As the best barrier layer of mask, meltblown cloth is a very fine material, and its interior is made up of many interlaced superfine fibers stacked in random directions. Melt-blown PP material with melt index of 1500 was selected. The finer the drawn filaments in the melt-blown process, the better the filtration performance. At the same time, we should consider whether we can provide the third-party inspection report of melt-blown materials.
Second, the melting temperature, screw extrusion speed
When the melting temperature is constant, the extrusion speed of the screw should be kept within a certain range: before a certain critical point, the faster the extrusion speed and the higher the basis weight, the greater the strength of meltblown cloth; When the critical value is exceeded, the strength of meltblown fabric will decrease, especially when the MFI is higher than MFI> 1000. It may be because the extrusion rate is too high, which leads to insufficient drafting and serious doubling of filaments, which reduces the bonding fibers on the fabric surface and the strength of melt-blown fabric.
Third, the hot air injection angle
Hot air injection angle mainly affects the stretching effect and fiber morphology. When the angle becomes smaller, the trickle will form parallel fiber bundles, resulting in poor uniformity of non-woven fabrics. If the angle tends to 90, it will produce highly dispersed turbulent airflow, which is beneficial to the random distribution of fibers on the condensation curtain, and finally the meltblown cloth has good anisotropy.
Fourth, the amount of hot air and wind speed
At the same temperature, screw speed and receiving distance (DCD), the faster the hot air speed, the smaller the fiber diameter, the softer the handle of the nonwoven fabric, and the more entangled the fibers, resulting in denser, smoother and higher strength of the web.
Verb (abbreviation for verb) receiving distance
If the receiving distance is too long, the longitudinal and transverse strength and bending strength will decrease, and the nonwoven fabric will feel fluffy, which will lead to the decrease of filtration efficiency and filtration resistance during melt blowing.
Six, melt-blown mold
The design and precision of melt-blown die directly affect the length, uniformity, toughness, fineness and many other aspects of wire drawing, thus having a decisive impact on the final coil quality.
Seven, fully add electret master batch and electrostatic electret treatment.
High-voltage corona treatment can make melt-blown fibers have lasting electrostatic charge and melt-blown fabrics have additional electrostatic adsorption without hindering breathing. After electret treatment, the filterability can be improved to 95% (that is, N95 mask standard: pneumatic diameter 0.075? m 0.020？ The filtration efficiency of M particles is above 95%).
Qingdao Zhongxin Huamei's above answer .....