Method for manufacturing glass sheet

Patent metadata

Field	Value
Publication number	US-2016200629-A1
Application number	US-201615079516-A
Country	US
Kind code	A1
Filing date	Mar 24, 2016
Priority date	Sep 25, 2013
Publication date	Jul 14, 2016
Grant date	—

Abstract

The present invention relates to a method for manufacturing a float glass containing a step of melting a glass raw material, a step of forming the glass melted by the preceding step into a glass ribbon while floating the glass on a molten metal, and a step of annealing the glass ribbon. In the forming step, a fluid containing a molecule having a fluorine atom is sprayed onto the glass ribbon to control a fluorine amount in the depth of up to 30 μm in the thickness direction from the upper surface of the glass ribbon to more than 0.23 mol %·μm.

First claim

1 . A method for manufacturing a float glass comprising a step of melting a glass raw material, a step of forming the glass melted by the preceding step into a glass ribbon while floating the glass on a molten metal, and a step of annealing the glass ribbon,
wherein, in the forming step, a fluid containing a molecule having a fluorine atom is sprayed onto an upper surface of the glass ribbon to allow the fluorine atom to penetrate up to a depth of 0.5 μm or more in a thickness direction from the upper surface, subsequently, before the step of annealing or in the step of annealing, the fluorine atom that has penetrated is allowed to penetrate up to a depth of 1 μm or more in the thickness direction from the upper surface to control a fluorine amount in the depth of up to 30 μm in the thickness direction from the upper surface of the glass ribbon to more than 0.23 mol %·μm, and thereafter, the glass ribbon is conveyed from the step of annealing.

2 . The method for manufacturing a float glass according to claim 1 , wherein the fluorine amount in the depth of up to 30 μm in the thickness direction from the upper surface of the glass ribbon is controlled to more than 0.23 mol %·μm and 21 mol %·μm or less.

3 . The method for manufacturing a float glass according to claim 1 , wherein temperature of the upper surface of the glass ribbon at the time of spraying the fluid is 600° C. or higher.

4 . The method for manufacturing a float glass according to claim 1 , wherein the fluid has a fluorine atom concentration of from 0.1% by volume to 15% by volume.

5 . The method for manufacturing a float glass according to claim 1 , wherein the float glass has a glass transition temperature Tg of 550° C. or higher, and temperature of the upper surface of the glass ribbon at the time of spraying the fluid is from (Tg+50)° C. to (Tg+460)° C.

6 . The method for manufacturing a float glass according to claim 5 , wherein the float glass has the Tg of higher than 600° C.

Assignees

• Asahi Glass Co Ltd

Inventors

• IKAWA Nobuaki
• Miyasaka Satoshi
• SHIRAI Masanobu
• MIURA Takenori
• Kato Ryosuke
• Yamanaka Kazuhiko
• Hayashi Yasuo
• Tanii Shiro

Classifications

• C03B18/02

  Forming sheets · CPC title

• C03B25/093

  being in a horizontal position on a fluid support, e.g. a gas or molten metal · CPC title

• C03C21/002 Primary

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