Wax emulsion technology has been around for decades and their manufacture is now well established. These aqueous formulations have found their way into products such as paints, coatings, inks and OPV’s, textile, flexible packaging, and wood, paper and corrugated coatings. A truly homogenized mixture can be ready-to-use and easily incorporated into other ingredients of a compatible charge by simple mixing. Their very fine particle size ensures thorough homogeneous incorporation with the other ingredients.
Certain types of waxes have been on the market and used for decades and more recently the switch to renewable, vegetable-based waxes have made their way into industry. Each type of wax has it’s own set of advantages and disadvantages. We will look at some of the properties that can influence type of wax and their formulation.
Physical characteristics of wax emulsions
The melting point.
When curing is required, the wax must have a lower melting point than the curing temperature, allowing it to melt migrate to the surface of the coating. As the coating cools the wax re-crystallize and forma a continuous film that encourages blooming.
Ideal thickness layer.
Formulators strive to use waxes that achieve a high dried wax density. To achieve this emulsion is formulated so that the particle size is a close as possible to the thickness of the coating layer. Concentrations can be adapted that utilize emulsions with a lower particle size that also can perform well if the material is formulated to achieve optimal results.
Proper pH value.
The emulsion should be within approximately one unit of the system to which it is added. Formulators can adjust the pH value of the wax emulsion by adding aqueous ammonia or acetic acid.
The choice of surfactants can also influence compatibility with the other ingredients, as well as the overall formulation stability.
Processing is Key
The order that ingredients are combined can play an important role in development of the wax emulsions, as does temperature, rate of cooling, and type of processing. Green Chem wax emulsions are homogenized and formulated and processed to achieve maximum stability.