Glass for chemical tempering, chemically tempered glass, and glass plate for display device

• US 10,370,286 B2
• Filed: 01/15/2015
• Issued: 08/06/2019
• Est. Priority Date: 09/27/2010
• Status: Active Grant

• Current Assignee: AGC, Inc.
• Original Assignee: AGC, Inc.
• Inventors: Endo, Jun, Akiba, Shusaku, Ono, Kazutaka, Nakashima, Tetsuya
• Primary Examiner(s): Yang, Z. Jim
• Application Number:
  US14/597,587
• Publication Number:
  US 20150126354A1
• Time in Patent Office: 1,664 Days
• CPC Class Codes: C03C 21/00 Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface
• CPC Class Codes: C03C 21/001 in liquid phase, e.g. molten salts, solutions
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 3/085 containing an oxide of a divalent metal
• CPC Class Codes: C03C 3/087 containing calcium oxide, e.g. common sheet or container glass
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: G02F 1/133302 Rigid substrates, e.g. inorganic substrates
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/315 Surface modified glass [e.g., tempered, strengthened, etc.]

Abstract

To provide glass to be used for chemically tempered glass, of which the strength is less likely to be reduced even when indentations are formed thereon. Glass for chemical tempering, which comprises, as represented by mole percentage based on oxides, from 62 to 68% of SiO₂, from 6 to 12% of Al₂O₃, from 7 to 13% of MgO, from 9 to 17% of Na₂O, and from 0 to 7% of K₂O, wherein the difference obtained by subtracting the content of Al₂O₃ from the total content of Na₂O and K₂O is less than 10%, and when ZrO₂ is contained, its content is at most 0.8%. Chemically tempered glass obtained by chemically tempering such glass for chemical tempering. Such chemically tempered glass has a compressive stress layer formed on the glass surface, which has a thickness of at least 30 μm and a surface compressive stress of at least 550 MPa.

Claims

1. A plate glass which comprises, as represented by mole percentage based on oxides, from 62 to 66% of SiO₂, from 7.5 to 9% of Al₂O₃, from 8 to 13% of MgO, from 9 to 16% of Na₂O, from 0.5 to 7% of K₂O, 0% B₂O₃, 0% ZnO, and from 0 to 1% of CaO, wherein the difference obtained by subtracting the content of Al₂O₃ from the total content of Na₂O and K₂O is at most 9%, and optionally ZrO₂ in an amount of at most 0.6%, wherein the plate glass has a glass transition point of at least 570°

C. and a specific gravity of at most 2.55.

2. The plate glass according to claim 1, wherein the content of CaO is from 0 to 0.5%.

3. The plate glass according to claim 1, wherein ZrO₂ is contained in an amount of at most 0.5%.

4. The plate glass according to claim 1 or 2, wherein the content of Na₂O is from 9 to 12.5%.

5. The plate glass according to claim 1 or 2, wherein the content of Na₂O is from 12 to 16%.

6. The plate glass according to claim 1 or 2, wherein the total content of CaO, SrO and BaO is at most 1%.

7. The plate glass according to claim 1 or 2, wherein the total content of SiO₂ and Al₂O₃ is more than 72% and at most 76%.

8. The plate glass according to claim 1 or 2, wherein the content of MgO is from 8 to 11%.

9. The plate glass according to claim 1 or 2, wherein the content of SiO₂ is from 63 to 65%.

10. The plate glass according to claim 1, wherein the total content of Na₂O and MgO is from 21 to 25%.

11. The plate glass according to claim 1, wherein ZrO₂ is contained in an amount of at most 0.6%.