The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 15, 1991
Filed:
Jul. 24, 1989
Kouichi Suzuki, Osaka, JP;
Kazuo Shibaoka, Osaka, JP;
Nippon Sheet Glass Co., Ltd., Osaka, JP;
Abstract
A process for producing a glass article protected from coloring by electron rays comprises preparing a soda-lime-silica glass, contacting the glass with a molten salt containing potassium ions so that sodium ions in a surface layer thereof are exchanged by potassium ions, and subjecting the glass to heat treatment so that the surface layer thereof in a depth to which the irradiated electron rays penetrate when electron rays are irradiated has a composition defined by a molar ratio of 0.4 to 0.65 for Na.sub.2 O/(Na.sub.2 O+K.sub.2 O). The soda-lime-silica glass is composed of 50-75% by weight of SiO.sub.2, 0.5-2.5% by weight of Al.sub.2 O.sub.3, 0-0.1% by weight of Fe.sub.2 O.sub.3, 5.0-14.0% by weight of CaO, 0-4.5% by weight of MgO, 5.0-16.0% by weight of Na.sub.2 O, 0-2.0% by weight of K.sub.2 O, 0-0.5% by weight of TiO.sub.2, and 0-0.5% by weight of SO.sub.3. The content of alkali metal oxides in the glass is 5% and above, and ratio of Na.sub.2 O in the alkali metal oxides is 65% and above.