The Case for Beta-HAA-Cure Polyester Powders
Posted on Tuesday, September 1, 2026
In North America, beta-hydroxyalkylamide (ß-HAA) or triglycidyl isocyanurate (TGIC)-free polyester powder coatings are increasing in popularity at a significantly faster rate than TGIC polyesters. Right now, depending on the market segment and source, ß-HAA cured polyesters hold 6% to 15% of the total exterior polyester market compared to TGIC-cured polyesters. The reasons that ß-HAA systems are taking volume away from TGIC are primarily regulatory and, to a much smaller extent, the perception that ß-HAA powders have superior application properties.
In the 1990s, European companies started to phase out the use of TGIC-containing polyesters because toxicology tests indicated that TGIC posed a danger to workers. Specifically, TGIC has been classified under the European Union's Classification, Labelling and Packaging (CLP) regulations as Mutagen Category 1B H340, meaning it might cause genetic defects. TGIC was identified as a Substance of Very High Concern (SVHC), and in 2012 was included on the candidate list. Everyone from formulators and plant workers to transport personnel, applicators and disposal workers had to be protected from contact with TGIC. With the resulting hazardous labeling, alternatives to TGIC polyesters were developed and promoted. Polyester resins cured with ß-HAA quickly gained acceptance because their hazard labeling was relatively mild, consisting primarily of nuisance dust.
Carboxy-functional polyester resins cured with TGIC had already set the standards for appearance, durability, mechanical properties and substrate protection. ß-HAA cured polyesters were successfully designed by companies like Syntech (now Synthomer), DSM (now Covestro) and Cytec (now Allnex) to meet the same standards. Initially, ß-HAA-cured polyester powder coatings had limitations on film thickness because their curing reaction produces water. If the water could not escape the melting film fast enough, pinholes became trapped in the coating, leading to appearance and corrosion resistance problems. However, Synthomer and others designed resins that allow the water to escape more efficiently. By engineering polyester resins with optimized reactivity profiles and tailored melt viscosities, entrapped water is released before the film immobilizes, allowing the vapor paths to heal completely and extending pinhole-free film thickness well beyond 4 to 5 mils.
Because of the mass production of TGIC in China, the initial cost of TGIC formulations was lower than that of the redesigned ß-HAA polyester systems. However, several powder coating manufacturers have reported that ß-HAA systems provide slightly better application properties, including transfer efficiency and reduced Faraday cage effects, bringing the cost-in-use of the two systems very close. The advantages also depend upon formulation and application processes.
Using the appropriate ß-HAA polyester resin system, it is possible to design a polyester powder coating that meets all the characteristics normally found in TGIC polyester systems. Low-temperature cure ß-HAA coating powders, such as Synthomer's Albecor line, cure at very low temperatures, enabling their use on MDF, TPOs and temperature-sensitive metal alloys. Low-temperature cure also allows production lines to operate at higher speeds for increased throughput and supports fast-cure formulations where coatings are melted and cured by residual induction heat. Other products easily meet or exceed AAMA 2605 durability standards. Another important product category includes low-gloss finishes ranging from near-zero matte to 60 GU (60°). Careful selection of polyester resins and additives gives formulators a wide range of gloss options.
The prognosis for TGIC in Europe is that it will remain under regulatory scrutiny as a hazardous material. In the United States, although the Environmental Protection Agency (EPA) and Occupational Safety and Health Administration (OSHA) are aware of Europe's position, the EPA has not designated TGIC as a TSCA High-Priority Substance or initiated a formal TSCA risk evaluation. For the immediate future, there is no indication of imminent regulatory action. However, Canada is generally more influenced by the European regulatory environment, and CLP restrictions could eventually emerge there. Individual U.S. states could also establish independent guidelines. At present, multinational OEMs remain the primary driver of ß-HAA adoption in North America, and that is unlikely to change.
Beyond regulatory considerations, many multinational OEMs increasingly favor ß-HAA technologies because they provide comparable coating performance while avoiding the hazard classifications associated with TGIC. As a result, ß-HAA systems often offer a simpler sustainability narrative.
Frederick Cummings is Technical Service Sr. Manager, North America, at Synthomer plc, Polyester Powder Coating Resins.