The perfect coating process should allow the wet coating film to flow and eliminate coating marks after construction, and obtain a uniform and smooth coating effect after drying, which is called the leveling property of the coating.
Leveling agent is one of the commonly used coating raw materials in coating production. Its function is to promote the gradual formation of a smooth and even coating film during the drying and film-forming process of the coating. Leveling agents are generally divided into organic silicon leveling agents and acrylic ester leveling agents.
Leveling agents can improve fluidity and prolong leveling time. It reduces the viscosity of the system by adjusting the solvent evaporation rate, thereby improving the flowability of the coating; The leveling agent also increases the wettability of the substrate. Due to its strong permeability, it can increase the moisture content of the coated material. It can eliminate the gas attached to the coated material as early as possible, avoiding the phenomenon of shrinkage and pinholes in the coating film. Leveling agents can form a monolayer on the surface of the coating, generating uniform and consistent surface tension. After the solvent evaporates, the leveling agent automatically forms a smooth, delicate, and uniform monolayer on the surface of the coating, improving the gloss and aesthetics of the coating. It can be said that leveling agents are important raw materials for improving the appearance of coatings.
The effectiveness of organic silicon leveling agents depends on the chemical structure of the resin and the amount used. For example, the molecular weight of the resin and the type of organosilicon group will affect its effectiveness. The test results show that there are strict requirements for the dosage of organic silicon leveling agent as a coating raw material. Adding too much can actually produce side effects such as shrinkage, poor adhesion, and poor recoating performance. Therefore, the selection of leveling agent must be based on the specific coating product, and the selection of leveling agent variety and dosage must be determined.
Acrylic leveling agents play an important role in the smoothness of coating surfaces. It increases wettability by reducing surface tension. Due to its limited compatibility with coating resins, it can be suspended on the surface of the coating in a very short time, forming a single molecular layer, ensuring the uniformity of surface tension and making the coating smooth and flat.
