3912 - Cellulose and its chemical derivatives, not elsewhere specified or included, in primary forms:

Chapter 39 of the Harmonized Tariff Schedule (HTS) deals with plastics and articles thereof. Within this chapter, heading 3912 specifically covers cellulose and its chemical derivatives that are not classified elsewhere. These are generally processed materials derived from cellulose, a natural polymer, through chemical modification. Examples include various forms of cellulose acetate, cellulose nitrates (including collodions, often used in photographic film and lacquers), and a range of cellulose ethers like methylcellulose, ethylcellulose, and carboxymethylcellulose. These materials are typically supplied in primary forms, such as powders, granules, or sheets.

Distinguishing heading 3912 from its sibling categories requires understanding the fundamental composition of the goods. Unlike other plastics and articles of plastics within Chapter 39, this heading is reserved for materials where the base polymer is cellulose and it has undergone specific chemical derivatization. For instance, it is separate from purely synthetic plastics like polyethylene or PVC, and also from unmodified natural forms of cellulose. The emphasis here is on chemically altered cellulose compounds.

The subcategories within 3912 provide further refinement based on the specific chemical derivative. "Cellulose acetates" represent a significant group, known for their use in films, fibers, and plastics. "Cellulose nitrates," characterized by their flammability, have historical and specialized applications. "Cellulose ethers" encompass a broad spectrum of compounds with diverse properties, often employed as thickeners, binders, and film formers in various industries. The "Other" category captures any cellulose derivatives not specifically enumerated.