Abstract:

With the rapid development of new spinning technology, air jet vortex spinning occupies an important position in the spinning field for its advantages of high spinning speed, high efficiency and short process. In recent years, the continuous innovation of air jet vortex spinning technology has broken through the bottleneck of many yarn varieties. The variety of yarns is becoming increasingly abundant, and the linear density tends to be fine and thick. Among yarns, the air jet vortex spinning coarse count yarn is mainly used in industrial textiles, with a wide selection of raw materials. Combined with the advantages of air jet vortex spinning, it shows a good application prospect. However, the spinning of coarse count yarns with air jet vortex spinning is still faced with many problems. Compared with the medium count yarn with air jet vortex spinning, the coarse count yarn has the problems of difficult yarn formation, weak wrapping ring, insufficient breaking strength, etc. Therefore, the 59.1 tex polyester air jet vortex spinning coarse count yarn is studied in this paper, and the wrapping effect is quantified to solve the problem of low breaking strength of the air jet vortex spinning coarse count yarn.

In order to improve the breaking strength of the air jet vortex spinning coarse count yarn, based on the yarn structure and spinning mechanism of air jet vortex spinning, starting from the wrapping effect, the wrapping effect is characterized, and the wrapping coefficient, a parameter for quantifying the wrapping effect, is proposed. The calculation formula of the wrapping coefficient is established, the area of the wrapped fiber and the total area of yarns in the air jet vortex spinning yarn image are extracted, and the yarn wrapping coefficient is calculated. On this basis, the relationship between the yarn wrapping coefficient and breaking strength is analyzed, and the functional relationship model between breaking strength and the wrapping coefficient is established. Based on this model, the process improvement is guided, the spinning speed and nozzle pressure of air jet vortex spinning are optimized, and the optimal process optimization parameters of yarn breaking strength are finally obtained by using the response surface analysis method. It is found that the breaking strength of the yarn increases with the increase of the wrapping coefficient, and the poor wrapping effect is the main reason for the deterioration of the breaking strength of the air jet vortex spinning yarn. The optimized spinning process involve the following parameters: a spinning speed of 430 m min and the nozzle pressure of 0.57 MPa. The wrapping coefficient is 0.502, and the breaking strength can reach 30.75 cN tex. According to the standard of polyester plain yarns in FZ T 12019—2018 Polyester Fiber Grey Yarn, the breaking strength grade of the yarn has been improved from the second grade to the first grade, with remarkable improvement effect.

In production practice, the wrapping level of yarns can be compared by calculating the wrapping coefficient proposed in this paper, and according to the established relationship model between the breaking strength and wrapping effect, the wrapping coefficient level whose performance meets the product requirements can be established, and then the process plan can be adjusted to achieve the goal of ensuring the performance of the spun coarse yarn and improving the production efficiency. Further research work can focus on the relationship model between the breaking strength and wrapping coefficient, which is suitable for more fiber raw materials and blending proportion.

Key words: air jet vortex spinning, coarse tex yarn, breaking strength, wrapping effect, process optimization

摘要： 为了研究喷气涡流纺粗特纱断裂强度随线密度增大而降低的原因，从包缠效果的角度，对其影响因素进行分析。提出喷气涡流纺纱线包缠效果的客观评价方法，构建量化指标包缠系数。检测喷气涡流纺不同线密度纱线的包缠系数，分析喷气涡流纺纱线的断裂强度与包缠效果的相关性，建立并验证喷气涡流纺粗特纱断裂强度与包缠系数之间的关系模型。结果表明：纱线断裂强度随包缠系数的增加逐渐增高，包缠效果不良是喷气涡流纺粗特纱断裂强度劣化的原因。在生产实践中，依据断裂强度与包缠系数的关系模型，优化涡流纺工艺，可使喷气涡流纺粗特纱断裂强度得到显著改善。

关键词: 喷气涡流纺, 粗特纱, 断裂强度, 包缠效果, 工艺优化