3921.13 - Of polyurethanes:

This HTS category, 3921.13, specifically addresses cellular plates, sheets, film, foil, and strip made from polyurethanes. These materials are characterized by a foam-like structure, containing a significant volume of gas within a solid matrix, offering properties such as insulation, cushioning, or buoyancy. They can be produced in various forms, from rigid panels to flexible foams.

Distinguishing this category from its siblings is crucial for accurate classification. For instance, 3921.11 covers similar cellular plastic products but is specifically for those derived from polymers of styrene, such as expanded polystyrene (EPS) or extruded polystyrene (XPS). Similarly, 3921.12 pertains to cellular products made from vinyl chloride polymers, commonly known as PVC foam sheets. Category 3921.14 is for cellular regenerated cellulose, while 3921.19 encompasses cellular products made from other plastic types not falling under the preceding categories. Therefore, the defining characteristic for 3921.13 is the polyurethane composition of the cellular plastic material.

Within the 3921.13 classification, further distinctions are made to refine the classification. The subcategory "Combined with textile materials" would apply to polyurethane cellular sheets that are laminated with, coated with, or otherwise incorporated with textile fabrics, presenting a composite material with enhanced properties. The "Other" subcategory covers all other polyurethane cellular plates, sheets, film, foil, and strip that do not meet the criteria for combination with textile materials.