Product classification
HS code for Halobutyl rubber: 4002.39
Rubber, synthetic, halo-isobutene-isoprene rubber (CIIR or BIIR), in primary forms or in plates, sheets or strip.
Classification of halobutyl rubber under HS 4002.39
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.
- Covers
- Chlorobutyl rubber (CIIR) in primary forms
- Bromobutyl rubber (BIIR) in bales
- Halogenated isobutene-isoprene rubber sheets
- Unvulcanized halobutyl rubber strips
- Synthetic halobutyl rubber crumbs
- Also under 4002.39
- Arlanxeo Chlorobutyl
- ExxonMobil Bromobutyl
- Lanxess Bromobutyl
- Tubeless tire inner liners
- Pharmaceutical bottle stoppers
Codes often confused with 4002.39
Common mistake. 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.
Top exporters and importers of HS 400239 (the code used for halobutyl rubber), 2025
In 2025, the largest exporter of HS 400239 (the code used for halobutyl rubber) in UN Comtrade data was the United States, with 23% of world exports; the largest importer in UN Comtrade data was China, with 18% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Figures cover everything classified under HS 400239, not only halobutyl rubber.
Top exporters 2025 · share of world exports
- 1 United States $336M 23% of world exports
- 2 Singapore $300M 20% of world exports
- 3 Belgium $236M 16% of world exports
World total: $1.5B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 China $310M 18% of world imports
- 2 Belgium $224M 13% of world imports
- 3 India $116M 6.8% of world imports
World total: $1.7B Reported figures on UN Comtrade ↗
How these figures are built
109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries that did not report are estimated from what other countries recorded trading with them. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).
Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.
Brazil NCM code for halobutyl rubber
Brazil classifies halobutyl rubber under NCM 4002.39.00: HS 4002.39 with 00 added.
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about halobutyl rubber
What is the HS code for Halobutyl rubber?
The HS code for Halobutyl rubber is 400239 (Rubber; synthetic, halo-isobutene-isoprene rubber (CIIR or BIIR), in primary forms or in plates, sheets or strip). The HS code for halobutyl rubber (both chloro and bromo types) in primary forms is 4002.39.
How do I classify Halobutyl rubber for customs?
Halobutyl rubber is classified under HS code 400239 — Rubber; synthetic, halo-isobutene-isoprene rubber (CIIR or BIIR), in primary forms or in plates, sheets or strip. This is a 6-digit subheading level code.
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.
Which countries are the top exporters of halobutyl rubber (HS 400239)?
In 2025, the top exporters of HS 400239 (the code used for halobutyl rubber) in UN Comtrade data were the United States ($336M, 23% of world exports), Singapore ($300M) and Belgium ($236M). World exports came to about $1.5B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Which countries are the top importers of halobutyl rubber (HS 400239)?
In 2025, the top importers of HS 400239 (the code used for halobutyl rubber) in UN Comtrade data were China ($310M, 18% of world imports), Belgium ($224M) and India ($116M). World imports came to about $1.7B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Is the HS code for Halobutyl rubber the same in all countries?
The base HS code 400239 for Halobutyl rubber is internationally standardized for the first 6 digits across 200+ countries. Individual countries may add additional digits for national tariff lines and specific classifications.
What is the NCM code for halobutyl rubber in Brazil?
In Brazil, halobutyl rubber (HS 400239) is classified under NCM 4002.39.00.