Sol—gel coatings for the substitution of fluoride or lead containing white decorations on glass

A SiO2-based sol was developed, which allows the deposition of thick (10 μm), crack free coatings on soda-lime glass. By homogeneous dispersion of TiO2 particles (10 nm to 250 nm in radius) lead and fluorine free white paints are obtained, which can be applied by spray coating to as produced glass without any pretreatment. The coatings can be densified using rapid firing in a tunnel furnace at a temperature of about 560°C for about 30 min, which is typical for firing of enamels. After this densification step, the coatings show good adhesion on soda-lime glass (class 0 of cross hatch cut and tape test) and excellent chemical durability according to Kesternich-Tests.