3909.50.20.00 - Cements

This HTS category, 3909.50.20.00, specifically covers polyurethanes when they are presented in primary forms and are classified as "Cements." These cements are typically formulations based on polyurethane resins, often dissolved or dispersed in a solvent or plasticizer, designed for adhesive or sealing applications. Their primary function is to bond different materials together, and they are characterized by their ability to form strong, flexible bonds upon curing.

This classification is distinct from its sibling categories. While all fall under polyurethanes in primary forms, 3909.50.10.00 covers "Elastomeric" polyurethanes, which are primarily characterized by their rubber-like elasticity in their cured state, not necessarily their adhesive properties as cements. The "Other" category, 3909.50.50.00, would encompass any polyurethane in primary form that does not fit the specific definition of elastomeric or cement-like adhesives.

As a leaf node, this category does not have further subcategories. Therefore, classification within 3909.50.20.00 relies on identifying polyurethane-based formulations explicitly intended and marketed for use as cements or adhesives, considering their physical form (e.g., liquid, paste) and their function in creating strong adhesive bonds. The key distinguishing factor for this sub-heading is the intended application as a bonding agent.