How can wrinkles caused by film curing be avoided?

Wrinkles on the film surface can occur during the drying and curing of the film. There are generally three types of wrinkles: wrinkles that occur during the initial film application, bead wrinkles that occur during repeated film application, and wrinkles caused by the action of acidic gases inside the oven.

The first type of wrinkles is more likely to occur when using epoxy resin-based coatings. Due to the catalytic effect of acidic gases in the oven, the surface of the film cures faster, leading to internal stress, shrinkage wrinkles, also known as air cracks or crystalline wrinkles.

The second type of wrinkles can occur when using alkyd resin coatings, coatings containing conjugated double bonds, or when excessive drying agents are used. When the oxidation and polymerization rates of the film's surface and interior are not consistent, differential stresses can lead to wrinkles.

The third type of wrinkles can occur when repeatedly applying alkyd resin coatings or styrene-alkyd resin coatings. This is because cross-linked coatings are reapplied before reaching their full cross-linking density, causing solvents in the coating to expand and create wrinkles.

In order to effectively prevent the first type of wrinkles, you can avoid spraying the film too thickly. You should also pay attention to reasonably determining the components of the curing agent to make the surface and interior of the coating film dry more evenly.

In order to prevent the second type of wrinkles, it is necessary to avoid using solvents with strong solubility in the surface coating and try to use weak solvents with fast volatility. When repeating coating, a certain coating gap needs to be maintained, and the top layer can only be sprayed after the bottom layer is fully cured.