What will happen to the surface condition of the coating after adding the levelling agent?
After adding leveling agent, the surface state of the coating will undergo significant changes, mainly in the following aspects:
1. Improvement of coating flatness
One of the main functions of leveling agent is to improve the flatness of the coating. After coating construction, the wet paint film can flow to eliminate paint marks and form a flat, smooth coating film. By reducing the surface tension between the coating and the substrate, the leveling agent enables the coating to have good wettability on the substrate, thus avoiding the production of defects such as shrinkage holes. At the same time, leveling agents also adjust the evaporation rate of solvents, reduce the viscosity of coatings, further improve the fluidity, extend the leveling time, and help to obtain a smoother coating.
2. improve the gloss of the coating
Leveling agent on the surface of the coating to form a very thin layer of single molecule layer, this layer of single molecule layer can homogenize the surface tension of the coating, reduce the uneven gloss phenomenon due to the difference in surface tension. Therefore, after adding leveling agent, the gloss of the coating will usually be improved, making the coating more bright and beautiful.
3. eliminate coating defects
Coatings in the drying process may be accompanied by sagging, shrinkage, pinholes and other film defects, these defects not only affect the appearance of the coating, but also may reduce the protective properties of the coating. Leveling agents can effectively eliminate these coating defects through their special chemical structure and action mechanism. For example, silicone leveling agents can significantly reduce the surface tension, better wetting of the coated substrate, thus reducing the production of defects such as shrinkage holes.
4. the effect on the adhesion of the coating
Although the leveling agent mainly acts on the surface state of the coating, it also has a certain effect on the adhesion of the coating. On the one hand, leveling agents help to enhance the adhesion between the coating and the substrate by improving the wettability and flatness of the coating. On the other hand, if the leveling agent is used improperly or in excess, it may cause the surface tension of the coating to be too low, which in turn affects the adhesion between the new coating and the old coating. Therefore, when using leveling agents, the amount added needs to be precisely controlled to ensure its positive effect on coating adhesion.
5. Precautions
Selection of leveling agent: suitable type of leveling agent should be selected according to the type of coating, usage and construction conditions. Different leveling agents have different chemical structures and action mechanisms, and are suitable for different types of coatings and construction environments.
Control of additive amount: The additive amount of leveling agent should be strictly controlled to avoid overuse leading to low surface tension of the coating or other undesirable consequences.
Coating treatment: Before recoating or other coating treatments, the coating should be carefully inspected and treated to ensure good adhesion between the new coating and the old coating.
In summary, the addition of a leveling agent results in significant changes in the surface condition of the coating, including improved leveling, increased gloss, elimination of defects, and some effect on adhesion. However, these changes are affected by a variety of factors such as the type of leveling agent, the amount added, and the treatment of the coating. Therefore, when using leveling agents, a combination of factors needs to be considered to obtain the best possible coating results.