Air filter medium, process of producing filter medium, air filter pack for air filters, and air filter unit for air filters

摘要

An air filter medium is provided with a porous film made from a polytetafluoroethylene, and a non-woven fabric laminated on at least one side of the porous film. The non-woven fabric has an apparent density satisfying the following equation: apparent density (g/cm<3>)<1.5x(basis weight (g/m<2>)/1000)+0.11. The filter medium is produced by a process that includes a first step of producing a porous film formed from a polytetrafluoroethylene, and a second step of laminating a non-woven fabric on at least one side of the porous film on heating roll that has undergone a non-adhesive treatment. The filter medium is used to manufacture an air filter pack, while the air filter pack is used to manufacture an air filter unit.