Mechanisms of Wax Action

The Blooming Mechanism

Molten wax particles float (or bloom) to the surface. The coating cools and re-crystallization of wax particles takes place, forming a thin but continuous wax-enriched surface layer. Generally, the softer the wax or lower the melting point, the more predominant the blooming mechanism becomes. The compatibility between the wax emulsion and other formulation components determines the wax migration rate (see figure 1).

Figure 1: Blooming Mechanism

The Ball Bearing Mechanism

In this case, solid wax particles migrate individually or protrude through to the surface.

By protruding slightly above the coating surface like ping-pong balls floating on a pool of water, they act as a physical spacer and prevent another surface from coming into close contact. Hard and high melting point waxes (HDPE, PTFE) operate using this mechanism under certain conditions. Both the particle density and the extent of protrusion influence the magnitude of the effect (see figure 2).

Figure 2: Ball Bearing Mechanism

Once at the surface, the layer of wax particles has the ability to modify the Coefficient of Friction (CoF) of the substrate, imparting the desired characteristics. This explains why waxes are often classified as "Surface Conditioner Additives".