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The main reason for shrinkage is the presence of incompatible substances with low surface tension in the paint film of the coating. When there are incompatible substances with low surface tension in the paint film, it is known that the flow of liquid is from areas with low surface tension to areas with high surface tension. The coating in this area will flow towards the edge, forming a pit and resulting in shrinkage. The main reasons for the formation of shrinkage cavities are as follows:

The first one is that the substrate has been contaminated, such as oil stains on the substrate. The surface tension in this area is relatively low, which can cause shrinkage.

The second is contamination during the manufacturing process or use of the coating. For example, oil stains, water droplets, or incompatible substances in the resin, such as resin anxiety, can also cause shrinkage.

The third factor is the influence of the environment. For example, in the vicinity of a spray painting factory, there are factories that produce organic silicon. Such factories are likely to have silicon pollution, which can adsorb onto the surface of the substrate and generate surface tension, thereby causing an impact. In addition, for example, if the water vapor in the air compressor is not completely released, it can also have an impact during the atomization process when the water vapor enters.

The fourth point is also related to the combination of formulas. For example, the defoamer used has not been thoroughly dispersed and stirred. Improper selection of defoamers can also cause shrinkage.

There are also four solutions to shrinkage:

The first one is to add leveling agents, such as organic silicon leveling agents, fluorocarbon modified acrylic leveling agents, and fluorosilicone leveling agents, all of which have strong anti shrinkage properties.

The second is to eliminate environmental impacts, such as organic silicon and silicon pollution, which may require thorough cleaning of the production line, and then release the water vapor from the air compressor.

The third step is to clean and polish the substrate, which may be of great help in preventing shrinkage holes.

The fourth step is to optimize the formula and process, such as selecting suitable defoamers,. After adding defoamers, thorough stirring, high-speed dispersion and grinding should be carried out. But it is even more important not to make low-level mistakes, such as adding drape additives to the formula system, which will inevitably cause problems such as poor leveling and shrinkage.

You still have to do it yourself.