Filter bags made of polyimide (or P.84) needle felt mixed with PTFE fibers result in a material with highly desirable properties.
It is a material that can be easily used at a constant operating temperature of 220-240 ° C. Due to the 80% PTFE content in this mixture, its chemical resistance is also very high. This reduces the risk of negative impact of NOx, SOx. This material is always formed on a PTFE fiber support, which significantly enhances its stability.
This needled felt is less brittle compared to 100% PTFE. The available weights are a median between P.84 (500-550g / m2) and 100% PTFE (700-780g / m2). Such a mixture results in a lower price than PTFE and a higher resistance than pure P.84.
The most commonly used weights are: 580, 630, 650, 680 g / m2. The oil / water-repellent PTFE-based finish additionally makes the needle felt anti-adhesive.