Preparation And Study Of Properties Of Waterborne Asphalt Coatings

Solvent-based epoxy coal tar coatings were used in the anti-corrosion coating of underwater and underground steel structures traditionally.With the environmental problems becoming severe increasingly,it is of great significance to develop waterborne asphalt coatings to replace solvent-based asphalt coatings.Waterborne asphalt coating with high performance was prepared by studying the physical blending of anionic emulsified asphalt and waterborne resins in this paper.The properties of waterborne asphalt coatings were tested according to national standards.In addition,the formulation of the coating was optimized.The contents of the paper can be mainly divided into two parts:In the first part,the effects of emulsified asphalt and different film-forming resins,the ratio of water-borne epoxy resin and curing agent,the ratio of water-based resin to emulsified asphalt,the type and amount of pigments on the properties of the paint film were studied.At the same time,the film-forming substance was characterized by Fourier infrared spectrometer;the dispersion of the pigment in the coating was characterized by Scanning Electron Microscope.Finally,a water-based asphalt coating with high performance was prepared.The following conclusions can be drew according to the results of these experiments.Waterborne bisphenol A type epoxy resin is more suitable for preparing asphalt paints with anionic emulsified asphalt.The epoxy resin composed of water-based epoxy resin 3520 and water-borne modified amine curing agent 8545 work well with emulsified asphalt.When the ratio of epoxy resin 3520 and curing agent 8545 is 4:1,the curing reaction is almost complete.And this conclusion was confirmed by Infrared spectroscopy of the cured product.The optimal mass ratio of waterborne epoxy resin system to emulsified asphalt is 4:6.Sericite with a flake-like structure acts as a layer barrier in coatings,and it can effectively improve the corrosion resistance of waterborne asphalt coatings.Zinc phosphate,an kind of active anti-rust pigment,can significantly improve the salt spray resistance of the coating.When the pigment composition is 90%sericite and 10%zinc phosphate and the pigment volume concentration（PVC）is 15%,the comprehensive performance of the coating is the best.The waterborne asphalt paint can resist 10%H₂SO₄ solution for 17 days,and the salt spray resistance can reach 27 days.The influence of defoamers,thickeners,and wetting agents in waterborne asphalt coating formulations on paint quality and coating quality were discussed in the second part.The results showed that the self-made waterborne asphalt coating showed better performance when the amount of polysiloxane defoamer LA-200 was 3‰,the inorganic bentonite thickener 0.5%,and choosing polyether organosilicon as the wetting agent.In addition,the self-made waterborne asphalt paint and commercial solvent-borne epoxy asphalt paint were tested and compared.The experimental results showed that the self-made water-based asphalt paint can rival with commercially available solvent-based paint in terms of comprehensive performance.