HS Code for Styrene polymer

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.

Products Included

• Styrene-butadiene copolymers (non-rubber)
• Styrene-isoprene copolymers in primary forms
• Methylstyrene polymers
• Styrene-maleic anhydride (SMA) resins
• Specialty styrene-based ion-exchange resins

Common Misclassification

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.

FAQ

What is the HS code for styrene polymer?

The HS code for styrene polymers (other than polystyrene, SAN, or ABS) in primary forms is 3903.90.

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.