From a customs classification standpoint, IR and natural rubber are distinct materials and classify under different headings. However, in many compounding applications they are technically interchangeable, and finished goods made from IR may carry the same end-use classification as those made from natural rubber. Importers should document the polymer type clearly to support accurate classification of both the raw material and any downstream articles.

Natural rubber latex contains proteins that can trigger Type I hypersensitivity reactions in sensitized patients. Synthetic IR, being protein-free, eliminates this allergen risk while maintaining comparable mechanical properties. This makes IR a preferred material for pharmaceutical stoppers, syringe plungers, and medical tubing where latex-free certification is required.