How is the strength and elongation of polypropylene staple fibers affected?

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

When the twist coefficient increases, the frictional resistance between wood fibers increases and it is not easy to slip off. This is a positive positive force for the strength of polypropylene staple fibers. However, as the twist coefficient increases, the fiber strength increases as the fiber tilts more and more. The effective component force decreases in the yarn axial direction, the fiber breakage in the yarn does not increase 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) Impact of joint stock

The combination of the single yarns makes the strands dry and uniform, and there is contact between the single yarns, which increases the cohesion between the outer fibers of the single yarns; the strength of the strands is greater than the sum of the strengths of the individual yarns.

(3) the arrangement of fibers in staple fiber yarns

The strength of rotor-spun yarn is lower than that of ring-spun yarn: in rotor-spun yarn, there are more irregularly arranged fibers such as half-folding, curling, looping, etc., and there is less normal transfer of fibers, resulting in poor fiber-to-fiber entanglement and contact. .

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