The role of coupling agents in coating synthesis

The role of silane coupling agents in coatings is mainly reflected in their ability to bridge the gap between organic film-forming substances and inorganic fillers, enabling fillers to disperse better and faster in organic matter. Organosilane coupling agents play a very significant role in improving the adhesion of coatings (making the bond between organic matter and coating layer tighter), durability, weather resistance, and toughness (making the bond between organic matter and filler coatings tighter).

The main reason for these effects is that silane coupling agents migrate to the interface between the coating and the substrate after coating, and the hydrophilic inorganic groups react with the moisture on the inorganic surface to form hydrogen bonds, making the bonding between the coating and the interface more firm. Even under water immersion conditions, organosilicon modified coatings still adhere well to various inorganic substrate surfaces.

Mechanism of action of coupling agent:

During the coating production process, silicon coupling agents can be added through the following steps (the recommended amount of silicon added is 0.5%)—3%）：

1. First, add water, surfactant, and retarder to the reaction vessel;

2. Add 5-10% copolymer premix to the reactor;

3. Heat the mixture to the optimal temperature, typically around 65-75 ℃;

4. Add silane coupling agent to the buffer tank when there is still 10% remaining in the mixture. After thoroughly mixing the silane and the remaining mixture, continue to add the mixture to the reactor at the controlled rate;

5. After adding the mixture, maintain sufficient time for the mixture to disperse evenly.