... permeability and width to produce Polyimide needle felt filter bag. P84 needle punched felt High Temperature resistant, Filter material, good ... applies in Cement kiln, Asphalt, Waster Incinerator, coal boilers, etc.P84 FELT/POLYIMIDE- Recommended continuous operation temperature: 475 F - Maximum ( ... to mineral acids: Good- Resistance to organic acids: Good P84 Needle Punched Felt For Filter Bag