Patent ID: 9072993
Filing Date: 2015-07-07
Classification: B01D

Abstract:
1. A filter medium comprising: a porous film including polytetrafluoroethylene, having an average pore diameter of at least 2.5 μm, and having a porosity of at least 95%; and a support material supporting the porous film, a pressure loss being less than 100 Pa when air is passed through the filter medium at a velocity of 5.3 cm/sec, a collection efficiency of NaCl particles being at least 95% when air including NaCl particles with a particle diameter of 0.3 μm is passed through the filter medium at a velocity of 5.3 cm/sec, a PF value being at least 30, where PF={−log [(100−collection efficiency (%))/100]/pressure loss (Pa)}×1000, and a dust holding capacity of polyalphaolefin particles held in the filter medium being at least 15 g/m