Formulators Forum—The Movement Towards PTFE-free Powder Coatings
Posted on Thursday, June 27, 2024
Powder coated surfaces are ubiquitous in our everyday lives, from household appliances to office furniture to automotive parts. The textured finish of powder coated surfaces not only enhances aesthetic appeal but also improves scratch resistance and grip. Traditionally, powder coating formulators have relied on polytetrafluoroethylene (PTFE) additives to impart texture. However, growing concerns around PTFE compounds have spurred innovation of PTFE-free alternatives.
How Do Texturing Agents Work?
Texturing agents are polymeric additives introduced into powder coating formulations. As the powder coating cures and flows during application, these additives rise to the surface while increasing the surface area, almost inflating, creating microscopic peaks and valleys that scatter light. Lower additive levels result in glossier finishes, while higher percentages create matte, textured surfaces with higher roughness. Unbalanced dosing can lead to bad flowability and disturbed film formation during curing, which can result in poor appearance and performance. Thus, properly dosed, PTFE has been the industry standard due to its efficiency and broad compatibility across various resin chemistries.
Why PTFE-free?
PTFE-containing additives have come under scrutiny due to their persistence, bioaccumulation potential, and toxicity concerns. Regulatory and consumer pressure have pushed formulators to develop effective substitutes that meet stringent health, safety, and environmental standards. Major powder coating producers have launched initiatives to eliminate PTFE compounds from their offerings. Developing reliable PTFE- free texturing additives has been a key focus area.
Advancements in PTFE-free Additives
Progress is being made in the development of additives that can achieve the performance levels of PTFE-additives. An example is Clariant’s Ceridust® 8170 M, a special PTFE- free wax compound that allows adjustment of surface gloss through variable dosing. Quantitative analysis shows the new additive can match and even exceed the performance of PTFE texturing agents. As illustrated in Figure 1, inclusion of 6% of the PTFE-free additive in black polyester powder coating systems yielded equivalent or lower gloss values compared to 1% PTFE additive, along with comparable surface roughness.
Achieving this performance will require other adjustments to the formulation depending on the final requirements of the powder producer. These requirements are often unique from application to application, and formulation assistance may be required to achieve the desired system performance.
Lab testing also demonstrated enhanced flow and reduced extrusion pressure compared to PTFE benchmarks. Adjustability and compatibility across multiple resin types and elimination of PTFE make the new additive an appealing option for formulators aiming to develop sustainable and high-performing powder coatings.
What’s Next?
The powder coating industry must adopt new technologies, and market forces are accelerating the transition away from PTFE. Continued innovation and testing will be critical for developing effective alternatives that meet performance requirements across diverse applications—from pipelines to auto parts to aluminum extrusions. The recently developed PTFE-free additive represents an early success, but more work is needed to replace PTFE compounds broadly. Collaboration between resin producers, additive suppliers, powder coatings producers, equipment manufacturers, and end users will pave the path to viable and sustainable PTFE-free powder coating solutions.
Tobias Niederleitner is head of marketing–coatings & inks, BU adsorbents & additives, for Clariant.