The Development Of The Water-based Epoxy Anti-corrosion Coating

Epoxy resin coating possesses the excellent properties of corrosion prevention and chemical resistance, has excellent adhesion to many carrier materials, can be solidified with a variety of curing agents and has flexible formulations as required. With these outstanding performances, it is leading in a dominant position to be used as binder among anticorrosion paints, epoxy resin also become the largest number and widest range of heavy-duty resin coating application. About 40% of the resin are used in paint manufacture each year in the world, most of which are used to prevent corrosion field. The excellent performance of epoxy resin have been fully reflected in solvent-based anti-corrosion coatings, the current anti-corrosion epoxy coating are solvent-based paints, but its research and application of water-based epoxy anti-corrosion coatings shares a very important position, water-based epoxy anti-corrosion coatings abroad are the fastest-growing varieties of waterborne anti-corrosion coatings.This article describes comparison tests of film-forming material, curing agent, pigment and additives, and makes choice to determine the raw materials with excellent performance for the preparation of water-borne anti-corrosion coating, which can greatly improve the film coating performance. By comparison tests, we determine to mainly use models GEM02 waterborne epoxy emulsion of Shanghai Kerry Green Limited for the film-forming material, and GCA02 for curing agent, which is coordinated with GEM02. Defoamer selects SN-318 and SN-31 of San Nopco Company, leveling agents adopts HX-5600 from Guangzhou Huaxia Additives Chemicals Co., Ltd., thickening agent uses HX-5440 of Huaxia, adhesion promoter uses A -171; the pigment mainly adopts the environment-friendly paints, such as zinc phosphate and aluminum tripolyphosphate, etc.We have discussed the effect factors of film coating performance. When the emulsion is about 40% (mass fraction), the film has good performance. When the equivalence ratio of epoxy / amine hydrogen is 1.1, this coating shares the best performance. At a higher temperature, the environmental temperature of film is excess than the polymer glass-transition temperature, which makes the active group fully cross-linking reaction and curing, so as to enhance the adhesion. With the increasing of PVC value, the salt water resistance performance of film coating is improved, while PVC is 30%, the coating of salt tolerance reaches a maximum, and has an excellent adhesion property.The drying and film-forming of epoxy resin film is a process which converts the soluble and fusible linear or branched-chain molecules into the final insoluble and infusible three dimensional structures. Through infrared spectroscopy, epoxy group in epoxy resin has reacted with the amidogen in curing agent and formed a dense coating. By the TGA (thermogravimetric analysis), it can be found that the water-based anti-corrosion coating hasn't any changes basically below 250℃, so it has better heatproof effect and can be used in areas of high temperature.