What are the characteristics of PTFE fiber

The raw materials for the production of tetrafluoroethylene are fluorite (calcium fluoride)(for the preparation of hydrogen fluoride) and chloroform. Anhydrous hydrogen fluoride reacts with chloroform to form difluoromethane, which boils at -41 and breaks down to form tetrafluoroethylene at 600-800.

PTFE was synthesized from tetrafluoroethylene monomer under the action of high temperature, high pressure and initiator polymerization. Suspension polymerization or emulsion polymerization is mainly used in industrial production. Due to its low surface energy, PTFE is insoluble in most solvents and has a high melt viscosity, so it cannot be prepared by conventional solution spinning or melt spinning.

At present, the main methods are carrier spinning, paste extrusion, membrane separation and air injection. Carrier spinning method is often used to prepare PTFE fiber method, that is, spinning with the polymerization of fiber forming substances, such as viscose, polyvinyl alcohol and so on. It is then sintered at high temperatures to carbonize the carrier, thereby removing the fibers to form material polymerization. In general, according to the classification of the carrier, it can be divided into dry spinning and wet spinning. The carrier spinning process is simple and the fiber line density is relatively uniform. However, the carrier amount of wet spinning is large, the spinning stock is not stable enough, and more energy is consumed in the dry spinning and sintering process. The paste extrusion method was published by DuPont in its patented method. It mixes PTFE powder with a volatile lubricating substance into a paste, extrudes spinning through the spinneret, and then dries and sintering to volatilize the lubricant, stretching to obtain an uneven white ribbon yarn, the resulting fiber does not have a precise fineness, and is usually thicker but has a higher breaking strength. The membrane splitting spinning method is to mix PTFE powder and lubricant evenly, and then process it into a cylindrical blank, and then roll it into a film, and then cut into a narrow strip of a certain width, and then stretch and burn PTFE fiber. The size of the fibers prepared by this method is not uniform enough, and the short fibers can be obtained by the cutting process and can be used to process needle felt products. This method requires a high processing temperature, but the process is simple, mature, pollution-free, has been used in large-scale production. The gas injection method is a method proposed in 2006, which is to put PTFE solid particles into the spinneret hole, pass through a high temperature inert gas stream (nitrogen or argon) under high pressure, and form a number of parallel PTFE microfibers with a diameter of 3 mm to 5 mm (from submicrons to several microns) in the hole under the gas injection. By adjusting the air pressure and temperature, nanoscale holes are formed on the surface of the fiber. 2. Application of high performance PTFE fiber Because PTFE fiber has good temperature resistance and chemical stability, PTFE short fiber can be used to develop filtration materials (such as composite with glass fiber), which is very suitable for filtering high temperature and high humidity dust and corrosion resistant gas. It has good low friction, smooth surface, easy dust removal and low running resistance, and its temperature resistance, insulation and heat insulation ensure its long service life. In addition, PTFE filament can also be twisted, warped, woven and other processes to make microporous film, and then combined with ion exchange resin, in the sewage treatment, chlor-alkali industry and other fields to play its role. PTFE can be combined with aramid fiber or nylon to make space suit insulation and tear protection layer, with UV resistance and good mechanical properties and thermal insulation properties. In construction, PTFE fibers can be used to make membrane structural building materials with good light transmission, which can reduce the cost of lighting and air conditioning. Its surface friction coefficient is low, not easy to accumulate ash, light weight, seismic, non-combustible, can effectively ensure building safety, large frame roof construction period reduced by about half. PTFE has stable chemical properties, non-toxic, good physiological compatibility, no rejection of the human body, convenient disinfection, and can be used to manufacture surgical sutures and human soft tissues, such as artificial blood vessels and hearts. Its advantages of antibacterial activity, long bending life and almost zero moisture regain have led to its continuous development in biomedical materials and other fields. Widely used in steel, cement, chemical industry, power plants, road construction, metallurgy, grain processing.

What are the characteristics of PTFE fiber

1. High temperature resistance: working temperature up to 250℃

2. Low temperature resistance: the temperature is reduced to -195℃, and the elongation of 5% can still be maintained

3. Corrosion resistance: resistance to most chemicals, good chemical inertness

4. Weather resistance: has the best aging resistance

5. Acid and alkali resistance: insoluble in strong acid and alkali and organic solvents

6. Antioxidant: resistant to corrosion by strong oxidants

7. Non-toxic: with physiological inertia

8. High lubrication: low coefficient of friction

The main use of PTFE is as an exhaust gas purification filter for waste incinerators and coal boilers. Non-metal bearings. Plastic fillers and sewing threads for reducing friction, among which filter materials are currently the largest application area of PTFE.