Why is Polypropylene Widely Used in the Melt-Blown Process? What Are the Characteristics of Polypropylene?

Polypropylene is widely used in the melt-blown process due to its following advantages:

1. Controllable polymer viscosity: Thermal degradation can be achieved by using oxidants or peroxides in the extrusion process, or through the mechanical shearing effect of the extruder, or by controlling the operating temperature, so as to adjust and control the melt viscosity as required.

2. Controllable molecular weight distribution: The melt-blown non-woven process requires a narrow molecular weight distribution to produce uniform ultra-fine fibers. With the help of new catalytic technologies (such as metallocene catalysts), polypropylene with extremely high melt flow rate (MFR) and extremely narrow molecular weight distribution can be produced.

3. Relatively high melting point: The heat resistance of polypropylene is sufficient for most product applications, and it has a relatively wide melting range. Therefore, it is very beneficial for the thermal bonding process commonly used in the non-woven process.

4. Facilitation of ultra-fine fiber production: If the melt viscosity of polypropylene is very low and the molecular weight distribution is very narrow, ultra-fine fibers can be produced in the melt-blown process with the same energy consumption and under the same drawing conditions. Therefore, the common fiber diameter of polypropylene melt-blown non-woven fabrics is 2-5 μm, or even finer.

Since the melt-blown process adopts high-pressure hot air for drawing, it requires the use of polymers with high melt flow rate, which is conducive to increasing production and reducing energy consumption. At present, most of the polypropylene chips used have a melt flow rate of 400-1200 g/10 min and a narrow molecular weight distribution, so as to produce ultra-fine fibers with the required linear density.

The polypropylene chips used in melt-blown production, processing and application must have a relatively high and uniform melt flow rate, a narrow molecular weight distribution, good melt-blown processing performance, and relatively uniform and stable chip quality, so as to ensure the process stability of melt-blown non-woven materials.