Defoamer for water-based coatings

Water solubility for defoamer is a very important performance indicator, because in the use of defoamer, the vast majority are and liquid mutual use, so the water solubility to a large extent can affect the use of defoamer.

In the liquid, the level of water solubility determines the quality of the use of defoamer, in the use of defoamer, the first step is to complete the first step is to fully dissolve the defoamer in the liquid. Only all the melting in the liquid, then in the stirring time defoamer can play its role.

Therefore, in alkyd emulsion coatings, it is recommended to use non-ionic pigment dispersants, and the dispersants and pigments should be added to the emulsion before the driers to prevent the driers from being adsorbed and reacted by the pigments and pigment dispersants. Loss of drying activity.

Section VI Anti-skinning agent
The skinning of air-drying coatings during use and storage is first the volatilization of the solvent, and then the surface oxidative polymerization and gelation. The early gel can be restored to its original fluid state by stirring. As time goes by, the gel gradually hardens and can be removed by filtration. If the film is hard enough, it can be directly cut and removed. Finally, the film thickened so that all the gel became solid and could not be used.

The high degree of polymerization of the binder in the air-drying paint, the high content of tung oil, and the high amount of drier can promote the skin formation. The skinning phenomenon not only causes a lot of loss, but also affects the appearance of the paint film, resulting in defects such as graining and roughness. There are three reasons for the formation of skinning: ①The surface of the coating is in contact with air, which montan based wax causes the surface to oxidize and polymerize; ②The gelation is promoted by the volatilization of the solvent; ③The combination of the above two factors destroys the colloidal balance of the binder.