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Question:

What are the effects of primer, intermediate paint and topcoat in exterior wall coating systems?

What are the effects of primer, intermediate paint and topcoat in exterior wall coating systems?

Answer:

In the atmosphere corrosive environment of the external wall coating coating system is usually divided into primer, intermediate paint and topcoat.The main role of the primer is to lay the foundation on the substrate, the substrate has a good adhesion, with anti-rust performance The primer has a good wetting property on the surface of the substrate, as well as the osmotic effect, which enhances the adhesion to the substrate The main effect of the intermediate paint is to increase the film thickness and thus play a more effective shielding effect. The primer and topcoat in the exterior paint coating structure should not be too thick, so the middle layer is usually also a high-solids, thick slurry coating with a thixotropic variant, and the intermediate paint is also able to work well with the primer and finish Combined with the role of the machine, the car, the middle layer but also to make the surface smooth, is conducive to the topcoat. The most commonly used intermediate paint is the epoxy cloud iron intermediate paint in heavy anti-corrosion coatings, there is no simple intermediate paint concept , Many times the so-called intermediate paint can be used as a separate primer, and even as a glossy and aesthetic performance requirements of the top parts of the use of topcoat The main role is to prevent the external environment of harmful corrosive media, such as oxygen , Water vapor, sulfur dioxide and the chemical atmosphere of the same time, the beauty of the topcoat of the paint is now more and more attention, and sometimes also requires the outer layer of varnish, such as aliphatic polyurethane varnish, in order to get more For the dense shielding film.

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