U.S. exports of Butyl Rubber (IIR) and Halobutyl Rubber (CIIR/BIIR) (SITC 23213) totaled $26.9M in August 2026.
Importers of Butyl Rubber (IIR) and Halobutyl Rubber (CIIR/BIIR) paid $118K in duties in August 2026, an average duty rate of 2.41% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule.
Last updated: August 2026 dataButyl rubber (IIR) and its halogenated derivatives — chlorobutyl (CIIR) and bromobutyl (BIIR) — are defined by their exceptionally low gas permeability, which makes them the standard material for tire inner liners, pharmaceutical stoppers, and pressure-sensitive sealants. Halobutyl grades carry reactive halogen sites that enable co-vulcanization with general-purpose rubbers, a processing advantage that commands a price premium over standard IIR. The distinction between IIR and CIIR/BIIR is commercially significant and should be clearly stated on shipping documents, as the grades serve different compounding applications.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
129 import shipments a month
Chlorobutyl (CIIR) and bromobutyl (BIIR) can be co-cured with diene rubbers like NR and SBR in the tire carcass, eliminating the need for a tie-gum layer. Standard IIR does not co-vulcanize readily with these polymers, making halobutyl grades the preferred choice for modern tubeless tire construction despite their higher cost.
The commercial invoice and certificate of analysis should clearly state whether the product is IIR, CIIR, or BIIR, along with the Mooney viscosity and halogen content where applicable. Customs examiners may request technical data sheets if the grade designation is ambiguous, particularly when the unit value differs significantly from typical IIR benchmarks.
Basic heading 41 of 239 in section 2
Basic heading 23213 · $26.9M of $7.8B
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ImportsExports
Imports
$4.9MYoY · free account
Exports
$26.9MYoY · free account
12-mo low · imports
Low · free accountOver the twelve months to August 2026, the U.S. imported $57.7M of Butyl Rubber (IIR) and Halobutyl Rubber (CIIR/BIIR) and exported $375.9M.
Through August 2026. Source: U.S. Census Bureau.
Exports · August 2026
destination
Brazil and Poland together take 42% of it.
customs district
Census does not publish district detail for this classification system.
origin
Census does not publish state detail for this classification system.
entry
Census does not publish port detail for this classification system.