Abstract:
A container glass composition that reduces U.V. light transmission below a wavelength of about 400 nanometers, the composition having melting and forming properties similar to soda-lime-silica glass and containing SiO 2 , CaO, MgO, K 2  O, SO -   3 , and a U.V. absorbing amount of about 0.4 to 0.8 weight percent FeO+Fe 2  O 3 , and about 2 to 4 weight percent of MnO+MnO 2 .

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______________________________________ 
    
     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      69-74Na.sub.2 O     11-15CaO             9-13MgO            0.005-3.0K.sub.2 O      0.005-1.0SO.sub.3       0.1-0.5Fe.sub.2 O.sub.3  + FeO          0.3-1.0MnO + MnO.sub.2          2.0-3.1______________________________________ 
    
     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______________________________________ 
    
     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       0.0043Na.sub.2 O     13.4096K.sub.2 O      0.3412MgO            0.0053CaO            11.0386MnO + MnO.sub.2          2.0070SrO            0.0020BaO            0.0005Al.sub.2 O.sub.3          8.6059Fe.sub.2 O.sub.3 + FeO          0.4015SiO.sub.2      70.8110SO.sub.3       0.3714______________________________________ 
    
     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-1Raw Materials     GRAMS______________________________________Quartz            354.26Soda Ash          112.81Sodium Nitrate    3.54Calcium Carbonate 96.14Magnesium Carbonate             2.50Alumina           1.91Calcium Sulphate  3.04Iron Oxides       1.97Manganese Oxides  12.32______________________________________ 
    
     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______________________________________EVALUATION OF 0.4, 0.6 and 0.8% Fe.sub.2 O.sub.3 at 2.0 and3.0% MANGANESE OXIDE LEVELSMELT       MELT     MELT    MELT  MELT   MELTD-1        D-2      D-3     D-4   D-5    D-6______________________________________SiO.sub.2  71.05   70.85    70.65 70.05 69.85  69.65Na.sub.2 O  13.36   13.36    13.36 13.36 13.36  13.36CaO    11.00   11.00    11.00 11.00 11.00  11.00K.sub.2 O  0.34    0.34     0.34  0.34  0.34   0.34Al.sub.2 O.sub.3  1.60    1.60     1.60  1.60  1.60   1.60SO.sub.3  0.25    0.25     0.25  0.25  0.25   0.25Fe.sub.2 O.sub.3  0.40    0.60     0.80  0.40  0.60   0.80MnO    2.00    2.00     2.00  3.00  3.00   3.00NaNO.sub.3  10#/    10#/     10#/  10#/  10#/   10#/  1000#   1000#    1000# 1000# 1000#  1000#  Sand    Sand     Sand  Sand  Sand   Sand______________________________________ 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    75.2D3      565.9          16.6     70.8D4      639.0           0.02    100.0D6      572.7          11.45    85.9______________________________________ 
    
     Extra melts: 
     
         ______________________________________D2      569.8          24.73  67.5D5      577.7          15.19  87.2______________________________________ 
    
     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______________________________________ 
    
     
         ______________________________________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                                        73.85FE    [N]     1     85.562                     85.562                           3.637  62.040                                        12.23ERR   [Y]     1     23.523                     23.523e1    [N]     0     0.000e2    [N]     0     0.000(e)           1     23.523                     23.523       70.568                                        13.92Total         3     507.087                     169.029______________________________________ 
    
     
         ______________________________________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                                        51.49FE     [Y]     1     12.320                     12.320ERR   [Y]     1     62.726                     62.726e1    [N]     0     0.000e2    [N]     0     0.000(e)           2     75.046                     37.523       112.570                                        48.51Total         3     232.047                     77.349______________________________________ 
    
     
         ______________________________________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                                        1186FE    [N]    1     1620.060                     1620.060                            2.387                                 941.457                                        27.87ERR   [Y]    1     678.603                     678.603e1    [N]    0     0.000e2    [N]    0     0.000(e)          1     678.603                     678.603     2035.810                                        60.27Total        3     3377.786                     1125.929______________________________________ 
    
     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.