9902.10.61 - Siloxanes and silicones, di-Me, polymers with Me silsesquioxanes and polypropylene glycol mono-Bu ether (CAS No. 68554-65-4), greater than 70 percent by weight, with less than 8 percent percent by weight siloxanes and silicones, di-Me, polymers with Me silsesquioxanes and polyethylene-polypropylene glycol mono-Bu ether, less than 8 percent by weight poly(oxy(methyl-1,2-ethanediyl)), α-butyl-ω hydroxyl (CAS No. 9003-13-8), less than 2 percent by weight oxirane, methyl-, polymer with oxirane, monobutylether (CAS No. 9038-95-3), less than 8 percent by weight silanamine, 1,1,1, trimethyl (CAS No. 68909-20-6) and less than 1 percent by weight silicon dioxide (CAS No. 7631-86-9) (provided for in subheading 3824.99.92)

This HTS classification, 9902.10.61, is a specific provision within Chapter 99, which pertains to temporary legislation and trade agreement modifications. It covers a very particular mixture of siloxanes and silicones. The key components include polymers formed from dimethyl siloxanes and methyl silsesquioxanes, combined with polypropylene glycol monobutyl ether, where this specific combination constitutes over 70% of the product's weight.

The distinctiveness of this classification lies in its highly specific chemical composition and the exclusion thresholds for other components. Unlike broader chemical classifications under Section VI of the HTS, which would cover general siloxanes and silicones, or other polymer preparations, 9902.10.61 is designed for a precise blend. It differentiates itself through the stringent percentage requirements for various co-polymers and additives, including polyethylene-polypropylene glycol monobutyl ether, oxirane polymers, and silicon dioxide, ensuring that only products meeting these exact parameters are classified here.

As this node is a leaf node, there are no further subcategories. Classification under 9902.10.61 is therefore determined solely by meeting all the detailed compositional requirements outlined in its description, specifically the presence of the primary siloxane/silicone polymer blend in excess of 70% by weight, alongside the precise limitations on the other specified chemical entities. This level of specificity is characteristic of special provisions designed to manage trade under specific policy objectives.