There are many types of traditional water-based paint defoamers, which are generally divided into three categories: mineral oil defoamers, polysiloxane defoamers, and other defoamers.
Mineral oil defoamers are more common and are mainly used in flat and semi-gloss emulsion paints.
Polysiloxane defoamers have low surface tension, strong defoaming and antifoaming ability, and do not affect gloss, but improper use can cause defects such as shrinkage of the coating film and poor recoatability.
Traditional water-based paint defoamers are incompatible with the water phase to achieve the purpose of defoaming, so it is easy to produce coating film surface defects.
In recent years, molecular-level defoamers have been developed.
This antifoaming agent is a polymer formed by directly grafting an antifoaming active substance onto a carrier substance. The polymer molecular chain is provided with a wetting hydroxyl group, and the defoaming active substance is distributed around the molecule, the active substance is not easy to aggregate, and has good compatibility with the coating system. Such molecular-grade defoamers are mineral oils, silicon-containing, and non-silicone non-oil polymers.
It has also been reported that this molecular-level defoamer uses super-grafted star polymers as incompatible surfactants and has achieved good results in water-based coating applications.