Chlorobutyl Rubber (CIIR) from Canada
Chlorinated isobutylene-isoprene rubber (CIIR) in primary pellet or bale form, where chlorinated monomer units predominate >95% by weight. Widely used in tire inner liners and pharmaceutical stoppers for air impermeability. Classified in 3911.90.70.00 as chlorinated synthetic rubber.
Duty Rate — Canada → United States
10%
Rate breakdown
9903.05.2910%Except for products described in headings 9903.05.85–9903.05.93, articles the product of Canada, as provided for in U.S. note 52 to this subchapter
Import Tips
• Include monomer weight breakdown certificate to satisfy note (a)(1) 'poly' designation rules
• Label as 'primary form' explicitly; compounded versions risk moving to 3926.90
• Avoid misdeclaration as regular butyl (4002.31); chlorination shifts to Chapter 39