Too high an increase in talc powder will result in a decrease in adhesion. This is because water-based coatings are basically single-component coatings, and the curing of the paint film is a physical change. When the primer is in direct contact with the board, the coating film is on the surface of the board. Or other, a series of "paint nails" are formed in the small grooves, and the size of the adhesion depends to a large extent on the penetration of the film-forming substance in the coating to the surface of the substrate and the number of "paint nails" formed. Talc With the addition of talc and other fillers, the adhesion of the coating film will decrease slightly.
Therefore, when talc and other fillers are used in water-based wood paints, we not only need to consider the type of talc, but also need to choose the amount of talc. In general, an appropriate amount of talc will enhance the hardness of the paint film and fill the performance, toughness and sandability, and can reduce the cost, but too much increase (for example, when PVC>CPVC, the resin can not completely wrap the wetting filler) will cause poor adhesion of the paint film, cracking of the paint film, Disadvantages such as poor light transmittance. Therefore, when choosing talc powder, we can test and select according to the PVC and CPVC of the formula.