As a key additive in the coating industry, silicone leveling agent significantly improves the leveling, gloss and defect resistance of the coating film by regulating the surface tension gradient of the coating. Its application has covered mainstream coating systems such as solvent-based, water-based, powder and UV curing.


Core mechanism of action
The silicone leveling agent is based on polysiloxane as the skeleton, and its function is optimized through molecular design.The silicon-oxygen bond (-Si-O-Si-) in its molecular chain gives the material low surface energy characteristics, which can spontaneously migrate to the surface of the coating to form a single molecular film, balancing the difference in surface tension.For example, polyether-modified silicone introduces the ethylene oxide/propane chain to reduce the surface tension while enhancing the compatibility with the resin, effectively eliminating the orange peel, shrinkage and other defects caused by the Bernard eddy current.For high-temperature curing systems, alkyl-modified silicones (such as MONENG-1060) can withstand temperatures above 200℃ to avoid recoating difficulties caused by thermal decomposition.


Typical application scenarios
Solvent-based coatings: In the original automobile paint, chemical bonding is used to participate in the curing reaction to improve the scratch resistance and fullness of the coating, while solving the problem of attenuation of inter-layer adhesion caused by high temperature baking.
Water-based coatings: High-molecular-weight silicone oil dispersions quickly migrate to the gas-liquid interface, reducing the surface tension of the water-based system to below 22mN/m, realizing the wetting of low-surface energy substrates such as polytetrafluoroethylene, and at the same time giving the coating film anti-watermark properties.
UV-curable coating: acrylate modified silicone, combining the leveling properties of silicone with the rapid film-forming characteristics of acrylate, enables the coating to complete the surface tension balance within 0.1 seconds to meet the needs of high-speed coating of electronic products.
Powder coating: Directly incorporated in powder form, the active group is released in the melting stage at 180℃ to form a three-dimensional network structure, which improves the adhesion resistance and wear resistance of the coating film.
Performance optimization strategy
In practical applications, the molecular weight, modified group and added amount need to be considered comprehensively.Low molecular weight (<5000) products have fast migration speed but are easy to stabilize and foam, and need to be used in combination with acrylic leveling agents; although high molecular weight (>100,000) products can provide excellent smoothness, the amount added needs to be controlled to avoid gloss loss.For example, in coil coatings, polyether/polyester double-modified silicone is used to achieve dual-use of water and oil by adjusting the EO/PO ratio, taking into account wettability and weather resistance.


Technology development trends
With the stricter environmental protection regulations, non-fluorination has become an important direction. Through the introduction of aromatic ring structure, all polyester modified products remain stable at high temperatures above 150℃, replacing traditional fluorine-containing leveling agents.At the same time, the nano-silicon ball composite technology reduces the surface roughness of the coating film to the nanoscale, realizes the superhydrophobic and self-cleaning functions, and promotes the evolution of silicone leveling agents to high-end and functional.