Ppg Industries, Inc.

David E Lecocq

George A Neuman

John F Sopko

Patricia Ruzakowski Athey

Royann L Stewart-Davis

Douglas S Dauson

A method for coating a moving substrate provides a coating having a chemical composition which varies continuously from the interface with the substrate to the opposite surface of the coating. The method involves directing a vapor coating composition toward a substrate surface and moving portions of the vapor in opposite directions. A vapor coating mixture may include a tin-containing precursor and a silicon-containing precursor. An accelerant, e.g. a phosphorus-containing precursor, may be used with the metal-containing precursors to increase the deposition rate of the coating. The coating deposited on the substrate has regions of continuously varying weight percent of silicon oxide and tin oxide as the distance from the substrate-coating interface increases, with the surface of the coating farthest from the substrate-coating interface being predominantly tin oxide. The regions of varying composition provide the coating with varying indices of refraction to eliminate iridescence to provide a coated article, particularly a tin oxide coated glass article, with a neutral color.

Method for coating a moving glass substrate

An apparatus for coating a glass ribbon has an exhaust on each side of a coating unit at different distances therefrom. With this arrangement, portions of the ribbon upstream and downstream of the coating unit are exposed to coating vapors from the coating unit for different periods of time. A coating mixture includes tin containing precursors and a silicon containing precursor. The silicon containing precursor has the structural formula ##STR1## where R.sub.1 is a group which does not have an oxygen available to form a peroxide, R.sub.2 is a functional group giving the silicon containing precursor the ability to be easily converted to silicon oxide coating, R.sub.3 is a bridging group to provide for multiple silicon atoms and R.sub.4 completes the bonding on the foundation silicon atom. An accelerant e.g. a phosphorus containing precursor may be used with the metal containing precursors to increase the deposition rate of the coating. The coating deposited on the glass has regions of continuously varying weight percent of silicon oxide and tin oxide as the distance from the glass-coating interface increases, with the surface of the coating farthest from the glass-coating interface being predominantly tin oxide. The regions within the coating provide the coating with different indices of refraction to eliminate iridescence resulting from increased thickness of the tin oxide at the outer coating surface and to provide the coated glass article with a neutral color. When phosphorus is used as the accelerant, the percent of crystallinity is reduced and approaches O, thereby reducing or eliminating the coating haze.

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Lower Burrell, PA, United States of America

David E Lecocq