Principles and Process of Polypropylene Multifilament Technology

Polypropylene multifilaments are typically produced using the melt-spinning method. After the raw polypropylene granules are melted at high temperatures, the melt is extruded through a spinneret to form fine streams; these solidify upon cooling while undergoing drawing and winding processes to form as-spun filaments. Subsequently, multiple as-spun filaments are combined into a multifilament yarn through twisting or plying, followed by finishing steps such as heat setting, crimping, and cutting to yield the final product. Throughout this process, parameters such as spinneret orifice diameter, draw ratio, and twist level directly influence the fiber morphology (e.g., trilobal, circular), linear density (denier), and strength of the multifilament.