Multifunctional Additive for Powder Coating Improves Dispersal During Extrusion
The polymer additive from Evonik promotes pigment wetting and reduces melt viscosity.
December 5, 2022
A new multifunctional polymer additive for powder coating formulations features easier dispersal during extrusion, according to Evonik’s Coating Additives business. Tego Powder Aid D01 achieves this by promoting pigment wetting and reducing melt viscosity, said the company.
Lower melt viscosity also leads to better degassing, which aids flow and leveling as the formulation cures and prevents the formation of pinholes in the coating, said Evonik. The polymer additive reportedly optimizes gloss development and ensures better distinctness of image (DOI) on the coating surface.
Tego Powder Aid D01 is suited both for formulations with inorganic fillers and pigments as well as organic pigments, including carbon black.
"Our new product offers a range of benefits for formulators who desire one multifunctional additive for various powder coating systems," said Maximilian Morin, who heads the Industrial & Transportation Coatings market segment. "Tego Powder Aid D01 generates a large effect in small amounts and acts as a synergist with other additives."
When the polymer additive is used with HAA curing systems for powder coatings, water is formed as a by-product. "The challenge during cross-linking is that the water needs to escape from the system. This can result in pinholes or small craters in the film," explained Bernhard Resch, a scientist in the Market Segment Industrial & Transportation Coatings. Low melt viscosity prevents this, as that improves homogenization of ingredients and leveling of the surface, according to Evonik. "Tego Powder Aid D01 prevents pinholes by increasing the degassing threshold and enables the application of thicker coating films," said Resch.
Powder coatings containing Tego Powder Aid D01 also show resistance to weathering, making the additive suitable for use in exterior applications. So-called overbake yellowing, even at elevated temperatures, is manageable, said Evonik. Because the additive imparts these properties to powder coating formulations without the use of surface-active waxes, trouble-free overcoating is possible.
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