In fact, these foams are mainly caused by mixing, equipment, added additives, raw materials and other reasons. If these foams are not treated, it will have an impact on the quality, appearance, cost, and canning of the product.                   There are two major types of water-based paints: emulsion paints and water-soluble paints. There are three main types of wax emulsion for paints: vinyl acetate, butylbenzene and acrylic acid, which are made by adding pigment paste to the emulsion after polymerization. In the process of stirring and blending often violent foaming. Foaming causes volume expansion, which reduces the utilization of the blending equipment. Foaming limits the stirring speed and prolongs the blending time, and also makes the pigment and filler not fully wetted. After blending and production, it can be injected into the packaging barrel, the continuous injection line is by volume rather than by weight, foaming makes the barrel can not be filled, and because the foam is gradually bursting, and will make the weight injected into the barrel uneven, interfering with continuous packaging. Emulsion paint in use, foam will cause surface defects, such as traps in the coating film. For example, there are traps in the coating film, i.e. the bubbles will be broken only when the paint is dry and the film is formed, making small holes or called fish eyes in the coating.