HS Code for IIR rubber

IIR rubber, or isobutene-isoprene rubber, is classified under HS code 4002.31. This classification is based on the chemical structure of the synthetic polymer. Chapter 40 of the Harmonized System covers rubber and articles thereof, with heading 4002 specifically addressing synthetic rubber and factice derived from oils. The sub-heading 4002.31 is dedicated to isobutene-isoprene (butyl) rubber in its primary forms, such as bales, blocks, or crumbs, or in unvulcanized plates, sheets, and strips. Butyl rubber is valued for its exceptional impermeability to gases and its high chemical resistance. The classification process requires identifying the monomer composition; for a product to fall under this code, it must meet the technical definition of synthetic rubber as provided in the Chapter 40 notes, which involves the ability to be cross-linked and undergo elastic recovery.

Products Included

• Standard butyl rubber (IIR) in bales
• Unvulcanized IIR sheets for industrial lining
• IIR crumbs for adhesive manufacturing
• Butyl rubber masterbatches in primary forms
• IIR strips for sealant production

Common Misclassification

IIR rubber is often confused with halo-isobutene-isoprene rubber (CIIR or BIIR), which is classified under HS code 4002.39. While both are butyl rubbers, the halogenated versions contain chlorine or bromine to improve vulcanization speed. Additionally, importers sometimes mistakenly use 4001.10, which is reserved for natural rubber latex, or 4002.11, which covers Styrene-butadiene rubber (SBR). Accurate classification depends on the specific chemical modification of the isobutene-isoprene chain.

FAQ

What is the HS code for IIR rubber?

The HS code for IIR (isobutene-isoprene) rubber in primary forms or sheets is 4002.31.

Does this code include finished inner tubes?

No, finished inner tubes made from IIR rubber are classified under heading 4013. HS code 4002.31 only applies to the raw material or unvulcanized intermediate forms.