Time：2018/9/14 Check：179
In recent years, to control VOC (volatile organic compounds) emissions, to adapt to the increasingly stringent environmental regulations, become the important direction of paint and water-based coatings research hot spot in [1]. Pre-coated coil coating as an important field of coatings industry, due to the performance and cost factors, its production technology is still in solvent dominate, only a few production lines using water-based paint. Therefore, in order to meet the needs of environmental protection, development and performance of waterborne coil coating is of great significance. Coil coatings is given priority to with unsaturated polyester resin and epoxy resin with resin, both has good comprehensive performance [2]. This study used water saturated polyester and water-borne epoxy resin physical mixing method, the excellent properties of combined and developed a low VOC water-borne coil primer, and discussed the main factors such as base resin, curing agent on the properties of the coating, and through electrochemical impedance spectrum analysis on the corrosion mechanism of waterborne coil primer.
Experiment 2,
2.1 test materials
Waterborne epoxy resin 682 and waterborne acrylic modified unsaturated polyester MB - 019, Beijing jin hui chemical application; Amino resin SM5717, jiangsu sanmu group; Strontium, zinc chrome yellow, huang aluminum tripolyphosphate, talcum powder, lithopone, titanium dioxide, wetting dispersant W - 511 and dimethyl ethanolamine, nanjing chemical reagent co., LTD. Deionized water, homemade.
The preparation of 2.2 primer
According to the coating formula, first part water-based resin, pigments and deionized water in a certain proportion to join small grinding machine grinding to scraper fineness of qualified, discharge, get dispersed good paste. Add the rest of the match in the paste paint with resin, crosslinking agent, additives and deionized water, high speed dispersing mixing 2 h, filtration, packaging.
2.3 the preparation of the coating
Choose 10 cm x 5 cm x 0.5 mm galvanized sheet, after preprocessing passivation, scrape rod roller made good primer above, get wet paint film, in 220 ~ 230 ° C baking 40 ~ 45 s, made model with bottom paint film. Then at the end of the film in the same way on the construction of form a complete set of paint, get the required base composite film, after the constant temperature and humidity of the indoor debugging test its performance.
2.4 characterization of coating
Coating adhesion in accordance with the GB/T9286-1998 "paint and varnish film cross test" test, pencil hardness according to GB/T6739-2006 "the paint and varnish film hardness pencil method, test, salt fog resistance according to GB/T1771-2007" paint and varnish determination of neutral salt fog resistance test, the coating was tested by European standard T bend and MEK resistance (methyl ethyl ketone) wipe the performance. Using Quanta200 type scanning electron microscopy (Dutch FEI company) was carried out on the coating surface morphology analysis, use EG&GPARSTAT 2273 electrochemical workstation (Princeton Applied Research) test coating of the electrochemical impedance spectra.
