Siloxane modified silica sol for surface coating

  Calcium silicate board is a new type of building and industrial board prepared by mixing calcareous materials, siliceous materials, reinforcing fiber materials, and additives in a certain proportion through a series of processes. It is a non-combustible A1 material with It has the advantages of moisture resistance, weather resistance, heat insulation and sound insulation, high strength, long service life, no moth, and corrosion resistance. It is an ideal decorative board for ceilings and partitions, and has broad development prospects. However, it is easily damaged and needs some protection.
   Spraying silica sol coating on the surface of calcium silicate board can improve its heat resistance, hydrophobicity and mechanical properties.
   Silica sol, also known as silicate solution, has a large specific surface area, small colloidal particles, low viscosity, and good dispersibility and permeability. However, since the rigidity of the silicon-oxygen bond is not enough to make the gel skeleton resist the capillary pressure generated by the volume shrinkage during the drying process, it is easy to form micro cracks or even larger cracks during the film forming process. In order to make up for these defects, the hardness, heat resistance, water resistance, and antifouling properties of the coating film can be improved by modifying the silica sol.
  After studying the effect of different content of methyltriethoxysilane on the modification of silica sol at different temperatures, a hydrophobic film was prepared on the glass surface by dipping and gravity methods, and the optical properties of the glass surface did not change significantly after coating. , But the hydrophobicity has been greatly improved. Liu Jianxiang and others used methyl trimethoxysilane and methyl ethoxy silicone oil to modify the methanol silica sol and found that the hydrophobically modified silica sol has a greater impact on the mechanical properties of the acrylic coating. Ren Zhiwei et al. used γ-glycidoxypropyltrimethoxysilane and methyltrimethoxysilane to co-hydrolyze modified silica-aluminum composite sol under acidic conditions, and added an amine curing agent to prepare an organic-inorganic curable at room temperature. Hybrid polysiloxane coating.