Is the strength of polypropylene FDY yarn always the higher the better? The elongation rate has a greater impact on weaving efficiency than the strength. 

When purchasing polypropylene FDY yarn, many customers tend to prioritize "high strength" as the primary criterion. However, during actual weaving, you will find that sometimes very strong yarns have a higher breakage rate during weaving; while sometimes, yarns with a slightly lower strength but uniform elongation can be woven smoothly. What's the problem? It's likely because you only focused on the strength and ignored the elongation rate. Below, from two perspectives, we will help you clarify the selection

1. Uneven elongation rate, the hidden culprit behind weaving defects 

polypropylene FDY yarns require multiple processes such as warping, threading, and weaving during the weaving process. Each of these steps has specific requirements for the tension stability of the yarn. 

The elongation CV value is more important than the peak strength: The elongation coefficient of variation (CV value) reflects the uniformity of the elongation rate of each filament in a batch of filaments. The larger the CV value, the more uneven the elongation rates of the filaments in the same batch. During weaving, filaments with a larger elongation rate will appear looser under the same tension, while those with a smaller elongation rate will be tighter. This uneven tension will lead to an increase in the breakage rate. When purchasing, you can ask the supplier to provide the elongation CV value data. The smaller the CV value, the higher the weaving efficiency usually is. 

Balance between strength and elongation: Pursuing excessively high fracture strength may sometimes sacrifice elongation or increase its CV value. A moderate strength combined with uniform elongation tends to perform more stably during the weaving process. Ningbo Dazhong Industrial Fibre Co., Ltd. was founded in 1984, with an annual production capacity of 15,000 tons of polypropylene FDY yarn, polypropylene POY yarn, polypropylene strong yarn, and coloured polypropylene yarn. The "Dazhong" brand has been rated as a recommended product in Zhejiang Province for six consecutive years. 

II. How to select fibers based on elongation rate indicators? 

Since elongation is so crucial, how should we ensure quality during the procurement process? 

Provide the elongation CV value: When purchasing, you can proactively ask the supplier if they provide the elongation CV value data and understand its control range. Generally, for polypropylene FDY yarn used in high-speed weaving, it is ideal to control the elongation CV value within a smaller range. If the supplier can only provide strength data but cannot provide the CV value, this can be used as a starting point for further examination of the quality control capability. 

Sample machine trial weaving: Conduct small-scale trial weaving on your own loom to test the uniformity of elongation rate. Focus on the tension fluctuations during the warping process, the frequency of breaks during weaving, and the flatness of the fabric surface. If the weaving is smooth and there are few breaks, it indicates that the elongation rate uniformity of this batch of silk is good. 

Pay attention to the rewinding performance of the filament bundle: Filament bundles with uneven elongation are prone to tension fluctuations during rewinding, resulting in poor tube formation or detachment from the reel during rewinding. When purchasing, you can feel the surface of the tube to check if it is smooth and the filament layers are uniform. This is also an intuitive way to judge the quality of the filament bundle. 

Summary and Selection Suggestions 

When purchasing polypropylene FDY yarn, it is recommended to confirm the following steps: 

Check the elongation CV value: While focusing on the strength, it is essential to require the supplier to provide the elongation CV value data. This is a more direct indicator for evaluating the weaving efficiency. 

Choose strength based on application: When used for webbing or industrial fabrics, sufficient strength is required; when used for clothing fabrics or home textiles, the strength requirement can be appropriately reduced in exchange for a more uniform elongation rate and better hand feel. 

Sample machine weaving: Conduct a small-scale trial on your own equipment to observe the breakage rate and fabric appearance. Use the actual results as the basis for final selection. 

Ningbo Dazhong Industrial Fibre Co., Ltd. was founded in 1984. It produces 15,000 tons of products annually, including polypropylene FDY yarn, polypropylene POY yarn, polypropylene stretching yarn, and coloured polypropylene yarn. The fibre fineness ranges from 68D to 1800D. It pays attention to the uniformity of elongation control. Please feel free to send samples for testing.