FILTER MATERIAL FOR AIR FILTERS

摘要

The objective of the present invention is to provide an air filter medium having a lower pressure drop and higher efficiency as compared to an air filter medium currently in use. This objective is achieved by providing an air filter medium comprising glass short fibers as its main fibers, characterized in that the main fibers are fibers that constitute 70% or greater by mass of the total blended raw material fibers, the glass short fibers are borosilicate short glass fibers having a fiber diameter of less than 5 µm and length to diameter ratio of approximately 500:1 to approximately 3000:1, the constituent fibers of the air filter are dispersed uniformly and, when said constituting fibers at a diluted concentration of 0.04% by mass are allowed to stand for 12 hours, the sedimentation volume is 450 cm 3 /g or greater.