Water-based coating system is divided into water-soluble system and latex system.
In the water-soluble system, it is necessary to strongly reduce the surface tension of the system, the most commonly used silicone leveling agent fluorocarbon type leveling agent, the role played by the same as they are applied to the solvent-based coating system. Of course, if you need a truly flat surface, acrylic leveling agents for water-based systems are necessary.
For latex systems, the film formation mechanism is completely different and the viscosity does not change with the evaporation of the solvent. The use of leveling agents in the formulation will likely improve the substrate wetting of the coating, and acrylic leveling agents can improve the film flatness, but the main flow properties of the coating are more controlled and adjusted by the addition of rheology control agents.
There are many types of leveling agents, and the types of leveling agents used in different coatings are not the same. The most commonly used leveling agent in oil-based coatings is acrylate polymer, which is usually used in solvent-based coatings and powder coatings, especially in the production and application of powder coatings is a must-use additive. The most commonly used leveling agent in water-based coatings is polyurethane, which is widely used especially in medium and high-grade emulsion paints. Other additives with leveling effect are silicones and alkali-swelling leveling thickeners. synthetic polymer wax
After the construction of paint, there is a flow and drying process of film formation, and then gradually form a flat, smooth and uniform coating film. Whether the coating film can achieve the characteristics of flat and smooth is called leveling property. A shrinkage is an irregular, bowl-like small depression formed on the coating film, making the film lose its flatness, often centered on a drop or a small piece of impurity and surrounded by a ring-shaped prism.
From the point of view of leveling, it is a special “point type” flow unevenness, produced on the surface of the coating film, its shape from the performance can be divided into flat type, crater type, point type, exposed bottom type, bubble type, etc.
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