Three Factors Influencing The Strength And Elongation Of Short Fiber Yarn

The main factors affecting yarn strength and elongation are fibre Properties and yarn structure. The strength and elongation of blended yarn are also closely related to the property difference and blending ratio of blended fiber. The influence of external factors such as temperature, humidity and strength testing conditions on the strength and elongation of yarn is basically the same as that of fiber.

　 1. Fiber properties

Fiber length and linear density:

When the fiber length is longer and the fiber is thinner, 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, and the fiber is fine and uniform, the yarn evenness is uniform, and the weak ring is few and not significant, which is conducive to the improvement of yarn strength.

Fiber strength:

When the fiber strength and elongation are large, the yarn strength and elongation are also large; The yarn strength is high when the fiber strength and elongation unevenness are small.

Surface friction property of fiber:

When the fiber surface friction coefficient µ increases, the sliding resistance between fibers is large, 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 staple yarn structure on its strength and elongation is mainly reflected in twist.

When the twist coefficient increases, the friction resistance between wood fibers increases and it is not easy to slip, which is a positive aspect of the strength of short fiber yarn. However, when the twist coefficient increases, with the increasing inclination of fibers, the effective component of fiber strength in the axial direction of the yarn decreases, and the different time of fiber breakage in the yarn increases, and the fiber inclination at the same time yarn The increase in diameter is a negative factor for the relative strength of yarns.

(2) Impact of joint stock

　　 Single yarn The combination of the two can make the ply yarn even, and the single yarns are in contact with each other, which increases the cohesion between the outer fibers of the single yarn; The strength of the ply yarn is greater than the sum of the strength of each single yarn.

(3) Arrangement of fibers in staple yarns

The strength of rotor spun yarn is lower than that of ring spun yarn: in rotor spun yarn, there are more fibers in irregular arrangement such as folding, crimping and looping, and fewer fibers in normal transfer, which results in poor contact between fibers and fibers, and more fibers slip off during drawing.