| The fingerprint resistant coating can provide galvanized sheet with corrosionresistance, fingerprint resistance, alkali wash and many excellent properties as anorganic - inorganic hybrid materials. Now, major domestic steel mills have beendepending on importing. This paint has be studied and prepared to meet Ltd. WuxiNew Dazhong'desires independently to change the situation.The fingerprint resistant paint is designed from the three aspects that ismembrane material, passivation agents and additives which based on theperformance requirements of fingerprint resistant coatings. Polyurethane modifiedby acrylic is selected as the membrane material of fingerprint resistant paintthrough performance tests of different kinds of emulsion; Ti-Zr composite system isselected as the passivation agents by the potential-pH diagram,and determined bysingle factor test zirconium salt as 0.3mass%, Ti salt as 0.3mass%, 0.5mass% of thecomplexing agent for the passivation solution; sealing agents, self-lubricant andcrosslinker are mainly studied as additives, and the results show that the silicananoparticles used as a sealing agent can give the film the highest density andcorrosion resistance, and 10mass% nano-modified silica dispersions with smallparticles are prepared successfully by compositing nano-silica with the silanecoupling agent. The rub resistance and crosslink density of the coating areimproved respectively after adding water-based wax and zirconium salts. Theadditive consists of 2mass% of nano-silica, 1mass% of water-based wax and0.2mass% of zirconium salts which are determined by orthogonal experiment.Finally, we achieve the optimization formulations of the fingerprint resistantcoating named HIT-1#. In addition, HIT-1# has reached the same level in themarket with the better overall performance comparing the performance with thecommercial paint,and has better black resistance than individual products.After completing the independent design of HIT-1# ,the pilot tests are carriedout in the production line of Ltd. Wuxi New Dazhong named plate-type gravitydrawn.During the trial defoamer is selected under certain conditions by thesimulation curve to the height of foam,and foam problem is solved by adding0.02mass% defoamer BYK012; the leveling problem of paint is solved through theopacity of paper for experimental simulation by adding 0.1mass% leveling agent L1;2mass% cosolvent QW903 is selected to make the coating of pre-and postevaporationrate evaporation rate reasonably through simulating evaporation rateunder the specific conditions; the amount of dry film coating is determined with the help of X-ray fluorescence spectrometry (XRF) by selecting Si as an embeddedelement, selecting the appropriate pulse height adjustment value (PHA) and thepeak point of view, and making the standard curve.Dry film weight of the coatingfor a production line has been achieved effective control of through the standardcurve.Finally, we study the failure mechanism of HIT-1# fingerprint resistant coating.The results of X-ray fluorescence spectroscopy (XPS) show that: the surface filmmainly cosists of resin and nano-silica. The metal content is more close to the base.Titanium which mainly exists in the form of titanium dioxide and the trivalenttitanium oxide is detected by XPS, so titanium plays a passive role to some extent.Zirconium exists in the form of zirconium dioxide. There are also a part ofzirconium which exists in the form of hydrogen phosphate salt and the carboncompounds, but only four price,and the passivation of zirconium salt is not found.Silicon exists in the form of silicon dioxide. Finally, we analyse the corrosion statewith the coating immersed in 3.5mass% NaCl solution. The hypothesis of failuremechanism of the coating is proposed according to the corrosion morphology andbode diagram analysis of HIT-1# coating under different immersion time. |
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