US2003061835A1PendingUtilityA1

Glass plate and method for tempering a glass plate

47
Assignee: ASAHI GLASS CO LTDPriority: Mar 30, 2001Filed: Mar 25, 2002Published: Apr 3, 2003
Est. expiryMar 30, 2021(expired)· nominal 20-yr term from priority
C03B 27/04C03C 3/087C03C 23/007C03B 27/0413C03B 27/00
47
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Claims

Abstract

A method for tempering a glass plate having a thickness of from 2 to 3 mm, and having an average linear thermal expansion coefficient of at least 88×10 −7 /° C. at a temperature of from 50 to 300° C. and a softening point of from 715 to 740° C., which comprises quenching the glass plate from an initial glass temperature of quenching at which the viscosity is within a range of from 10 9 to 10 10 poise to a temperature at which the viscosity is 10 12 poise, so that the heat transfer coefficient h (W/m 2 K) satisfies the following formula (1), where t (mm) is a glass plate thickness: h >4970.5-3149.9 t +550.3 t 2   formula (1)

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
         1 . A method for tempering a glass plate having a thickness of from 2 to 3 mm, and having an average linear thermal expansion coefficient of at least 88×10 −7 /° C. at a temperature of from 50 to 300° C. and a softening point of from 715 to 740° C., which comprises quenching the glass plate from an initial glass temperature of quenching at which the viscosity is within a range of from 10 9  to 10 10  poise to a temperature at which the viscosity is 10 12  poise, so that the heat transfer coefficient h (W/m 2 K) satisfies the following formula (1), where t (mm) is a glass plate thickness:  
         h> 4970.5−3149.9 t+ 550.3 t   formula (1)  
     
     
         2 . A method for tempering a glass plate having a thickness of from 2 to 3 mm, and having an average linear thermal expansion coefficient of at least 88×10 −7 /° C. at a temperature of from 50 to 300° C. and a softening point of from 715 to 740° C., which comprises quenching the glass plate from an initial glass temperature of quenching at which the viscosity is within a range of from 10 9  to 10 10  poise to a temperature at which the viscosity is 10 12  poise, so that the heat transfer coefficient h (W/m 2 K) satisfies the following formula (2), where t (mm) is a glass plate thickness:  
         h> 2123.6 ·t   −1.4641   formula (2)  
     
     
         3 . The method for tempering a glass plate according to  claim 1 , wherein a glass plate having the following composition is tempered:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   SiO 2   
                   66.0-74.0 mass %, 
                 
                     
                   Al 2 O 3   
                   1.5-4.0 mass %, 
                 
                     
                   CaO 
                   7.0-10.0 mass %, 
                 
                     
                   MgO 
                   3.8-6.0 mass %, 
                 
                     
                   Na 2 O 
                   12.6-14.6 mass % and 
                 
                     
                   K 2 O 
                   0.4-2.0 mass %, 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
                
               
            
           
         
       
       in a total amount of these components of at least 96 mass %, and  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   SiO 2  + Al 2 O 3   
                   70.0-74.0 mass %, 
                 
                     
                   CaO + MgO 
                   12.0-14.5 mass % and 
                 
                     
                   Na 2 O + K 2 O 
                   13.5-15.5 mass %. 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         4 . The method for tempering a glass plate according to  claim 3 , wherein a glass plate having the following composition is tempered:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Al 2 O 3   
                   2.0-4.0 mass %, 
                 
                     
                   CaO + MgO 
                   12.5-14.5 mass % and 
                 
                     
                   CaO/MgO 
                   (mass ratio) = 1.7-2.2. 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         5 . The method for tempering a glass plate according to  claim 2 , wherein a glass plate having the following composition is tempered:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   SiO 2   
                   66.0-74.0 mass %, 
                 
                     
                   Al 2 O 3   
                   1.5-4.0 mass %, 
                 
                     
                   CaO 
                   7.0-10.0 mass %, 
                 
                     
                   MgO 
                   3.8-6.0 mass %, 
                 
                     
                   Na 2 O 
                   12.6-14.6 mass % and 
                 
                     
                   K 2 O 
                   0.4-2.0 mass %, 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
                
               
            
           
         
       
       in a total amount of these components of at least 96 mass %, and  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   SiO 2  + Al 2 O 3   
                   70.0-74.0 mass %, 
                 
                     
                   CaO + MgO 
                   12.0-14.5 mass % and 
                 
                     
                   Na 2 O + K 2 O 
                   13.5-15.5 mass %. 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         6 . The method for tempering a glass plate according to  claim 5 , wherein a glass plate having the following composition is tempered:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Al 2 O 3   
                   2.0-4.0 mass %, 
                 
                     
                   CaO + MgO 
                   12.5-14.5 mass % and 
                 
                     
                   CaO/MgO 
                   (mass ratio) = 1.7-2.2. 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         7 . The method for tempering a glass plate according to  claim 3 , wherein the glass plate has at least one member selected from the group consisting of Fe 2 O 3 , CoO, Se, NiO, Cr 2 O 3 , MnO, V 2 O 5 , TiO 2 , CeO 2 , SnO, ZnO and SO 3  added thereto.  
     
     
         8 . The method for tempering a glass plate according to  claim 5 , wherein the glass plate has at least one member selected from the group consisting of Fe 2 O 3 , CoO, Se, NiO, Cr 2 O 3 , MnO, V 2 O 5 , TiO 2 , CeO 2 , SnO, ZnO and SO 3  added thereto.  
     
     
         9 . The method for tempering a glass plate according to  claim 1 , wherein the glass plate has a thickness of from 2 to 3 mm.  
     
     
         10 . The method for tempering a glass plate according to  claim 1 , wherein the glass plate is obtained by a float process.  
     
     
         11 . The method for tempering a glass plate according to  claim 1 , wherein the glass plate is used as a window glass for automobiles.  
     
     
         12 . A glass plate which has the following composition:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   SiO 2   
                   66.0-74.0 mass %, 
                 
                     
                   Al 2 O 3   
                   2.0-4.0 mass %, 
                 
                     
                   CaO 
                   7.0-10.0 mass %, 
                 
                     
                   MgO 
                   3.8-6.0 mass %, 
                 
                     
                   Na 2 O 
                   12.6-14.6 mass % and 
                 
                     
                   K 2 O 
                   0.4-2.0 mass %, 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
                
               
            
           
         
       
       in a total amount of these components of at least 96 mass %, and  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   SiO 2  + Al 2 O 3   
                   70.0-74.0 mass %, 
                 
                     
                   CaO + MgO 
                   12.5-14.5 mass %, 
                 
                     
                   Na 2 O + K 2 O 
                   13.5-15.5 mass %, and 
                 
                     
                   CaO/MgO 
                   (mass ratio) = 1.7-2.2. 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
               
            
           
         
       
     
     
         13 . The glass plate according to  claim 12 , which is obtained by tempering a glass plate having the following composition:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Al 2 O 3   
                   2.0-4.0 mass %, 
                 
                     
                   CaO + MgO 
                   12.5-14.5 mass % and 
                 
                     
                   CaO/MgO 
                   (mass ratio) = 1.7-2.2. 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         14 . The glass plate according to  claim 12 , which comprises SrO or BaO instead of CaO.  
     
     
         15 . The glass plate according to  claim 12 , which comprises SrO or BaO instead of MgO.  
     
     
         16 . The glass plate according to  claim 12 , which has at least one member selected from the group consisting of Fe 2 O 3 , CoO, Se, NiO, Cr 2 O 3 , MnO, V 2 O 5 , TiO 2 , CeO 2 , SnO, ZnO and SO 3  added thereto.  
     
     
         17 . The glass plate according to  claim 12 , which has a thickness of from 2 to 3 mm.  
     
     
         18 . The glass plate according to  claim 12 , which is obtained by a float process.  
     
     
         19 . The glass plate according to  claim 12 , which is used as a window glass for automobiles.

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