Patent Publication Number: US-6037286-A

Title: UV absorbing container glass compositions

Description:
The present invention relates to an ultraviolet light absorbing container glass composition containing SiO 2 , Al 2  O 3 , Na 2  O, CaO, MgO, K 2  O, SO 3  and, preferably, about 0.4 to 0.8 weight percentage of FeO+Fe 2  O 3  and about 2 to 3 weight percentage of MnO+MnO2 based on the weight of the glass composition. 
     BACKGROUND OF THE INVENTION 
     It is desirous to provide a substantially clear or a lightly tinted flint container glass composition to provide relatively clear transparent flint glass containers that absorb UV light so as to protect the liquid inside such as Champagne or wine. 
     As to prior art showing Fe 2  O 3  or any amount of MnO in glass composition there are the following documents: 
     1. Central Glass Co. U.S. Pat. No. 5,362,689. 
     2. Corning (Morgan) U.S. Pat. No. 5,422,755. 
     3. Guardian Industries U.S. Pat. No.5,214,008. 
     4. Ferro (Roberts) U.S. Pat. No. 4,859,637. 
     5. Chemical Composition of Container Glasses--Sharp (Table 1) 1930&#39;s. 
     Central Glass Co. U.S. Pat. No. 5,362,689 discloses a soda-lime-silica sheet glass composition that contains Fe 2  O 3  (0.1-0.60) and 5-350 ppm MnO. The MnO is used in trace amounts. The ultraviolet absorbing ingredients appear to be CeO 2 , TiO 2  and SO 3 . In Column 5, lines 55-66, the addition of very small amounts of MnO are discussed and there is disclosed a prohibition against the use of larger amounts of MnO. 
     Coming (Morgan) U.S. Pat. No. 5,422,755 discloses a soda-potassia-silica glass composition for an ophthalmic lens. There is disclosed the use of V 2  O 5  (1.5-3.5% ) and MnO 2  (1-4%). The 
     Guardian Industries U.S. Pat. No. 5,214,008 shows a soda-lime silica glass composition for a flat glass. CeO 2  and other UV absorbing ingredients such as TiO 2 , MoO 2 , V 2  O 5  and Fe 2  O 3  are disclosed, for instance, in Column 2, line 28-50. 
     Ferro (Roberts) U.S. Pat. No. 4,859,637 shows lead-free glass compositions with a U.V. absorbing material selected from the group consisting of cerium oxide, manganese oxide, iron oxide, cobalt oxide, copper oxide, vanadium oxide and molybdenum oxide. The glass is used with a ceramic pigment to form an ink composition. 
     The reprint &#34;Chemical Composition of Commercial Glasses&#34;. (Sharp) shows in Table 1 some ancient soda-lime-silica glass compositions containing (0.54-0.9), Fe 2  O 3 , and low amounts (0.61-0.97) of MnO, apparently present from contamination. 
     OBJECTS OF THE INVENTION 
     It is an object of the present invention to provide a relatively transparent, clear flint container glass composition containing oxides of iron and oxides of manganese that absorb UV light to thereby protect liquids such as Champagne and wine from unwanted exposure to the UV light. 
     It is an object of the present invention to provide an ultraviolet light absorbing soda-lime-silica container glass composition consisting essentially of the following ingredients in approximately weight percents; 
     
         ______________________________________                                    
       Ingredients                                                        
                Weight                                                    
______________________________________                                    
       SiO.sub.2                                                          
                69-74                                                     
       Na.sub.2 O                                                         
                11-15                                                     
       CaO       9-13                                                     
       MgO      0.5-2                                                     
       K.sub.2 O                                                          
                0.1-0.5                                                   
       SO.sub.3.sup.-                                                     
                0.1-0.5                                                   
       Fe.sub.2 O.sub.3  + FeO                                            
                0.4-0.8                                                   
       MnO + MnO.sub.2                                                    
                2.0-3.0                                                   
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     These and the other objects will be apparent from the specification and claims that follow. 
     SUMMARY OF THE INVENTION 
     The present invention provides a soda-lime-silica container glass composition consisting essentially of the following ingredients in approximately weight percent; 
     
         ______________________________________                                    
Ingredients    Weight                                                     
______________________________________                                    
SiO.sub.2      69-74                                                      
Na.sub.2 O     11-15                                                      
CaO             9-13                                                      
MgO            0.005-3.0                                                  
K.sub.2 O      0.005-1.0                                                  
SO.sub.3       0.1-0.5                                                    
Fe.sub.2 O.sub.3  + FeO                                                   
               0.3-1.0                                                    
MnO + MnO.sub.2                                                           
               2.0-3.1                                                    
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     The present invention also preferably provides the following: 
     
         ______________________________________                                    
       Ingredients                                                        
                Weight %                                                  
______________________________________                                    
       SiO.sub.2                                                          
                69-74                                                     
       Na.sub.2 O                                                         
                11-15                                                     
       CaO       9-13                                                     
       MgO      0.5-2                                                     
       K.sub.2 O                                                          
                0.1-0.5                                                   
       SO.sub.3 0.1-0.5                                                   
       Fe.sub.2 O.sub.3  + FeO                                            
                0.4-0.8                                                   
       MnO + MnO.sub.2                                                    
                2.0-3.0                                                   
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     DETAILED DESCRIPTION OF THE INVENTION 
    
    
     The following examples illustrate the present invention. 
     EXAMPLE 1 
     A UV absorbing flint container glass composition was made by mixing raw batch ingredients including quartz, soda ash, sodium nitrate, potassium carbonate, alumina, sodium sulfate, iron oxides and manganese oxides and melting the batch to provide a container glass composition (BDB-1) containing the following ingredients, in approximate percentage by weight: 
     
         ______________________________________                                    
Percentage by weight:                                                     
Ingredients    Percentage by weight:                                      
______________________________________                                    
Cl.sub.2       0.0043                                                     
Na.sub.2 O     13.4096                                                    
K.sub.2 O      0.3412                                                     
MgO            0.0053                                                     
CaO            11.0386                                                    
MnO + MnO.sub.2                                                           
               2.0070                                                     
SrO            0.0020                                                     
BaO            0.0005                                                     
Al.sub.2 O.sub.3                                                          
               8.6059                                                     
Fe.sub.2 O.sub.3 + FeO                                                    
               0.4015                                                     
SiO.sub.2      70.8110                                                    
SO.sub.3       0.3714                                                     
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     The glass was melted at 2700° F. for about 61/4 hours in a gas furnace with excess air and an oxidizable batch atmosphere. The glass can be processed like a soda-lime silica glass and it absorbs ultra violet light. 
     The amount of each raw batch material for Example 1 is as follows: 
     
         ______________________________________                                    
Composition - DBD-1                                                       
Raw Materials     GRAMS                                                   
______________________________________                                    
Quartz            354.26                                                  
Soda Ash          112.81                                                  
Sodium Nitrate    3.54                                                    
Calcium Carbonate 96.14                                                   
Magnesium Carbonate                                                       
                  2.50                                                    
Alumina           1.91                                                    
Calcium Sulphate  3.04                                                    
Iron Oxides       1.97                                                    
Manganese Oxides  12.32                                                   
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     EXAMPLE 2 
     Following the procedure of Example 1, additional melts D-1, D-2, D-3, D-4, D-5 and D-6 were made according to Table 1 below. 
     
                       TABLE 1                                                     
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EVALUATION OF 0.4, 0.6 and 0.8% Fe.sub.2 O.sub.3 at 2.0 and               
3.0% MANGANESE OXIDE LEVELS                                               
MELT       MELT     MELT    MELT  MELT   MELT                             
D-1        D-2      D-3     D-4   D-5    D-6                              
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SiO.sub.2                                                                 
       71.05   70.85    70.65 70.05 69.85  69.65                          
Na.sub.2 O                                                                
       13.36   13.36    13.36 13.36 13.36  13.36                          
CaO    11.00   11.00    11.00 11.00 11.00  11.00                          
K.sub.2 O                                                                 
       0.34    0.34     0.34  0.34  0.34   0.34                           
Al.sub.2 O.sub.3                                                          
       1.60    1.60     1.60  1.60  1.60   1.60                           
SO.sub.3                                                                  
       0.25    0.25     0.25  0.25  0.25   0.25                           
Fe.sub.2 O.sub.3                                                          
       0.40    0.60     0.80  0.40  0.60   0.80                           
MnO    2.00    2.00     2.00  3.00  3.00   3.00                           
NaNO.sub.3                                                                
       10#/    10#/     10#/  10#/  10#/   10#/                           
       1000#   1000#    1000# 1000# 1000#  1000#                          
       Sand    Sand     Sand  Sand  Sand   Sand                           
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 COMMENTS:                                                                
 1) Melt D1 uses 0.40 wt % Fe2O3 and 2.0% manganese oxide (5.64:1 molar   
 ratio of Mn to Fe)                                                       
 2) Melt D2 uses 0.60 wt % Fe2O3 and 2.0% manganese oxide (3.71:1 molar   
 ratio of Mn to Fe)                                                       
 3) Melt D3 uses 0.80 wt % Fe2O3 and 2.0% manganese oxide (2.82:1 molar   
 ratio of Mn to Fe)                                                       
 4) Melt D4 uses 0.40 wt % Fe2O3 and 3.0% manganese oxide (8.46:1 molar   
 ratio of Mn to Fe)                                                       
 5) Melt D5 uses 0.60 wt % Fe2O3 and 3.0% manganese oxide (5.57:1 molar   
 ratio of Mn to Fe)                                                       
 6) Melt D6 uses 0.80 wt % Fe2O3 and 3.0% manganese oxide (4.23:1 molar   
 ratio of Mn to Fe)                                                       
 
    
     The glass composition of Example 1 (DBD-1) and Example 2 (D1 through D6) were tested and found to reduce the transmission of ultraviolet light and in addition, possess melting and forming properties similar to commercially feasible soda-lime glass. 
     U.V. glass analyses for melts D1 through D6 (Example 2) are as follows: 
     U.V. Glass DOE Analysis For `D` Series Melts 
     The measured values for dominant wavelength, brightness, and purity for the D series glass melts were analyzed with an ANOVA Program to determine any significant effect, the percent contribution and test validity. The following table summarizes the results from these tests: 
     Details of the U.V. absorption form melts D1, D2, D3, D4, D5, and D6 are as follows: 
     
         ______________________________________                                    
        Dominant       %        %                                         
Melt    Wavelength     Brightness                                         
                                Purity                                    
______________________________________                                    
D1      580.1          20.47    75.2                                      
D3      565.9          16.6     70.8                                      
D4      639.0           0.02    100.0                                     
D6      572.7          11.45    85.9                                      
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     Extra melts: 
     
         ______________________________________                                    
D2      569.8          24.73  67.5                                        
D5      577.7          15.19  87.2                                        
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     The attached three sheets show the ANOVA results. The conclusions are: 
     
         ______________________________________                                    
1.    Dominant wavelength:                                                
      Significant constituents:  Mn 12%  Fe 28%                           
      Error 60% = marginal test (0-60% good, 60-80% marginal,             
      &gt;80% poor)                                                          
2.    Brightness:                                                         
      Significant constituents:  Mn 51%                                   
      Insignificant                                                       
      Error 60% = marginal test (0-60% good, 60-80% marginal,             
      &gt;80% poor)                                                          
3.    Purity:                                                             
      Significant constituents:  Mn 74%  Fe 12%                           
      Error 14% = good test                                               
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         ______________________________________                                    
ANOVA Table - Raw Data (D1 thru D6 Series)                                
Source                                                                    
      Pool    Df    S     V     F      S&#39;    rho %                        
______________________________________                                    
MNO   [N]     1     398.003                                               
                          398.003                                         
                                16.920 374.480                            
                                             73.85                        
FE    [N]     1     85.562                                                
                          85.562                                          
                                3.637  62.040                             
                                             12.23                        
ERR   [Y]     1     23.523                                                
                          23.523                                          
e1    [N]     0     0.000                                                 
e2    [N]     0     0.000                                                 
(e)           1     23.523                                                
                          23.523       70.568                             
                                             13.92                        
Total         3     507.087                                               
                          169.029                                         
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         ______________________________________                                    
ANOVA Table - Raw Data (D1 thru D6)                                       
Source                                                                    
      Pool    Df    S     V     F      S&#39;    rho %                        
______________________________________                                    
MN    [N]     1     157.001                                               
                          157.001                                         
                                4.184  119.478                            
                                             51.49F                       
E     [Y]     1     12.320                                                
                          12.320                                          
ERR   [Y]     1     62.726                                                
                          62.726                                          
e1    [N]     0     0.000                                                 
e2    [N]     0     0.000                                                 
(e)           2     75.046                                                
                          37.523       112.570                            
                                             48.51                        
Total         3     232.047                                               
                          77.349                                          
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         ______________________________________                                    
ANOVA Table - Raw Data (D1 thru D6)                                       
Source                                                                    
      Pool   Df    S      V      F    S&#39;     rho %                        
______________________________________                                    
MN    [N]    1     1079.123                                               
                          1079.123                                        
                                 1.590                                    
                                      400.519                             
                                             1186                         
FE    [N]    1     1620.060                                               
                          1620.060                                        
                                 2.387                                    
                                      941.457                             
                                             27.87                        
ERR   [Y]    1     678.603                                                
                          678.603                                         
e1    [N]    0     0.000                                                  
e2    [N]    0     0.000                                                  
(e)          1     678.603                                                
                          678.603     2035.810                            
                                             60.27                        
Total        3     3377.786                                               
                          1125.929                                        
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     The useful Mn to Fe ratio is one that minimizes color and maximizes U.V. absorption. For example, D-1 (Mn/Fe=5.64/1) has a hint of yellow or amber. A small amount of cobalt could be used resulting in a slight green color. D-2 has slightly better U.V. protection and has a faint or slight green-yellow color (Mn/Fe=3.71/1). D-3 (Mn/Fe=2.82/1) has slightly better U.V. protection than does D-2 and is slightly green. D-4 is faintly purple (excess Mn +3 ) and a ratio=8.46/1. D-5 approximates D-3 in U.V. protection, ratios=5.57/1. D-6 has poor U.V. protection, and has a slightly darker green-yellow tint ratio=4.23/1. 
     The Mn/Fe ratio generally can be from about 2.8/1 to about 6.5/1. The best results generally are about 5.2/1 to 5.8/1 for the Mn/Fe ratio. 
     Manganese oxide is added to oxidize the iron to the +3 state which is the UV absorbing ingredient. Mn +3  is a purple color in glass but becomes colorless in the +2 state as the iron is oxidized.