 1 , wherein the contents of Cr 2 O 3  and of CoO satisfy the relationship:  
         100×Cr 2 O 3 /(CoO) 2 >7.  
     
     
         10 . The glass composition as claimed in  claim 1 , wherein the glass composition comprises a redox of greater than 0.20.  
     
     
         11 . The glass composition as claimed in  claim 1 , wherein the glass composition comprises an excitation purity of less than 9%.  
     
     
         12 . The glass composition as claimed in  claim 1 , wherein the glass composition comprises a dominant wavelength at least equal to 487 nm.  
     
     
         13 . The glass composition as claimed in  claim 1 , which further comprises agents which modify the optical properties in certain parts of the spectrum, in particular in the ultraviolet region, such as wherein said agents are selected from the group consisting of CeO 2 , TiO 2 , WO 3 , La 2 O 3 , V 2 O 5 , and mixtures thereof.  
     
     
         14 . The glass composition as claimed in  claim 13 , wherein the content of agents does not exceed 2%.  
     
     
         15 . The glass composition as claimed in  claim 1 , wherein the glass composition comprises:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Fe 2 O 3  (total iron) 
                   >0.45% 
                 
                     
                   FeO 
                   >0.15% 
                 
                     
                   CoO 
                    10 to 50 ppm 
                 
                     
                   Cr 2 O 3   
                   10 to 300 ppm 
                 
                     
                   CuO 
                    0 to 400 ppm 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
               
            
           
         
         the glass exhibiting a light transmission LTA of greater than 70% and a selectivity of greater than 1.3 under a thickness of the order of 3.15 mm.  
       
     
     
         16 . The glass composition as claimed in  claim 15 , wherein the glass composition comprises an excitation purity of less than 9%.  
     
     
         17 . The glass composition as claimed in  claim 1 , wherein the glass composition comprises:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Fe 2 O 3  (total iron) 
                   >0.4%, 
                 
                     
                   FeO 
                   >0.12%, 
                 
                 
                 
                 
                 
               
                     
                   CoO 
                   <35 
                   ppm 
                 
                     
                   Cr 2 O 3   
                   10 to 300 
                   ppm 
                 
                     
                   CuO 
                   0 to 400 
                   ppm 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
               
            
             
                
                
                
                
                
               
            
           
         
         the glass exhibiting a light transmission LTA of greater than 60% and a selectivity of greater than 1.3 under a thickness of the order of 3.85 mm.  
       
     
     
         18 . The glass composition as claimed in  claim 17 , wherein the glass composition comprises a light transmission of greater than 70% and a selectivity of greater than 1.4.  
     
     
         19 . The glass composition as claimed in  claim 1 , wherein the glass composition comprises:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Fe 2 O 3  (total iron) 
                   >0.3%, 
                 
                     
                   FeO 
                   >0.1%, 
                 
                     
                   CoO 
                   <25 ppm 
                 
                     
                   Cr 2 O 3   
                   10 to 300 ppm 
                 
                     
                   CuO 
                    0 to 400 ppm 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
               
            
           
         
         the glass exhibiting a light transmission LTA of greater than 60% and a selectivity of greater than 1.3, under a thickness of the order of 4.85 mm.  
       
     
     
         20 . The glass composition as claimed in  claim 19 , wherein the glass composition comprises a dominant wavelength at least equal to 487 nm.  
     
     
         21 . A glass sheet formed by floating on a bath of molten metal, with a chemical composition as defined by  claim 1 .  
     
     
         22 . A window, in particular an automobile window, characterized in that it comprises at least one glass sheet as claimed in  claim 21.