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Taixing Hongyang reveals to you the knowledge points about the stretching temperature, multiple and speed of polypropylene high-strength yarn!

The first is the drawing temperature of polypropylene high-strength yarn:

Regarding the stretching of polypropylene high-strength yarns, two-stage stretching is used whether it is one-step or two-step methods. When the temperature is higher than 70°C, the unstable quasicrystalline structure in the nascent fiber is easily transformed into a stable monoclinic crystal, which is not conducive to the increase of the post-drawing ratio, so the drawing temperature is generally 50-60°C. Through one-stage stretching, the crystallinity and orientation of the fiber are increased, and the tensile stress is increased. Therefore, the two-stage stretching is performed at a higher temperature to achieve the desired effect. The second-stage stretching temperature is 120~ 130°C is suitable.

Next is the drawing ratio of polypropylene high-strength yarn:

The draw ratio of polypropylene high-strength yarn is mainly determined by process parameters. To increase the strength of polypropylene high-strength yarns, a higher draw ratio must be used. Within a certain range, as the stretching ratio increases, the strength of the polypropylene high-strength yarn will increase.

Then the drawing speed of polypropylene high-strength yarn:

The drawing speed of polypropylene high-strength yarns should be low. The stretching process is essentially the process of rearranging the macromolecules and their structural units in the fiber. Polypropylene fiber has high molecular weight and high elasticity. If the stretching speed is too high, the development of tensile deformation cannot keep up with the change of tensile stress. Macromolecules and their various unit structures do not have enough time for orientation and crystallization. The strength of high-strength polypropylene fiber Will fall.

The above is the relevant knowledge points about the stretching temperature, multiple and speed of polypropylene high-strength yarn compiled by the editor of Taixing Hongyang.