It is found that compared with the coatings prepared by lithium-based bentonite, the coatings prepared by magnesium aluminum silicate have good suspension, flow resistance, flow resistance and hardening process performance, especially hardening performance. Polyvinyl butyral (PVB) with small molecular weight improves the leveling property of suspension coatings compared with PVB with large molecular weight. At the same time, the coating also has good suspension and hardening resistance. In a certain range, increasing the solid content of the coating can improve the technological properties of the coating, especially the suspension. The solid content has increased from 45% to 60%, and the 24-hour suspension can reach about 95%, up 20% year-on-year; /kloc-after 0/68 hours, the suspension can reach about 90%. Fumed silica (white carbon black) can significantly improve the suspension coating.
Through orthogonal test and range analysis, suspending agent is the main factor affecting the technical properties of coatings. It controls various technical properties of the coating, including viscosity, suspension, leveling, yield value and flow resistance. With the increase of suspending agent content, the viscosity, suspensibility, yield value and flow resistance of the coating increase, while the leveling, brush resistance and fluidity first increase and then decrease. The best formula obtained by orthogonal test has the best coating technological properties: suspending agent 1.2%, 1.2% phenolic resin, PVB0.3% and fumed silica 0.3% (all percentages of the coating). Casting iron castings in the production site with the coating with the best performance has the advantages of good flow resistance, good fluidity, uniform coating, smooth surface, not easy to peel off, easy to clean after casting, and smooth surface of the castings after cleaning, completely avoiding sand sticking.
Key words: alcohol-based coatings; Suspending agent; Solid content; PVB； Calcined silica; Process performance