Lithium-aluminosilicate flat float glass
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Abstract
Lithium-aluminosilicate flat float glass with a high thermal stability, which can be chemically and thermally tempered and is refined without using the standard refining agents arsenic oxide and/or antimony oxide, having a composition which, in % by weight based on the total composition, contains the following main constituents:
160 Citations
61 Claims
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1-28. -28. (canceled)
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29. A lithium-aluminosilicate flat float glass with a high thermal stability, which can be chemically and thermally tempered and is refined without using the standard refining agents arsenic oxide and/or antimony oxide, having a composition which, in % by weight based on the total composition, comprising:
-
Li2O
2.5-6.0Σ
Na2O + K2O<
4B2O3
0-<
4Al2O3
15-30SiO2
55-75Σ
TiO2 + ZrO2<
2 (in order to avoid the crystallization ofundesirable beta-quartz and/or keatite solid solutions). - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61)
Li2O 3.0-6.0
Σ
Na2O + K2O<
2Σ
MgO + CaO + SrO + BaO<
4ZnO 0-1.5 B2O3
0-<
4Al2O3 18-28
SiO2 60-72
Σ
TiO2 + ZrO2<
2 (in order to avoid the crystallizationof undesirable beta-quartz and/or keatite solid solutions) SnO2 0.1-1.5
(as refining agent) F 0-2
P2O5 0-3.
-
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51. The flat float glass according to claim 29, having a coefficient of thermal expansion α
-
20/300 of between 3.8 and 4.5·
10−
6/K, a transformation temperature Tg of between 600 and 680°
C., a working point VA of between 1280-1320°
C., and, in % by weight based on the total composition, comprises;
Li2O 3.5-5.0
Σ
Na2O + K2O<
1.5Σ
MgO + CaO + SrO + BaO<
3
ZnO 0-1.0 B2O3
0-<
3Al2O3 19-26
SiO2 62-70
Σ
TiO2 + ZrO2<
1.5 (in order to avoid thecrystallization of undesirable beta-quartz and/or keatite solid solutions) SnO2 0.1-1.0
(as refining agent) F 0-1.8 P2O5 0-2.
-
20/300 of between 3.8 and 4.5·
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52. The flat float glass according to claim 29, having a fluorine content F of 0.1-1.2% by weight.
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53. The flat float glass according to claim 29, wherein the glass is technically BaO-free.
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54. The flat float glass according to claim 29, wherein, to achieve a low number of bubbles, in addition to the refining agent SnO2, at least one further chemical refining agent which is compatible with the float process.
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55. The flat float glass according to claim 54, wherein said at least one further chemical refining agent is cerium oxide, a sulphate compound, a chloride compound or a fluorine compound.
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56. The flat float glass according to claim 29, wherein, to achieve a low number of bubbles the glass melt is refined physically, for example by means of reduced pressure or by means of high temperature >
- 1680°
C.
- 1680°
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57. The flat float glass according to claim 29, having an Fe2O3 content of less than 250 ppm and a TiO2 content of less than 1% by weight, and a light transmission, at a thickness of 4 mm, of >
- 90%.
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58. The flat float glass according to claim 29, wherein the absorption in the UV and/or infrared is set adding at least one composition selected from the group consisting of iron oxide, selenium oxide, nickel oxide, cobalt oxide, cerium oxide, copper oxide, and titanium oxide, in a total quantity of <
- 1% by weight.
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59. The flat float glass according to claim 29, having a color cast which is present as a result of contamination or UV- and/or IR-absorbing substances is reduced by the addition of at least one decolorizing agent elected from the group consisting of manganese oxide or selenium oxide, or a color-change agent selected from the group consisting of cobalt oxide, nickel oxide, chromium oxide or rare earth oxides, and the color locus is shifted towards the achromatic point.
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60. The flat float glass according to claim 29, wherein the glass is colored using a coloring agent.
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61. The flat float glass according to claim 60, wherein said coloring agent is selected from the group consisting of vanadium, chromium, cobalt, iron, chromium, copper, and a nickel compound, and the light transmission at a thickness of 4 mm is <
- 80%.
Specification