1) Strength of sewing thread yarn
The fiber breaking strength is increased. Although the slippage length increases and the number of slippage fibers in the yarn section increases relatively, the total strength of the broken fibers will be greatly improved. Therefore, the higher the breaking strength of the fiber, the higher the yarn strength.
2) Friction performance of sewing thread yarn
When the friction coefficient u of the fiber surface increases, the sliding resistance between the fibers increases, the slip length Lc decreases, the proportion of slip fibers decreases, and the yarn strength increases. Increasing the number of crimps of the fibers can increase the sliding resistance between the fibers, which is not only conducive to the smooth progress of the spinning process, but also contributes to the improvement of the yarn strength.