PTFE's Chinese name is polytetrafluoroethylene, commonly known as "non-stick coating" or "easy to clean material.
This material has acid and alkali resistance, resistance to various solvents, almost insoluble in all solvents. At the same time, PTFE seals have the characteristics of high temperature resistance, its friction coefficient is very low, so it can be used for lubrication, but also become the ideal coating for easy to clean the inner layer of water pipe.
PTFE seals are produced by free radical polymerization of PTFE. Industrial polymerization is carried out by stirring in the presence of large amounts of water to disperse the heat of the reaction and to facilitate temperature control.
Polymerization is generally carried out at 40 ~ 80℃, 3 ~ 26 kg force/cm 2 pressure, can use inorganic persulfate, peroxides as initiators, can also use REDOX initiation system.
The heat release was 171.38kJ per mole of PTFE polymerization. Dispersion polymerization requires the addition of perfluorinated surfactants, such as perfluorooctanoic acid or its salts.
Shortcomings of PTFE seals:
1. PTFE seals
With "cold flow". That is, the plastic deformation (creep) of material products under long time continuous loading, which brings certain limitations to its application. For example, when PTFE is used as a seal, the bolt is tightened so tightly that it exceeds a specific compression stress, which will cause the washer to produce "cold flow" (creep) and be squashed. These shortcomings can be overcome by adding appropriate filler and improving the structure of parts.
2. PTFE seals have outstanding non-viscosity, limiting its industrial application. It is an excellent anti-stick material, which in turn makes it very difficult to bond to other surfaces.
3. the linear expansion coefficient of PTFE sealing material is 10~20 times of steel, larger than most plastics, its linear expansion coefficient with the change of temperature and very irregular changes. In the application of PTFE, if attention to this aspect of the performance is not enough, it is easy to cause losses.
Application of PTFE material:
1. Can be used for rod, tube, plate, cable material, raw material belt and other materials production, after secondary processing can also be made into sheet, film and a variety of Shenyang sealing products, can also be used as a lubricant, thickening agent.
2 can be used as plastics, rubber, paint, ink, lubricating oil, grease and other additives.
3. Can be pressed into thin wall tube, fine bar, special-shaped bar, wire and cable insulation layer, rolled into thin belt for pipe wire buckle all special PTFE sealing material.
4. Used in machinery, electronics, chemical industry for spraying, impregnation, etc.
5. Can make film, tube plate rod, bearing, PTFE seals, valves and chemical pipe, pipe fittings, equipment container lining, etc., used in electrical appliances, chemical aviation, machinery and other fields.
6 PTFE seals are mainly used in the electrical industry, in aerospace, aviation, electronics, instruments, computers and other industries used as power and signal line insulation layer, corrosion resistance, wear-resistant material.
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