Applications fine powder PTFE

Chemical Applications. The chemical processing industry uses large amounts of granular and fine powder PTFE. Soft packing appHcations are manufactured from dispersions, and hard packings are molded or machined from stocks and shapes made from granular resin. 

Table 5.7. Types of Tubing and Applications Made from Fine Powder PTFE...

Major applications of unsintered polytetrafluoroethylene are as tape in thread sealing and wrapping electrical cables, and as rod and tape in packings. Important properties of PTFE like chemical resistance, broad service temperature, low friction, flexibility, high machine direction strength, and deformability in the cross direction make unsintered fine powder PTFE ideal for these applications. 

Daikin Industries, Ltd. Polyflon TFE PTFE Applications Fine powders (0.2-0A pm) for - tapes, tubes, spaghetti tubes, fine electric wire Dispersions (ADG) for - Anti-stick coatings, cast film, impregated glass fabric. ... 

Electrical Applications. The largest application of PTFE is for hookup and hookup-type wire used in electronic equipment in the military and aerospace industries. Coaxial cables, the second largest appHcation, use tapes made from fine powder resins and some from granular resin. Interconnecting wire appHcations include airframes. Other electrical appHcations include computer wire, electrical tape, electrical components, and spaghetti tubing. 

PTFE aqueous dispersions are made by the polymerization process used to make fine powders. Raw dispersions are polymerized to different particle sizes.24 The optimum particle size for most applications is about 0.2 pm. The dispersion from the autoclave is stabilized by the addition of nonionic or anionic surfactants, followed by concentration to a solids content of 60 to 65% by electrodecantation, evaporation, or thermal concentration.25 After further modification with chemical additives, the commercial product is sold with a polymer content of about 60% by weight, viscosity of several centipoise, and specific gravity around 1.5. The processing characteristics of the dispersion depends on the conditions for the polymerization and the type and amounts of the chemical additives contained in it. 

Another application of PTFE dispersions is the preparation of a variety of compositions with other materials, such as mineral fillers, other polymers in powdered form by co-coagulation. The dispersion of the other component is blended with the PTFE dispersion and the blend is then coagulated. The resulting composition can be processed by extrusion with lubricants (see processing of fine powders) or by compression molding.16... 

Different resins have been developed for use in different reduction-ratio application ranges (105,106). The powders suitable for high reduction-ratio applications, such as wire coatings, are not necessarily suitable for the medium reduction-ratio applications, such as tubings, or the low reduction-ratio applications, such as thread-sealant tapes or pipe liners. Applications and processing techniques are being used, which utilize the unique combination of properties offered by PTFE in fine powder form (107-109). 

PEEK and polytetrafluoroethylene (PTFE) are highly incompatible. However, fine PTFE powder is commonly added to PAEK to act as an internal lubricant in tribiological applications. The PTFE smears across the wear surface and reduces interfacial friction. This reduces interfacial forces and the heat build-up that can lead to failure by melting. PTFE is particularly suitable in applications where there is no external lubricant and the compounds are often reinforced with carbon fibre. PEEK can also be added to PTFE to improve the wear properties of PTFE - although other less expensive polymers can have similar effects. More recently PAEK and PTFE have been blended so as to produce melt-processable PTFE which has a number of interesting properties [24]. This is perhaps the most luilikely example of the use of PAEK to improve the melt-processability of an otherwise hard-to-process material. 

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