Coating leveling is one of the important properties of coatings, and poor leveling has a significant impact on appearance, thereby reducing the quality of coatings. The relationship between leveling agents and coating leveling and fluidity is like that between cold medicine and cold. Cold medicine can treat colds, while leveling agents can improve the leveling and fluidity of coatings.
The flow and film formation process of paint occurs under the action of external force, which allows the paint to spread out; The driving force for leveling is the surface tension of the coating itself, and leveling is the main process for achieving a smooth and even coating film. Only when coatings have both good leveling and fluidity can they form a smooth and even coating film.
There are many factors that affect the flow and leveling of coatings, such as raw materials, fluid properties, surface morphology, drying time, etc. Today, we will mainly explore the impact of the latter three factors.
1. Fluid properties. The fluids of coatings can be roughly divided into five types: Newtonian fluids, plastic fluids, pseudoplastic fluids, expanding fluids, and thixotropic fluids. Different fluids have different effects on the flow and leveling of coatings. For example, pseudoplastic fluids and thixotropic fluids have excellent properties in preventing sedimentation, anti foaming, and anti shrinkage, but they have a negative impact on leveling and gloss.
2. Surface morphology. The surface morphology of coatings is mainly influenced by the painting tool and substrate. The impact of different painting methods and tools on the regularity of the coating varies, and the greater the irregularity, the more difficult it is to level; It is difficult to form a smooth and even coating on a rough substrate surface.
3. Drying time. The drying time of coatings is essentially the rate of solvent evaporation. The longer the coating maintains low viscosity, the more sufficient time is left for the leveling stage, and the possibility of forming a smooth and flat coating is also higher.
Many coating problems are complex, and simple adjustments to pigments, solvents, etc. cannot solve the problem. More targeted substances are needed—— Leveling agent. Anti shrinkage, anti orange peel, anti color fading, anti extinction, anti light leakage, and anti ripple, leveling agents have excellent properties in improving the leveling and flowability of coatings.
