The Role And Disadvantages Of Wax Emulsion In Water-based Coatings

The role and disadvantages of wax emulsion in water-based coatings. With the help of surfactants, the wax in the molten state is dispersed in water to make a stable emulsion. This type of product is called emulsified wax. There are many types of emulsified wax and a wide range of applications. Almost all wax products can be provided in the form of emulsions. In addition, there are various compoundings according to different needs. There are countless types of wax emulsions used on the market, and each has its own differences.

The role of wax emulsion in water-based coatings:

01 Anti-adhesion:
Wax particles are suspended in the coating in the form of solid particles, and float to the surface of the coating during the drying process to form isolation, which has a good anti-adhesion effect. In practice, factors such as the particle size, polarity, compatibility of the emulsification system, and density of wax particles of wax particles all affect the anti-adhesion of the system. In practice, we found that low melting point wax sometimes has a better anti-adhesion effect than high melting point wax.

02 Changes in surface friction coefficient:
The wear resistance and scratch resistance of the coating are related to the surface friction coefficient. Hard waxes such as polyethylene wax can reduce the coefficient of friction on the coating surface, so that when an object contacts the coating surface, the tendency to slide is greater than the tendency to scratch. For example, printing inks, wood paints, etc. require a low coefficient of friction on the coating surface to resolve external impacts to prevent scratches.

03 Wear resistance:

In addition to the coefficient of friction on the surface, the wear resistance of the coating film is also closely related to the toughness of the wax layer. Of course, the protruding thickness of the wax coating also has a great influence, which is why the wear resistance of large-particle micro-powder wax is significantly better than other wax products. However, the relationship between the particle size of the wax particle and the gloss of the coating is very large. If the gloss of the coating film is high, the particle size and particle morphology of the wax have strict requirements. To a certain extent, gloss and coating wear resistance are a contradiction.

04 Gloss adjustment:

Generally speaking, even wax emulsion will not increase the gloss of the coating in a high-gloss system, and the effect on the gloss can be ignored at most. However, in practice, wax emulsions often play a role in improving the lubricity of coatings, improving the uniformity and leveling of coatings, thereby improving the gloss of coatings. Wax with a particle size greater than 0.2um will definitely affect the gloss, and the degree of its extinction is related to the wax particle size, particle morphology, and dispersion method.

Wax emulsions, especially microemulsions, have a certain film-forming property and can form a coating on the substrate. Because wax has excellent hardness, polishability, feel, hydrophobicity, good chemical resistance and stability, and is non-toxic, coatings based on wax emulsions are often used in the fields of polishing agents, water repellents, and rust-proof coatings.

“Oil-to-water” is the top priority of the current coatings industry, but solvent-based coatings and water-based coatings have great differences in drying speed, anti-sticking, water resistance and other properties. Low molecular weight wax products can help improve the above properties. Due to the wide range of applications, performance requirements vary. It is very important for manufacturers and technicians of wax products to communicate and cooperate with downstream industries.