Endurable water-repellent glass for automobiles

Endurable water-repellent coated layers have been formed on safety glasses for automobiles via a sol-gel based spray coating process. Coated films are composed of a silica underlayer ( similar to 800 Angstrom) and a fluorocar bon layer in which the formed silica shows a definite surface roughness and acts as the enhancement factor for chemical and mechanical durability. Dur ability is a function of the degree of surface roughness, structural finene ss and homogeneity. Dual stage aging in silica sol controls a wide range of surface roughness. Water-repellency is degraded gradually by a combination of sunlight (ultraviolet), water, and abrasion. Spray coating on large siz e and curved safety glasses was successfully carried out. (C) 1999 Elsevier Science S.A. All rights reserved.