9902.11.31 - Micro-porous, ultrafine, spherical polyamide powders of polyamide 6 (CAS No. 356040-79-4), polyamide-12 (CAS No. 338462-62-7) and polyamide 6, 12 (CAS No. 356040-89-6) (provided for in subheading 3908.10.00 or 3908.90.70)

This HTS classification, 9902.11.31, specifically covers micro-porous, ultrafine, spherical polyamide powders. These powders are derived from specific types of polyamides, including polyamide 6 (CAS No. 356040-79-4), polyamide-12 (CAS No. 338462-62-7), and polyamide 6, 12 (CAS No. 356040-89-6). The designation within Chapter 99 indicates that these goods are subject to temporary legislation or modifications proclaimed pursuant to trade agreements or specific agricultural adjustment acts, often implying a controlled or restricted import status.

Distinguishing this category from its siblings within the broader HTS framework is crucial for accurate classification. While other sibling categories in Chapter 99 might address different types of temporary import restrictions or special provisions, this specific code isolates polyamide powders with distinct physical characteristics (micro-porous, ultrafine, spherical) and chemical compositions (polyamide 6, 12, or 6,12). The reference to subheadings 3908.10.00 or 3908.90.70 within the description helps to link these specialized powders back to their broader material classification under Chapter 39, but this 9900 series code signifies a unique, temporary regulatory treatment.

As a leaf node within the HTS, this category does not have further subcategories. Classification into 9902.11.31 is definitive based on the specified material type, physical form, and the fact that these particular polyamide powders are subject to the temporary measures outlined in Chapter 99. Importers must ensure that the imported material precisely matches the description of micro-porous, ultrafine, spherical polyamide powders of the listed polyamides to fall under this classification.