Home
<p>The leveling agent is a common surface active agent, and the leveling agent plays a great role at the interface. Next, the Yincai editor will talk about the application and characteristics of leveling agents in coatings.</p><p><br></p><p>The leveling agent is a common surfactant, and the<a href="https://www.pc-additive.com/leveling-agent.html" rel="noopener noreferrer" target="_blank"> leveling agent</a> plays a great role at the interface. Next, the 258 platform editor will talk about the application and characteristics of leveling agents in coatings.</p><p><br></p><p>leveling agent is a kind of surface active agent that people often use and are familiar with. It is called a surfactant, not because of its structure, but because of its role at the interface. It has limited compatibility with resin solvents, and is squeezed out to the air/liquid interface to play a surface active role. The surface tension of the coating is in a balanced state, and the surface defects caused by the difference in surface tension are overcome.</p><p><br></p><p>The role of leveling agent in coatings</p><p><br></p><p>There are many shortcomings and shortcomings in the performance of coatings, which cannot be solved by using resins, pigments, and solvents alone. Use some additives. Leveling agent is an indispensable one of these additives.</p><p><br></p><p>Anti-shrinkage</p><p><br></p><p>Shrinkage on the surface of the coating film is a common problem. The reason for shrinkage is the imbalance of surface tension. The material that produces shrinkage has a lower surface tension than the coating film, and is called shrinkage donor. The surface tension of the coating film is higher than that of the shrinkage cavity donor body, which is called the shrinkage cavity acceptor. The reasons can include the following:</p><p><br></p><p>① When several resins are mixed together, they can be compatible or even form a transparent coating film when the solvent is matched properly. However, when the solvent is not properly matched, some resin will precipitate during the solvent volatilization process, resulting in colloidal particles that become shrinkage donor bodies.</p><p><br></p><p>②The pollution of external objects, low-energy floating objects in the air, and silica gel particles in the drying tunnel fall on the surface of the coating film.</p><p><br></p><p>③The paint is mixed with materials with low surface energy such as insoluble oil, silicone oil, rubber particles and other materials.</p><p><br></p><p>④The surface tension of the substrate is unbalanced, and some places are contaminated by substances with low surface energy or the surface energy of the substrate is too low.</p><p><br></p><p>⑤ Add substrate wetting agent to coatings containing pigments or matt powders that have not been treated with wetting dispersant, then substrate wetting agent will be adsorbed to the surface of exposed particles, and shrinkage donor body will be formed. Such maladies often occur in water-based matt paints.</p><p><br></p><p><br></p><p>A good way to overcome shrinkage is to use a substrate wetting agent combined with a silicone-based surface condition control agent. Some primers do not need or cannot use leveling agents, and the substrate wetting agent alone can achieve the purpose of anti-cratering. For example, SP-998 low foam wetting agent.</p><p><br></p><p>Anti orange peel, prevent color blooming, prevent light leakage and blooming</p><p><br></p><p>The root cause of these ills is the imbalance of surface tension between the surface layer and the lower layer of the coating film due to solvent volatilization, the lower layer is low and the upper layer is high. In addition, the density of the surface layer is greater than that of the lower layer. The lower layer of solvent-rich paint pushes it to the surface by surface tension, and gravity causes the surface layer of paint to sink, which creates a sinking, expanding, and rising eddy motion. The result is a hexagonal grid with irregular edges. Call it the "Benal" vortex. The new solvent-rich paint at the center of the grid has a low surface tension and pushes it toward the edge, where it accumulates to form a small mound, which is orange peel. This movement can also cause differences in color and pigment content. This is the main reason that causes the color paint to bloom, and the uneven arrangement of the sub-powder of the matt paint causes light leakage and matting.</p><p><br></p><p>Marangoni movement is the main source of these ills. As long as the surface tension of the coating film is reduced, the underlying paint cannot be pushed to the surface, and the above-mentioned ills cannot be produced. Therefore, it is a good way to add organic silicon leveling agents that can control the surface state and reduce the surface tension. For example, Bocheng Chemical's SP-934, SP-953 and so on. Te If the silicone additives cannot solve the problem, then consider choosing organic fluorine additives. But pay attention to cost and foam stability.</p><p><br></p><p>prevent ripples</p><p>Waviness is also caused by uneven surface tension. But pay attention to whether it is facade spraying or flat spraying. In plane spraying, the coating film drying speed is uneven, and the surface tension of the fast-drying area is higher than that of the slow-drying area. At this time, the surface tension will push the paint in the slow-drying area to move to the fast-drying area, resulting in ripples in the left and right directions. This can be solved with a silicone-based leveling agent that reduces surface tension. But when the facade spraying produces up and down ripples, it is better not to use a leveling agent that reduces the surface tension to solve it, otherwise it will become more and more serious.</p><p><br></p><p>This is because the paint falls, and the surface tension underneath is higher than the surface tension above, so the paint is pushed from the bottom to the top, and the gravity sinks, which produces up and down ripples. The more you add a leveling agent that lowers the surface tension, the more you depend on the surface tension below, the stronger the upward pushing force and the stronger the ripples. A good way is to add a leveling agent that does not reduce the surface tension.</p>
products
