What is the difference between automotive primer and topcoat?

1 Answers
SanGabriela
07/29/25 4:55pm
Automotive primer and topcoat differ mainly in their composition. Primer consists of four components: resin, solvent, filler, and additives, while topcoat is composed of three components: resin, solvent, and additives. The primary difference lies in the fact that topcoat contains little to no filler. Additionally, their functions vary. The functional differences between automotive primer and topcoat are as follows: 1. Topcoat functions: It provides scratch resistance, gloss hardness, transparency and texture, aging resistance, and yellowing resistance. These characteristics are primarily reflected in the topcoat, and its quality directly affects the overall quality of the paint film. 2. Primer functions: (1) Filling effect: It fills the capillary pores in the steel plate, facilitating the application of paint on the surface. (2) Supporting the topcoat: It ensures that the topcoat can adhere tightly to the car's surface. (3) Providing fullness: The primer contains many powder materials, which contribute to the thickness of the paint. (4) Cost reduction and energy savings: The price of primer is generally lower.
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