Method of making a glass laminate having controlled strength

• US 9,346,699 B2
• Filed: 01/14/2015
• Issued: 05/24/2016
• Est. Priority Date: 10/06/2008
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Amosov, Alexey Sergeyevich, Burdette, Steven Roy, Madapusi, Shriram Palanthandalam, Nikulin, Ilia Andreyevich
• Primary Examiner(s): Halpern, Mark
• Application Number:
  US14/596,470
• Publication Number:
  US 20150210583A1
• Time in Patent Office: 496 Days
• Field of Search: 65/291.9, 65/90, 651/21
• US Class Current: 1/1
• 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

A method for making a glass laminate sheet including:

• • selecting a core glass composition and a clad glass composition combination for a glass laminate structure;
  • determining and comparing the viscosity and coefficient of thermal expansion (CTE) profiles for each of the selected core and the clad glass compositions with each other over a temperature range of interest including the onset of viscoelasticity to ambient temperature; and
  • processing the selected core and clad glass composition in a laminate fusion draw apparatus to form a laminate glass sheet in accordance with at least one difference condition for the clad effective coefficient thermal expansion (CTE_{eff core}) and the core effective coefficient thermal expansion (CTE_{eff core}). Another method for making a glass laminate sheet includes controlling the cooling rate to control the resulting strength of the laminate.

Claims

1. A method for making a glass laminate sheet comprising:

selecting a first core glass composition and a second clad glass composition combination for a glass laminate structure;

determining and comparing the viscosity and coefficient of thermal expansion (CTE) profiles for each of the first core and the second clad glass compositions with each other over a temperature range of interest including the onset of viscoelasticity to ambient temperature; and

processing the selected first core glass composition and the second clad glass composition in a laminate fusion draw apparatus to form a laminate glass sheet in accordance with at least one difference condition for the clad effective coefficient thermal expansion (CTE_{eff clad}) and the core effective coefficient thermal expansion (CTE_{eff core}).

2. The method of claim 1 wherein at least one difference condition for the clad CTE_eff and the core CTE_eff comprises at least one of:

maximum strengthening, strength degradation, or temperature independent strengthening.

3. The method of claim 2 wherein maximum strengthening comprises having the core CTE_eff always greater than clad CTE_eff.

4. The method of claim 2 wherein strength degradation comprises having:

the clad CTE_eff initially less than the core CTE_eff;

in the crossover or transition region, the clad CTE_eff is greater than the core CTE_eff;

or

below the glass transition region, the clad CTE_eff is less than to the core CTE_eff.

5. The method of claim 2 wherein temperature independent strengthening comprises having the clad CTE_eff being comparable to the core CTE_eff over a temperature range of 200 to 580°

C.

6. The method of claim 1 wherein determining comprises calculating an area (A) metric of the formula:

7. The method of claim 1 further comprising determining the compressive stress of the clad layer in the resulting glass laminate sheet.

8. The method of claim 1 wherein the resulting glass laminate sheet comprises a two layer (clad:

core) laminate structure, or a three layer (clad;

core;

clad) laminate structure.

9. The method of claim 1 further comprising:

determining and comparing the viscosity and coefficient of thermal expansion (CTE) profiles for each of the first core and the second clad glass compositions with each other over an applicable temperature range including the onset of viscoelasticity to ambient temperature.

10. A method for making a glass laminate sheet comprising:

selecting a combination of a first core glass composition and a second clad glass composition for a glass laminate structure;

and

processing the selected first core glass composition and the second clad glass composition in the glass transition region in a laminate fusion draw apparatus at cooling rate of from 1 to 15°

C. per second to form the laminate glass sheet having a selected strength property.

11. The method of claim 10 wherein the cooling rate is from 2 to 10°

C. per second.

12. The method of claim 10 wherein the cooling rate is from 3 to 8°

C. per second.

13. The method of claim 10 wherein the cooling rate is from 4 to 6°

C. per second.

14. The method of claim 10 wherein the selected strength property comprises a lower strength of from 206 to 210 MPa for a lower cooling rate of 1 to 3°

C. per second.

15. The method of claim 10 wherein the selected strength property comprises a higher strength of from 214 to 218 MPa for a higher cooling rate of 8 to 12°

C. per second.