HS Code for Polymeric MDI

Polymeric MDI, or poly(methylene phenyl isocyanate), is classified under HS code 3909.31. This classification is governed by the General Rules of Interpretation (GRI) 1 and 6, which prioritize the terms of the headings and subheadings. Heading 3909 covers amino-resins, phenolic resins, and polyurethanes in primary forms. Subheading 3909.31 specifically identifies poly(methylene phenyl isocyanate), often referred to as crude MDI or PMDI. Unlike pure 4,4'-MDI, which is a chemically defined compound classified in Chapter 29, polymeric MDI is a mixture of isomers and higher-order oligomers. According to Chapter 39 Note 3, the term "primary forms" applies to liquids and pastes, including dispersions and solutions, as well as blocks of irregular shape, lumps, powders, granules, flakes, and similar bulk forms. Polymeric MDI is a critical raw material in the production of rigid polyurethane foams and is classified here because it is a polymer in a primary form that has not yet been processed into a finished article. The classification is further supported by the Explanatory Notes to the Harmonized System, which clarify that mixtures of isocyanates with a specific degree of polymerization belong in Chapter 39.

Products Included

• Crude MDI (Methylene diphenyl diisocyanate)
• Polymeric MDI (PMDI)
• Poly(methylene phenyl isocyanate) in liquid form
• Isocyanate mixtures with higher functionality

Common Misclassification

Polymeric MDI is frequently confused with pure MDI (4,4'-methylene diphenyl diisocyanate), which is classified under HS code 2929.10. The distinction lies in the chemical definition; pure MDI is a single, chemically defined organic compound, whereas polymeric MDI is a mixture of isomers and oligomers. Additionally, it may be confused with other amino-resins under 3909.39 if the specific poly(methylene phenyl isocyanate) structure is not identified.

FAQ

What is the HS code for Polymeric MDI?

The HS code for Polymeric MDI is 3909.31, which specifically covers poly(methylene phenyl isocyanate) in primary forms.

What is the difference between HS 2929.10 and 3909.31?

HS 2929.10 is for chemically defined isocyanates like pure MDI, while 3909.31 is for polymeric versions which are mixtures of molecules with varying chain lengths.