Tube-drawable glass, method for the production and use
A glass has a maximum crystallization rate (KG max ) of at most 0.20 μm/min in a temperature range of 700° C. to 1250° C. and a hydrolytic stability according to a hydrolytic class 1 HGA1 according to ISO 720:1985. In the case of a sample thickness of 2 mm of the glass, a ratio of a minimum transmittance in a wavelength range of 850 nm to 950 nm to a maximum transmittance in a wavelength range of 250 nm to 700 nm is in a range of 1.9:1 to 15:1.
1. A glass, having a maximum crystallization rate (KG max ) of at most 0.20 μm/min in a temperature range of 700° C. to 1250° C. and a hydrolytic stability according to a hydrolytic class 1 HGA1 according to ISO 720:1985, wherein in the case of a sample thickness of 2 mm of the glass a ratio of a minimum transmittance in a wavelength range of 850 nm to 950 nm to a maximum transmittance in a wavelength range of 250 nm to 700 nm is in a range of 1.9:1 to 15:1, wherein the glass comprises cations of the following components in the given portions (in % by cation):
Component
Portion
silicon
40-80
boron
0-20
aluminum
0-25
sodium
2-22
potassium
0.1-10
chromium
0.05-0.5
cobalt
0.03-0.5;
wherein a sum of the portions of the cations of sodium and potassium is in a range of 10 to 25% by cation, wherein a sum of the portions of the cations of chromium and cobalt is in a range of 0.15 to 0.55% by cation, and wherein a sum of the portions of the cations of magnesium, calcium, strontium, barium and zinc is at most 15% by cation, wherein a ratio of the sum of the portions of the cations of sodium and potassium to the sum of the portions of the cations of cobalt and chromium is in a range of 40:1 to 150:1.
2. The glass of claim 1 , wherein the glass comprises cations of the following components in the given portions (in % by cation):
Component
Portion
magnesium
0-5
calcium
0-15
strontium
0-5
barium
0-5
zinc
0-10
zirconium
0-10
titanium
0-10.
3. The glass of claim 1 , wherein the glass has a diffusivity D in a range of 5 to 50 μm 2 per hour.
4. The glass of claim 1 , wherein a transmittance in the whole wavelength range of 850 nm to 950 nm is at least 75%.
5. A glass article, comprising a glass and having a thickness in a range of 0.02 mm to 5 mm, the glass having a maximum crystallization rate (KG max ) of at most 0.20 inn/min in a temperature range of 700° C. to 1250° C. and a hydrolytic stability according to a hydrolytic class 1 HGA1 according to ISO 720:1985, wherein in the case of a sample thickness of 2 mm of the glass a ratio of a minimum transmittance in a wavelength range of 850 nm to 950 nm to a maximum transmittance in a wavelength range of 250 nm to 700 nm is in a range of 1.9:1 to 15:1, wherein the glass comprises cations of the following components in the given portions (in % by cation):
Component
Portion
silicon
40-80
boron
0-20
aluminum
0-25
sodium
2-22
potassium
0.1-10
chromium
0.05-0.5
cobalt
0.03-0.5;
wherein a sum of the portions of the cations of sodium and potassium is in a range of 10 to 25% by cation, wherein a sum of the portions of the cations of chromium and cobalt is in a range of 0.15 to 0.55% by cation, and wherein a sum of the portions of the cations of magnesium, calcium, strontium, barium and zinc is at most 15% by cation, wherein a ratio of the sum of the portions of the cations of sodium and potassium to the sum of the portions of the cations of cobalt and chromium is in a range of 40:1 to 150:1.
6. The glass article of claim 5 , wherein the glass comprises cations of the following components in the given portions (in % by cation):
Component
Portion
magnesium
0-5
calcium
0-15
strontium
0-5
barium
0-5
zinc
0-10
zirconium
0-10
titanium
0-10.
7. The glass article of claim 5 , wherein the glass has a diffusivity D in a range of 5 to 50 μm 2 per hour.
8. The glass article of claim 5 , wherein a transmittance in the whole wavelength range of 850 nm to 950 nm is at least 75%.
9. A method for the production of a glass or a glass article comprising the glass, the method comprising:
melting glass raw materials to form a glass melt;
treating the glass melt to form a treated glass melt; and
cooling the treated glass melt to obtain the glass or the glass article comprising the glass, the glass having a maximum crystallization rate (KG max ) of at most 0.20 μm/min in a temperature range of 700° C. to 1250° C. and a hydrolytic stability according to a hydrolytic class 1 HGA1 according to ISO 720:1985, wherein in the case of a sample thickness of 2 mm of the glass a ratio of a minimum transmittance in a wavelength range of 850 nm to 950 nm to a maximum transmittance in a wavelength range of 250 nm to 700 nm is in a range of 1.9:1 to 15:1, wherein the glass comprises cations of the following components in the given portions (in % by cation):
Component
Portion
silicon
40-80
boron
0-20
aluminum
0-25
sodium
2-22
potassium
0.1-10
chromium
0.05-0.5
cobalt
0.03-0.5;
wherein a sum of the portions of the cations of sodium and potassium is in a range of 10 to 25% by cation, wherein a sum of the portions of the cations of chromium and cobalt is in a range of 0.15 to 0.55% by cation, and wherein a sum of the portions of the cations of magnesium, calcium, strontium, barium and zinc is at most 15% by cation, wherein a ratio of the sum of the portions of the cations of sodium and potassium to the sum of the portions of the cations of cobalt and chromium is in a range of 40:1 to 150:1.
10. The method of claim 9 , further comprising:
chemically hardening the glass or the glass article by ion exchange.
11. The method of claim 9 , wherein the treating comprises at least one of down draw, overflow fusion, redrawing, floating, tube-drawing, Danner method, Vello method or A-drawing method.