As with any coating,
formulation variables are critical to the processing and performance characteristics.
The powder coating formulation is much like a liquid coating formulation except
that most of the components are in solid, melt processable form. The main raw material
components used in powder coatings are described below.
are the key component of powder
coatings; the range of resins used is increasing steadily in an attempt to meet
the more demanding needs of new market sectors.
For more information on resins, please visit the
major resin types
section of our powder coating techno brief.
Curing agents are used according to
the type of resin system employed and the final properties required of the coating.
Accelerators are used to increase
the cure reaction rate.
Pigments are generally solid particulate
materials such as titanium dioxide or carbon black.
Fillers are used to reduce the cost
of the coating formulation and / or to improve specific properties such as flow,
surface texture, lubricity, etc. Common fillers are barytes, calcite, mica, talc,
whiting, and wollastonite.
Extenders, such as aluminum silicate,
are used to provide opacity and act as a filler.
Degassing agents are particularly
important in low-bake systems. They are used to eliminate / dissipate gas bubbles
that may cause film porosity and embrittlement or poor finish.
Dry Flow agents improve the free flow
of powders within the production delivery systems.
Flow agents enhance film properties
and minimize / eliminate surface defects by improving the flow of the molten coating.
Examples of flow agents include polyacrylates, silicones, surfactants, and fluorinated
Matting agents are used to reduce
the gloss of the cured film.
Texturing agents are used to control
/ enhance the gloss level of cured films.
Rheological additives provide viscosity
control to molten coatings for improved edge coverage or for textured surface effects.
Waxes are added to the formulation
to provide slip, hardness, scratch and mar resistance, and to act as free flow powders
and anti-bridging agents in processing.