3909.50 - Polyurethanes:

This HTS category, 3909.50, specifically covers polyurethanes in their primary forms. Polyurethanes are versatile polymers formed by the reaction of isocyanates with polyols. They are known for their wide range of properties, including excellent abrasion resistance, tear strength, and flexibility, making them suitable for diverse applications.

Within the broader scope of amino-resins, phenolic resins, and polyurethanes (3909), this subheading distinguishes polyurethanes from other resin types. Unlike urea resins (3909.10), melamine resins (3909.20), or phenolic resins (3909.40), polyurethanes are characterized by their specific chemical structure and the resulting material properties.

The subcategories under 3909.50 further refine the classification of polyurethanes based on their specific form and intended use. These include "Elastomeric" polyurethanes (3909.50.10), which exhibit rubber-like elasticity; "Cements" (3909.50.20), typically referring to adhesive formulations; and "Other" (3909.50.50) for polyurethanes that do not fall into the preceding specific subheadings. This granular classification allows for precise tariff application based on the exact nature of the polyurethane product.