Hot-formed, chemically prestressable glass articles with a low proportion of crystals and methods and devices for producing

Patent metadata

Field	Value
Publication number	US-11878939-B2
Application number	US-202016986196-A
Country	US
Kind code	B2
Filing date	Aug 5, 2020
Priority date	Aug 5, 2019
Publication date	Jan 23, 2024
Grant date	Jan 23, 2024

Abstract

A hot-formed, chemically prestressable glass article having a low percentage of crystals or crystallites, in particular a plate-shaped, chemically prestressable glass article, as well as to a method and a device for its production are provided. The glass article has a composition including the components SiO 2 , Al 2 O 3 , and Li 2 O and a content of seed formers (ZrO 2 , SnO 2 , and TiO 2 ) of at least 0.8 wt %, as well as at most ten crystals, including crystallites, per kilogram of glass, which have a maximum diameter greater than 1 μm and up to at most 5 μm.

First claim

What is claimed is:

1. A chemically prestressable, hot-formed, plate-shaped glass article, comprising:
a thickness that is at least 0.4 mm and at most 2 mm;
a composition comprising SiO 2 , Al 2 O 3 , and Li 2 O;
a content of ZrO 2 , SnO 2 , and TiO 2 in a sum total of at least 0.8 wt %; and
at most ten crystals or crystallites per kilogram of glass that have a maximum diameter greater than 1 μm and less than or equal to 5 μm.

2. The glass article of claim 1 , wherein the maximum diameter is up to at most 2 μm.

3. The glass article of claim 1 , wherein the glass article comprises a maximum crystal growth rate Kgmax of 2 μm/min to 16 μm/min in a temperature range of 925° C. to 1100° C.

4. The glass article of claim 3 , wherein the maximum crystal growth rate of is 5.9 μm/min to 6.4 μm/min.

5. The glass article of claim 1 , wherein the composition comprises, in wt %:
SiO 2 57 to 69,
Al 2 O 3 17 to 25,
B 2 O 3 0 to 7,
Li 2 O 3 to 5.5,
Na 2 O 0.3 to 7, and
a sum of a content of Al 2 O 3 and SiO 2 between at least 75 and at most 92.

6. The glass article of claim 5 , wherein the composition comprises:
SiO 2 61 to 67,
Al 2 O 3 17 to 21,
B 2 O 3 0 to 4.5,
Li 2 O 3.5 to 5,
Na 2 O 0.8 to 4.5,
K 2 O 0 to 1
MgO 0 to 2
CaO 0 to 4.5,
SrO 0 to 2,
ZnO 0 to 3
P 2 O 5 0 to 3
ZrO 2 0 to 3,
TiO 2 0 to 3, and
SnO 2 0 to 2.

7. The glass article of claim 6 , wherein the composition further comprises contaminants and/or refining agents and/or coloring constituents in amounts up to 2 wt %.

8. The glass article of claim 1 , further comprising a thickness that is at least 0.5 mm and at most 1 mm.

9. The glass article of claim 1 , further comprising a thickness that is at least 0.5 mm.

10. The glass article of claim 1 , further comprising a thickness that is at most 1 mm.

11. The glass article of claim 1 , wherein the composition comprises 0.3 to 7 wt % Na 2 O.

12. The glass article of claim 1 , wherein the glass article does not have any crystals or crystallites with a maximum diameter that is greater than 5 μm.

Assignees

• Schott Ag

Inventors

• Schmiady Thomas
• Seuthe Thomas
• Hessenkemper Jörg
• Leukel Sebastian
• Krüger Susanne

Classifications

• C03C3/097 Primary

  containing phosphorus, niobium or tantalum · CPC title

• C03B17/064

  by the overflow downdraw fusion process; Isopipes therefor · CPC title

• C03C3/083

  containing aluminium oxide or an iron compound · CPC title

• C03C3/085

  containing an oxide of a divalent metal · CPC title

• C03C3/087

  containing calcium oxide, e.g. common sheet or container glass · CPC title