PTFE fiber is a kind of synthetic fiber made of polytetrafluoroethylene resin powder by special production technology. Although PTFE resin belongs to thermoplastic resin, it has unusually high melt viscosity, so it can’t be produced by general chemical spinning process. PTFE fiber has excellent chemical stability of tetrafluoroethylene, so it is widely used as filter materials in high temperature, strong acid, alkali and other environments. 100%PTFE filter material or filter material containing PTFE fiber has become the first choice for waste incineration, blast furnace gas purification, cement kiln tail gas and other special conditions.
PTFE fibers are generally divided into two types
1. PTFE white curly short fiber is generally produced by membrane cracking method, and its fiber strength is greater than that of brown fiber produced by emulsion spinning method. The fiber can also be made into various colored fibers by pigment addition technology according to needs. It is suitable for high temperature environment, excellent in chemical stability, low in shrinkage and anti-aging.
2. PTFE filament fiber is a monofilament fiber manufactured by drawing method, which is mainly used for manufacturing PTFE sewing thread or weaving base cloth.
There are four production methods of PTFE fiber.
1. Emulsion spinning method (see chemical fiber spinning). It is the main method used in industry. Polytetrafluoroethylene emulsion (concentration 60%) with an average molecular weight of about 3 million and a particle size of 0.05～0.5m is mixed with fiber-forming carriers such as viscose or polyvinyl alcohol to make spinning solution. After spinning, the carrier is carbonized at high temperature, and the polymer is sintered to continuously form fibers. This method can produce fibers with small fineness, but it is easy to produce structural defects during sintering, and it is mixed with carrier carbide, so the strength is low and it is brown.
2. Paste extrusion spinning method. Polytetrafluoroethylene powder and volatile matter are blended into paste, extruded by screw, spun into ribbon fiber through narrow slot spinneret, and then fibrillated by needle roller, the fiber with higher strength and larger fineness can be made.
3. Membrane splitting spinning (see chemical fiber spinning). The PTFE powder is sintered into a cylinder, and after cutting or cutting, hot stretching and other treatments are carried out to produce white fiber with low strength.
4. Melt spinning method. The high strength fiber was prepared by melting the copolymer of tetrafluoroethylene, 4% ~ 5% perfluoroethylene and perfluoropropyl ether and spinning.
Post time: Feb-02-2023