Method for producing glass sheet, and glass sheet

Patent metadata

Field	Value
Publication number	US-10358381-B2
Application number	US-201515114726-A
Country	US
Kind code	B2
Filing date	Jan 28, 2015
Priority date	Jan 31, 2014
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

The glass sheet production method of the present invention is a method for producing a surface-modified glass sheet, including a gas contact step of bringing hydrogen fluoride (HF) gas, hydrogen chloride (HCl) gas, and water vapor into contact with at least one principal surface of a glass sheet. A gas containing the hydrogen fluoride (HF) gas is used in the gas contact step, and in the gas containing the hydrogen fluoride (HF) gas, a volume ratio of the water vapor to the hydrogen fluoride (HF) gas (volume of water vapor/volume of HF gas) is 8 or more.

First claim

The invention claimed is:

1. A method for producing a surface-modified glass sheet, comprising a gas contact step of bringing hydrogen fluoride (HF) gas, hydrogen chloride (HCl) gas, and water vapor into contact with at least one principal surface of a glass sheet, wherein
a gas containing the hydrogen fluoride (HF) gas is used in the gas contact step, and in the gas containing the hydrogen fluoride (HF) gas, a volume ratio of the water vapor to the hydrogen fluoride (HF) gas (volume of water vapor/volume of HF gas) is 8 or more, and
the surface-modified glass sheet comprises a dense structure in at least one principal surface thereof, wherein the glass sheet satisfies the following relations:
pre-heat-treatment ER<1.5(nm/min); and
ΔER=post-heat-treatment ER−pre-heat-treatment ER<4.0(nm/min),

where: the pre-heat-treatment ER is an etching rate (nm/min) of the principal surface as measured when the principal surface is etched using 0.1 mass % hydrofluoric acid at 50° C. as an etchant; the post-heat-treatment ER is an etching rate (nm/min) of the principal surface as measured when the principal surface is etched using 0.1 mass % hydrofluoric acid at 50° C. as an etchant after a heat treatment in which the glass sheet is heated for 220 seconds to increase a temperature of the principal surface from room temperature to a temperature 95° C. higher than a glass transition temperature of the glass sheet and immediately thereafter the glass sheet is naturally cooled at room temperature; and the ΔER is an amount of change in the etching rate (nm/min) of the principal surface before and after the heat treatment.

2. The method for producing a surface-modified glass sheet according to claim 1 , wherein in the gas contact step, the glass sheet has a temperature ranging from a temperature 40° C. higher than a glass transition temperature to a temperature 120° C. higher than the glass transition temperature.

3. The method for producing a surface-modified glass sheet according to claim 1 , wherein in the gas contact step, a mixed gas containing hydrogen fluoride (HF) gas, hydrogen chloride (HCl) gas, and water vapor is brought into contact with the at least one principal surface of the glass sheet.

4. The method for producing a surface-modified glass sheet according to claim 1 , wherein
the gas contact step comprises: a hydrogen fluoride (HF) gas contact step; and a hydrogen chloride (HCl) gas contact step,
in the hydrogen fluoride (HF) gas contact step, a first gas is brought into contact with the at least one principal surface of the glass sheet, the first gas containing hydrogen fluoride (HF) gas and water vapor but containing no acid gas other than hydrogen fluoride (HF) gas, and
in the hydrogen chloride (HCl) gas contact step, a second gas is brought into contact with the at least one principal surface of the glass sheet, the second gas containing hydrogen chloride (HCl) gas but containing no acid gas other than hydrogen chloride (HCl) gas.

5. A glass sheet comprising a dense structure in at least one principal surface thereof, wherein the glass sheet satisfies the following relations:
pre-heat-treatment ER<1.5(nm/min); and
ΔER=post-heat-treatment ER−pre-heat-treatment ER<4.0(nm/min),

where: the pre-heat-treatment ER is an etching rate (nm/min) of the principal surface as measured when the principal surface is etched using 0.1 mass % hydrofluoric acid at 50° C. as an etchant; the post-heat-treatment ER is an etching rate (nm/min) of the principal surface as measured when the principal surface is etched using 0.1 mass % hydrofluoric acid at 50° C. as an etchant after a heat treatment in which the glass sheet is heated for 220 seconds to increase a temperature of the principal surface from room temperature to a temperature 95° C. higher than a glass transition temperature of the glass sheet and immediately thereafter the glass sheet is naturally cooled at room temperature; and the ΔER is an amount of change in the etching rate (nm/min) of the principal surface before and after the heat treatment.

6. The glass sheet according to claim 5 , wherein
the glass sheet is a glass sheet for heat treatment to be subjected to a heat treatment, and
the heat treatment is a heat treatment for thermal tempering.

7. The glass sheet according to claim 5 , wherein
the glass sheet is a glass sheet for chemical strengthening to be subjected to chemical strengthening,
a dealkalized layer is formed at least in the principal surface of the glass sheet, and
the dense structure is formed in a surface of the dealkalized layer.

8. The glass sheet according to claim 5 , wherein
an alkaline elution amount is less than in a glass sheet that has the same thickness and the same composition as the glass sheet and that does not have a dense structure formed in its surface.

9. The glass sheet according to claim 5 , wherein
the glass sheet is a glass sheet for functional film formation having the principal surface as a surface on which a functional film is to be formed, and
an alkaline elution amount is less than in a glass sheet that has the same thickness and the same composition as the glass sheet for functional film formation and that does not have a dense structure formed in its surface.

10. The glass sheet according to claim 9 , wherein the functional film is formed by sputtering or thermal CVD.

11. The glass sheet according to claim 5 , wherein
the glass sheet is a glass sheet for shower booths, and
an alkaline elution amount is less than in a glass sheet that has the same thickness and the same composition as the glass sheet for shower booths and that does not have a dense structure formed in its surface.

12. The glass sheet according to claim 5 , wherein
the glass sheet is a glass sheet for ships, and
an alkaline elution amount is less than in a glass sheet that has the same thickness and the same composition as the glass sheet for ships and that does not have a dense structure formed in its surface.

Assignees

• Nippon Sheet Glass Co Ltd

Inventors

• Tanaka Satoshi
• Koyo Hirotaka
• Mitani Kazuishi
• Saito Yasuhiro
• Tsuri Keiko

Classifications

• C03C23/008

  comprising a lixiviation step · CPC title

• C03C15/00 Primary

  Surface treatment of glass, not in the form of fibres or filaments, by etching (etching or surface-brightening compositions, in general C09K13/00) · CPC title

• C03C3/087

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

• B63B19/02

  Clear-view screens; {Windshields (canopies connected to windshields B63B17/02)} · CPC title

• C03B18/02

  Forming sheets · CPC title