The Universal Selection Source: Coatings Ingredients

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Selection Guide

Techno Brief: Powder Coatings

Powder coatings impart significant durability and resistance to abrasion, corrosion and chemicals in comparison to liquid coatings.  Environmental advantages have led the way for the conversion of liquid coatings to powder coatings. In this guide you will learn about advantages, disadvantages, formulation, future trends and their different end-markets applications.

Formulation

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 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 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.

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