Gray glass composition

Abstract

Abstract The present invention provides a glass composition having a neutral gray color and a luminous (visible) transmittance within a range that allows the glass to be used in the forward vision areas of a vehicle. The base glass is a soda-lime-silica composition and iron, cobalt, selenium and/or nickel are added as colorants. In one particular embodiment of the invention which is essentially nickel-free, a neutral gray colored glass with a luminous transmittance (C.I.E. illuminant A) of 60% and higher at a thickness of 3.9 millimeters may be attained by using as colorants: 0.30 to 0.70 wt. % Fe₂O₃, no greater than 0.21 wt. % FeO, 3-50 PPM CoO and 1-15 PPM Se, and preferably 0.32 to 0.65 wt. % Fe₂O₃, 0.065 to 0.20 wt. % FeO, 5 to 40 PPM CoO and 1 to 9 PPM Se. In an alternate embodiment of the invention which includes nickel oxide as a colorant, a neutral gray colored glass with a luminous transmittance of 60% and higher at a thickness of 3.9 millimeters may be attained by using 0.15 to 0.65 wt. % Fe₂O₃, no greater than 0.18 wt. % FeO, 15-55 PPM CoO, 0-5 PPM Se and 25-350 PPM NiO as colorants, and preferably 0.17 to 0.60 wt. % Fe₂O₃, 0.04 to 0.16 wt. % FeO, 20 to 52 PPM CoO, 0 to 3 PPM Se and at least 50 PPM NiO.

Inventors

• 👤 John Franklin Krumwiede
• 👤 Anthony Vincent Longobardo
• 👤 Larry John Shelestak

Bibliographic Details