HS code · 6-digit subheading
HS Code 3909.31 – Amino-resins; n.e.c. in heading no. 3909, in primary forms, poly(methylene phenyl isocyanate) (Crude MDI, polymeric MDI)
HS code 3909.31 is the 6-digit subheading for amino-resins, n.e.c. in heading no. 3909, in primary forms, poly(methylene phenyl isocyanate) (Crude MDI, polymeric MDI). It is used for polymeric MDI, crude MDI, MDI prepolymers, MDI-based rigid foam systems and MDI-based binders.
What HS 3909.31 covers
This HS code specifically covers poly(methylene phenyl isocyanate), commonly known as Crude MDI or polymeric MDI, in its primary forms. MDI is a critical intermediate chemical in the production of polyurethanes, which are incredibly versatile polymers. International trade in MDI primarily involves large chemical manufacturers exporting to industries that produce a vast array of end products, including rigid and flexible foams for insulation, furniture, and automotive seating, as well as coatings, adhesives, sealants, and elastomers. Key things to know are its role as a foundational building block for polyurethane systems, its global demand driven by construction, automotive, and appliance sectors, and the need for specialized handling due to its reactive nature. Major players in this trade are global chemical giants, and its supply chain is crucial for numerous manufacturing sectors worldwide.
- Covers
- Polymeric MDI
- Crude MDI
- MDI prepolymers
- MDI-based rigid foam systems
- MDI-based binders
- MDI-based elastomers
- MDI-based adhesive components
- Examples
- BASF Lupranate MDI
- Covestro Desmodur MDI
- Dow PAPI MDI
- Wanhua Wannate MDI
Codes often confused with 3909.31
Common mistake. This code can be confused with other amino-resins under 390939 if the specific MDI chemical identity is not clearly established, or with finished polyurethane products under 390950 or later chapters if not in primary forms.
Top exporters and importers of HS code 390931, 2025
In 2025, the largest exporter of HS code 390931 in UN Comtrade data was China, with 17% of world exports; the largest importer in UN Comtrade data was China, with 8.1% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Top exporters 2025 · share of world exports
- 1 China $1.3B 17% of world exports
- 2 Germany $1.2B 15% of world exports
- 3 Belgium $1.1B 13% of world exports
World total: $8.0B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 China $628M 8.1% of world imports
- 2 Türkiye $518M 6.7% of world imports
- 3 India $431M 5.6% of world imports
World total: $7.8B 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 3909.31
Brazil does not split HS 3909.31: its NCM code is 3909.31.00.
All Brazil NCM codes in heading 39.09 →
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text is official; the English is our translation.
Questions about HS 3909.31
What is HS code 390931?
HS code 390931 is a 6-digit subheading in the Harmonized System that covers: Amino-resins; n.e.c. in heading no. 3909, in primary forms, poly(methylene phenyl isocyanate) (Crude MDI, polymeric MDI). This HS code specifically covers poly(methylene phenyl isocyanate), commonly known as Crude MDI or polymeric MDI, in its primary forms. MDI is a critical intermediate chemical in the production of polyurethanes, which are incredibly versatile polymers. International trade in MDI primarily involves large chemical manufacturers exporting to industries that produce a vast array of end products, including rigid and flexible foams for insulation, furniture, and automotive seating, as well as coatings, adhesives, sealants, and elastomers. Key things to know are its role as a foundational building block for polyurethane systems, its global demand driven by construction, automotive, and appliance sectors, and the need for specialized handling due to its reactive nature. Major players in this trade are global chemical giants, and its supply chain is crucial for numerous manufacturing sectors worldwide.
What products fall under HS code 390931?
Polymeric MDI, Crude MDI, MDI prepolymers, MDI-based rigid foam systems, MDI-based binders, MDI-based elastomers, MDI-based adhesive components
What are common misclassifications for HS code 390931?
This code can be confused with other amino-resins under 390939 if the specific MDI chemical identity is not clearly established, or with finished polyurethane products under 390950 or later chapters if not in primary forms.
Which countries are the top exporters of goods under HS code 390931?
In 2025, the top exporters of HS code 390931 in UN Comtrade data were China ($1.3B, 17% of world exports), Germany ($1.2B) and Belgium ($1.1B). World exports came to about $8.0B, 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 goods under HS code 390931?
In 2025, the top importers of HS code 390931 in UN Comtrade data were China ($628M, 8.1% of world imports), Türkiye ($518M) and India ($431M). World imports came to about $7.8B, 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.
How is HS code 390931 structured?
HS code 390931 is a 6-digit subheading under the Harmonized System. The first 2 digits (39) identify the chapter, digits 3-4 (09) identify the heading, and digits 5-6 (31) specify the subheading. This code is standardized globally by the World Customs Organization.
What is the Brazil NCM code for HS code 390931?
In Brazil, HS code 390931 is NCM 3909.31.00. The last two digits are 00 because Brazil does not split this HS code further.