Predominant comonomer test governs copolymer classification; polystyrene beads fell under the specific heading, not the residuary entry.

For copolymers and polymer blends under Chapter 39, classification depends on the comonomer that predominates by weight over every other single comonomer, with comonomers falling in the same heading treated as one comonomer. On the factual record, styrene was the predominant monomer in the polystyrene co-polymer beads, and no technical material displaced that finding. The residuary sub-heading 3903.90 could apply only if the goods did not fall within a specific preceding sub-heading. The goods were therefore classified as polystyrene under sub-heading 3903.10, and the assessee's classification was sustained.

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Issues: Whether polystyrene co-polymer beads were classifiable under sub-heading 3903.10 as polystyrene, or under sub-heading 3903.90 as an other/residuary polymer.

Analysis: Chapter Note 4 to Chapter 39 requires copolymers and polymer blends to be classified under the heading covering the comonomer that predominates by weight over every other single comonomer, and comonomers whose polymers fall in the same heading are treated as a single comonomer. The product was found, on the factual record, to have styrene as the predominant monomer by weight, and no technical material was produced to dislodge that position. The residuary sub-heading 3903.90 could be invoked only if the product did not fall under any of the preceding sub-headings.

Conclusion: The goods were correctly classifiable as polystyrene under sub-heading 3903.10, and not under sub-heading 3903.90.

Final Conclusion: The Revenue's challenge to the classification failed, and the assessee's classification was sustained with the consequential duty position under the notified heading.

Ratio Decidendi: For copolymers and polymer blends, classification follows the predominant comonomer by weight where the relevant chapter note so provides, and a residuary entry cannot be used when the goods are covered by a specific sub-heading.

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