- ▸ Hardener/crosslinker for high-durability, light-stable two-component (2K) polyurethane coatings
- ▸ Crosslinks hydroxyl acrylic and polyester resins into weatherable, chemical-resistant films
- ▸ Automotive OEM and refinish clearcoats and basecoats
- ▸ Industrial-maintenance and protective coatings
A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.
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HDI isocyanurate trimer is the most widely used light-stable PU crosslinker — the isocyanurate (trimer) of HDI, giving the highest weathering and thermal durability in two-component polyurethane coatings. Identity: CAS 28182-81-2.
What it is
HDI isocyanurate trimer (CAS 28182-81-2) is a liquid aliphatic polyisocyanate with a thermally stable isocyanurate ring core and low free-monomer content. It is the benchmark hardener for high-durability 2K PU.
How it works
Its NCO groups react with polyol hydroxyls to crosslink; the isocyanurate ring gives outstanding UV, thermal and chemical resistance and non-yellowing performance, ideal for exterior-durable coatings.
Applications
It is used as the hardener in high-durability automotive refinish and OEM, aerospace and protective polyurethane coatings, with a hydroxyl polyol. Compare HDI biuret and the low-viscosity HDI trimer.
Forms, grades and handling
Supplied as a clear liquid (often in solvent) in drums and bulk; specify NCO content and viscosity. Properties are typical reference values; the Certificate of Analysis (CoA) for the lot you buy governs. Isocyanates are moisture-sensitive and require respiratory/skin precautions; handle per the current Safety Data Sheet (SDS). Each lot ships with CoA, TDS and SDS.
Bulk supply and RFQ
RawSource sources HDI Isocyanurate Trimer Polyisocyanate direct from producers in bulk, with CoA, TDS and SDS per lot. Tell us your binder system, cure schedule and the performance you need, and we will quote the right grade. See the polyurethane catalysts guide for the catalysts that drive these reactions.
Typical Properties
Typical reference values, not a specification; the Certificate of Analysis (CoA) for the lot governs.
| Property | Typical Value |
|---|---|
| Chemical / class | Aliphatic polyisocyanate (HDI trimer) |
| Function | Light-stable PU crosslinker (high durability) |
| CAS Number | 28182-81-2 |
| Handling | Refer to the current SDS |
Regulatory & registration requirements
- TSCA (US):
- REACH (EU): Not determined from public registry
- EC number: 500-060-2
TSCA Inventory flag XU: a substance exempt from reporting under the Chemical Data Reporting Rule (40 CFR 711) (EPA flag legend).
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Frequently Asked Questions
What is HDI isocyanurate trimer used for?
HDI isocyanurate trimer (CAS 28182-81-2) is the benchmark light-stable aliphatic polyisocyanate crosslinker for high-durability two-component polyurethane coatings (automotive, aerospace, protective), giving outstanding UV, thermal and chemical resistance.
How is bulk HDI isocyanurate trimer supplied and quoted?
RawSource supplies HDI isocyanurate trimer in bulk with CoA, TDS and SDS per lot. Pricing is quote-based on grade and volume; submit an RFQ with your binder system and cure schedule.
What is the REACH and TSCA regulatory status of HDI Isocyanurate Trimer Polyisocyanate?
HDI Isocyanurate Trimer Polyisocyanate (CAS 28182-81-2) is listed as Active on the U.S. EPA TSCA Inventory; its REACH registration status is not determined from the public ECHA registry.