Epoxy silicone high temperature coating formulation and preparation

With the development of modern industrial, military and aerospace technologies, the steel strength of the application is getting higher and higher, and the higher the strength, the more sensitive the impurity ions are. Steel corrodes faster at higher temperatures. In order to avoid steel failure, the use of high temperature coating protection is an effective method, it is easy to construct, low cost, and widely used.
high temperature-resistant coatings generally refers to paint film in more than 200 degrees C does not fall off, can still maintain appropriate physical and mechanical properties of the coating. Its protective concept can be roughly divided into two kinds: one is to use the denseness of the coating, to prevent the corrosion medium outside the coating from invading the substrate, and the other is to rely on anti-corrosion pigments and fillers to inhibit corrosion. These two functions complement each other and act together as a protective function.
common silicone high-temperature coatings mainly focus on high-temperature performance, but there are problems such as adhesion and corrosion resistance, and some special high-temperature equipment for high-temperature coating corrosion resistance is very demanding. Therefore, in the design of high temperature coating formulation, we need to consider the mechanical properties of the paint film, heat resistance and corrosion resistance requirements
coating / coating preparation paint preparation
in the resin to add zinc phosphate, talcum powder and other fillers and additives, stirring well, and then grind with a sander to the specified fineness, add solvent dispersion, filtration, that is, the finished paint components; The two parts are polyphosphonate resin; The three parts are aluminum powder. Its weight ratio is 100:3110:10120.
coating preparation
coating preparation includes substrate treatment, coating construction and coating curing. Substrate treatment: the horse mouth iron plate with organic solvent oil removal, polishing rust removal, and then with solvent cleaning, drying.
coating construction: the paint parts in accordance with the prescribed proportion of preparation, stirring evenly, air spray area brush construction horse mouth iron plate, table dry and then carry out the next construction. The coating thickness is controlled at 40pm to 80pm.
coating curing: the completed construction of the horse mouth iron plate in the oven, heat up to a certain temperature, retain a certain amount of time after removal, cooling to room temperature, performance testing.
heat resistance
tested by GBT/173512009. Put the test sheet of the horse's mouth iron plate coated with high temperature coating into the maffle furnace and increase it from room temperature to phosphate pigment, etc. We used zinc phosphate and aluminum tripolyphosphate for testing, both of which had little effect on the heat resistance of the coating. Zinc phosphate mainly inhibits the initial corrosion, while aluminum tripophosphate inhibits the corrosion that has been produced. The synergy between the two can improve the corrosion resistance of the coating with reduced dosing. Figure 1 shows the effect of phosphate dosing on the resistance of coatings to salt mist. In this study, fillers were selected with talcum powder, mica, precipitated sulphate, light calcium carbonate and so on. According to the characteristics of pigments themselves, the paint fillers varieties commonly used and stable quality performance were selected, and the amount and proportion of fillers were determined through experiments.
In addition to the choice of
alum powder directional agent
after the paint construction, due to aluminum powder scales in aluminum powder itself diameter ratio, treatment methods are different and other reasons, although there is a certain orientation in the coating, but there is still a large proportion of the direction of dissistency, which will reduce the tightness of the coating and the barrier to impurity particles. Using a certain amount of aluminum powder directional agent, can improve the orientation of aluminum powder scales, improve the tightness of the coating and temperature resistance and other properties.
coating performance is best when the amount of powder directional agent is y2c0. Continue to increase the amount of use, the improvement of coating performance is not obvious, but will increase the viscosity of the coating, not conducive to coating construction.
Other Additives
In addition to aluminum powder directional agents, in order to enable various fillers to be better dispersed in the resin, and improve the adhesion of silicone coatings to the substrate, a wetting dispersant was chosen; In order to improve the surface condition of the coating, a leveling agent was selected. In order to improve the production status of coatings, the desiccant was selected; Wait a minute.
the coating has been applied to engine components made of high-strength steel. The results show that the coating process has good performance, temperature resistance is up to the requirements, the performance of the force and corrosion is good, and the comprehensive performance is up to the requirements of use.
Conclusion
Epoxy silicone resin as the main film, with appropriate curing agents, functional pigments, etc., to prepare a good physical mechanical properties and corrosion-resistant properties, at a high temperature of 300 degrees C can be long-term use of epoxy silicone high temperature aluminum powder coating. Aluminum powder can improve the high temperature resistance and tightness of the coating, the dosing of 10% 120% is appropriate; Aluminum powder directional agent can improve the arrangement of aluminum powder, thereby improving the hardness of the coating, denseness, temperature resistance and protection performance, the use of y2c0, the best results. The compound phosphate can improve the salt spray resistance of the coating, and the salt spray resistance of the coating increases with the increase of phosphate addition. The comprehensive performance of the coating is better when the phosphate dosing is 10% and 20% limited by the paint base ratio.
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