- ▸ Hardener component in high-solids, low-VOC two-component polyurethane coatings
- ▸ Automotive refinish and OEM clearcoats requiring gloss and UV color stability
- ▸ Industrial-maintenance and protective topcoats with abrasion and chemical resistance
- ▸ Wood and plastic coatings where low application viscosity is needed
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.
Request SDS →
HDI allophanate is a low-viscosity, light-stable PU crosslinker — an HDI allophanate polyisocyanate offering very low viscosity and good flexibility for high-solids two-component polyurethane coatings. Identity: CAS 28182-81-2.
What it is
HDI allophanate (CAS 28182-81-2) is an aliphatic HDI-based polyisocyanate with allophanate linkages, giving notably low viscosity and a more flexible network than biuret/isocyanurate.
How it works
Its NCO groups crosslink with polyol hydroxyls to a durable, non-yellowing film; the allophanate structure provides low viscosity (high-solids) and flexibility, useful where coating toughness and elongation matter.
Applications
It is used in high-solids, flexible two-component polyurethane coatings (automotive, industrial), with a hydroxyl polyol. Compare HDI trimer and HDI biuret.
Forms, grades and handling
Supplied as a clear liquid 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 Allophanate 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 allophanate) |
| Function | Light-stable PU crosslinker (low-viscosity) |
| 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 allophanate used for?
HDI allophanate (CAS 28182-81-2) is a low-viscosity, light-stable aliphatic polyisocyanate crosslinker for high-solids, flexible two-component polyurethane coatings, reacting with a hydroxyl polyol.
How is bulk HDI allophanate supplied and quoted?
RawSource supplies HDI allophanate 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 Allophanate Polyisocyanate (Low-Viscosity)?
HDI Allophanate Polyisocyanate (Low-Viscosity) (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.