4810.31.10 - In strips or rolls of a width exceeding 15 cm or in rectangular (including square) sheets with one side exceeding 36 cm and the other side exceeding 15 cm in the unfolded state

This HTS classification, 4810.31.10, specifically covers kraft paper and paperboard that meets stringent criteria for chemical processing and weight, and is intended for purposes other than writing, printing, or graphic applications. The material must be bleached uniformly throughout the mass, with over 95 percent of its fiber content originating from wood obtained via chemical processes. Furthermore, its weight must not exceed 150 grams per square meter (g/m²). The physical form is also critical: it must be presented in strips or rolls exceeding 15 cm in width, or in rectangular or square sheets where one side exceeds 36 cm and the other exceeds 15 cm when unfolded.

Distinguishing this category from its sibling "Other" is key; this code is for the precisely defined kraft paper and paperboard as described, whereas the "Other" designation would apply to similar kraft papers and paperboards that do not meet all the specific technical and physical requirements outlined. The emphasis here is on the technical specifications of the kraft paperboard itself, not its end-use in graphic applications.

Within this classification, further subdivisions exist to refine the categorization of these specific kraft papers and paperboards. Subcategories like "Folding carton stock" (4810.31.10.20) and "Base stock for trays, dishes, plates, cups and the like" (4810.31.10.40) exist to segregate products based on their intended application in packaging and food service industries. The remaining "Other" subcategory serves as a catch-all for goods that fit the primary description of 4810.31.10 but do not fall into these more specialized end-use classifications.