In recent years, the production methods of polyester industrial yarn have made great progress, and there are swelling viscosity increasing and liquid crystal.

A series of new technologies, such as spinning, one-step spinning, liquid isothermal bath spinning, heat pipe spinning, etc

The strength and yield of the high tenacity polyester filament sewing thread make it possible

The classic method of preparing high tenacity polyester filament spinning thread is low pre orientation and high drawing. Usually, the conventional spinning and drawing two-step process is adopted. Udy non drawn yarn is spun first, and then multi-stage high-power drawing is carried out. The spinning speed is between 600 ~ 1000m / min.

Due to the small investment, low production technology and quick launch, domestic manufacturers mostly use this method to produce high tenacity polyester fiber sewing thread. This method has backward technology, large floor area, low fiber strength, unstable product quality, large consumption and high production cost.

The process flow of manufacturing high tenacity polyester filament sewing thread is as follows:

Polyester bright chip - pre crystallization process - solid phase tackifying process - low pressure spinning process - winding

Process - Balance - drafting process

In the two-step process, the quality of the post-treatment process is the key to determine the strength of the high tenacity polyester fiber sewing thread. Only sufficient stretching close to the ultimate tensile multiple can make the fiber strength reach the maximum value. Due to the large stress in stretching, great deorientation effect and shrinkage after setting, the general strength decreases.

It is reported that the domestic conventional polyester is used to form the primary fiber with relatively uniform structure by controlling the spinning process in the high tenacity polyester fiber sewing thread, and then improve the tensile ratio in the subsequent process to increase the fiber strength. The high tenacity polyester fiber sewing thread with strength of 6.6cn/dt and elongation of less than 10% is produced, However, the spinning speed is low, the production efficiency is low, the winding is small, there are more wool, the unit consumption is large, and there is a lack of effective setting, and the heat shrinkage rate is high. Generally, the boiling water shrinkage rate reaches about 8-13%.