High Cis Elastomeric Polyisobutylene HMW from Canada
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 — Canada → United States
10%
Rate breakdown
9903.05.2910%Section 301 (forced labor) — additional 10% ad valorem on products of Canada
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