Product classification
HS code for Unsaturated polyester resin: 3907.91
Polyesters, n.e.c. in heading no. 3907, unsaturated, in primary forms.
Classification of unsaturated polyester resin under HS 3907.91
Unsaturated polyester resins are classified under HS code 3907.91. This classification is based on the chemical composition of the polymer and its physical state at the time of import. Chapter 39 of the Harmonized System covers plastics and articles thereof, with heading 3907 specifically dedicated to polyacetals, other polyethers, and epoxide resins, as well as polycarbonates, alkyd resins, and other polyesters. The subheading 3907.91 is reserved for polyesters that are 'unsaturated,' meaning they contain double bonds in the polymer chain that allow for cross-linking (curing) into a thermoset plastic. To qualify for this code, the resin must be in a 'primary form,' which the HS defines as liquids, pastes, blocks, lumps, powders, or granules. These resins are widely used in the production of fiber-reinforced plastics (FRP). The classification remains in 3907.91 even if the resin is dissolved in a volatile organic solvent, provided the solvent does not exceed 50% of the total weight of the solution. If the solvent exceeds this limit, the product may be reclassified as a varnish or paint in Chapter 32.
- Covers
- Liquid unsaturated polyester resins
- Casting resins in primary forms
- Unsaturated polyester resin solutions (solvent <50%)
- Thermosetting polyester powders
- Gel coats in primary forms
- Also under 3907.91
- Ashland Derakane
- Reichhold Polylite
- AOC Aliancys
- Scott Bader Crystic
- BASF Palatal
Codes often confused with 3907.91
Common mistake. The most common misclassification occurs with saturated polyesters, which are classified under HS code 3907.99. Saturated polyesters, such as those used for textile fibers or film (e.g., PET), do not have the reactive double bonds found in 3907.91. Additionally, if the resin is mixed with pigments and solvents to the point of being a finished coating, it might be incorrectly placed in 3208 (paints and varnishes) instead of 3907.91.
Top exporters and importers of HS 390791 (the code used for unsaturated polyester resin), 2025
In 2025, the largest exporter of HS 390791 (the code used for unsaturated polyester resin) in UN Comtrade data was Italy, with 11% of world exports; the largest importer in UN Comtrade data was Germany, with 8.8% 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 390791, not only unsaturated polyester resin.
Top exporters 2025 · share of world exports
- 1 Italy $318M 11% of world exports
- 2 China $308M 11% of world exports
- 3 United States $278M 9.6% of world exports
World total: $2.9B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 Germany $253M 8.8% of world imports
- 2 Spain $176M 6.1% of world imports
- 3 United States $159M 5.5% of world imports
World total: $2.9B 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 unsaturated polyester resin
Brazil classifies unsaturated polyester resin under NCM 3907.91.00: HS 3907.91 with 00 added.
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about unsaturated polyester resin
What is the HS code for Unsaturated polyester resin?
The HS code for Unsaturated polyester resin is 390791 (Polyesters; n.e.c. in heading no. 3907, unsaturated, in primary forms). The HS code for unsaturated polyester resin in primary forms is 3907.91.
How do I classify Unsaturated polyester resin for customs?
Unsaturated polyester resin is classified under HS code 390791 — Polyesters; n.e.c. in heading no. 3907, unsaturated, in primary forms. This is a 6-digit subheading level code.
What defines a primary form for this resin?
Primary forms include liquids and pastes, including dispersions (emulsions and suspensions) and solutions, as well as blocks of irregular shape, lumps, powders, granules, flakes, and similar bulk forms.
Which countries are the top exporters of unsaturated polyester resin (HS 390791)?
In 2025, the top exporters of HS 390791 (the code used for unsaturated polyester resin) in UN Comtrade data were Italy ($318M, 11% of world exports), China ($308M) and the United States ($278M). World exports came to about $2.9B, 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 unsaturated polyester resin (HS 390791)?
In 2025, the top importers of HS 390791 (the code used for unsaturated polyester resin) in UN Comtrade data were Germany ($253M, 8.8% of world imports), Spain ($176M) and the United States ($159M). World imports came to about $2.9B, 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 Unsaturated polyester resin the same in all countries?
The base HS code 390791 for Unsaturated polyester resin 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 unsaturated polyester resin in Brazil?
In Brazil, unsaturated polyester resin (HS 390791) is classified under NCM 3907.91.00.