Claims
- 1. A tempered glass body in a form suitable for use as a fire and safety glass pane, having in the tempered state the following properties:
- a compressive stress of at least 80 N/mm.sup.2 to about 120 N/mm.sup.2,
- a coefficient of thermal expansion .alpha..sub.20/300 between 3 and 6.times.10.sup.-6 K .sup.-1,
- a specific thermal stress .phi. between 0.3 and 0.5 n/(mm.sup.2 .times.K),
- a glass transition temperature Tg between 535.degree. and 850.degree. C.,
- a product of the specific thermal stress .sigma. multiplied by (Tg-20.degree. C.) between 180.degree. and 360N/mm.sup.2,
- a temperature at a viscosity of 10.sup.13 dPas above 560.degree. C.,
- a softening temperature at a viscosity of 10.sup.7.6 dPas above 830.degree. C.,
- a working temperature at a viscosity of 10.sup.4 dPas (working temperature) below 1300.degree. C.,
- said glass consisting essentially of the following composition in weight percent based on oxides:
- ______________________________________SiO.sub.2 73-78B.sub.2 O.sub.3 9-12Al.sub.2 O.sub.3 1.5-4Li.sub.2 O 0-4Na.sub.2 O 1-5K.sub.2 O 1-5MgO 0-3CaO 1-3SrO + BaO 0-2ZnO 1-2ZrO.sub.2 0.5-3.SIGMA. alkali metal oxides 5-7.SIGMA. MgO + CaO + SrO + BaO + ZnO + ZrO.sub.2 6-10.______________________________________
- 2. A glass body according to claim 1, in the form of a glass pane under a compressive stress of 80-120N/mm.sup.2.
- 3. A glazing comprising a glass pane according to claim 1, mounted in a frame.
- 4. In a process of tempering a glass in an air tempering plant in order to produce a prestressed glass body, according to claim 1 the improvement wherein said glass, in weight percent based on oxides, consists essentially of:
- ______________________________________SiO.sub.2 73-78B.sub.2 O.sub.3 9-12Al.sub.2 O.sub.3 1.5-4Li.sub.2 O 0-4Na.sub.2 O 1-5K.sub.2 O 1-5MgO 0-3CaO 1-3SrO + BaO 0-2ZnO 1-2ZrO.sub.2 0.5-3.SIGMA. alkali metal oxides 5-7.SIGMA. MgO + CaO + SrO + BaO + ZnO + ZrO.sub.2 6-10.______________________________________
- 5. A glass body according to claim 1 having a thickness of 5-7 mm.
- 6. A glazing according to claim 3, wherein the glass pane has a thickness of 5-7 mm.
- 7. A glass body according to claim 1 which will disintegrate into fine pieces in compliance with DIN 1249, part 12, in the event of mechanical breaking.
- 8. A glass body according to claim 3 which will disintegrate into fine pieces in compliance with DIN 1249, part 12, in the event of mechanical breaking.
- 9. A glass body according to claim 5 which will disintegrate into fine pieces in compliance with DIN 1249, part 12, in the event of mechanical breaking.
- 10. A glass body according to claim 6 which will disintegrate into fine pieces in compliance with DIN 1249, part 12, in the event of mechanical breaking.
- 11. A glass body according to claim 7 which will provide fire resistance for at least 30 minutes in compliance with DIN 4102, part 13.
- 12. A glass body according to claim 8 which will provide fire resistance for at least 30 minutes in compliance with DIN 4102, part 13.
- 13. A glass body according to claim 9 which will provide fire resistance for at least 30 minutes in compliance with DIN 4102 part 13.
- 14. A glass body according to claim 11 which will provide fire resistance for at least 30 minutes in compliance with DIN 4102, part 13.
Priority Claims (1)
Number |
Date |
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Kind |
43 25 656.7 |
Jul 1993 |
DEX |
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Parent Case Info
This application is a divisional of U.S. application Ser. No. 08/283,853, filed Aug. 1, 1994, now U.S. Pat. No. 5,656,558.
US Referenced Citations (10)
Foreign Referenced Citations (4)
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25 19 176 |
Nov 1976 |
DEX |
29 41 215 |
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DEX |
42 30 607 |
Jan 1994 |
DEX |
2 067 549 |
Jul 1981 |
GBX |
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Entry |
Chemical Abstr., vol. 77, No. 20 (129954h), Nov. 13, 1972. |
Chemical Abstr., vol. 103, No. 2 (10373h), Jul. 15, 1985. |
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Divisions (1)
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Number |
Date |
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Parent |
283853 |
Aug 1994 |
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