Powder coating is a new type of pure solid powder coating without solvent. It has the characteristics of non-solvent, non-polluting, saving energy and resources, reducing labor intensity and high coating mechanical strength. Powder coatings are mainly divided into two categories: thermoplastic powder coatings and thermosetting powder coatings. In the past 10 years, the development of powder coatings in the world has been very fast, with an average annual growth rate of 8%-15%, which is a very promising industry.

However, powder coatings have their particularities compared to liquid coatings. This special property is also reflected in the selection of pigments and fillers. Here we briefly introduce you to the basic knowledge of the use of pigments and fillers in powder coatings:

Filler selection

Adding a certain amount of filler to the powder coating can increase the hardness of the coating and other mechanical properties, and can reduce the cost, which is an effective way to adjust the cost of powder coatings.

The pigments and fillers used in powder coatings are mainly barium sulfate and titanium dioxide, while bentonite, talc, quartz powder, etc. can be regarded as functional fillers, and the overall amount is very small.

There are also two types of barium sulfate: precipitation type and barite type. The former is made by chemical reaction, and the latter is made by grinding natural barite.

The issues that should be paid attention to when choosing fillers are:

The whiteness of the filler should be high, which can reduce the amount of titanium dioxide.

There should be less impurities. Taking into account the particularity of the powder coating process, more impurities in the filler will affect the surface decoration of the coating film (the coating surface has more particles and poor leveling). Do not choose fillers with too coarse particle size, because they are not easy to disperse and wear to the screw. The filler should be loose, not agglomerated, and the water content should be low.