Study on Properties of Meltblown Nonwoven Polypropylene

Nonwoven Fabric has become an increasingly important filter material due to their excellent filtration performance, high yield and simple processing technology. The non woven Filter Cloth Material has adjustable fiber fineness, messy and fluffy three - dimensional structure, high porosity, good filtration efficiency, and high production efficiency. Melt - blown method is one of the important ways to form Non Woven Fabric in one step. At present, most of the raw materials used in the preparation of Non Woven Fabric Roll by melt - blown method are polypropylene. Polypropylene has low cost, good strength, good acid and alkali resistance, and organic solvent resistance, etc.

As the melt index of PP particles increases gradually, that is, the fluidity increases. The air permeability of the product decreases gradually, that is, the air permeability decreases, and the fiber diameter gradually becomes thinner. This is due to the fact that the melt with better fluidity is more likely to be drawn and refined by hot air after passing through the spinneret hole. In addition, the addition of zirconium - based degradants helps to form a finer fibrous structure. The main reason is that the zirconium - based degrading agent breaks the partial molecular chain of polypropylene, improves the mobility of the molecular chain, and increases the melt fluidity, which makes it easier to be stretched and refined by hot air.

With the increase of pump supply, the air permeability of the product gradually increases, and the fiber diameter gradually becomes thicker. This is because the pump supply increases, that is, the thin flow of melt fibers formed per unit time increases. Under the condition of constant hot air flow, the tensile force equivalent to the unit mass of the melt decreases, so the fiber diameter becomes larger. On the one hand, as the pump supply increases, the melt pressure increases, and the extrusion expansion of the melt at the exit of the spinneret is also more obvious, which is also one of the important reasons for the doubling. The curing slows down, the adhesion between fibers and the phenomenon of doubling are intensified. These factors all increase the average diameter of the fibers and the pore size of the mesh, and the air permeability of the product increases.

As the hot air pressure gradually increases, the air permeability of the product gradually decreases. That is, the air permeability decreases. After the fibers are ejected from the spinneret holes, the fibers are further refined under the pulling action of hot air. Higher hot air pressure is more conducive to the refinement of fibers, so as the hot air pressure gradually increases, the fiber diameter gradually becomes smaller and reaches the nanometer level. However, if the wind pressure is too high, the fiber will be more easily broken during the stretching process, resulting in a lot of free flying flowers, which will reduce the weight of the product and increase the air permeability.