Substrate wetting agents can increase adhesion

Substrate wetting agents can improve the adhesion between coatings and substrates, and are generally used for wetting harsh substrates such as metals, plastics, and minerals, allowing them to combine well with coatings. So how did the substrate wetting agent specifically improve?

Firstly, we need to start with surface tension. Nowadays, water-based coatings have the advantage of being environmentally friendly in their use, but the trouble brought by unpolluted water is also significant. The surface tension of water is relatively high, while the surface tension of most substrates is relatively low. As is well known, if the surface tension of the coating is lower than that of the substrate, the adhesion is good, so the adhesion between water-based coatings and the substrate is poor, especially for metals, plastics, etc.

Secondly, the consequences of poor integration. Poor adhesion results in easy detachment of the coating applied to the substrate, leading to the phenomenon of "paint peeling", severely limiting the application of metals, plastics, and other materials.

Finally, understand the principle of substrate wetting agents. Substrate wetting agents belong to the category of surfactants and are composed of two parts: hydrophilic and lipophilic. When a water-based coating covers the surface of the substrate, a portion of the wetting agent is at the bottom of the coating, which comes into contact with the wetted surface. The hydrophilic chain segments are adsorbed on the solid surface, and the hydrophilic group extends outward into the water, in contact with the water, forming a sandwich structure with the wetting agent as the intermediate layer, achieving the purpose of wetting; The other part exists on the surface of the liquid, where its hydrophilic group comes into contact with the liquid, and the hydrophobic group forms a single-molecule layer in the air, reducing the surface tension of the coating.

Overall, the substrate wetting agent improves the permeability and surface tension of the coating, resulting in a very good adhesion between the water-based coating and the substrate, and increasing the adhesion between the two.