UV absorbing container glass compositions

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 , Na 2 O, CaO, MgO, K 2 O, SO - 3 , and a U.V. absorbing amount of about 0.3 to 1.0 weight percent FeO + Fe 2 O 3 , and about 2 to 3.1 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 + MnO 2 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. Patent No. 5,362,689. 2. Corning (Morgan) U.S. Patent No. 5,422,755. 3. Guardian Industries U.S. Patent No. 5,214,008. 4. Ferro (Roberts) U.S. Patent No. 4,859,637. 5. Chemical Composition of Container Glasses - Sharp (Table 1) 1930's. 6. JP-A- 49 098 816 (also as Derwent abstract, Accession no. 75-36593W) 7. US-A- 5 656 560 8 US-A- 5 851 940 Central Glass Co. U.S. Patent 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. Corning (Morgan) U.S. Patent 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%). There is no discussion of the use of Fe 2 O 3 or calcia in the glass composition. Guardian Industries U.S. Patent 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, lines 28-50. Ferro (Roberts) U.S. Patent 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 "Chemical Composition of Commercial Glasses". (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. The Derwent abstract of JP-A- 49/ 098 816 discloses IR-absorbing glass having colouring components giving the glass a grey or bronze colour. The colouring components are the following iron oxide (Fe 2 O 3 ) 0.05 - 1.0 wt% manganese oxide (MnO 2 ) 0.05 - 5.0 wt% chromium oxide (Cr 2 O 3 ) 0.002 - 0.1 wt% copper oxide (CuO) 0.005 - 0.5 wt% US-A- 5 656 560 discloses a bronze-tinted or grey-tinted soda lime silicate glass, in particular useful for the manufacture of flat glass. This glass is characterized in that one or more of the following colourant additives be present in the following proportions: Fe 2 O 3 0-0.45 weight % V 2 O 5 0.0-0.5 weight % MnO 2 0.5-2 weight % NiO 0.0-0.05 weight % CuO 0.0-0.1 weight % CoO 0.0-0.008 weight % US-A- 5 851 940 which forms only prior art according to Art 54(3) EPC, relates to blue soda-lime-silica glass compositions having improved UV and IR absorption. The colourant in this glass composition consists of: 0,4 to 2.0% total iron oxide as Fe 2 O 3 0.15 to 2.00% manganese oxide as MnO 2 0.005 to 0.025% cobalt oxide as Co, and 0 to 1.00% titanium oxide as TiO 2 The glass is useful for automotive or architectural applications. 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 weight percents : Ingredients Weight SiO 2 69 - 74 Na 2 O 11 - 15 CaO 9 - 13 MgO 0.5 - 2 K 2 O 0.1 - 0.5 SO 3 x 0.1 - 0.5 Fe 2 O 3 + FeO 0.4 - 0.8 MnO + MnO 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 weight percent : Ingredients Weight SiO 2 69 - 74 Na 2 O 11 - 15 CaO 9 - 13 MgO 0.005 - 3.0 K 2 O 0.005 - 1.0 SO 3 0.1 - 0.5 F 2 O 3 + FeO 0.3 - 1.0 MnO + MnO 2 2.0 - 3.1 , preferably 2.2 - 2.8 and more preferably 2.4 - 2.6 wt%. Suitable compositions are further those wherein : at least 80 % of the total iron content is in the ferric state, or the total initial iron content is present as Fe 2 O 3 and FeO and the ratio of Fe 2+ /Fe 3+ is 0.3 to 0.1, or Fe 2 O 3 is 0.6 wt % and MnO + MnO 2 is 2 to 3 wt%. The present invention also preferably provides the following: Ingredients Weight % SiO 2 69 - 74 Na 2 O 11 - 15 CaO 9 - 13 MgO 0.5 - 2 K 2 O 0.1 - 0.5 SO 3 0.1 - 0.5 Fe 2 O 3 + FeO 0.4 - 0.8 MnO + MnO 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 (DBD-1) containing the following ingredients, in percentage by weight: Ingredients Percentage by weight: Cl 2 0.0043 Na 2 O 13.4096 K 2 O 0.3412 MgO 0.0053 CaO 11.0386 MnO + MnO 2 2.0070 SrO 0.0020 BaO 0.0005 Al 2 O 3 1.6059 Fe 2 O 3 + FeO 0.4015 SiO 2 70.8110 SO 3 0.3714 The glass was melted at 1482 °C (2700°F) for about 6 1/4 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 Potassium Carbonate 2.50 Alumina 7.91 Calcium Sulphate 3.04 Iron Oxides 1.97 Manganese 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. EVALUATION OF 0.4, 0.6 and 0.8% Fe 2 O 3 at 2.0 and 3.0% MANGANESE OXIDE LEVELS MELT D-1 MELT D-2 MELT D-3 MELT D-4 MELT D-5 MELT D-6 SiO 2 71.05 70.85 70.65 70.05 69.85 69.65 Na 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 2 O 0.34 0.34 0.34 0.34 0.34 0.34 Al 2 O 3 1.60 1.60 1.60 1.60 1.60 1.60 SO 3 0.25 0.25 0.25 0.25 0.25 0.25 Fe 2 O 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 3 10#/1000# Sand 10#/1000# Sand 10#/1000# Sand 10#/1000# Sand 10#/1000# Sand 10#/1000# Sand COMMENTS: 1) Melt D-1 uses 0.40 wt% Fe2O3 and 2.0% manganese oxide (5.64 : 1 molar ratio of Mn to Fe) 2) Melt D-2 uses 0.60 wt% Fe2O3 and 2.0% manganese oxide (3.71: 1 molar ratio of Mn to Fe) 3) Melt D-3 uses 0.80 wt% Fe2O3 and 2.0% manganese oxide (2.82 : 1 molar ratio of Mn to Fe) 4) Melt D-4 uses 0.40 wt% Fe2O3 and 3.0% manganese oxide (8.46 : 1 molar ratio of Mn to Fe) 5) Melt D-5 uses 0.60 wt% Fe2O3 and 3.0% manganese oxide (5.57 : 1 molar ratio of Mn to Fe) 6) Melt D-6 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 from melts D1, D2, D3, D4, D5, and D6 are as follows: Melt Dominant 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 Extra melts: D2 569.8 24.73 67.5 D5 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, >80% poor) 2 Brightness: Significant constituents: Mn 51% Insignificant Error 60% = marginal test (0-60% good, 60-80% marginal, >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' 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 ANOVA Table - Raw Data (D1 thru D6) Source Pool Df S V F S' 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 ANOVA Table - Raw Data (D1 thru D6) Source Pool Df S V F S' 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 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 tint 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.

Claims: A soda-lime-silica container glass composition consisting essentially of the following ingredients in weight percents; Ingredients Weight SiO 2 69 - 74 Na 2 O 11 - 15 CaO 9 - 13 MgO 0.005 - 3.0 K 2 O 0.005 - 1.0 SO 3 0.1 - 0.5 Fe 2 O 3 + Feo 0.3 - 1.0 MnO + MnO 2 2.0 - 3.1 A composition as defined in claim 1 in which the UV absorption ranging from 290 to 390 nm is much greater than that of flint soda-lime glass. A composition as defined in claim 1 in which at least 80% of the total iron content is in the ferric state. A composition as defined in claim 1 in which the amount of MnO+MnO 2 is 2.2 to 2.8 wt. percent. A composition as defined in claim 1 in which the amount of MnO + MnO 2 is 2.4 to 2.6 wt. percent. A composition as defined in claim 1 in which the total initial iron content is as present Fe 2 O 3 and FeO and the ratio of Fe 2+ /Fe 3+ is 0.3 to 0.1. A composition as defined in claim 1 in which FeO + Fe 2 O 3 is 0.6 wt. percent and MnO + MnO 2 is 2 to 3 wt. percent. A glass container made of the glass composition of claim 1. A soda-lime-silica container glass composition that absorbs U.V. light and consists essentially of the following ingredients in weight percents : Ingredients Weight SiO 2 69 - 74 Na 2 O 11 - 15 CaO 9 - 13 MgO 0.5 - 2 K 2 O 0.1 - 0.5 SO 3 0.1 - 0.5 Fe 2 O 3 + FeO 0.4 - 0.8 MnO + MnO 2 2.0 - 3.0

Inventors: CLARK ROBERT N, FENSTERMACHER JAMES E, HAMMEL JOSEPH J, WEISER STEVEN M, CLARK, ROBERT N., FENSTERMACHER, JAMES E., HAMMEL, JOSEPH J., WEISER, STEVEN M.
Applicants: OWENS BROCKWAY GLASS CONTAINER, OWENS-BROCKWAY GLASS CONTAINER INC.
Application year: 1999
Main classification: C03C3
IPC codes: C03C3, C03C4