Plate glass production method, plate glass, and laminated glass production method

Patent metadata

Field	Value
Publication number	US-2017334759-A1
Application number	US-201715651572-A
Country	US
Kind code	A1
Filing date	Jul 17, 2017
Priority date	Jan 21, 2015
Publication date	Nov 23, 2017
Grant date	—

Abstract

Provided is a sheet glass production process for properly producing sheet glass having a convex shape in section in a width direction orthogonal to the advancing direction of a glass ribbon. A glass ribbon G 2 advancing on molten metal 22 is heated so as to have both edge portions G 2 B heated more intensely than a central portion G 2 A in a width direction thereof in an upstream zone of the molten metal bath, and a plurality of rolls 23 are rotated in contact with both edge portions G 2 B of the glass ribbon G 2 such that upstream rolls 23 A in an advancing direction F 1 have a lower peripheral speed than downstream rolls 23 B in the advancing direction.

First claim

What is claimed is:

1 . A process for producing sheet glass comprising:
floating and advancing a glass ribbon on a molten metal surface in a molten metal bath; bringing a plurality of rolls into contact with both edge portions of the glass ribbon in a width direction of the glass ribbon to form the glass ribbon in a planar shape; heating both edge portions of the glass ribbon more intensely than a central portion of the glass ribbon in the width direction in an upstream zone of the molten metal bath; and rotating the rolls such that upstream rolls in an advancing direction of the glass ribbon have a lower peripheral speed than downstream rolls in the advancing direction, thereby to produce sheet glass having a central portion in a width direction thereof formed so as to have a greater thickness than both edge portions thereof.

2 . The process according to claim 1 , wherein the glass ribbon is heated by only heaters disposed adjacent to both edge portions of the glass ribbon in the width direction without substantially using a heater disposed adjacent to the central portion of the glass ribbon in the upstream zone.

3 . The process according to claim 1 , wherein the glass ribbon on a surface of the molten metal bath is heated at a cooling rate of at most 6.1° C./m in both edge portions in the width direction.

4 . The process according to claim 1 , wherein the glass ribbon is heated such that a location where the edge portions of the glass ribbon in the width direction on the surface of the molten metal bath have a viscosity of 10 4.9 (dPa·sec) is at least 15 m apart from a location where the edge portions of the glass ribbon in the width direction on the surface of the molten metal bath have a viscosity of 10 6.1 (dPa·sec).

5 . The process according to claim 1 , wherein among rolls that are disposed in zones where the edge portions of the glass ribbon in the width direction on the surface of the molten metal bath have a viscosity of at most 10 5.3 (dPa·sec), at least a pair of rolls adjacent to each other in the advancing direction of the glass ribbon has a peripheral speed difference of at least 35 (m/h) therebetween.

6 . The process according to claim 1 , wherein the most upstream rolls in the advancing direction of the glass ribbon have a peripheral speed of at most 100 (m/h).

7 . The process according to claim 1 , wherein R/S as a ratio of a peripheral speed R of the most upstream rolls in the advancing direction of the glass ribbon to a peripheral speed S of the most downstream rolls in the advancing direction is from 0.01 to 0.32.

8 . The process according to claim 1 wherein the peripheral speed of the most upstream rolls in the advancing direction and the advancing speed of the glass ribbon in an annealing station are controlled so as to satisfy the following formula:
(the peripheral speed (m/h) of the most upstream rolls)/(the advancing speed of the glass ribbon in the annealing station)≦0.07×(a desired thickness (mm) of the central portion of the glass ribbon in the width direction in the annealing station)

9 . The process according to claim 1 , wherein the difference between the maximum value and the minimum value in the thickness of the sheet glass produced from the glass ribbon is at least 0.1 mm.

10 . The process according to claim 1 wherein the sheet glass produced from the glass ribbon has a principal surface with a maximum height Rz of at most 0.3 μm in accordance with JIS B 0601-2001 in a roughness curve having a reference length of 25 mm.

11 . Sheet glass formed in a rectangular shape and having at least one principal surface formed as a convex surface, wherein the convex surface has two long sides, and a segment passing through the center of gravity of the convex surface and connecting the two long sides at the shortest distance such that a first point and a second point lie at intersections between the two long sides and the segment, wherein when the sheet glass is placed on a horizontal place, the first point lies at a smaller one of the thicknesses of the sheet glass in the vertical direction while the second point lies on the convex surface at a position of the segment that is apart from the first point by ⅖ of the length of the segment, wherein there is a straight line connecting between a point of the convex surface where the thickness of the sheet glass in the vertical direction is maximum between the first point and the second point, and a point on the convex surface where the thicknesses of the sheet glass in the vertical direction is minimum between the first point and the second point, and wherein the straight line forms an angle of from 0.005 deg. to 0.1 deg. with the horizontal.

12 . The sheet glass according to claim 11 , wherein the sheet glass has a principal surface with a maximum height Rz of at most 0.3 μm in accordance with JIS B 0601-2001 in a roughness curve having a reference length of 25 mm.

13 . The sheet glass according to claim 11 , wherein the difference between the maximum value and the minimum value in the thickness of the sheet glass is at least 0.1 mm.

14 . A process for producing laminated glass, comprising:
preparing wedge-shaped glass by cutting the sheet glass produced by the process recited in claim 1 ; and laminating and pressing the wedge-shaped glass and other sheet glass with an interlayer being interposed therebetween.

15 . A process for producing laminated glass, comprising:
cutting the sheet glass recited in claim 11 to prepare wedge-shaped glass; and laminating and pressing the wedge-shaped glass and other sheet glass with an interlayer being interposed therebetween.

16 . The process according to claim 14 , wherein the other sheet glass is the wedge-shaped glass.

Assignees

• Asahi Glass Co Ltd

Inventors

• Yamato Takamitsu
• Sunaga Kouhei
• Hasegawa Akira
• Sugahara Akira

Classifications

• B32B17/10036 Primary

  comprising two outer glass sheets · CPC title

• Y10T428/24479

  including variation in thickness · CPC title

• C03B18/18 Primary

  Controlling or regulating the temperature of the float bath; Composition or purification of the float bath · CPC title

• C03B18/06 Primary

  using mechanical means, e.g. restrictor bars, edge rollers · CPC title

• C03B18/04

  Changing or regulating the dimensions of the molten glass ribbon · CPC title