3911.90 - Other:

HTS code 3911.90 encompasses a broad range of synthetic resins and polymer materials not elsewhere specified or included within Chapter 39. This category serves as a residual for products falling under Note 3 of Chapter 39, which are generally defined as other products of primary forms of plastics, not specifically detailed in preceding headings. The "Other" designation signifies that goods classified here meet the general criteria of Note 3 but do not fit into the more specific subheadings within 3911.

This heading distinguishes itself from its siblings by excluding specific categories of resins. HTS code 3911.10.00.00 specifically covers petroleum resins, coumarone, indene, or coumarone-indene resins, and polyterpenes. Similarly, 3911.20.00.00 is dedicated to poly(1,3-phenylene methylphosphonate). Therefore, 3911.90.XX.XX is for all other materials within the scope of Note 3 that are not captured by these distinct headings, focusing on their polymeric nature and primary form.

Within 3911.90, further subdivisions exist to refine classification. The subheading 3911.90.10.00, for instance, is designated for "Elastomeric" products, highlighting a key physical characteristic: their ability to deform under stress and return to their original shape. This distinction allows for more precise tariff application based on the material's performance properties, differentiating it from non-elastomeric materials that may fall under other "Other" classifications within 3911.90.