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    Application of PTFE Fiber in Filter Bags
     Mar 31, 2022|View:316

    PTFE is a polymer chemical material containing polytetrafluoroethylene. Packaging, electronic and electrical, chemical energy, corrosion-resistant materials and Teflon high-performance special coatings are widely used in fluorine coatings based on Teflon. Today, let's talk about the application of PTFE fiber in filter bags.

    Application of PTFE Fiber in Filter Bags

    The raw materials for the manufacture of PTFE fiber and tetrafluoroethylene are fluorine ore (calcium fluoride) (for HF manufacture) and chloroform. Reacting anhydrous HF with chloroform to obtain difluoro monochloromethane, boiling the gas at - 41 and decomposing it at a high temperature of 600-800 to obtain tetrafluoroethylene. PTFE, which is formed by polymerization of tetrafluoroethylene monomer through high temperature, high pressure and initiator, is mainly used in suspension polymerization or emulsion polymerization in industrial production. Polytetrafluoroethylene has low surface energy, is not easily soluble in most solvents, and has high melt viscosity. It can not be prepared by ordinary solution spinning and melt spinning. At present, carrier spinning method, slurry extrusion method, membrane crack method, air jet method and so on are mainly used. Carrier spinning is a general method for manufacturing PTFE fibers. Its purpose is to spin with fiber forming polymers such as adhesive and PVA as carriers, and then sinter at high temperature to carbonize the carriers and remove the fibers to form polymers. The general classification of visual carrier can be divided into dry spinning and wet spinning. The carrier spinning process is simple and the fiber linear density is relatively uniform, but the wet spinning carrier is used more, the spinning stock solution is stable, and the energy consumption in the dry spinning sintering process is more. Paste extrusion method is a method disclosed by DuPont patent. PTFE powder and some volatile lubricating substances are prepared into a paste, spun with a nozzle, and then dried and sintered to volatilize the lubricant. After stretching, uneven white ribbon wires are obtained. The obtained fibers have no correct size, generally coarse, but high breaking strength. Membrane splitting spinning method is to evenly mix PTFE powder and lubricant, process it into cylindrical embryo, then roll it into film, obtain narrow strip with a certain width through cutting process, and then obtain PTFE fiber through stretching, sintering and other processes. The size of the fiber prepared by this method is uneven, and the short fiber can be obtained through the cutting process, which can be used for the processing of needle felt products. This method requires high processing temperature, but the process is simple, mature and pollution-free. It is used in large-scale production.

    The air jet method is to put PTFE solid particles into the spinning hole, pass through the high-temperature inert gas flow (nitrogen or argon) under high pressure, form a number of parallel PTFE micron fibers with a diameter of 3mm-5mm and submicron to several microns in the hole under the air jet, and form nano microns on the fiber surface by adjusting the air pressure and temperature. PTFE fiber has good temperature resistance and chemical stability. PTFE short fiber can be used to develop filter materials (such as composite with glass fiber), which is very suitable for the filtration of high temperature and high humidity dust and corrosion-resistant gas. It has good low friction, smooth surface, dust removal, low running resistance, and its temperature resistance, insulation and temperature insulation ensure long service life. In addition, PTFE filament twisting, warping, weaving and other processes can also be used to manufacture micro porous films, which can be compounded with ion exchange resin to play its role in sewage treatment, chlor alkali industry and other fields. PTFE is UV resistant and has good mechanical and temperature insulation properties. It can be compounded with aramid or nylon to prepare thermal insulation layer and tear proof layer in spacesuit. In architecture, the building material that can make membrane structure with PTFE fiber has excellent light transmittance and can reduce the cost of lighting and air conditioning. It has low surface friction coefficient, is not easy to accumulate ash, is light in weight, is anti-seismic and non combustible, can effectively ensure building safety, and can shorten the construction period of large frame roof by about half. PTFE is chemically stable, non-toxic, and has good physiological compatibility. It does not cause human heterogeneity and is convenient for disinfection. Therefore, it can be used in the manufacture of surgical sutures and human soft tissues such as artificial blood vessels and hearts. It has the advantages of anti microbial, long bending life and almost zero tidal rate, and continues to develop in the field of biomedical materials. It is widely used in steel, cement, chemical industry, power plant, highway construction, metallurgy, grain processing, etc.

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