Polypropylene (PP) fiber is one of the most moisture-resistant synthetic fibers. Its moisture regain is close to 0 under standard conditions. When it is wet, it absorbs only 0.6% moisture by weight and does not change its properties. Polypropylene fiber has good wear resistance and high elastic recovery. When the load increases, the creep elongation of polypropylene fibers is larger than that of polyester fibers. Polypropylene fiber can withstand 90 degrees Celsius temperature. The chemical properties of polypropylene are the best among all chemical fibers. It has both acid and alkali resistance. It has good resistance to other acids except oxidizing acids such as chlorosulfonic acid and concentrated nitric acid.
The alkali resistance of polypropylene fibers is also strong. Except for the strong caustic sodium, other alkali has no effect on it. Polypropylene fibers have good electrical insulation properties, but polypropylene fibers are easily decomposed by light and heat. Polypropylene fibers are excellent thermoplastic fibers.
Due to the limitation of low temperature resistance only, polypropylene needle-punched filer felt is specially used in wet and low temperature conditions. Polypropylene filter rolls are often used in low temperature pulse jet filter bags of smelters and in pulse jet filter bags of chemical and pharmaceutical factories.
