Mechanisms of Wax Action
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
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".