Commercialization of sol–gel based transparent functional coatings

Sol–gel based transparent functional coatings such as easy-to-clean coatings, anti-glare coatings, anti-reflective coatings, and anti-fingerprint coatings have been developed and commercialized for display applications. These coatings can be applied by a spray process on the glass substrates followed by a low temperature curing at 100° to 150 °C. Hydrophobic easy-to-clean coatings exhibit high water contact angles at ≥115°, with an excellent wear durability by passing 10,000 cycles using #0000 steel wool under 1 kg load. In addition, easy-to-clean coatings show a silky touch feel with a coefficient of friction of less than 0.03. Anti-glare coatings without particles have a gloss value between 50 to 100 gloss units, an adhesion of 5B, a pencil hardness ≥8 H, and no sparkling issues on touch screen displays. A combination of easy-to-clean coatings on top of anti-glare coatings significantly increases the stylus pen durability. Single-layer anti-reflective coatings show a transmittance increase of 1.5% to 2.0% by spray coating on a single side of the glass substrate, or a transmittance increase of more than 4.0% by dip-coating on a polycarbonate substrate. Anti-fingerprint coatings show less obvious fingerprints on the coated glass surface compared to those on uncoated glass surface. These coating solutions have been scaled up to 1000 kg batch in PPG’s Tianjin plant, China.