5408.31 - Unbleached or bleached:

This HTS category, 5408.31, encompasses woven fabrics manufactured from artificial filament yarn that are either unbleached or bleached. These fabrics fall under the broader classification of woven fabrics of artificial filament yarn, excluding those specifically obtained from materials of heading 5405. The key defining characteristic of this subcategory is the state of the fabric's coloration – it has not undergone dyeing, printing, or weaving with yarns of different colors.

This classification is distinguished from its siblings by the absence of color treatment. HTS code 5408.32 covers similar fabrics that have been dyed, while 5408.33 is for woven fabrics made with yarns of different colors, and 5408.34 applies to those that have been printed. Therefore, the primary differentiator for 5408.31 is the uncolored state of the woven artificial filament fabric.

Within this category, further subdivisions exist to refine the classification based on the presence of other materials. Specifically, there is a subcategory for fabrics mixed mainly or solely with wool or fine animal hair, indicating a blend with natural protein fibers. The remaining fabrics, not falling into this specific blend, are classified under the "Other" designation, 5408.31.20.