Fiber size, pore size, and air permeability are three important properties in melt blown (MB) webs. Air permeability governs the air resistance or the pressure drop of the air through the web. One of the major applications of MB webs is for air filters. Fiber size dominates the web air filtration efficiency. Liquid filtration is another major application of MB webs. Pore size of the web determines the rated particle size in liquid filtration. Air permeability can be easily determined by air permeability testers. Fiber size and pore size in MB webs are difficult to measure by optical microscopy or other methods. However, they can be determined in fibrous products from the air flow rate through the web.
References
1.
GoeminneH., “The Geometrical and Filtration Characteristics of Metal-Fiber Filters - A Comparative Study,”Filtration and Separation1974 (August), pp. 350–355.
2.
WrotnowskiA.C., Felt Filter Media, American Felt Co., Glenville, CT, 1968.
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GroverElliot B., and HambyD.S., Handbook of Textile Testing and Quality Control, Textile Book Publishers, Inc., A Division of Interscience Publishers, Inc., New York, 1960, pp. 212–220.
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WagnerJ. Robert, “The relationship of filter media 1st and 3rd bubble point and maximum pore size,”TAPPI Journal, pp. 108, 199–202, vol. 78, No. 4, 1995.
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HindsWilliam C., Aerosol Technology, John Wiley & Sons, New York, 1982.
9.
ASTM F902, “Standard Practice for Calculating the Average Circular-Capillary-Equivalent Pore Diameter in Filter Media from Measurements of Porosity and Permeability,”American Society for Testing Materials, 1926 Race St. Philadelphia, PA 19103, 1984.
10.
ASTM Method D737, “Standard Test Method for Air Permeability of Textile Fabrics,”American Society for Testing Materials, 1926 Race St. Philadelphia, PA 19103, 1984.
11.
AdamsonArthur W., Physical Chemistry of Surfaces, Interscience Publishers, a division of John & Sons, New York, 1967.
