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