There are various factors that impact the performance of powder coatings, like the molecular weight distribution of the resin particles, surface modifications of various kinds of fillers, and the purity and chemical properties of the ingredients.
Excluding such factors, the particle size and shape of the powder are also some of the main parameters that contribute to the determination of powder coating’s final mechanical properties. In particular, the flowability, gloss, utilization rate, and adhesion properties of powder coating will be altered by changing the size and shape of the powder.
Hence, it is vital to regulate the size and shape of the particle in optimal ranges across the entire production process to improve the final mechanical performance of the powder coating.
This article concentrates on the main production processes of powder coating and explores how such processes tend to impact the size and shape of powder particles and ultimately the final performance of the product.
The Melting and Mixing of Fillers and Resin
As the first step of the powder coating production process, the melting and mixing of fillers and resin are considered to be the basis of the mechanical properties of the coating.
In this step, one of the biggest challenges involves making a uniformly dispersed mixture of resin and fillers. This hugely relies on the particle size distribution. To examine the relationship between the particle size and the mixing quality, two kinds of titanium dioxide used as fillers are characterized.
As noted in Figure 1, Titanium Dioxide B’s particle size was considerably smaller than that of Titanium Dioxide A, and thus must be, theoretically, more evenly mixed than Titanium Dioxide A. But in practice, it was harder to evenly mix B than A.
