Pigments for Powder Coatings
ECKART is a global supplier of Pigments for Powder Coatings. This technology is very efficient since over 98% of the powder coating actually becomes applied to the substrate. Powder coatings exhibit excellent surface quality
They are more cost efficient and have higher manufacturing productivity in comparison to other coating technologies. Together with the need for more environmentally friendly paint systems a trend towards highly aesthetic coatings exists, especially concerning color and effect.
Contact Powder Coating
There are two main pigment categories, leafing and non-leafing pigments.
Leafing Pigments for Powder Coatings
Leafing pigments will not be wetted by the powder coating thus they will orientate on top of the coating surface. Due to these orientation properties leafing pigments will lead to highly brilliant and even chrome like finishes when used in powder coatings. Along with the superior optical performance there comes also the disadvantage of little resistance to mechanical and chemical stress. In many cases a protective top coat is required.
The non-leafing pigments are well embedded into the matrix of the powder coating film which gives an additional barrier effect providing further protection for the pigments against mechanical and chemical influences. Compared to leafing pigments the metallic effect is reduced and less brilliant.
Metallic Powder Coatings
Metallic Powder coatings containing non-leafing aluminum pigments are showing significantly better resistance to mechanical strength, and against corrosive chemicals, compared to powder coatings containing leafing aluminum pigments.
There are different pigment categories of non-leafing pigments available to meet different requirements:
- Superior pigment category: PCUplus
- Ultra-high-performance pigment category: PCU
- High-performance pigment category: PCS
- Standard pigment category: PCR and PCA
Each pigment category includes pigment grades of different particle sizes, providing a variety of optical effects, ranging from crystalline sparkle to silky gloss (see diagram below).
The resistance qualities play a major role when choosing the right pigment for powder coatings. Depending on the field of application, ECKART provides the customer different grades of resistance.
Due to the barrier effect of the chemical coating, pigments in the “Standard” category provide a certain measure of protection against corrosive chemicals. Depending on the type fineness, these products can also be used in outdoor applications; however, they must be appropriately tested for their suitability for the intended end application.
- Leafing: Define Leafing Pigment for Powder Coating
- Non-Leafing: Define Non-leafing Pigment for Powder Coating
Compared to the “Standard” series, this pigment category provides a more complete and stable surface coating. The pigments thus show greater chemical stability.
The products of this category are non-leafing aluminum and pearlescent pigments, which show an extremely high chemical resistance.
Stable, more stable, STANDART® PCUplus 800 - their maximum resistance to chemicals is indisputably the one characteristic that makes our new non-leafing pigments for powder coatings so globally unique.
Numerous tests with mortars and chemicals prove it: STANDART® PCUplus 800 effortlessly withstands even very aggressive strains. In comparison, STANDART® PCUplus 800 shows no or hardly any detectable color changes under high chemical strain.
In spite of its fineness, STANDART® PCUplus 800 is as stable as our highly resistant, coarser pigments of the STANDART® PCU series.
STARBONDING is the perfect way to manufacture high-quality metallic and pearlescent effect powder coatings. As our partner you supply the basic powder coating to us as pre-material.
With the STARBONDING method, ECKART transforms your basic powder coatings into bonded powder coatings using metallic and / or pearlescent effect pigments.
The defined method of the thermo-mechanical process of STARBONDING provides powder coatings in which the platelet effect pigments are perfectly fixed on the surfaces of the spherical particles of the basic powder coating.
The most important benefits for your customers are: unlike the dry-blending method, this process enables bonded powder coatings to be reliably applied.
ECKART STARBONDING locations:
- for Europe at the main facility in Hartenstein, Germany
- for North America at the production site in Painesville, Ohio, USA
Define Zinc Pigments for Powder Coatings
STANDART® Zinc Flake AT and STANDART® Zinc Flake GTT are platelet pigments consisting of metallic zinc, providing excellent corrosion protection properties for powder coating primers.
Apart from offering cathodic corrosion protection, they provide – due to their lamellar structure – an additional barrier effect in the powder coating film, resulting in a significantly reduced permeability to corrosive agents.
For formulating powder coating primers the platelet zinc pigments Zinc Flake AT and Zinc Flake GTT are normally combined with other anti-corrosive pigments. Particularly combinations with other platelet substrates (e. g. with micaceous iron or aluminum pigments) as well as with spherical inorganic or metallic substances such as iron/zinc phosphates (silicates or zirconates) or zinc dust have been successfully proved in practice.
For the production of zinc-based powder coating primers, Zinc Flake AT or Zinc Flake GTT (10%–15%) are added with the other anti-corrosive pigments (40%– 60%) at the premix stage, followed by extruding, grinding and sieving.
Safety When Handling
In principle, powder coatings present less of a safety risk than conventional wet paint systems do. Compared to solvent vapour/air mixtures, a powder/air mixture requires 50 to 100 times more energy for ignition. Although all flammable powders or dusts which form explosive mixtures with air are potential hazard sources, they may be transported, stored and processed safely if the appropriate requirements are taken into consideration and the relevant safety measures are met.
The minimum ignition energy of aluminium pigments depends significantly on the specific surface area of the pigment particles and on their degree of fineness. Especially fine aluminium pigments (average particle size <10µm) partially display a very low minimum ignition energy of less than 1mJ.
In order to enure safe handling of aluminium pigment powders, is is very important to follow the relevant safety measures from the initial production stage to the final processing step of the aluminium pigmented metallic powder coatings (we would ask you to have a look at the recommendations from ECKART and GDA).