Glass for chemical strengthening, chemically-strengthened glass, and method for producing chemically-strengthened glass

Patent metadata

Field	Value
Publication number	US-2016355430-A1
Application number	US-201615179067-A
Country	US
Kind code	A1
Filing date	Jun 10, 2016
Priority date	Dec 13, 2013
Publication date	Dec 8, 2016
Grant date	—

Abstract

A glass is a glass sheet containing, as expressed by mass percentage based on oxides, 63 to 75% of SiO 2 , 3 to 12% of Al 2 O 3 , 3 to 10% of MgO, 0.5 to 10% of CaO, 0 to 3% of SrO, 0 to 3% of BaO, 10 to 18% of Na 2 O, 0 to 8% of K 2 O, 0 to 3% of ZrO 2 , and 0.005 to 0.25% of Fe 2 O 3 . The glass has a temperature (T2) at which a viscosity thereof reaches 10 2 dPa·s of 1525° C. or lower. In the glass, R 2 O/Al 2 O 3 is 2.0 or more and 4.6 or less (in the formula, the R 2 O is Na 2 O+K 2 O).

First claim

1 . A glass that is a glass sheet comprising, as expressed by mass percentage based on oxides, 63 to 75% of SiO 2 , 3 to 12% of Al 2 O 3 , 3 to 10% of MgO, 0.5 to 10% of CaO, 0 to 3% of SrO, 0 to 3% of BaO, 10 to 18% of Na 2 O, 0 to 8% of K 2 O, 0 to 3% of ZrO 2 , and 0.005 to 0.25% of Fe 2 O 3 , having a temperature (T2) at which a viscosity thereof reaches 10 2 dPa·s of 1525° C. or lower, wherein R 2 O/Al 2 O 3 is 2.0 or more and 4.6 or less (in the formula, the R 2 O is Na 2 O+K 2 O).

2 . The glass according to claim 1 , comprising 1% or more of CaO.

3 . The glass according to claim 1 , wherein the R 2 O/Al 2 O 3 is 2.4 or more.

4 . The glass according to claim 1 , wherein the R 2 O is 10 to 18%.

5 . The glass according to claim 1 , wherein Al 2 O 3 is 4% or more, MgO is 3.5% or more, CaO is 5% or more, and BaO is 1% or less.

6 . The glass according to claim 1 , wherein CaO is less than 5%, BaO is 1% or less and the R 2 O/Al 2 O 3 is 3.2 or less.

7 . The glass according to claim 1 , wherein K 2 O is 2% or less.

8 . The glass according to claim 1 , further comprising, as expressed by mass percentage based on an oxide, 1% or less of B 2 O 3 .

9 . The glass according to claim 1 , wherein the T2 is 1510° C. or lower.

10 . The glass according to claim 1 , having a devitrification temperature of not higher than a temperature (T4) at which the viscosity thereof reaches 10 4 dPa·s.

11 . The glass according to claim 1 , further comprising, as expressed by mass percentage based on an oxide, 0.2% or less of TiO 2 .

12 . The glass according to claim 1 , having a glass transition point (Tg) of 530° C. or higher.

13 . The glass according to claim 1 , having a mean linear thermal expansion coefficient at 50 to 350° C. of 100×10 −7 ° C. −1 or less.

14 . The glass according to claim 1 , formed according to a float process.

15 . The glass according to claim 1 , which is applicable to a chemical strengthening treatment.

16 . A chemically strengthened glass obtained by chemically strengthening the glass of claim 15 .

17 . The chemically strengthened glass according to claim 16 , having a surface compressive stress of 580 MPa or more and a depth of compressive stress of 5 μm or more and 30 μm or less.

18 . A method for producing a chemically strengthened glass, comprising a chemical strengthening step of subjecting the glass of claim 1 to an ion-exchange treatment.

Assignees

• Asahi Glass Co Ltd

Inventors

• Yamazaki Shuji
• Koike Akio
• Kase Junichiro
• Akiba shusaku
• Miyasaka Junko
• Ohara Seiki

Classifications

• C03C3/087 Primary

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

• C03C4/18

  for ion-sensitive glass · CPC title

• C03C2204/00

  Glasses, glazes or enamels with special properties · CPC title

• C03C21/002

  to perform ion-exchange between alkali ions (C03C21/005 takes precedence) · CPC title