(1) The influence of polypropylene staple fiber structure on its strength and elongation is mainly reflected in the twist

When the twist coefficient increases, the frictional resistance between wood fibers increases and it is not easy to slip off. This is a strong positive side for the strength of polypropylene staple fibers, but as the twist coefficient increases, the fiber tends to become larger and larger, and the fiber strength increases. The effective component force in the axial direction of the yarn is reduced, and the fiber breakage in the yarn is not uniform at the same time, and the increase in the yarn diameter when the fiber is inclined is an unfavorable factor for the relative strength of the yarn.

(2) The impact of the joint stock

The cooperation of the single yarns makes the plyyarn strips evenly distributed, and the single yarns have contact between them, so that the cohesion between the outer fibers of the single yarns is increased; the strength of the strands is greater than the sum of the strengths of the individual yarns.

(3) Arrangement of fibers in spun yarn

The strength of the rotor yarn is lower than that of the ring yarn: in the rotor yarn, there are more irregularly arranged fibers, such as folding, curling, and ringing, and there are fewer normal transfer fibers, resulting in poor fiber and fiber cohesion, and more slipping fibers during stretching. .

In short, the factors affecting the strength and elongation of polypropylene staple fiber are mainly the two aspects of the fiber properties and yarn structure of the yarn. The strength and elongation of the blended yarn are closely related to the difference in the properties of the blended fiber and the blending ratio. The external factors such as temperature, humidity and strength test conditions have the same effect on the strength and elongation of the yarn.