3909.40.00.00 - Phenolic resins

This HTS category, 3909.40.00.00, specifically classifies phenolic resins. These resins are thermosetting polymers produced through the reaction of phenol with an aldehyde, most commonly formaldehyde. They are known for their hardness, heat resistance, and electrical insulating properties. Phenolic resins can be found in various forms, including powders, granules, liquids, and sheets, and are often used as adhesives, binders, molding compounds, and in the production of laminates, coatings, and friction materials.

This classification is distinct from its siblings, 3909.10 (urea resins and thiourea resins), 3909.20 (melamine resins), and the other amino-resins. While all are thermosetting polymers, phenolic resins are characterized by their phenolic base, differing from the urea, thiourea, or melamine-based structures of the other categories. The subsequent subdivision, 3909.50, covers polyurethanes, which are fundamentally different polymers with distinct chemical structures and properties.

As a leaf node, 3909.40.00.00 does not have further subcategories. Therefore, classification within this code relies on correctly identifying the material as a phenolic resin. Examples of goods that would fall under this classification include basic phenolic molding compounds, uncured phenolic resin solutions, and solid phenolic resins intended for further processing into finished articles. The key determinant is the chemical composition and the characteristic manufacturing process of phenolic resins.