 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.
Resins
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 center.
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 alkyl esters.
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. |
