Self-cleaning coatings can be used on the surface of substrates (such as glass ceramics or wood stone, etc.), relying on the hydrophobic and hydrophilic physical properties of the coating itself, it can play the role of antifouling and easy cleaning.
This formula is a self-cleaning coating based on modified hydrophobic SiO2, which consists of the following components and their mass percentages: Fluorosilicone resin 25-45%, hydroxyl-terminated polydimethylsiloxane-coated modified nano-SiO2 15- 30%, aromatic hydrocarbon ester mixed solvent 30-55%, and curing agent, the relative mass ratio of curing agent to the above components ranges from 0.4:100 to 0.72:100.
The hydroxyl-terminated polydimethylsiloxane coated modified nano-SiO2 is made by the following process steps:
A) Mix and disperse the gas phase SiO2 powder in the xylene solution, the concentration range of the powder relative to the solution is 0.01g/ml～0.1g/ml, first stir at 2500～3000 rpm for 20～60 minutes, and then ultrasonic Disperse for 10-20 minutes until the dispersion is uniform;
B), the solution prepared in step A is added with hydroxyl-terminated polydimethylsiloxane with a viscosity range of 1,500 to 800,000 mPa·s, and the mass ratio of hydroxyl-terminated polydimethylsiloxane to gas-phase SiO2 is 1:1 ~1:10, mix well;
C), add dibutyltin dilaurate to the solution prepared in step B as a catalyst, the amount added is 0.1% to 1% relative to the total mass of hydroxyl-terminated polydimethylsiloxane and gas phase SiO2, stir, and heat up to 60°C ～80℃, the reaction time is controlled at 0.5～8 hours. The obtained product is centrifuged first, and then baked in an oven at 80℃～160℃ for 6～18 hours, and the hydroxyl-terminated polydimethylsiloxane coating modification is completed. Preparation of permanent nano-SiO2.
In this formula, hydroxyl-terminated polydimethylsiloxane is used to coat and modify nano gas-phase SiO2. Due to the graft coating of hydroxyl-terminated polydimethylsiloxane, it can effectively reduce the number of hydrophilic hydroxyl groups on the surface of SiO2 particles. At the same time, due to the coating modification of macromolecular polymers, it can inhibit the clustering phenomenon of nano-SiO2 particles mixed into polymers, improve the dispersion efficiency of nano-SiO2 and promote the hydrophobicity of the paint film surface.
