Product classification
HS code for Styrene polymer: 3903.90
Styrene polymers, in primary forms, n.e.c. in heading no. 3903.
Classification of styrene polymer under HS 3903.90
HS code 3903.90 serves as a residual category for polymers of styrene in primary forms that do not meet the specific criteria for other subheadings within heading 3903. Chapter 39 covers plastics and articles thereof, with heading 3903 focusing on styrene-based polymers. While 3903.11 and 3903.19 cover polystyrene, and 3903.20 and 3903.30 cover SAN (styrene-acrylonitrile) and ABS (acrylonitrile-butadiene-styrene) respectively, 3903.90 captures other copolymers where styrene is the predominant monomer by weight. This includes various styrene-based resins and specialty copolymers used in industrial applications such as high-impact modifications or specific chemical resistances. The term 'primary forms' refers to liquids, pastes, blocks, lumps, powders, granules, or flakes. Classification here requires an analysis of the monomer composition; if the styrene monomer units predominate over any other single comonomer unit by weight, and the product is not specifically named elsewhere, 3903.90 is the correct designation. This follows the application of Note 4 to Chapter 39, which dictates the classification of copolymers based on the constituent monomer that prevails by weight. This code is essential for specialty resins that do not fit the standard definitions of general-purpose polystyrene or the well-known ABS/SAN engineering plastics.
- Covers
- Styrene-butadiene copolymers (non-rubber)
- Styrene-isoprene copolymers in primary forms
- Methylstyrene polymers
- Styrene-maleic anhydride (SMA) resins
- Specialty styrene-based ion-exchange resins
- Also under 3903.90
- Kraton Polymers (SBS, SIS, SEBS)
- Sartomer (Styrene-Acrylic)
- Polyscope (SMA)
- Asahi Kasei (SBR)
- Dynasol (SBS)
Codes often confused with 3903.90
Common mistake. Styrene polymers are often misclassified under 3903.19 (Polystyrene) if the user does not realize the material is a copolymer. They are also frequently confused with 4002.11 or 4002.19 (SBR - Styrene-butadiene rubber). The distinction depends on whether the material meets the definition of 'synthetic rubber' in Note 4 to Chapter 40, which involves specific vulcanization and elongation tests.
Top exporters and importers of HS 390390 (the code used for styrene polymer), 2025
In 2025, the largest exporter of HS 390390 (the code used for styrene polymer) in UN Comtrade data was South Korea, with 18% 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 390390, not only styrene polymer.
Top exporters 2025 · share of world exports
- 1 South Korea $663M 18% of world exports
- 2 United States $619M 17% of world exports
- 3 Germany $330M 9.0% of world exports
World total: $3.7B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 China $747M 18% of world imports
- 2 Mexico $293M 7.2% of world imports
- 3 Germany $277M 6.8% of world imports
World total: $4.1B 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 codes for styrene polymer
Brazil splits HS 3903.90 into 3 NCM codes. Pick the one that matches your product:
- 3903.90.10Methyl methacrylate-butadiene-styrene copolymers
- 3903.90.20Acrylonitrile-styrene-butyl acrylate copolymers
- 3903.90.90Other styrene polymers in primary forms
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about styrene polymer
What is the HS code for Styrene polymer?
The HS code for Styrene polymer is 390390 (Styrene polymers; in primary forms, n.e.c. in heading no. 3903). The HS code for styrene polymers (other than polystyrene, SAN, or ABS) in primary forms is 3903.90.
How do I classify Styrene polymer for customs?
Styrene polymer is classified under HS code 390390 — Styrene polymers; in primary forms, n.e.c. in heading no. 3903. This is a 6-digit subheading level code.
How is this different from ABS plastic?
ABS plastic has its own specific HS code, 3903.30. Code 3903.90 is only for styrene polymers that do not qualify as ABS, SAN, or pure polystyrene.
Which countries are the top exporters of styrene polymer (HS 390390)?
In 2025, the top exporters of HS 390390 (the code used for styrene polymer) in UN Comtrade data were South Korea ($663M, 18% of world exports), the United States ($619M) and Germany ($330M). World exports came to about $3.7B, 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.
Which countries are the top importers of styrene polymer (HS 390390)?
In 2025, the top importers of HS 390390 (the code used for styrene polymer) in UN Comtrade data were China ($747M, 18% of world imports), Mexico ($293M) and Germany ($277M). World imports came to about $4.1B, 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 Styrene polymer the same in all countries?
The base HS code 390390 for Styrene polymer 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 styrene polymer in Brazil?
Brazil splits HS 390390 into 3 NCM codes, so the right one for styrene polymer depends on the product's details: 3903.90.10 (Methyl methacrylate-butadiene-styrene copolymers), 3903.90.20 (Acrylonitrile-styrene-butyl acrylate copolymers), 3903.90.90 (Other styrene polymers in primary forms).