TGIC or HAA? A Practical Guide to Curing Systems for Outdoor Polyester Powder Coatings
Classification: Industry News
Sep 10,2026
TGIC or HAA? A Practical Guide to Curing Systems for Outdoor Polyester Powder Coatings
Chemistry, film performance and export compliance compared in one place
Outdoor polyester powder coatings need a crosslinker, and the default for decades was TGIC - triglycidyl isocyanurate. Today formulators choose between TGIC and HAA (β-hydroxyalkylamide, the "TGIC-free" chemistry), a decision that shapes film performance, labelling and market access.
Two chemistries, two behaviours
TGIC reacts its epoxy groups with the carboxyl groups of the polyester and releases no by-products, so thick films cure cleanly. HAA reacts its hydroxyl groups with the same carboxyls but releases water during cure, so thick sections need effective degassing to avoid pinholes. Both cure under typical polyester schedules of 180-200°C for 10-15 minutes.
TGIC vs HAA at a glance
Criterion | TGIC | HAA (TGIC-free) |
Chemistry | Epoxy-functional isocyanurate | Hydroxyl-functional amide |
By-product | None; thick-film friendly | Water; degassing essential |
Weathering | Excellent retention | Excellent; proven in architecture |
Regulatory | EU: toxic, mutagen cat. 2; labelling | "TGIC-free"; fewer restrictions |
Best fit | Heavy sections, thick films | European export, thin film |
Why compliance changed the conversation
TGIC is harmonised-classified in the EU as toxic and a category-2 mutagen, triggering labelling above 0.1% and practical pressure from major buyers. For exporters, "TGIC-free" has become a procurement requirement in many European and brand-led projects, while TGIC remains common, economical and technically excellent in markets without such restrictions. The right answer depends on where the coating will be sold.
A decision guide
- Exporting to Europe or supplying brand-led OEMs? Choose HAA, document the TGIC-free status and strengthen degassing in thick-film recipes.
- Coating heavy sections or thick films where a by-product-free cure matters? TGIC remains attractive where regulation allows it.
- Never dose by habit: calculate from the acid value of your polyester, then confirm with gel-time and impact trials before mass production.
Henan ICASON Chemical Co., Ltd. supplies complete TGIC and HAA curing systems for outdoor polyester powder coatings, with regulatory documentation for each export market. Contact our export team for a compliance and performance review of your recipe. |
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