Effect of mechanical and chemical wear on soil attachment and cleanability of sanitary ware with additional coatings

We studied three different types of additional coatings on sanitary ware glazes for their cleanability and resistance to mechanical and chemical wear. The additional coatings were two commercial fluoropolymer films, one experimental sol-gel-derived titania film, and an outer glassy layer fired on the substrate in two different ways. The surface chemical durability was tested by soaking them up to 7 days in a weakly alkaline detergent solution. In the mechanical testing, the surfaces were subjected to different abrasions, steel wool and a moist microfiber cloth rotated against the surfaces at a constant load. Surface topography was studied with white light confocal and scanning electron microscopy. We determined surface hydrophilicity and hydrophobicity by water contact angle measurements. The surfaces were stained with model dirt; they were then wiped with a moist microfiber cloth. The soil pick-up and removal were measured colorimetrically. The additional coatings did not markedly affect surface topology. Chemical wear by an alkaline detergent solution and mechanical abrasion by steel wool severely damaged the fluoropolymer films. Sol-gel-derived ceramic titania coating and double-glazed surfaces had satisfactory resistance to chemical and mechanical wears. Cleanability clearly increased for surfaces with the fluoropolymer and sol-gel-derived titania coatings. The glassy additional layers decreased the surface roughness, but did not affect attachment of the soil on the surfaces.