Leveling agent is a commonly used coating additive, which can promote the formation of a smooth, smooth and uniform coating film during the drying and film forming process of the coating. It is a common additive in paint and paint construction. What is the role of leveling agent? Is the leveling agent dangerous?

The role of leveling agent:
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 agents in oil-based coatings are acrylic polymers, which are usually used in solvent-based coatings and powder coatings, especially in powder coatings. It is necessary to use additives in the production and application process. The most commonly used leveling agent in water-based coatings is polyurethane, which is especially widely used in medium and high-grade latex paints. Other additives with leveling effect include silicones and associative alkali swelling and leveling thickeners.
                                            
After the coating is applied, there is a process of flowing and drying to form a film, and then a smooth, smooth and uniform coating film is gradually formed. Whether the coating film can achieve the characteristics of flatness and smoothness is called leveling. Shrinkage refers to the irregular, bowl-shaped small depressions formed on the coating film, which makes the coating film lose its flatness. It is often centered on a drop or a small piece of impurity, and a ring-shaped edge is formed around it.

From the perspective of leveling, it is a special "point-type" unevenness that occurs on the surface of the coating film. Its shape can be divided into flat, crater, point, bottom-opening, and bubble in terms of performance.式等。 Equations and so on.

Acrylic leveling agents are generally synthesized by polymerizing butyl acrylate with amines and alkyl esters. The polymerization temperature is controlled at 80-90°C, the solvent is toluene, xylene, cyclohexane, etc., and the relative molecular weight of the polymer is controlled at 4000- 10000, the narrower the molecular weight distribution, the better the leveling effect.

Acrylic leveling agents are mainly used in the production and construction of powder coatings. Leveling agents are commonly used to improve the appearance of the coating film and eliminate surface defects such as orange peel, shrinkage, pinholes, and edge shrinkage. The leveling agent eliminates the surface defects of the coating film by reducing or changing the surface tension and interfacial tension, and by promoting the uniformity of the surface tension during curing. A high-quality leveling agent can reduce the melt viscosity of the system, thereby helping to melt mixing and pigment dispersion, improve the wettability of the substrate, improve the flow and leveling of the coating, help remove surface defects and help The release of air.

In powder coatings, the most commonly used leveling agents are acrylate homopolymers and copolymers and modified polysiloxanes. However, polyacrylate-based leveling agents are less sensitive to excessive use and contamination than polysiloxanes. Therefore, the most popular systems used in the coatings industry are still acrylic polymers.
                                
Silicone leveling agents can be used in oil-based coatings and some varieties can also be used in water-based coatings. This type of leveling agent is prone to quality defects due to its poor compatibility with paint and its low surface tension, such as inaccurate dosage or improper combination. In recent years, some additives manufacturers have made various modifications to silicone-based leveling agents, increasing the compatibility and the scope of application year by year. And because of its small dosage, the effect is remarkable. Therefore, in terms of consumption and development of new varieties, silicone-based leveling agents may have a relatively large development in the future.

Polyurethane leveling agents are generally used in water-based coatings, especially in systems containing emulsions. It has both leveling and thickening properties. It is made by reacting polyethylene oxide with isocyanate and then fat modification. This leveling agent is currently produced by many domestic additives factories, and some varieties are equivalent to foreign levels. With the improvement of the domestic level of additives and the increase in varieties, people’s awareness of leveling agents has gradually increased, and consumption will also increase. It will increase year by year.