The fracture process analysis of High Tenacity Nylon Filament Sewing Thread is a problem. Due to the effect of twisting, the fibers in the yarn are tightly embraced. The fracture process of High Tenacity Nylon Filament Sewing Thread is the process of fiber fracture and mutual slippage in the yarn. It can be known from experience that the reason for the low utilization rate of fiber strength in the tow is the different timing of fiber breakage in the silk.

For normal High Tenacity Nylon Filament Sewing Thread, when the yarn breaks, the fiber breaks mainly. Regarding the process of fiber fracture and destruction in yarn, different scholars have different opinions. At present, there are two diametrically opposed opinions.

One point of view: When the High Tenacity Nylon Filament Sewing Thread starts to be stretched, the fiber buckle decreases and the straightness increases, showing the initial elongation deformation. At this time, the cross-section of the pearl ray begins to shrink, which increases the pressure of the outer fiber on the inner fiber in the yarn. In the spun yarn spun by the traditional High Tenacity Nylon Filament Sewing Thread method, any small segment is the outer cylindrical helix length, the inner fiber cylindrical helix is ​​short, and the central fiber is straight. Therefore, the outer fiber has a large elongation and a high tension; the inner fiber has a small elongation and a low tension; the central fiber may not be elongated, or may even be crumpled, and the pressure of the fibers in each layer is uneven. Therefore, the outer fibers that grow up during the stretching of the spun yarn are first broken, and then gradually expand to the inner fibers.

Another point of view: In the yarn formation process before stretching, the tension of the inner and outer fibers is uniform. At the same time, within a section of the yarn, because the fiber transfer is not obvious, the arrangement of the fibers in the High Tenacity Nylon Filament Sewing Thread can be approximated Seen as a layered spiral arrangement of cylindrical rows.