Development Andapplication Of UV-curing PU Acrylate Hydrophobic Coatings

As people becoming more and more concerned for the environment protectionand energy utilization, more and more attentions are paid on new coatings withcharacteristics of green, high efficiency and low carbon energy saving. Radiationcuring method is adopted in UV (Ultraviolet) curable coating for its characteristics of“5E”(Efficient, Energy Saving, Enabling, Economical, Environmental), which makesit possible that UV curable coating has become a kind of “Green Coatings”developing fast recently.Some disadvantages of UV-curing PU acrylate coatings, including curing speed,flexible, viscosity, maneuverability, fingerprint resistant and corrosion resistance, etc,have been studied in this paper. Meanwhile a further discussion has been played onsurfaces hydrophobic property of coatings.Firstly a tri-functionality polyurethane acrylic prepolymer (PUA) with lowmolecular weight was synthesized by using hydroxypropyl acrylate (HPA) and1,6-hexamethylene diisocyanate (HDI) trimer as main component. Then functionalpolymethylmethacrylate (PMA) with high solid but low viscosity was synthesized byusing acrylics, methacrylate, butyl acrylate and other additives. We finally prepareda new UV-curing PUA coating by using the former PUA as main resin and reactivediluent, acrylic copolymer, photoinitiators as additives. The influence of the base resin,reactive diluent, acrylic copolymer, photoinitiators and other additives on UV curablecoating performances was discussed. The optimal formulation and process forsynthesis of the coating were achieved. The coating achieved exhibits good adhesiveforce and washing resistance. The pencil hardness was5H~6H and adhesive force waslevel “0”. The glass transition temperature(Tg) of the coatings was60.9℃, and theflexibility of film is level1mm, exhibiting good comprehensive property.The UV-curing PUA coating was combined with lotus leaf surface, according tothe hydrophobic effect of the coating. Considering about the affecting factors ofhydrophobicity, AF-G04, MQ-silicone and modified SiO2nano-particles were addedinto coatings system. Based on the discussion of relationship between hydrophobiceffect of lotus leaf surface with stratifying structure and the ratio of low surface freeenergy, and the former polyurethane acrylic prepolymer (PUA) coating, a new type ofUV-curing hydrophobic PUA coating with hydrophobic effect was prepared. Thecontact angle of this coatings could reach70~80°. Furthermore, hydrophobic,corrosion resistance and self-cleaning property of the UV-curing PUA coating were deeply improved, which makes it possible to be widely applied.