3911.20.00.00 - Poly(1,3-phenylene methylphosphonate)

This HTS category, 3911.20.00.00, specifically covers Poly(1,3-phenylene methylphosphonate). This synthetic polymer falls under Chapter 39, which deals with plastics and articles thereof. Its inclusion in Section VII indicates its classification within the broader scope of plastics and rubber-related materials.

Within its immediate parent category, "Petroleum resins, coumarone-indene resins, polyterpenes, polysulfides, polysulfones and other products specified in note 3 to this chapter, not elsewhere specified or included, in primary forms," this specific subdivision distinguishes itself by its precise chemical composition. Unlike the sibling category 3911.10.00.00, which encompasses petroleum resins, coumarone-indene resins, and polyterpenes, or the broader "Other" category (3911.90), this code isolates Poly(1,3-phenylene methylphosphonate) based on its unique phosphonate structure.

As a leaf node within the HTS system, 3911.20.00.00 does not have further subcategories. Therefore, the classification relies on correctly identifying the material as Poly(1,3-phenylene methylphosphonate) in its primary form. This means the substance should be in a raw or unprocessed state, such as powders, granules, or blocks, as is typical for plastics before fabrication into finished articles.