HS Code for Halobutyl rubber

Halobutyl rubber is classified under HS code 4002.39. This classification falls within Chapter 40, which covers rubber and articles thereof. Heading 4002 is dedicated to synthetic rubber and factice derived from oils, in primary forms or in plates, sheets, or strip. Halobutyl rubber, which includes Chlorobutyl (CIIR) and Bromobutyl (BIIR), is a halogenated derivative of isobutene-isoprene rubber (butyl rubber). While regular butyl rubber is classified under 4002.31, the halogenated versions are specifically directed to 4002.39. The addition of chlorine or bromine to the rubber polymer improves its vulcanization rate and adhesion properties, but for customs purposes, it remains a synthetic rubber in a primary form. To qualify for this code, the product must be in a primary form such as bales, blocks, or crumbs, or in unvulcanized plates, sheets, or strips. Once the rubber is further manufactured into finished goods like inner tubes or gaskets, it moves to other headings within Chapter 40.

Products Included

• Chlorobutyl rubber (CIIR) in primary forms
• Bromobutyl rubber (BIIR) in bales
• Halogenated isobutene-isoprene rubber sheets
• Unvulcanized halobutyl rubber strips
• Synthetic halobutyl rubber crumbs

Common Misclassification

The most common misclassification is HS code 4002.31, which is reserved for non-halogenated isobutene-isoprene (butyl) rubber. Importers must distinguish between the two based on the presence of halogen atoms in the chemical structure. Another error involves HS code 3902.30, which covers propylene copolymers; although polyisobutylene is related, synthetic rubber must meet the requirements of Note 4 to Chapter 40 regarding vulcanization and elongation. If the product is already shaped into a specific article, such as a tire inner tube, it should be classified under 4013.10 instead of the raw material code.

FAQ

What is the HS code for halobutyl rubber?

The HS code for halobutyl rubber (both chloro and bromo types) in primary forms is 4002.39.

Is chlorobutyl rubber classified differently than bromobutyl?

No, both chlorobutyl rubber and bromobutyl rubber are halogenated derivatives of butyl rubber and are grouped together under the same HS code, 4002.39.