 The spinning process includes melt extrusion amount, draft hot air velocity and melt temperature.
1. Melt extrusion
The amount of polymer melt extruded affects the linear density and output of the fiber.
The higher the grams per minute of the polymer melt extruded from the fuse hole, the thicker the fiber. Therefore, on the premise of ensuring the fiber fineness of melt blown non-woven fabric, the number of spinneret holes must be increased to increase the output of melt blown.
2. Draft heat flow rate
The secondary heat flow rate is the main process parameter in the melt injection process, which directly affects the fineness of the fiber. For a certain amount of polymer melt extrusion and a certain melt viscosity, the higher the draft air velocity, the drafting effect on the polymer melt microflow on the spinning production line?? The larger, and the thinner the fiber.
In industrial production, high-speed ventilation hot air is usually used to compensate for the change of fiber diameter caused by the increase of polymer extrusion, that is, the flow rate of secondary hot air must match the polymer extrusion.
3. Melting temperature
Melt blown temperature refers to the working temperature, and the nozzle can be used to adjust the viscosity of polymer melt. The melting temperature is usually higher than the melting point of PP resin, making it in a viscous flow state. When other process conditions remain unchanged, the lower the viscosity of the polymer melt, the finer the melt droplet flow. Therefore, micro fibers can be easily obtained by using high MF polymer chip materials in the melt spraying process. However, too small melt viscosity will lead to excessive extension of melt flow, and the formation of ultra-short ultrafine fibers will fly into the air and cannot be collected. It is also called "flying" phenomenon in the process of melt spraying. Therefore, in order to prevent the melt from cracking under the action of shear force, the melt viscosity range of polypropylene materials commonly used for melt blowing is 50-300pas.
| 
