Method and apparatus for making a glass laminate

• US 10,294,139 B2
• Filed: 08/29/2018
• Issued: 05/21/2019
• Est. Priority Date: 10/06/2008
• Status: Expired due to Fees

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Hu, Guangli, Zhang, Bin, Zhou, Chunfeng
• Primary Examiner(s): Lazorcik, Jason L
• Application Number:
  US16/115,998
• Publication Number:
  US 20180370837A1
• Time in Patent Office: 265 Days
• CPC Class Codes: B32B 17/06 comprising glass as the main or only constituent of a layer, next to another layer of a specific material
• CPC Class Codes: C03B 17/02 Forming molten glass coated with coloured layers; Forming molten glass of different compositions or layers; Forming molten glass comprising reinforcements or inserts
• CPC Class Codes: C03B 17/064 by the overflow downdraw fusion process; Isopipes therefor
• CPC Class Codes: C03B 17/067 combined with thermal conditioning of the sheets
• CPC Class Codes: C03B 17/068 Means for providing the drawing force, e.g. traction or draw rollers
• CPC Class Codes: C03C 1/00 Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C03C 3/093 containing zinc or zirconium

Abstract

An apparatus for making a glass laminate, including:

• • a source of a glass core sheet;
  • a source of a first force that tensions the glass core sheet in a first axial direction;
  • a source of a second force that tensions the glass core sheet in a second axial direction; and
  • at least one molten glass reservoir extending along a length of the apparatus and on opposite sides of the glass core sheet that delivers a source of at least two glass clads to the opposite side surfaces of the bi-axially tensioned glass core sheet. Also disclosed are methods for making a glass laminate sheet using the disclosed apparatus, as defined herein.

Claims

1. A method for strengthening a glass laminate, the glass laminate having a glass core sheet and at least one glass clad layer on at least one of the opposite sides of the glass core sheet, comprising:

heating the glass laminate, the glass laminate having the glass core sheet has a strain point having a difference of at least 50°

C. compared to the strain point of the at least one glass clad layer;

applying biaxial force to the glass core sheet while the glass clad layers are in a state of stress relaxation;

cooling the glass laminate; and

releasing the biaxial force on the glass core sheet.

2. The method of claim 1, wherein the strengthened glass laminate has a compressive stress on the clad layers that is increased by from 10 MPa to 200 MPa compared to an unstrengthened glass laminate.

3. The method of claim 1, wherein heating the glass laminate is accomplished at from 560 to 600°

C.

4. A method for strengthening a glass laminate, the glass laminate having a glass core sheet and a glass clad layer on at least one of the opposite sides of the glass core sheet, comprising:

a first heating of the glass laminate to 50°

C. below the strain point of the glass core sheet, and the glass core sheet has a strain point of at least 50°

C. higher than the strain point of the glass clad layer;

a second heating of the glass laminate to between the anneal point of the glass clad and the strain point of the glass core sheet, the second heating is accomplished at a temperature above the strain point of the clad layer and below the strain point of the core sheet;

bi-axially tensioning the second heated glass laminate at from 10 to 50 MPa for a sufficient time for the stress in the clad layers to relax;

cooling the laminate to ambient temperature; and

removing the bi-axial tensioning.

5. The method of claim 4, wherein removing the bi-axial tensioning creates a compressive stress on glass clad layers.