Chlorobutyl Rubber (CIIR) from China
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 — China → United States
35%
Rate breakdown
9903.03.0110%Except for products described in headings 9903.03.02–9903.03.11, articles the product of any country, as provided for in subdivision (aa) of U.S. note 2 to this subchapter
9903.88.0225%Except as provided in headings 9903.88.12, 9903.88.17, 9903.88.20, 9903.88.54, 9903.88.59, 9903.88.61, 9903.88.63, 9903.88.66, 9903.88.67, 9903.88.68, 9903.88.69, or 9903.88.70, articles the product of China, as provided for in U.S. note 20(c) to this subchapter and as provided for in the subheadings enumerated in U.S. note 20(d)
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