Product classification
HS code for Natural polymer: 3913.90
Polymers, natural and modified natural, in primary forms (excluding alginic acid, its salts and esters).
Classification of natural polymer under HS 3913.90
The classification of natural polymers under HS code 3913.90 is determined by the chemical origin and the degree of modification of the substance. Chapter 39 of the Harmonized System generally covers plastics and polymers. While most headings in this chapter deal with synthetic polymers derived from petroleum or coal, heading 3913 is reserved for polymers that occur naturally or are modified versions of natural polymers that do not fit into more specific categories like proteins or starches. Subheading 3913.90 acts as a residual category for these substances, provided they are in primary forms such as liquids, pastes, blocks, or powders. This classification is essential for chemical manufacturers and importers who deal with bio-based materials that serve as precursors for specialized industrial applications. The logic follows that if a polymer is not synthesized from monomers but is instead extracted from biological sources and potentially chemically altered (without losing its polymer character), it belongs here. This includes complex carbohydrates and other organic macromolecules that are not elsewhere specified in the nomenclature. The primary form requirement is strict; once these polymers are shaped into finished articles, they move to other headings within Chapter 39 or other chapters entirely.
- Covers
- Chitin and chitosan extracted from crustacean shells
- Chemical derivatives of natural rubber such as chlorinated rubber
- Hardened proteins (excluding those used as glues)
- Dextran and other modified polysaccharides
- Natural polymers in solutions or dispersions
- Also under 3913.90
- Kitozyme Chitosan
- Pharmacosmos Dextran
- CP Kelco Gellan Gum
- Cargill Xanthan Gum
- Ingredion Modified Starch
Codes often confused with 3913.90
Common mistake. Natural polymers are frequently misclassified under HS code 3913.10, which is specifically reserved for alginic acid and its salts. Another common error is using codes from 3901 to 3911, which are strictly for synthetic polymers like polyethylene or PVC. Furthermore, if the natural polymer has been processed into a specific finished good, it must be classified under the heading for that article (e.g., 3926 for general plastic articles) rather than the primary form code 3913.90. Some importers also confuse these with proteins of Chapter 35, such as casein (3501) or gelatin (3503).
Top exporters and importers of HS 391390 (the code used for natural polymer), 2025
In 2025, the largest exporter of HS 391390 (the code used for natural polymer) in UN Comtrade data was Sweden, with 32% of world exports; the largest importer in UN Comtrade data was South Korea, with 12% 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 391390, not only natural polymer.
Top exporters 2025 · share of world exports
- 1 Sweden $1.1B 32% of world exports
- 2 China $803M 23% of world exports
- 3 United States $344M 9.8% of world exports
World total: $3.5B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 South Korea $412M 12% of world imports
- 2 United States $388M 11% of world imports
- 3 Japan $240M 6.7% of world imports
World total: $3.6B 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 natural polymer
Brazil splits HS 3913.90 into 9 NCM codes. Pick the one that matches your product:
- 3913.90.11Chlorinated/hydrochlorinated rubber, bulk forms
- 3913.90.12Chlorinated rubber in other forms
- 3913.90.19Other chemical derivatives of natural rubber
- 3913.90.20Xanthan gum
- 3913.90.30Dextran
- 3913.90.40Hardened proteins
- 3913.90.50Chitosan, its salts or derivatives
- 3913.90.60Chondroitin sulphate
- 3913.90.90Other natural or modified natural polymers
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about natural polymer
What is the HS code for Natural polymer?
The HS code for Natural polymer is 391390 (Polymers, natural and modified natural; in primary forms (excluding alginic acid, its salts and esters)). The HS code for natural polymers and modified natural polymers in primary forms, excluding alginic acid, is 3913.90.
How do I classify Natural polymer for customs?
Natural polymer is classified under HS code 391390 — Polymers, natural and modified natural; in primary forms (excluding alginic acid, its salts and esters). This is a 6-digit subheading level code.
Does this code include synthetic plastics?
No, synthetic plastics are classified under headings 3901 through 3911. HS code 3913.90 is exclusively for polymers of natural origin or their modified versions.
Which countries are the top exporters of natural polymer (HS 391390)?
In 2025, the top exporters of HS 391390 (the code used for natural polymer) in UN Comtrade data were Sweden ($1.1B, 32% of world exports), China ($803M) and the United States ($344M). World exports came to about $3.5B, 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 natural polymer (HS 391390)?
In 2025, the top importers of HS 391390 (the code used for natural polymer) in UN Comtrade data were South Korea ($412M, 12% of world imports), the United States ($388M) and Japan ($240M). World imports came to about $3.6B, 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 Natural polymer the same in all countries?
The base HS code 391390 for Natural 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 natural polymer in Brazil?
Brazil splits HS 391390 into 9 NCM codes, so the right one for natural polymer depends on the product's details: 3913.90.11 (Chlorinated/hydrochlorinated rubber, bulk forms), 3913.90.12 (Chlorinated rubber in other forms), 3913.90.19 (Other chemical derivatives of natural rubber), 3913.90.20 (Xanthan gum), 3913.90.30 (Dextran), 3913.90.40 (Hardened proteins), and more.