High Cis Elastomeric Polyisobutylene HMW from Japan
High molecular weight (HMW) elastomeric polyisobutylene with high cis content, over 95% isobutylene by weight, imported as primary polymer under HTS 3902.20.10.00. Ideal for sealants, roofing membranes, and vibration dampeners due to superior elasticity. Primary form ensures classification before vulcanization.
Duty Rate — Japan → United States
12.5%
Rate breakdown
9903.05.4912.5%Except for products described in headings 9903.05.85–9903.05.92, articles the product of Japan, with an ad valorem (or ad valorem equivalent) rate of duty under column 1 less than 12.5 percent, as provided for in U.S. note 52 to this subchapter
Import Tips
• Conduct FTIR spectroscopy for customs verification of structure
• Differentiate from butyl rubber copolymers to stay in 3902
• Beware of moisture absorption affecting elasticity claims