Method for producing aluminosilicate glass
The invention relates to a method for producing aluminosilicate glass that is devoid of alkali and that has a B 2 O 3 content of between 0 and <5 wt.-% and a BaO content in excess of 5.5 wt.-%. Said method is characterised by the addition of between 0.05 wt.-% and 1.0 wt.-% SnO 2 during the preparation of the mixture.
1. A process for producing an alkali-free aluminosilicate glass comprising charging an alkali-free aluminosilicate glass batch comprising, in % by weight based on oxide,
B 2 O 3 <5,
BaO>5.5, and
SnO 2 , 0.05–1.0;
and subsequently melting and hot forming a resultant alkali-free aluminosilicate glass.
2. A process according to claim 1 ,
wherein the alkali-free aluminosilicate glass batch (in % by weight based on oxide) comprises:
SiO 2
46+14 64
Al 2 O 3
12+14 26
B 2 O 3
+12 +12 0+14 +21 5
MgO
0+14 7
CaO
+11 3+14 14
SrO
+11 0+14 11
BaO
+11 6+14 25
ZrO 2
0+14 5
TiO 2
+11 +12 0+14 0.6
P 2 O 5
0+14 9
SnO 2
0.05+14 1.+10
3. A process according to claim 2 ,
wherein the alkali-free aluminosilicate glass batch (in % by weight based on oxide) comprises:
SiO 2
+22 55+14 64+12 +12
Al 2 O 3
13+14 18
B 2 O 3
+12 +12 0+14 +21 5
MgO
0+14 7
CaO
+11 5+14 14
SrO
0+14 8
BaO
+11 6+14 17
ZrO 2
0+14 2
TiO 2
+11 +12 0+14 0.5
SnO 2
0.05+14 1.+10
4. process according to claim 3 ,
wherein the alkali-free aluminosilicate glass batch (in % by weight based on oxide) comprises:
SiO 2
59+14 62
Al 2 O 3
13.5+14 15.5
B 2 O 3
+12 +12 3+14 +21 5
MgO
2.5+14 5+11 +12
CaO
+11 8.2+14 10.5
BaO
8.5+14 9.5
ZrO 2
+11 +12 0+14 1.5
TiO 2
+11 +12 0+14 0.5
SnO 2
0.05+14 1.+10
5. A process according to claim 3 ,
wherein the alkali-free aluminosilicate glass batch (in % by weight based on oxide) comprises:
SiO 2
+22 58+14 62+12 +12
Al 2 O 3
+11 +12 14+14 17.5
B 2 O 3
0+14 1
MgO
0+14 7
CaO
5.5+14 14+12
SrO
0+14 8
BaO
+11 6+14 17
ZrO 2
+11 +12 0+14 1.5
TiO 2
+11 +12 0+14 0.5
SnO 2
0.05+14 1.+10
6. A process according to claim 5 ,
wherein the alkali-free aluminosilicate glass batch (in % by weight based on oxide) comprises:
SiO 2
+22 58+14 62+12 +12
Al 2 O 3
+11 +12 15+14 17.5
B 2 O 3
0.2+14 0.7
MgO
+12 +12 0+14 +21 1
CaO
5.5+14 14+12
SrO
0+14 8
BaO
+11 6+14 10
ZrO 2
0.05+14 1+12 +10
TiO 2
+11 +12 0+14 0.5
SnO 2
0.05+14 1.+10
7. A process according to claim 2 ,
wherein the alkali-free aluminosilicate glass batch (in % by weight based on oxide) comprises:
SiO 2
46+14 63
Al 2 O 3
12+14 25
MgO
0+14 5
CaO
+11 3+14 14
SrO
+11 0+14 11
BaO
+11 6+14 15
with MgO +30 +0 CaO +30 +0 SrO +30 +0 BaO
+23 25
with SrO +30 +0 BaO
+24 10
ZrO 2
0.1+14 5+11 +12
P 2 O 5
0.1+14 9+11 +12
SnO 2
0.05+14 1.+10
8. A process according to claim 1 , wherein the alkali-free aluminosilicate batch comprises 0.1%–0.5% by weight of SnO 2 .
9. A process according to claim 1 , wherein no evaporation fining agents are added.
10. A process according to claim 1 , wherein no decomposition fining agents are added.
11. A process according to claim 1 , wherein the alkali-free aluminosilicate glass batch (in % by weight based on oxide) further comprises:
CeO 2
+11 +12 0+14 0.6
MoO 3
0+14 2
WO 3
0+14 2
V 2 O 5
+11 +12 0+14 0.2
MnO 2
+11 +12 0+14 0.2
Fe 2 O 3
+11 +12 0+14 0.5
where CeO 2 +30 +0 MoO 3 +30 +0 WO 3 +30 +0 V 2 O 5 +30 +0 MnO 2 +30 +0 Fe 2 O 3
+12 0+14 3.
12. A process according to claim 1 , wherein the alkali-free aluminosilicate glass batch is free from As 2 O 3, Sb 2 O 3, CdO, PbO, Bi 2 O 3 , except for unavoidable impurities.
13. Alkali-free aluminosilicate glass having a composition as follows (in % by weight based on oxide)
SiO 2
46+14 64
Al 2 O 3
12+14 26
B 2 O 3
+12 +12 0+14 +21 5
MgO
0+14 7
CaO
+11 3+14 14
SrO
+11 0+14 11
BaO
+11 6+14 25
ZrO 2
0+14 5
TiO 2
+11 +12 0+14 0.6
P 2 O 5
0+14 9
SnO 2
0.05+14 1.+10
14. Alkali-free aluminosilicate glass according to claim 13 ,
having
a composition as follows (in % by weight based on oxide):
SiO 2
+22 55+14 64+12 +12
Al 2 O 3
13+14 18
B 2 O 3
+12 +12 0+14 +21 5
MgO
0+14 7
CaO
+11 5+14 14
SrO
0+14 8
BaO
+11 6+14 17
ZrO 2
0+14 2
TiO 2
+12 +11 0+14 0.5
SnO 2
0.05+14 1.+10
15. Alkali-free aluminosilicate glass according to claim 14 ,
having
a composition as follows (in % by weight based on oxide):
SiO 2
59+14 62
Al 2 O 3
13.5+14 15.5
B 2 O 3
+12 +12 3+14 +21 5
MgO
2.5+14 5+12 +11
CaO
+11 8.2+14 10.5
BaO
8.5+14 9.5
ZrO 2
+11 +12 0+14 1.5
TiO 2
+11 +12 0+14 0.5
SnO 2
0.05+14 1.+10
16. Alkali-free aluminosilicate glass according to claim 14 ,
having
a composition as follows (in % by weight based on oxide):
SiO 2
+22 58+14 62+12 +12
Al 2 O 3
+11 +12 14+14 17.5
B 2 O 3
0+14 1
MgO
0+14 7
CaO
5.5+14 14+12
SrO
0+14 8
BaO
+11 6+14 17
ZrO 2
+11 +12 0+14 1.5
TiO 2
+12 +11 0+14 0.5
SnO 2
0.05+14 1.+10
17. Alkali-free aluminosilicate glass according to claim 16 ,
having
a composition as follows (in % by weight based on oxide):
SiO 2
+22 58+14 62+12 +12
Al 2 O 3
+11 +12 15+14 17.5
B 2 O 3
0.2+14 0.7
MgO
+12 +12 0+14 +21 1
CaO
5.5+14 14+12
SrO
0+14 8
BaO
+11 6+14 10
ZrO 2
0.05+14 1+10 +12
TiO 2
+12 +11 0+14 0.5
SnO 2
0.05+14 1.+10
18. Alkali-free aluminosilicate glass according to claim 13 ,
having
a composition as follows (in % by weight based on oxide):
SiO 2
46+14 63
Al 2 O 3
12+14 25
MgO
0+14 5
CaO
+11 3+14 14
SrO
+11 0+14 11
BaO
+11 6+14 15
where MgO +30 +0 CaO +30 +0 SrO +30 +0 BaO
+23 25
where SrO +30 +0 +0 BaO
+24 10
ZrO 2
0.1+14 5+11 +12
P 2 O 5
0.1+14 9+11 +12
SnO 2
0.05+14 1.+10
19. Alkali-free aluminosilicate glass according to claim 13 , further comprising
CeO 2
+11 +12 0+14 0.6
MoO 3
0+14 2
WO 3
0+14 2
V 2 O 5
+11 +12 0+14 0.2
MnO 2
+11 +12 0+14 0.2
Fe 2 O 3
+11 +12 0+14 0.5
where CeO 2 +0 +30 +0 MoO 3 +0 +30 +0 WO 3 +0 +30 +0 V 2 O 5 +0 +30 +0 MnO 2 +0 +30 +0 Fe 2 O 3
+12 0+14 3.
20. Alkali-free aluminosilicate glass according to claim 13 , which, except for unavoidable impurities, is free from As 2 O 3 , Sb 2 O 3 , CdO, PbO, Bi 2 O 3 .
21. A process for producing an alkali-fre aluminosilicate glass, comprising melting a composition comprising (in % by weight based on oxide):
B 2 O 3
+21 5;
BaO
+22 5.5; and
SnO 2
0.05+14 1.0
and glass components constituting the aluminosilicate glass.
22. A process according to claim 21 , further comprising batch charging the composition wherein the SnO 2 is added during batch charging.
23. A process according to claim 21 , wherein the SnO 2 is added during melting.
24. A process according to claim 22 , further comprising hot forming a glass made after melting.
25. A process according to claim 21 , wherein the composition comprises 0.1%–0.5%, by weight based on oxide of SnO 2 .