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The strength of polypropylene high strength yarn is affected by production process factors

Spinning process.

Melting temperature: Melting temperature has an important effect on the strength of polypropylene high strength yarn. High temperature will lead to degradation of polypropylene molecular chain and decrease of strength. If the temperature is too low, the fluidity of the melt will be poor, the spinning will be difficult, and the strength of the silk will be affected. In general, the appropriate melting temperature should be in the appropriate range above the melting point of polypropylene, usually between 200 ° C - 230 ° C.

Extrusion speed: Extrusion speed is closely related to the tensile multiple of polypropylene high strength yarn. Appropriately increasing the extrusion speed can increase the tensile ratio of the silk, improve the orientation of the molecular chain, and thus enhance the strength. But the extrusion speed is too high will lead to instability of the wire, hair, broken wire and other problems, but reduce the strength.

Cooling conditions: The cooling rate and cooling method will affect the crystallinity and crystal structure of the polypropylene filament. Rapid cooling can make the molecular chain too late to fully crystallize, forming smaller crystals, thereby improving strength and toughness. Air cooling or water cooling is usually used for cooling, and the cooling speed and temperature need to be adjusted according to the specific production process.

Drawing process

Drawing ratio: Drawing is the key process to improve the strength of high strength polypropylene fiber. Appropriate increase of the tensile ratio can make the molecular chain orientation along the tensile direction, improve the degree of orientation and crystallinity, and thus significantly enhance the strength. However, too high tensile ratio will lead to fracture or stress concentration, reducing strength. Generally speaking, the stretching factor between 5-8 times is more appropriate.

Tensile temperature: Tensile temperature also has a great impact on the strength of polypropylene high strength yarn. Within a certain range, increasing the tension temperature can reduce the internal friction of the molecular chain, make the tension easier to carry out, improve the degree of orientation and strength. However, too high temperature will relax the molecular chain, decrease the degree of orientation and reduce the strength. The tensile temperature is usually within the appropriate range above the glass transition temperature of polypropylene, generally between 80 ° C and 120 ° C.

Heat setting technology

Heat setting temperature: Heat setting can eliminate the internal stress generated during the tensile process of high strength polypropylene fiber, improve dimensional stability and strength. The appropriate heat setting temperature can further crystallize and Orient the molecular chain, and enhance the strength of the silk. If the heat setting temperature is too low, the effect is not obvious, and too high temperature will lead to molecular chain degradation or excessive contraction, reducing the strength. The general heat setting temperature is between 120℃ and 150℃.

Heat setting time: The length of heat setting time will also affect the strength of polypropylene high strength yarn. The time is too short, the internal stress is not completely eliminated, and the strength is limited; Too long a time will waste energy, and may even cause the performance of the strip to decline. Usually the heat setting time is between tens of seconds to a few minutes, which needs to be adjusted according to the specifications of the silk and the production process.

"Hongyang" brand polypropylene high strength yarn products have small color difference, good color fastness, high strength, and are widely used in decorative belts, safety belts, marking lines, etc.The company's main product:  polypropylene high strength yarn , polypropylene filament, polypropylene air change yarn，polyester air change yarn, ribbon.

Taixing Hongyang New Materials Technology Co., Ltd. has consistently adhered to the "excellent quality, customer first, quality service, adhere to the contract," the purpose, with high-quality products, good reputation, selling the country. Wholeheartedly with the domestic business win-win cooperation and common development!