Particulate matter (PM) and airborne viruses pose significant threats to both the environment and public health. As the most viable solution to prevent the inhalation of these pollutants, there is an urgent demand for face masks with excellent filtration efficiency and low-pressure drop. In this study, a crimped masterbatch (CM) is added to polypropylene feedstocks to produce curling fibers through melt-blown spinning. These curled fibers exhibit low filtration resistance and effective dust-holding performances when used for air filtration. The effect of adding CM on fiber diameter, pore size, crimp, porosity, roughness, and surface potential was studied. The filtration performance of the materials, including the PM filtration capabilities, recirculation filtration, and loading test performance, were also investigated. The results demonstrate that the degree of fiber crimp can be adjusted by incorporating varying amounts of CM. This curling was caused by the uneven shrinkage that occurred due to variations in thermal contraction between these polymers. The curled fibers created a fluffy structure in the fiber network and modified the distribution of pore sizes within it. Under the same filtration conditions as sodium chloride aerogel, CM-2 (PP:CM 8:2) exhibited similar filtration efficiency (95.54% vs. 94.74%), lower filtration resistance (88.68 Pa vs. 108.88 Pa), higher quality factor (0.035 Pa-1 vs. 0.028 Pa-1) and better dust holding capacity (10.39 g/m2 vs. 9.20 g/m2) compared to CM-0 (PP:CM 10:0). After 30 days of indoor storage, the filtration efficiency of CM-2 remained above 94%. The self-curling melt-blown filtration material developed here could potentially be applied in the field of protective masks.
Keywords: curling fibers; electrostatic decay; fluffiness; low pressure filtration; melt-blown nonwoven.