The appeal of powder coatings extends beyond excellent mechanical properties like durability, hardness and abrasion resistance. Operators are increasingly choosing powder coatings to minimize their carbon footprint, as these coatings are generally formulated without solvents that release volatile organic compounds (VOCs) during the curing process.
The Advantages of Low-Bake Powder Coatings
The introduction of low-bake powder formulations that require less heat to cure further enhances this technology’s sustainable advantages*. These versatile coatings are being adopted globally for a wide range of applications that range from construction machinery to office furniture.
Understanding the Low-Bake Difference
While high-quality polymers, pigments and additives are essential components of powder coatings, proper curing is crucial for optimal UV protection, chemical and corrosion resistance and aesthetics.
Curing transforms paint particles into a hard, durable finish that bonds with the substrate. Although curing requirements vary by chemistry and formulation, most industrial powder coatings require thermal heat to initiate this cross-linking chemical reaction.
Conventional powder coatings typically require curing temperatures between 325° Fahrenheit (°F) to 400°F (163° to 204° Celsius). In contrast, advanced low-bake powder formulations cure at significantly lower temperatures, ranging from 250°F to 325°F (121°C to 163°C), resulting in significant energy savings.
Expanding Application Possibilities
Beyond energy efficiency, the reduced oven temperatures have made powder coatings a suitable solution for previously challenging substrates like heat-sensitive plastic, wood and wood composites.
Although powder coatings were initially developed in the 1940s for metal, their use on higher density metals is far more recent. Thicker, heavier metals often present challenges in achieving uniform temperatures necessary for optimal adhesion and finish quality. Low-cure powder coatings facilitate even heating across varying thicknesses, enhancing efficiency and preserving structural integrity by minimizing the risk of thermal stress that can warp or distort metal components. Additionally, low-bake powder coatings also offer a wider curing window which improves process stability by optimizing curing at a broader temperature range. This feature reduces the risk of over- or under-baking on parts with divergent densities, ensuring consistent quality.
Accelerating Production Cycles
Speed-curing capabilities are another significant advantage driving the adoption of low-bake powder formulations. Many of these coatings cure up to 25% faster than conventional powder systems and require less cooling time. The result is faster production cycles, a benefit of particular importance for high-volume operators.
Some low-bake powder formulations can be cured at ultra-low temperatures. Solutions like PPG's ENVIROCRON® Low Bake powder coatings can cure at temperatures 20°C to 40°C lower than traditional powder coatings, around 250–260°F (121–127°C), helping to further reduce energy costs and CO2 emissions.
PPG’s low bake powder portfolio includes a variety of chemistries including epoxy, epoxy-polyester, as well as standard and ultradurable polyesters.
PPG’s Low-Bake Portfolio
The company recently introduced a low-bake portfolio for customers throughout Europe:
In the U.S., PPG introduced ENVIROCRON® HEATSENSE™ powder coating in 2020, specifically designed for heat-sensitive wood and wood-composite applications, such as medium-density fiberboard (MDF), hardwood and plywood and dense heavy metals. Since then, PPG has continued to invest in research and development to expand its global low-bake powder portfolio.
Key Benefits of Low-Bake Powder Coatings
- Energy Efficiency: These coatings cure at lower temperatures, reducing energy consumption and costs associated with the curing process.
- Improved Productivity: Faster curing and cooling times can enhance productivity by allowing for quicker turnaround and increased throughput.
- Environmental Benefits: Lower curing temperatures result in reduced CO2 emissions, contributing to a lower carbon footprint.
- Versatility: Lower temperatures make powder coating viable for heat-sensitive and high-density substrates.
- Process Stability: Wide curing windows reduce the risk of over- or undertaking.
- Fewer defects: Low-cure powders resist blooming, even on dark colors, reducing the need for rework.
Low-bake powder coatings represent a significant advancement in coating technology, offering numerous benefits that enhance efficiency, sustainability and application versatility.
*Sustainably advantaged products are identified using PPG's internal methodology that validates product attributes and their contribution towards the UN Sustainable Development Goals.