What factors affect the strength and elongation of polypropylene staple fiber yarns

The main factors that determine the strength and elongation of polypropylene staple fiber yarns are fiber properties and yarn structure. The blended yarn is also affected by the property difference of the blended fiber and the blending ratio.

1. Fiber properties

Fiber length, linear density:

When the fiber length is longer and the fiber is finer, the friction resistance between the fibers in the yarn is larger and it is not easy to slip off, so the yarn strength is higher.

When the fiber length uniformity is good, the fiber is fine and even, the yarn yarn is dry and uniform, and the weak rings are few and not significant, which is conducive to the improvement of yarn strength.

Strength of fiber:

When the strength and elongation of the fiber are large, the strength and elongation of the yarn are also large. The yarn strength is high if the fiber is strong and the elongation irregularity is small.

Surface friction properties of fibers:

When the friction coefficient μ of fiber surface increases, the sliding resistance between fibers increases, the slippage length lc decreases, the proportion of slippage fibers decreases, and the yarn strength increases. Increasing the crimp number of fibers can increase the sliding resistance between fibers.

2. Yarn structure

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

When the twist increases, the friction resistance between wood fibers increases and it is not easy to slip off, which is conducive to increasing the strength of polypropylene staple fibers. However, when the twist increases, the effective component of the strength of polypropylene staple fibers in the yarn axis decreases with the increasing tilt of polypropylene staple fibers, and the asymmetry of fiber breakage in the yarn increases. At the same time, the increase of yarn diameter is a negative factor to the relative strength of yarn.

(2) The impact of joint stock

The combination of single yarn makes the strand dry evenly, and there is contact between single yarn, so that the adhesion between the outer fibers of single yarn increases. The strength of the strand is greater than the sum of the strength of the individual yarn.

(3) The arrangement of polypropylene staple fiber in staple fiber yarn

The strength of the spinning cup yarn is lower than that of the ring spindle yarn: in the spinning cup yarn, there are more irregular arrangement fibers such as folding, crimping and circling, and fewer normal transfer fibers, resulting in poor contact between the fibers and the fibers, and more slip-off fibers during stretching.

Hai'an County Qinfeng Chemical Fiber Co., Ltd. specializes in production and sales：polypropylene staple fiber, polyester Staple Fiber, functional polypropylene short fiber, functional polyester staple fiber, hydrophilic polyester staple fiber,  polypropylene, PP staple fiber, polyester staple fiber.