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

Patent metadata

Field	Value
Publication number	US-2016355432-A1
Application number	US-201615179433-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 for chemical strengthening is a glass sheet containing, as expressed by mass percentage based on oxides, 60 to 75% of SiO 2 , 3 to 12% of Al 2 O 3 , 2 to 10% of MgO, 0 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 , 0 to 0.3% of TiO 2 , 0.005 to 0.2% of Fe 2 O 3 , and 0.02 to 0.4% of SO 3 . The glass has a sheet thickness of 0.2 mm or more and 1.2 mm or less. A value of β-OH measured without polishing both front and back surfaces of the glass sheet is lower than a value of β-OH measured after polishing surface layers of both the front and back surfaces of the glass sheet by 50 μm or more each.

First claim

1 . A glass for chemical strengthening that is a glass sheet comprising, as expressed by mass percentage based on oxides, 60 to 75% of SiO 2 , 3 to 12% of Al 2 O 3 , 2 to 10% of MgO, 0 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 , 0 to 0.3% of TiO 2 , 0.005 to 0.2% of Fe 2 O 3 , and 0.02 to 0.4% of SO 3 , and having a sheet thickness of 0.2 mm or more and 1.2 mm or less, wherein a value of β-OH measured without polishing both front and back surfaces of the glass sheet is lower than a value of β-OH measured after polishing surface layers of both the front and back surfaces of the glass sheet by 50 μm or more each.

2 . The glass for chemical strengthening according to claim 1 , wherein the glass sheet is formed according to a float process.

3 . The glass for chemical strengthening according to claim 2 , from which the surface layers of both the front and back surfaces of the glass sheet has not been polished away after being formed according to the float process.

4 . The glass for chemical strengthening according to claim 1 , wherein a difference between the value of β-OH measured without polishing both the front and back surfaces of the glass sheet and the value of β-OH measured after polishing the surface layers of both the front and back surfaces of the glass sheet by 50 μm or more each is 0.003 mm −1 or more.

5 . A chemically strengthened glass obtained by chemically strengthening the glass for chemical strengthening of claim 1 .

6 . The chemically strengthened glass according to claim 5 , having a surface compressive stress of 600 MPa or more and a depth of compressive stress of 6 μm or more and 30 μm or less.

7 . The chemically strengthened glass according to claim 5 , having a surface compressive stress of 700 MPa or more and a depth of compressive stress of 8 μm or more and 20 μm or less.

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

9 . A glass that is a glass sheet comprising, as expressed by mass percentage based on oxides, 60 to 75% of SiO 2 , 3 to 12% of Al 2 O 3 , 2 to 10% of MgO, 0 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 , 0 to 0.3% of TiO 2 , 0.005 to 0.2% of Fe 2 O 3 , and 0.02 to 0.4% of SO 3 , and having a sheet thickness of 0.2 mm or more and 1.2 mm or less, wherein a value of β-OH measured without polishing both front and back surfaces of the glass sheet is lower than a value of β-OH measured after polishing surface layers of both the front and back surfaces of the glass sheet by 50 βm or more each.

10 . The glass according to claim 9 , wherein, after being formed according to a float process, the surface layers of both the front and back surfaces of the glass sheet has not been polished away.

11 . The glass according to claim 9 , wherein a difference between the value of β-OH measured without polishing both the front and back surfaces of the glass sheet and the value of β-OH measured after polishing the surface layers of both the front and back surfaces of the glass sheet by 50 μm or more each is 0.003 mm −1 or more.

12 . The glass according to claim 9 , wherein the glass sheet is applicable to a chemical strengthening treatment.

13 . A chemically strengthened glass obtained by chemically strengthening the glass of claim 12 .

Assignees

• Asahi Glass Co Ltd

Inventors

• Kase Junichiro

Classifications

• C03C3/085

  containing an oxide of a divalent metal · CPC title

• C03C2204/00

  Glasses, glazes or enamels with special properties · CPC title

• C03C4/18

  for ion-sensitive glass · CPC title

• C03C21/002

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

• C03C3/087 Primary

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