What Are PTFE Filter Membrane Used For?

Introduction and Microstructure of PTFE Membrane

PTFE membrane is a microporous membrane made of polytetrafluoroethylene as raw material, using special technology, through calendering, extrusion, biaxial stretching, and other methods. There are different types of PTFE membranes based on their uses. The PTFE membrane has a fibril-like microporous structure with a porosity of more than 85%, 1.4 billion micropores per square centimeter, and a pore size range of 0.02μm-15μm.

Main structure
1. The surface morphology of the PTFE microporous membrane is a spider web-like microporous structure. Pores are formed between the microfibers, and the arrangement direction of the microfibers is basically parallel to the stretching direction; the connection of the fiber bundles is the node, which is formed by the entanglement and connection of many microfibers.
2. PTFE membrane is an asymmetric membrane, and the size of the micropores on the front and back of the membrane is different.
3. The micropore size of the cross-section of the membrane is larger than that of the surface, and the size of the longitudinal and transverse micropores is also different, and the longitudinal micropores are larger than the transverse direction.
4. The cross section of the membrane is a network structure. There are very complex changes in the three-dimensional structure of the pores, such as network connection, pore inlay, pore channel bending, etc. There may be multiple micropores to form a channel, and there may be a micropore with Multiple channels are connected.

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Classification and application

1. PTFE garment membrane
Using the pore-forming properties of polytetrafluoroethylene plastic resin, the microporous membrane is made by the biaxial stretching method. The membrane surface can reach more than one billion micropores per square centimeter, and the diameter of each micropore (0.1μm-0.5μm) is several hundred times smaller than the diameter of water molecules (20μm-100μm) and smaller than that of water vapor molecules (0.0003μm-0.0004 μm) is tens of thousands of times larger, so that water vapor can pass through, but water droplets cannot pass through. Using this microporous structure can achieve excellent waterproof and moisture-permeable functions; in addition, because the pores are extremely small and irregularly arranged in the longitudinal direction, the wind cannot pass through. Through it, it has the characteristics of wind resistance and warmth. After compounding with other fabrics, it is widely used in military clothing, medical clothing, casual clothing, special protective clothing such as fire protection, anti-virus, flooding operations, outdoor sports clothing, and so on.

2. PTFE air filter membrane
Using PTFE microporous membrane unique node fibrillary, smooth surface, chemical resistance, air permeability, and water resistance, large air permeability, flame retardant, high-temperature resistance, strong acid, and alkali resistance, and non-toxicity, it can be used for air purification, atmospheric dust removal, and so on. The products made of the membrane have high filtration efficiency, up to 99.99%, near zero emission; low operating resistance, fast filtration speed; long service life, which can be reused, thus reducing operating costs. It is mainly used for flue gas filtration of various industrial furnaces such as chemical industry, iron, and steel, metallurgy, carbon black, power generation, cement, and waste incineration. Polytetrafluoroethylene filter membrane, the pore size of the membrane can be controlled between 0.2~15μm, and the porosity can reach more than 85%.

3. PTFE air purification membrane
Made of polytetrafluoroethylene, the air purification membrane is stretched to form a microporous membrane. With a special process, laminated on various fabrics and substrates, this membrane is to become a new type of filter material. The membrane has a small pore size (0.05~0.45μm), uniform distribution and large porosity, which can achieve purification and ventilation, by filtering all dust particles including bacteria, while maintaining air circulation. The common use is in medical, biochemical, and other industries.