The oil content of polyacrylonitrile fibers and its impact on the processability

The oil content of polyacrylonitrile fibers is a key indicator that affects the smoothness of spinning and subsequent processing. The oil agent adheres to the surface of the fibers and performs functions such as lubrication, anti-static, and cohesion. If the oil content is too high or too low, it will directly alter the processability of the fibers. It is necessary to control it reasonably in combination with the processing technology.

When the oil content is low, there is a prominent problem of static electricity and cohesion. When the oil content is insufficient, the surface of the fibers lacks an adequate protective layer of oil agent, resulting in an increase in friction coefficient. During the friction between fibers and between fibers and the guide components of the equipment, static electricity is likely to occur. Static electricity causes the individual fibers to repel each other, float, and disperse, resulting in loose yarns, reduced cohesion, and difficulties in the processes of stretching, gathering, and winding. This can lead to hairiness, broken fibers, and disorderly yarn arrangement.

At the same time, the smoothness of the fibers is insufficient, and during the passage through rollers, guide hooks, and tensioners, the resistance is relatively high, with significant fluctuations in tension, causing uneven yarn thickness and poor formation. These problems will increase the frequency of equipment shutdown, reduce production efficiency, increase the number of defective products, and are not conducive to the stable production of subsequent spinning and weaving.

When the oil content is high, the risk of slippage and contamination increases. If the oil content is too high, the oil film on the surface of the fibers becomes too thick, resulting in a low friction coefficient. The yarn is prone to slipping. In the stretching process, the adhesion force between the fibers and the rollers is insufficient, causing uneven stretching, tension loss, and inconsistent elongation of the yarn bundle. The finished product indicators fluctuate greatly.

Excess oil also transfers to the surface of the equipment rollers and the guide components, gradually accumulating and forming oil stains, contaminating the yarn and causing oil spots. Excessive oil also reduces the cohesion of the yarn bundle, making it prone to layering, loose winding, and adhesion during storage and transportation. In some scenarios, the excess oil can also interfere with subsequent dyeing, setting, and other post-processing procedures.

Key points for controlling within a reasonable range

A suitable oil content can balance the friction coefficient, suppress static electricity, enhance the cohesion of individual fibers, stabilize the tension of the yarn bundle, reduce hairiness and broken fibers, ensure regular winding and formation, and be compatible with subsequent processing. When selecting types and conducting production control, one should not only consider the numerical value but also adjust comprehensively based on the oil agent formula, environmental temperature and humidity, processing speed, and product usage. In a low-humidity environment, static electricity is more likely to accumulate, and the anti-static ability of the oil agent is required to be higher; in high-speed processing conditions, the uniformity and adhesion strength of the oil film are more strictly required.

In actual production, priority should be given to ensuring uniform oil adhesion, avoiding local lack of oil or accumulation of oil. Then, combined with sample testing and spinning, observe the conditions of hairiness, broken fibers, and winding formation to find a control scheme that is suitable for the process, ensuring the stable processability of polyacrylonitrile fibers.