Innovation Hotspots in Powder Coatings

While trends in technology areas such as powder coatings don’t change significantly from year to year, as topics such as low-temperature-cure and sustainability would top this list every edition, it is always interesting to discuss where powder coating companies and raw material suppliers are actively innovating. That is not to say that topics such as low-temperature-cure powder coating are not being worked on, but this article will discuss areas where there continues to be movement in a significant manner.

Of interest here are the areas where companies playing catch-up are asking a lot of questions at conferences, while those at the forefront of technology are giving just enough information to let everyone know they are the technology leaders. Three such technology areas are improved aesthetics, dielectric powder coatings, and PFAS-free materials.

Improving aesthetics in powder coatings remains an active area of research, especially in architectural coatings, where powder coatings continue to compete with liquid coatings for market share. While powder coatings excel in several areas, such as single-coat, direct-to-metal applications and environmental profile, they still lag behind liquid coating in some aesthetic categories, including smoothness, gloss range, and metallic finishes.

Smoothness is directly related to film build, so improving smoothness requires doing so at increasingly lower film builds. This is important because the single factor that most inhibits powder coatings in an as-applied cost comparison is the need to be applied at higher film build, which is required to achieve a smooth coating with adequate coverage and hiding. However, developing smoother powder coatings is not as straightforward as it may seem at first glance.

Modifying the binder by lowering the glass transition temperature (T_g) will result in improved flow, but it often creates challenges with powder processing and storage stability. As a result, formulators go well beyond working with lower T_g materials and consider options such as crystallinity, hybrid materials, and additives to improve processing and storage stability without negatively affecting flow during the curing cycle.

Gloss range is another area where powder coatings continue to improve. Gloss control in powder coatings is not as straightforward as it is in liquid coatings. Rather than relying on large-particle-size extender pigments to reduce gloss, powder coatings must use techniques such as controlled incompatibility and differential cure. (This is a highly complex topic that will not be discussed in detail here.) Over the past several years, powder coating companies have continued to develop methods of expanding the achievable gloss range, even in the extremely challenging AAMA 2605 space, and now rival the gloss range available with liquid coatings in most applications.

Finally, we are seeing continued improvement in metallic finishes. Powder coatings have historically struggled with the dispersion and orientation of metallic pigments needed to create a bright, uniform appearance. To address this challenge, the industry relies on a process known as metallic bonding, in which a polymer matrix, metallic pigment, and additives are combined using specialized mixing equipment prior to being dry-blended into the finished powder coating.

Many powder coating companies use third parties to perform this process, but those at the forefront of the technology conduct the metallic bonding in-house and keep the details of both the formulation and process very close to the vest. These companies understand that architects and brand owners are looking for a consistent, bright metallic appearance that creates a sense of depth, and they market their products accordingly.

As powder coating companies continue to improve smoothness, gloss range capability, and metallic appearance, they will increasingly take market share from liquid coatings in decorative applications over metal substrates. While a rising tide may lift all boats, the companies that can deliver superior aesthetics without sacrificing the durability and environmental profile that powder coatings are known for will ultimately rise to the top.

The electrification trend is transforming coating requirements in a variety of ways, but the topic most frequently discussed with respect to powder coatings is the need for dielectric coatings that provide electrical insulation. From hairpin stators in electric motors to data centers, powder coatings are increasingly being used to isolate conductive components and prevent the flow of electricity between them.

Powder coatings perform particularly well in these types of applications because they can be applied at high film builds in a single coat, offer excellent dielectric performance, and protect substrates in extremely harsh environments. Additionally, powders can be formulated to provide thermal conductivity without compromising their ability to electrically insulate the substrate. The balance of these properties is becoming increasingly important as electronic components become more compact and power densities continue to increase.

In powder coatings, PFAS-containing materials typically fall into two main categories: resins used to achieve the exterior durability required for AAMA 2605-compliant architectural coatings and additives used to impart specific properties to the coating. While significant effort is being directed toward replacing the fluoropolymer resins used in architectural coatings, a high level of uncertainty remains regarding whether equivalent long-term performance can be achieved with alternative chemistries.

The additive side of the equation is moving much more quickly and has become a highly active area of product development, however. PFAS-containing additives, most often PTFE, have been used in powder coatings for many years to improve scratch and mar resistance or to create textured finishes. Replacement materials for scratch and mar resistance are relatively well understood, although their usage often results in some reduction in performance compared to PTFE-containing systems.

That said, replacement of the texturizing additives has proven to be quite challenging. The tight sand texture produced by the PTFE-based additives has been difficult to replicate with alternative materials and remains an active area of research. Raw material suppliers have introduced several new technologies that do a relatively good job of recreating the desired texture, but achieving a matte finish while maintaining a tight, consistent texture can still be difficult with some of the commercially available alternatives. As a result, powder coating manufacturers continue to work closely with raw material suppliers to fine-tune these systems.

While many of the industry’s long-term priorities remain relatively unchanged, the areas where companies are investing their R&D resources provide insight into where differentiation is occurring. Whether it is improve aesthetics to compete more effectively with liquid coatings, developing dielectric coatings for emerging electrification markets, or eliminating PFAS without sacrificing performance and appearance, these are the areas where innovation is actively shaping the next generation of powder coating materials.

Read in CoatingsTech.

How can we help you? Let’s start talking: https://chemquest.com/lets-start-talking/