Meta-Aramide (MA) needle felt, also known under the trade name “Nomex” (from DuPont needle felt manufacturer), is used in dry industrial filtration when process temperatures exceed 160ºC. Filter bags made from Aramid can operate at a constant temperature of up to 200ºC. However, the service life of the bags at this temperature depends on the consistency of the air-dust mixture. This needle felt can withstand short-term temperature peaks of up to 220ºC, but for no longer than a few minutes (per peak).
This needle felt is widely used in the foundry industry, gypsum industry, cement industry, road construction, and for drying of aggregates.
Meta-Aramide can also be used in filtration material called “Asphalt”, a mixture of aramide and polyseter fibers, among others. It falls in-between the properties of Aramide and polyester needle felts. This material can withstand a constant operating temperature of 160ºC and short-term temperature peaks of up to 180ºC, values which conventional polyesters never reach. Moreover, the price of “Asphalt” is very competitive compared to pure “Nomex”.