HDI Biuret Trimer (Desmodur N 100)

HDI Biuret trimer is a high-functionality polyisocyanate derived from 1,6-hexamethylene diisocyanate, containing residual monomeric HDI (<0.25%). It qualifies under HTS 2929.10.3500 as an isocyanate per Chapter notes allowing derivatives of listed compounds. Primarily used as crosslinking agent in durable industrial coatings.

Import Duty Rates by Country of Origin

Origin CountryMFN RateCh.99 SurchargesTotal Effective Rate
🇨🇳China6.5%+35.0%41.5%
🇲🇽Mexico6.5%+10.0%16.5%
🇨🇦Canada6.5%+10.0%16.5%
🇩🇪Germany6.5%+10.0%16.5%
🇯🇵Japan6.5%+10.0%16.5%

Alternative Classifications

This product could be classified differently depending on its characteristics or intended use.

3824.99Lower: 15% vs 41.5%

If diluted in >30% solvent for spray application rather than pure reactive form

Chapter note (e) excludes solutions 'particularly suitable for specific use' from Chapter 29

3909.50.50.00Lower: 41.3% vs 41.5%

If polymerized beyond reactive isocyanate stage into polyurethane polyisocyanate resin

Advanced polymerization changes from low-MW isocyanate (2929) to polymer (Ch.39)

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Import Tips & Compliance

Provide analytical certificate showing NCO content (typically 21-22%) and residual monomer <0.3% to confirm isocyanate identity

Moisture exclusion critical—use nitrogen-blanketed containers to prevent gelling during ocean transit

Avoid classification disputes by documenting it's not a 'finished coating' (3208/3209) but reactive intermediate