Polymers & Resins Available — Bulk Only

HDI Isocyanurate Trimer Polyisocyanate

CAS 28182-81-2

HDI isocyanurate trimer is a low-monomer aliphatic polyisocyanate resin built on the thermally stable isocyanurate (trimer) ring of hexamethylene diisocyanate (HDI). It is used as the hardener in two-component polyurethane coatings requiring high durability and light stability

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CAS Number
28182-81-2
Material Family
Polymers & Resins
At a Glance
Material Family
Polymers & Resins
Record Type
Polymer fluid
Primary Role
Crosslinking / Curing
Functional Roles
Applications & Use Cases
  • 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
Safety & Handling
Full SDS available on request

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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Chemical Identity
CAS Number
28182-81-2
Synonyms & Trade Names
HDI trimer HDI isocyanurate hexamethylene diisocyanate isocyanurate trimer HDI homopolymer (isocyanurate) aliphatic polyisocyanate hardener Comparable to Desmodur N3300 / N3390 Comparable to Tolonate HDT Comparable to Duranate TPA-100
Full Description

The isocyanurate ring gives this HDI polyisocyanate strong thermal and hydrolytic stability, and crosslinking it with hydroxyl-functional acrylic or polyester resins produces 2K polyurethane films with excellent light stability, weathering performance and chemical resistance. It is a workhorse hardener for automotive OEM and refinish clearcoats and basecoats, industrial-maintenance systems and protective coatings. Compared with the biuret grade, the trimer typically offers higher functionality and improved hardness and weatherability. RawSource supplies HDI isocyanurate-trimer polyisocyanate in bulk to coating and CASE formulators

Comparable to Desmodur N3300: RawSource supplies this as an independent equivalent (an offset) to Desmodur N3300 — it is an HDI isocyanurate trimer polyisocyanate hardener. It is not genuine Desmodur N3300-branded material, and RawSource is not affiliated with, authorized by, or endorsed by Covestro.

Desmodur N3300 is a registered trademark of Covestro, used here solely for nominative comparison to identify the equivalent grade. RawSource supplies an independent equivalent product; confirm equivalence against your specification and the Certificate of Analysis.

Disclaimer. Information on this page — including properties, identifiers, hazard, transport (DOT/UN) and tariff (HS) classifications, and applications — is provided for general reference and is compiled from authoritative public sources (e.g. PubChem/ECHA, 49 CFR 172.101, the Harmonized Tariff Schedule). Values are typical and are not a guaranteed specification; the Certificate of Analysis (CoA) for the lot purchased governs. Products are sold for industrial and professional use only. Nothing here is a medical, health, or efficacy claim or advice. Always consult the current Safety Data Sheet (SDS) before handling, storage, transport or disposal, and confirm regulatory status, classification and suitability for your application and jurisdiction. Hazard, transport and tariff classifications must be verified for your specific shipment. RawSource makes no warranty, express or implied, and assumes no liability for use of this information. Trademarks. Third-party trademarks and brand names are the property of their respective owners; any reference is nominative — used only to identify a comparable product — and does not imply affiliation with, sponsorship by, or endorsement by the trademark owner.