Water is colorless, transparent, odorless, non-toxic and harmless, and is ubiquitous. The freezing point is 0 and the boiling point is 100, so water-based paints should be kept above 0. Water, chemically stable, non-flammable and non-explosive, so water-based coatings are non-dangerous goods, and the production, storage, and transportation processes are very safe.
According to the paint manufacturer, according to the similar compatibility principle, the binder and pigment and filler as the basic components of the paint are emulsified and dispersed in water with the help of emulsifier and dispersant respectively. Emulsifiers are also called surfactants. One end of the molecular chain is polar and the other end is non-polar. The film-forming substances are often organic polymer materials, which exist in the micelles formed by surfactants after emulsification, and are isolated from each other by the protection of the electric double layer or steric hindrance, so as to be stably suspended in water.
According to the paint manufacturer, the pigments and fillers of the paint are adsorbed on the surface of the pigments and fillers by the negatively charged dispersant to form a dispersion of pigments and fillers, which exists in water. Such dispersants may be inorganic salts such as some metaphosphates. Modern coating production often uses polymeric dispersants, such as the sodium or ammonium salts of polyacrylic acid.
Water-based coatings have become the new favorite in the current furniture industry, and are closely related to water. The feature is that water replaces the organic solvent in oil-based coatings as a dispersion medium. Compared with oil-based paint, it does not use organic solvents and does not contain harmful substances such as benzene, toluene, xylene, and formaldehyde. Non-toxic and non-irritating odor, saving resources, more environmentally friendly.
Paint manufacturers said that the water used for water-based paint is not tap water in the general sense. It is the deionized water obtained after special treatment. The basic requirement is that it is clean and free of mechanical impurities. Commonly contained calcium and magnesium plasma will affect the stability of the paint liquid and bath paint in the electrophoretic paint. It also contains bacteria and microorganisms, which will affect the quality stability of coating products, but deionized water requires professional equipment operation, so it will generate more production costs.
But in general, paint manufacturers point out that deionized water is still much cheaper than organic solvents. Coatings consist of resins, pigments, fillers, additives and solvents. With the decrease of water content, the arrangement of discrete latex particles becomes more compact from evacuation. Under the action of capillary pressure and surface tension, the latex particles are squeezed and deformed, and the latex particles diffuse each other to form a film. Volatilization is the key but not the only factor, such as whether the volatilization is orderly or complete, has a very important influence on the film-forming quality of water-based coatings. The film formation can not only consider the coating itself, but also consider the type of furniture substrate, coating method, coating equipment, drying method and other factors, in order to give full play to the performance and achieve excellent surface coating effect.
