Preparation And Film Properties Of Inorganic Silicon/Titanium Sols

In daily life,metal products including hoods,microwave ovens or ovens are often contaminated by oil stains in the high temperature and high oil pollution environment,plastic products such as fan blades,home appliances and furniture are also easy to adhere to various dirt.These oils and grime are difficult to clean and remove.In this paper,the silica sol easy-to-clean coating was developed for metal surface to solve the difficult problem of easy contamination of metal surface with oil stain.At the same time,titanium sol dustproof coating was developed for plastic surface to solve the technical problem of easy dusting on plastic surface.（1）A high-hardness and easy-to-clean hydrophilic potassium silicate/lithium silicate（K₂SiO₃/Li₂SiO₃）composite coating for a metal surface was prepared by a sol-gel method with potassium silicate（K₂SiO₃）and lithium silicate（Li₂SiO₃）as inorganic components,γ-glycidyloxypropyltrimethylsilane（KH560）as a coupling agent and the polyether modified silicone as a wet agent.The effects of the modulus,solid contents,lithium/potassium ratios,and additives on the coating properties were studied.It was found that the coating film display excellent hydrophilicity and easy cleaning performance when the potassium silicate and lithium silicate mixed solution had a modulus of 3.0,solid content is 20%,the ratio of lithium silicate to potassium silicate is 2:1.The durability of the coating’s easy-to-clean performance improved by addition of potassium tetraborate（K₂B₄O₇）as a curing agent without reducing the hydrophilicity of the coating.The final coating properties were tested including hardness,abrasion resistance,acid resistance,alkali resistance,water resistance,heat and humidity resistance,and boiling water resistance.The easy-to-clean coating developed by this project has a high hardness up to 6H.It can maintain good easy-cleaning performance and appearance after 10,000 rubs.The easy-cleaning performance and its durability of the coating are superior to those of existing foreign advanced products.（2）A TiO₂/SiO₂ composite sol for dust-proof coating on plastic surfaces was prepared with tetrabutyl titanate（TBOT）and tetraethyl orthosilicate（TEOS）as precursors,ethanol and water as a mixed solution,acid as a hydrolysis rate controlled agent.The effects of the types and amounts of acids,the amounts of water,the reaction temperatures and times on the dust resistance of the coating were studied.It was found that a stable anatase titanium sol with an average particle diameter of about 150 nm was prepared when tetrabutyl titanate and 6 wt%water were catalyzed by 1.5%hydrochloric acid at 70°C for 3-4 hrs.The hydrophilic and hydrophobic coatings with water contact angles of 13.9°and 116.3°were prepared by addition of hydrophilic silica sol and different fluorine-containing silanes,and the dust-proof rate of anatase titanium sol films are high up to 91.0%and 87.4%,respectively.The dust-proof mechanism was studied and found that the surface of the coating was dense and possessed a large amount of SiO₂ and TiO₂ particles,the dust-proof effect of the coating may attribute to the hydrophilic and hydrophobic alternating structures.