... filters according to customers' requirements. 1) Material: polyester, polypropylene, PPS, PTFE and all compound needle punched filter felt.2 ... according to customers’ requirements, such as polyester, polyester, polypropylene, PPS, PTFE and all compound needle punched filter felt. ... filtration in chemical,carbon black, iron and steel, non-ferrous metallurgy, coal-fired boiler, refractory and cement industries ...