The dominant overall finishing trend will continue to be replacement of liquid finishing with powder coating for environmental impact reasons
Powder coatings today
The dominant overall finishing trend will continue to be replacement of liquid finishing with powder coating for environmental impact reasons. Improvements in both coating and application technology will promote much broader powder use.
The technology improvements are driven by needs primarily in the automotive, appliance and general industrial markets. The improvements encompass raw material, coating manufacturing and application sophistication changes.
The automotive industry continues to expand powder coating from under-hood, trim and wheels to body applications. Improvements in powder coating for automotive use include clarity, adhesion, leveling and UV-resistance properties in clear coatings; lowered temperature cure without appearance and property sacrifices; and application sophistication incorporating robotics, airflow control and high transfer efficiency.
In the appliance arena, the use of precoated stock (blank and coil) offers dramatic growth potential for powder coatings. Here, powder coatings must melt, flow and level, and cure quickly (25 to 60 seconds) while retaining the aesthetic and resistance properties the appliance industry currently enjoys.
The coatings must also be post-formable with the degree of formability required being dependent on the end use. Application sophistication is also required to deposit even, thin films at line speeds of 30 to 80 fpm for blank coating and more than 100 fpm for coil coating. Again, airflow control/minimization and transfer or charging efficiency are critical.
Curing appearance-critical coatings at high line speeds is a major part of the technology improvement. Issues being addressed are matching infrared (IR) wavelength/intensity to coating and substrate; using combinations of IR, convection and induction curing to provide a rapid leveling and cure package with minimal powder surface interruption; and the overall cleanliness of the cure system.
As the automotive and appliance industries move to more sophisticated coatings and coating application systems, the need is for individual powder coatings to work with the process. This trend for designing coating and process, in concert, will continue to grow and spread to the general industrial market as applications once off-limits for powder (too many colors, too fast, too deep to penetrate and multiple coating layers) convert in growing numbers.
Other trends, influenced largely by the general industrial marketplace, are increased “stock product” offerings and greater availability of small custom batches. The proliferation of powder manufacturing equipment suppliers and the growth of raw material suppliers support the trend among regional paint suppliers to add powder manufacturing, while the maturing European market continues to provide new suppliers of both powder coatings and powder application equipment.
Overall, the increased number of suppliers will most benefit small- to medium-size powder users with price stability and greater product availability. However, the growing trend among large powder users to forge partnerships with single suppliers will continue to marry powder coating developments to the application process, as well as the end use requirements.