What are the factors that affect the strength of polypropylene high-strength yarns?

1. The influence of melt index

The melt index of the raw material indicates to a certain extent the molecular weight of the raw material. Under the same process conditions, the amount of fiber increases. The degree of molecular entanglement is large, and the strength of the drawn fiber increases with the increase of molecular weight. When the molecular weight is low, slippage between molecular chains is easy to occur, which is manifested in the decrease of fiber strength. In the spinning process of polypropylene high-strength yarns, several raw materials with different melt indexes are used.

During the trial spinning process, it was found that under the same process conditions, the melt index of the raw materials was different, and the strength of the finished yarn was different, and showed a certain regularity.

Under the same spinning temperature, the same draw ratio and the same process parameters, the lower the melt index of the polypropylene chip, the higher the strength of the polypropylene high-strength yarns.

2. The influence of stretching ratio

The stretching process of the nascent fiber is to destroy the original structure of the nascent fiber and generate a new order structure. Under the action of tensile stress and thermal effect, the activity of the macromolecular segment is increased, and various structural units slide the fiber. Axial orientation gathers, rearranges, and adds new bonding points, so that more molecular chains of the fiber are in a particularly good stress-bearing state, and the regularity of the three-dimensional structure (ie crystallization) is generated. The fiber density increases with the increase of the stretching ratio. .

As the draw ratio increases, the strength of the fiber increases, and the draw ratio makes a greater contribution to the strength of the fiber.

Shandong Huimin Taili Chemical Fiber Products Co., Ltd. was established in 2017. After several years of hard work, it has developed into a large-scale professional chemical fiber trading company integrating production and sales. The main products are: polyester fiber, polypropylene fiber, Polyacrylonitrile fiber, polypropylene mesh fiber, polypropylene fiber, polyester fiber and other chemical fiber products.