Multilayer glass sheets prepared by co-drawing using the overflow down-draw fusion method

Abstract

Transparent glass sheets having increased mechanical strength include an inner layer surrounded by surface compressive layers wherein the difference of the coefficient of thermal expansion of the inner layer and the surface compressive layer is greater than 50×10−7° C.−1 and wherein the surface compressive layer has a compressive stress of at least about 300 MPa.

Description

[0001] Related Application Cross Reference [0002] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61 / 359409, filed June 29, 2010, and entitled "Glass Sheets with Improved Mechanical Strength," the contents of which are incorporated herein by reference The basis of the application is hereby incorporated by reference in its entirety. Field of Invention [0003] The present invention relates generally to glass sheets, and more particularly to glass sheets having improved mechanical strength. Background technique [0004] It has long been believed that the mechanical strength of a glass article can be significantly increased if the outer surface of the glass is in compression. It has also been studied to strengthen glass by using adjacent glass layers that differ in coefficient of thermal expansion (CTE). [0005] In addition, it is known that the mechanical strength of glass flakes can be significantly increased by using the io...

AI Technical Summary

Problems solved by technology

However, these methods are limited by the amount of ion exchange that can be achieved depending on the composition and size of the glass

Additionally, these methods significantly increase production cost and time, require significant additional production space, and present waste disposal issues

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