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Thiol-Terminated Polysulfide Prepolymer LP-3

Thiol-Terminated Polysulfide Prepolymer LP-3 is a viscous, elastomeric liquid used in aerospace sealants and coatings. Classified under HTS 3911.90.10.00 for elastomeric polysulfides in primary forms per subheading rules on polymer content. Its mercaptan-terminated structure provides elasticity for high-performance applications.

Import Duty Rates by Country of Origin

Origin CountryMFN RateCh.99 SurchargesTotal Effective Rate
🇨🇳ChinaFree+37.5%37.5%
🇲🇽MexicoFree+10.0%10%
🇨🇦CanadaFree+10.0%10%
🇩🇪GermanyFree+10.0%10%
🇯🇵JapanFree+12.5%12.5%

Alternative Classifications

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

3907.99Lower: 19% vs 37.5%

If chemically modified with significant silane additives

Modified polymers not specifically covered go to 'Other' in 3907 series for polysiloxanes or derivatives.

3910.00.00Higher: 40.5% vs 37.5%

If for silicone-based elastomers

Silicones are distinctly classified in 3910, separate from polysulfides in 3911.

4006.90Lower: 15.2% vs 37.5%

If imported as unvulcanized rubber compound

Compounded with fillers or vulcanizing agents, it becomes Chapter 40 unvulcanized rubber.

Not sure which classification is right?

The Tariff Assistant works through the GRI rules on your specific product to reach the right HTS code — and can price the duty on it in the same conversation.

Import Tips & Compliance

• Submit technical data sheets proving >95% polysulfide monomer content to qualify under 3911.90.10

• Avoid misdeclaration as rubber by confirming it's unvulcanized primary form, not Chapter 40 material