US2002065187A1PendingUtilityA1

Glass sheet intended to be thermally toughened

Assignee: SAINT GOBAINPriority: Mar 2, 1998Filed: Nov 26, 2001Published: May 30, 2002
Est. expiryMar 2, 2018(expired)· nominal 20-yr term from priority
C03C 3/087C03C 4/00
40
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Claims

Abstract

The subject of the invention is a glass sheet intended to be thermally toughened, the matrix of which is of the silica-soda-lime type, having an expansion coefficient α of greater than 100×10 −7 K −1 , a Young's modulus E of greater than 60 GPa and a thermal conductivity k of less than 0.9 W/m.K.

Claims

exact text as granted — not AI-modified
1 . A glass sheet intended to be thermally toughened, comprising a silica-soda matrix, wherein said sheet has an expansion cofficient α of greater than 100×10 −7 K −1 , a Young's modulus E of greater than 60 GPa and a thermal conductivity k of less than 0.9 W/m.K.  
     
     
         2 . The glass sheet of  claim 1 , wherein said sheet has a Poisson's ratio of greater than 0.21.  
     
     
         3 . The glass sheet of  claim 2 , wherein said sheet has a specific heat of greater than 7.40 J/kg.K.  
     
     
         4 . The glass sheet of  claim 1 , wherein said sheet has a specific heat of greater than 7.40 J/kg.K.  
     
     
         5 . The glass sheet of  claim 1 , wherein said sheet has a density of greater than 2520 kg/m 3 .  
     
     
         6 . The glass sheet of  claim 1 , wherein said sheet satisfies the relationship: 
       α· E/K> 8000. 
     
     
         7 . The glass sheet of  claim 1 , wherein said matrix comprises, in percentages by weight, the following constituents:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   SiO 2   
                   45-69% 
                 
                     
                   Al 2 O 3   
                   0-14% 
                 
                     
                   CaO 
                   0-22% 
                 
                     
                   MgO 
                   0-10% 
                 
                     
                   Na 2 O 
                   6-24% 
                 
                     
                   K 2 O 
                   0-10% 
                 
                     
                   BaO 
                   0-12% 
                 
                     
                   B 2 O 3   
                   0-6% 
                 
                     
                   ZnO 
                   0-10% 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
       and satisfies the relationships: 
       Na 2 O+K 2 O>20%Na 2 O+K 2 O+CaO>27%. 
     
     
         8 . The glass sheet of  claim 1 , wherein said matrix comprises, in percentages by weight, the following constituents:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   SiO 2   
                   45-69% 
                 
                     
                   Al 2 O 3   
                   0-14% 
                 
                     
                   CaO 
                   0-22% 
                 
                     
                   MgO 
                   0-10% 
                 
                     
                   Na 2 O 
                   6-24% 
                 
                     
                   K 2 O 
                   0-10% 
                 
                     
                   BaO 
                   0-12% 
                 
                     
                   B 2 O 3   
                   0-6% 
                 
                     
                   ZnO 
                   0-10% 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
       and satisfies the relationships: 
       Na 2 O+K 2 O>17%Na 2 O+K 2 O+CaO>35%. 
     
     
         9 . The glass sheet of  claim 1 , wherein said matrix comprises, in percentages by weight, at least one of Na 2 O and K 2 O in amounts which satisfy the following relationship: 
       Na 2 O+K 2 O>17%. 
     
     
         10 . The glass sheet of  claim 1 , wherein said matrix comprises, in percentages by weight, the following constituents:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   SiO 2   
                   45-69%  
                 
                     
                   Al 2 O 3   
                   0-14% 
                 
                     
                   CaO 
                   0-22% 
                 
                     
                   MgO 
                   0-10% 
                 
                     
                   Na 2 O 
                   6-24% 
                 
                     
                   K 2 O 
                   0-10% 
                 
                     
                   BaO 
                   0-12% 
                 
                     
                   B 2 O 3   
                   0-6%  
                 
                     
                   ZnO 
                   0-10% 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
       and satisfies the relationships: 
 (a) Na 2 O+K 2 O>17%, and  
 (b) Na 2 O+K 2 O+CaO>29% when at least one of Na 2 O>18%, K 2 O>5%, and Al 2 O 3 <3%.  
 
     
     
         11 . The glass sheet of  claim 9 , wherein said matrix comprises, in percentages by weight, at least one of TiO 2  and Al 2 O 3  in amounts which satisfy the relationship: 
       TiO 2 +Al 2 O 3 <3%. 
     
     
         12 . The glass sheet of  claim 1 , wherein said matrix comprises, in percentages by weight, at least one of Na 2 O, K 2 O, CaO, and Al 2 O 3  in amounts which satisfy the following relationships: 
 (a) Na 2 O+K 2 O>17%, and    (b) Na 2 O+K 2 O+CaO>29% when at least one of Na 2 O>18%, K 2 O>5%, and Al 2 O 3 <3%.    
     
     
         13 . The glass sheet according to  claim 1 , wherein said sheet has a thickness of less than 2.5 mm and is thermally toughened.  
     
     
         14 . The glass sheet of  claim 1 , wherein said matrix comprises Na 2 O and optionally one or more of K 2 O, CaO or Al 2 O 3  in amounts which satisfy the following relationship: 
       Na 2 O+K 2 O+CaO>29 wt % 
       when at least one of Na 2 O>18 wt %, K 2 O>5 wt %, and Al 2 O 3 <3 wt %.  
     
     
         15 . The glass sheet of  claim 1 , wherein said matrix has a CaO content of 10.4 to 22 wt %.  
     
     
         16 . A glass sheet intended to be thermally toughened, comprising a silica-soda matrix, wherein said sheet has an expansion cofficient α of greater than 100×10 −7 K −1 , a Young's modulus E of greater than 60 GPa and a thermal conductivity k of less than 0.9 W/m.K and said matrix has a SiO 2  content of 45 to 65 wt %, wherein said matrix comprises Na 2 O and optionally K 2 O in amounts which satisfy the following relationship: 
       Na 2 O+K 2 O>20wt %. 
     
     
         17 . A glass composition comprising, in percentages by weight:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   SiO 2   
                   45-69% 
                 
                     
                   Al 2 O 3   
                   0-14% 
                 
                     
                   CaO 
                   0-22% 
                 
                     
                   MgO 
                   0-10% 
                 
                     
                   Na 2 O 
                   6-24% 
                 
                     
                   K 2 O 
                   0-10% 
                 
                     
                   BaO 
                   0-12% 
                 
                     
                   B 2 O 3   
                   0-6% 
                 
                     
                   ZnO 
                   0-10%, 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
       wherein the glass has a viscosity η in poise, a forming temperature at which log η=3.5, and a liquidus temperature which is less than or equal to the forming temperature.  
     
     
         18 . The glass composition of  claim 17 , wherein the liquidus temperature is between 10° C. and 30° C. less than the forming temperature.  
     
     
         19 . The glass composition of  claim 18 , wherein the glass has an expansion coefficient of greater than 100×10 −7 K −1 .  
     
     
         20 . The glass composition of  claim 19 , wherein the glass has a Young's modulus of greater than 60 GPa.  
     
     
         21 . The glass composition of  claim 19 , wherein the glass has a thermal conductivity of less than 0.9 W/m.K.

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