Spandex yarn has inherent and durable elasticity. Compared with rubber band, it is not only stronger, but also more durable. It is widely used in three-dimensional protection of sanitary products, elastic belts of diapers, elastic waistlines, waist loops of training pants, etc. However, it also has its own limitations, such as the aesthetic feeling of the product is slightly worse and thicker. This paper introduces the production process, product characteristics and drawing ratio of spandex fiber.

1.Production process and product characteristics of spandex yarn

Spandex yarn is a kind of block copolymer fiber with polychlorinated formate as the main component. China's output accounts for 70% of the world 's. Its production technology is mature, and the process flow is divided into two stages: polymerization and spinning. Many domestic manufacturers have developed low oil products suitable for the sanitary products industry.

The elasticity of the elastic part of sanitary products is related to its dosage and elastic modulus. Even if different manufacturers have the same specifications, the tension and elasticity are not exactly the same. The modulus is related to its formula and production technology. Generally, those with high elastic modulus have high resilience and elastic recovery rate. High elastic modulus has higher cost performance than low elastic modulus - less amount and lower residual deformation. Low elastic modulus has higher tension and more stable resilience curve.

2.Stretching ratio of spandex yarn

The maximum stretching rate of spandex yarn is more than 5.0 times, and the general effective stretching is 2.5~3.5 times. Comparing the stress / strain curves of different stretching ratios, it is found that there is no significant difference in wearing elasticity of different stretching ratios.

3.Spandex yarn application process and Countermeasures - balance between elastic comfort and close fitting leak proof

Physical activity requires close fitting and comfortable protection. The ideal elastic material should have a stable rebound curve, which can provide a fit for users of different body types. The absorption function core can play a better effect.

Spandex yarn with high resilience can increase the absorption time of the core and effectively prevent leakage. Reduce the risk of side leakage. But the wrinkles on the surface are easy to cause skin scratches and discomfort.

Imagine -- the core of the discharge and dam of the tidal river is the riverbed. The leakproof barrier is a dam, and the height rises and falls with the activities of the body. The higher the height of the dam, the greater the pressure at the bottom, the better the leakage prevention effect and the lower the comfort. Therefore, it is necessary to find a balance between comfort and personal leakage prevention.

4.Spandex yarn application process and Problem Countermeasures - uncoiling and tension control

All packages of spandex yarn are packed in round tubes, which are divided into active uncoiling and side withdrawal uncoiling without stopping.

At present, most baby diaper equipment adopts active unwinding, and some training pants adopt side unwinding, regardless of advantages and disadvantages, but side unwinding can eliminate its loss caused by shutdown and replacement, which is favored by some users.

There are two main reasons why spandex yarn breaks in the production process: one is abnormal quality, such as adhesion, node splitting, improper storage and handling, etc. In addition, there are also improper application processes, such as insufficient uncoiling tension due to short active uncoiling, and large differences in conduction tension of guide wheels near the main machine end.

Elastic spandex yarn is sensitive to tension changes, and both the spandex guide wire path and guide wheel have an impact on its transportation. Reasonable use of technology should reduce path resistance and avoid excessive guide wheels.

Some training pants production lines use up to 50 pieces of spandex, and poor maintenance of the guide wheel often leads to high-frequency wire breakage and shutdown. Through proper guide wheel maintenance and tension control, wire breakage can be effectively eliminated, and the status of its production process can be included in the process, data and visual management.

At present, spandex yarn has been widely used in the field of sanitary products because of its characteristics. Understanding the relevant knowledge of spandex fiber is conducive to its better development.