Method of producing an alkali-free glass
AssigneeNippon Electric Glass Co., Ltd.
InventorsJun Naka, Toshiharu Narita, Shinkichi Miwa, Shigeru Yamamoto
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Abstract
An alkali-free glass applicable to a light transparent glass substrate in a liquid crystal display essentially consists, by weight, of basic elements of 40-70% SiO2, 6-25% Al2O3, 5-20% B2O3, 0-10% MgO, 0-15% CaO, 0-30% BaO, 0-10% SrO, and 0-10% ZnO, and a fining agent of a combination of 0.05-3% Sb2O3 and at least one of 0.05-2% SnO2 and 0.005-1% Cl2, which fining agent makes the resultant glass free from bubbles without the use of toxic As2O3 which has been known as the fining agent in the art.
Claims5
A method of producing an alkali-free glass having a basic composition consisting essentially, by weight, of 40-70% SiO2, 6-25% Al2O3, 5-20% B2O3, 0-10% MgO, 4.5-15% CaO, 0-30% BaO, 0-10% SrO, and 0-10% ZnO, and containing substantially no alkali metal oxide, said method comprising the steps of preparing a glass batch of the basic composition, including an addition of a fining agent consisting of a combination of 0.05-3% Sb2O3, and at least one of 0.05-2% SnO2 and 0.01-2 wt % chloride in terms of Cl2, melting said glass batch into a glass melt, and forming said glass melt into a desired shape.
Dependencies are inferred from the claim text.