Spinnability is an important application characteristic to measure the difficulty of spinning fine fibers from high polymer raw materials. It refers to the characteristic that after the melt is ejected from the spinneret hole, the melt trickle forms continuous fibers with certain physical and mechanical properties.

The properties related to spinnability of high polymer raw materials are mainly divided into physical properties and chemical properties.

The physical properties of raw materials mainly refer to: melting point, softening point, glass transition temperature, shear viscosity, tensile viscosity, crystallinity, moisture content, impurity content, etc.

The chemical properties of raw materials mainly refer to molecular structure, molecular weight, molecular weight distribution, stability, etc..

The physical and chemical properties of polymer raw materials have an important impact on the spinnability of the melt. Taking PP as an example, its molecular structure is required to be isotactic, with small molecular weight, appropriate melt index (spunbonded method and melt blown method are different), molecular weight distribution width less than 4, water content less than 500mg / kg, impurity content less than 250mg / kg, etc.

When the spinnability of the polymer is poor, it is manifested as: the spinning melt temperature fluctuates, the melt pressure is high, there is melt dripping, and it can not withstand high-speed drafting.

At the same time, it is prone to wire breakage, easy degradation, many monomers, large smoke, short service cycle of filter screen spinneret, easy to cause shutdown failure, etc.