| There are many modification methods such as copolymerization,graft polymerization,cross-linking,blending,etc.to overcome acrylic resin shortcomings in order to obtain high performance.Fluororesin and silicone have excellent hydrophobic,corrosion resistance,cold resistance,thermal oxidation stabilities,anti-sticking properties,etc.Nano-SiO2 has many excellent properties and a wide range of applications in the functional coatings for its particular nanometer effect.This paper included that fluosilicate-containing acrylic resins were synthesized via free radical co-polymerization based on the acrylate monomers,vinyl-terminated silicone compound,organ-fluorine monomers and nano-SiO2,and that they were cross-linked with the isocyanate curing agent to prepare hydrophobic coating films.The detail abstract as follows:1.The nano-SiO2/fluorinated polyacrylate resin(SiO2-FPEA)was prepared via free radical solution copolymerization based on acrylate monomers and the modified nano-SiO2 by a silane coupling agent(Kh570).And the nano-SiO2/fluorinated acrylic polyurethane(SiO2-FPAU)coating was obtained by cross-linked with an isocyanate curing agent.Then the structure and properties of coating films were characterized by Fourier transform infrared spectroscopy,scanning electron microscopy,thermogravimetry,mechanical properties and chemical resistance tests,etc.The results show that the as-prepared SiO2-FPAU coating film possesses good hydrophobicity,and the silica nano-particles can form rough micro/nanostructure on the coating surface.The three dimensional cross-linked network structure provides that the SiO2-FPAU films with improved/better mechanical properties,water resistance,chemical resistance,thermal stabilities,and anti-ageing performance,and a long soak in chemical solution had no significant influence on the appearance of the coating films,and the surface gloss loss rate is lower than 30.0%after artificial aging 720 h.2.The water-borne fluoro-silicate polyacrylate resin(WFSiPA)was prepared via free radical emulsion copolymerization based on the vinyl-terminated silicone compound and acrylate monomers containing hydroxyl,carboxyl,alkyl or fluorine alkyl.Then the two-component coatings were obtained by mixed the WFSiPA emulsion with a water-borne isocyanate curing agent.The influence of reaction temperature,dosage of emulsifiers,emulsifier ratio,dosage of initiator,acrylic acid,silicone monomer and fluoro monomers on emulsion polymerization process were studied in detail.And the effects of silicone monomer,fluoro monomers,curing agent on performances of the coating films were investigated.The result shows that the optimal condition of polymerization was found as follows:75～80℃,0.4～0.6 wt%initiator,3.5 wt%emulsifier,3.0 wt%acrylic acid,organic silicon within 5.0 wt%,fluoro monomers within 16.0 wt%.The fluorine-and silicon-containing segments are inclined to migrate to surface and minimize surface energy in formation process of the film.And the water resistence,solvent resistance,pencil hardness and adhesion of coating films have significantly improved by adding curing agent in WFSPA emulsion.The as-prepared fluosilicate acrylic polyurethane hydrophobic coating films have good integrated performance,and could be great potentially applied in the hydrophobic coating fields as main film substances. |
