9902.11.21 - Poly[(dimethyl butanedioate-co-1-(2-hydroxyethyl)-2,2,6,6-tetramethylpiperidin-4-ol)] (CAS No. 65447-77-0) (provided for in subheading 3907.99.50)

HTS Code 9902.11.21 classifies a specific polymer, Poly[(dimethyl butanedioate-co-1-(2-hydroxyethyl)-2,2,6,6-tetramethylpiperidin-4-ol)] (CAS No. 65447-77-0). This classification falls under Chapter 99, which is reserved for temporary legislation, temporary modifications to trade agreements, and specific import restrictions. The presence of this code indicates that the described polymer is subject to special provisions, rather than being classified under the general chemical chapters of the HTS. Its classification is explicitly provided for in subheading 3907.99.50, suggesting it is a polyester and the Chapter 99 designation imposes additional, temporary rules.

This category is distinct from the general HTS classifications that would otherwise apply to polymers or specific chemical compounds. Its placement within Chapter 99 signifies that its import is subject to temporary legislation or trade agreement modifications, which may include quotas, special duties, or other restrictions not found in the permanent HTS structure. Unlike siblings that represent distinct product categories (e.g., live animals), this node represents a specific item under a special classification regime.

As a leaf node, HTS Code 9902.11.21 has no further subcategories. Therefore, classification under this code is definitive for the specified polymer when imported under the conditions governed by Chapter 99. Importers must refer to the specific legislative or proclamation text associated with this Chapter 99 designation to understand the precise import requirements, duties, or restrictions applicable to this substance.