Study Of Epoxy Non-isocyanate Polyurethane Heavy-duty Coatings Preparation And Of Film Performance

As a protective metal material, the heavy-duty coating is widely used in modern giant projects, it was used in harsh corrosive enviroments, and achieved long-term preservation. As a heavy-duty coatings material, environmental protection concept, and the excellent protection performance should be taken into consideration at the same time, but the used epoxy and modified epoxy heavy-duty coatings can’t achieve that.In this thesis, the corresponding five-membered cyclic carbonate was prepared by chemical method using bisphenol A-type and bisphenol F-type epoxy resin which were smaller molecular weights as matrix resin, then different epoxy non-isocyanate polyurethane heavy-duty coatings were prepared using polyether amine polyether as curing agent. The performance and the influence factors of the heavy-duty coatings were discussed and details were as follows:Preparation of epoxy-cyclic carbonate:choosing epoxy resin with relatively low molecular weight, and react with carbon dioxide to produce the epoxy-cyclic carbonate, under the condition of high temperature, pressure and catalyst. The epoxy resins used in the experiment include epoxy E-51, epoxy NPEF-170.Preparation of epoxy non-isocyanate polyurethane heavy-duty coatings:the coatings contain two components:component A includes epoxy-cyclic carbonate resin systems, fillers and additives consisting, component B is composed of the curing agent and additives. The pigments and fillers include sericite powder, nano-zinc oxide, talc powder and so on, and curing agents include D-230, D-400and T-403.Performance tests:the performance testing of epoxy non-isocyanate heavy-duty coatings contains liquid technical indicators, physical and mechanical properties, the corrosion resistance and dielectric indicator.Test results of liquid technical indicators showed:when the epoxy conversion rate is between25%to45%, the viscosity of coating is suitable for construction. The solid content of the coating is more than98%, the hiding power is170～210g/cm2, fineness is50～70μm.Test results of the coating performance test showed:in the epoxy-D-230coating system, the cured coating’s dry time is24～30min, drying time is2-2.5h, hardness is4H, adhesion is first level, flexibility is1～2mm, coating thickness is500～700μm; in epoxy-D-400coating system, the cured coating dry time is27～40min, drying time is2～3h, hardness is3-4H, adhesion is first level, flexibility is1mm, coating film thickness is500～600μm. The epoxy NPEF-170is better than E-51epoxy with flexibility and short drying time.Results of coating corrosion and media resistance and test showed:the film samples were tested according to the national standard in40%sulfuric aci,40%sodium hydroxide solution,30%sodium chloride,30%hydrochloric acid solution industry, and soaked in27.5%of industrial hydrogen peroxide for72hours with no significant changes, salt spray resistance were more than1000h, the best was higher than4000h.Finally,the results of experimental showed that, preparation process for the performance of the epoxy non-isocyanate polyurethane heavy-duty coatings is simple, convenient to construct, with intermittent short time and a wide using range. What’s more, its mechanical properties, corrosion resistance and dielectric properties are all excellent, and achieve the purpose of environmental protection.