| Currently, In addition to powder coating and electrophoretic paint, the solvent-basedcoatings are major paint for engineering machinery.In the painting process, one liter paintcontains0.6liters solvent at least,and our spray booth can not achieve effective recovery oforganic solvents, thus causing a great amount of VOC emissions.With the gradual improvement ofnational laws and regulations,the raising of people’s environmental awareness,research andapplication of environment-friendly paint has become an urgent task.Such as powder coatings,UV-curable coatings and waterborne paints.Due to the large and complex features of structuralparts,it is not suitable for powder coatings and UV curable coatings,So water-based paint hasbecome an inevitable choice to replace solvent-based coatings.In order to ensure corrosion resistance of the structure,It uses a two-component epoxyprimer coating and two-component polyurethane topcoat.The purpose of this paper is to develop ahigh-performance water-based epoxy primer to fit the needs of construction machinery.Considerable performance waterborne epoxy coatings with solvent-based epoxy coatings has beenreceived through some researches that the effects of water epoxy resin,anti-corrosionpaint,pigment volume concentration (PVC) and curing agent on various performance ofwaterborne epoxy coatings.In the study of waterborne epoxy resin,the DOW6001,4001, XCM-41,Cytec2384werechosed as a research object.The basic properties of the coatings were tested and compared,theresults show that DOW4001can not meet a demand for construction machinery coatings exceptthe film hardness and flexibility;In the salt spray test, DOW xcm-41film blistering in less than480hours;Cytec2384film has failed in adhesion and resistance to salt sprayperformance;however,DOW6001film can meet all requirements of construction machinery.In the study of anti-corrosion paint, a second-generation phosphate (Molybdenum zinc phosphate,Iron and zinc phosphate),zinc, aluminum tripolyphosphate and calcium ion exchangesilica gel were chosed as the research object. the test and contrast of basic properties of thecoatings finds that because of a higher solubility and conductivity of molybdenum zincphosphate,film blisters with a large area in salt spray resistance test over100hours.Zinc used inthis study has a poor purity(it contains parts of elemental zinc)so that the film has a badperformance;Aluminum tripolyphosphate film can not meet the demand in resistance to liquidsand resistant to salt spray performance;Calcium ion exchange silica film has a serious blisteringaround the scratches;Iron and zinc phosphate film (Heubach ZPA) has excellent performanceswhich can meet all demands of primer used in construction machinery.Pigment volume concentration (PVC) of20%,30%,35%,40%,45%werestudied.Film-sectional scanning electron microscopy showed, the base material can better wrapfillers when PVC is30%,film has a good compactness and excellent various properties;when thePVC is20%, the pigment particles are not continuous,Film appears point rust phenomenon afterthe salt spray resistance test;And PVC is greater than30%, the base material is not sufficient towrap fillers,the poor denseness film can not meet the requirements of construction machinery.In the study of appropriate proportions with the epoxy emulsion (6001) and the curingagent (8001),6001/8001is3.5:1,4:1,4.5:1and5:1were studied,FT-IR results showed that nomatter how much the amount of curing agent,there has been an epoxy group in crosslinkingproduct.The coating performance test results show that the6001/8001was3.5:1, the film has agreater water absorption, has a significant blistering and rusting phenomenon;6001/8001is4：1and5:1,the film still occur point corrosion phenomenon;And6001/8001was4.5:1, the coatingperformance can meet demand for construction machinery.In summary, selecting DOW6001as the base film material, Heubach ZPAas a chemicalrust paint, pigment volume concentration (PVC) of30%,6001/8001being4.5:1and appropriateadditives gets two-component waterborne epoxy coatings that has comparable performance withsolvent-based epoxy coatings and can meet all performances and can be used as ahigh-performance water-based epoxy primer for prime in construction machinery. |
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