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Publicado en : 28-10-21
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Polytetrafluoroethylene (PTFE), a strong, tough, waxy, nonflammable synthetic resin produced by the polymerization of tetrafluoroethylene. Known by such trademarks as Teflon, Fluon, Hostaflon, and Polyflon, PTFE is distinguished by its slippery surface, high melting point, and resistance to attack by almost all chemicals. These properties have made it familiar to consumers as the coating on nonstick cookware; it is also fabricated into industrial products, including bearings, pipe liners, and parts for valves and pumps.
PTFE was discovered serendipitously in 1938 by Roy Plunkett, an American chemist for E.I. du Pont de Nemours & Company (now DuPont Company), who found that a tank of gaseous tetrafluoroethylene refrigerant had polymerized to a white powder. During World War II it was applied as a corrosion-resistant coating to protect metal equipment used in the handling of radioactive material for the Manhattan Project. For more than a decade after the war, PTFE saw little commercial use, owing to difficulties encountered in devising methods for processing the slippery, high-melting material. DuPont released its trademarked Teflon-coated nonstick cookware in 1960.
PTFE Fine Powders
Chemours is a leading producer of fluoropolymers that include Teflon? PTFE (polytetrafluoroethylene) fine powder resins.
These fine powders may be paste-extruded to create continuous-length PTFE articles such as tubes, tapes, and membranes. PTFE fine powder is the preferred fluoropolymer for many applications, including breathable hydrophobic membranes, aerospace/automotive hoses, and high-performance wires and cables.
Features and Benefits
This family of fine powder fluoropolymer resins offers a wide range of characteristics that include:
Excellent thermal stability
High stress crack resistance
High reduction ratio
Excellent color and clarity
Polytetrafluroethylene ultrafine powder
PTFE ultra-fine powder can be prepared by irradiation at room temperature, followed by ultrafine grinding. Fresh PTFE material, scrap or recycled PTFE waste, etc., can be used to fabricate ultrafine powder. The use of recycled PTFE or waste to produce ultrafine powder can reduce the cost and achieve the recycling of resources. PTFE ultrafine powder is widely used as a functional additive in the fields of engineering plastics, anticorrosion coatings, nonstick coatings, coil coatings, powder coatings, and inks. Shamrock Technologies (the United States), Solvay Company (Italy), Lubrizol Corporation (Germany), Kitamura Company Ltd. (Japan) and many other companies produce PTFE ultrafine powder. In recent years, domestic Chinese enterprises have also made great progress in the technology of manufacturing PTFE ultrafine powder.
The particle size of PTFE powder is usually tens to hundreds of microns, which is suitable for producing PTFE sheet and pipe. PTFE ultrafine powder can be made by polymerization, radiation degradation, and thermal cracking. The irradiated PTFE becomes very brittle, and can be further fabricated into ultrafine powder by grinding or air-jetting. The particle size is closely related to the absorbed dose. The higher the absorbed dose, the lower the relative molecular weight of PTFE, and the smaller the particle size of ultrafine powder. At present, PTFE ultrafine powder is mainly prepared by radiation degradation at home and abroad, since high energy beam can effectively break the molecular chains of PTFE at room temperature. For recycled PTFE, a very high absorbed dose is required for the fabrication of PTFE ultrafine powder. Hence, it is normally irradiated by EB accelerators. PTFE ultrafine powder is mainly used as an additive in lubricating oil and grease, ink, paint, engineering plastics, leather, rubber, etc., in order to improve antifriction and scratch-resistance.
PTFE teflon powder is available as a white powder, often called fine powder. PTFE fine powder is generally converted into usable articles (shapes, wire insulation and tapes, etc) via paste extrusion, followed by post extrusion heating to remove residual hydrocarbon solvents and to increase material density.
Products manufactured with genuine Teflon PTFE fine powder are rated for continuous service temperatures up to 260°C (500°F).
The properties of Teflon PTFE fine powder are very similar to those of standard Teflon? PTFE granular material.
Insulation for wire and cable, tubing, pipe liners, films, sintered and unsintered tapes, micro-porous membranes, heat shrink tubing, bushings, push/pull cables, profile shapes and other end use components requiring a high performance fluoroplastic material.
5 Key Products That Are Enhanced With PTFE Micropowders
Polytetrafluoroethylene (PTFE) micropowders are used as additives in thousands of products. They can add lubricity or improve friction and wear characteristics of base materials. Because PTFE micron powder is milled very fine, it can be compounded in rubber, plastics, or dispersed in liquids. Here are 5 ideal applications:
PTFE lubricant powders are superior to the conventional anti-scuff agents that are used in inks. They enhance the preparation of offset, heat-set, gravure and flexographic inks. They improve the rub and scuff resistance of printed stock. And they reduce “blocking,” the undesirable adhesion of a painted surface to another painted surface or material, reducing rejects.
In addition, micropowders can be easily dispersed at room temperature to make processing cheaper and more efficient. Their lubrication properties reduce friction so they slide and stack easier, and their temperature resistant properties allow them to be used in temperatures up to 260 °C.
Coatings and Industrial Finishes
PTFE powders can be added to many industrial finishes to improve surface lubrication, reduce blocking and promote scuff resistance. For example, they impart abrasion resistance, corrosion resistance and anti-friction properties in bakeware and cookware, and can be used to provide a non-stick surface.
Most bakeware and cookware are fabricated from strips of steel or aluminum that are pre-treated with a PTFE coating. Micropowders also act as a processing aid during the stamping, folding and cutting manufacturing process.
PTFE micropowders are added to decorative, masonry, aircraft and marine paints to improve their water resistance, scuff and abrasion resistance, and anti-fouling properties. These powders can also reduce flammability and improve paint’s spreading rate.
The benefits of micropowder lubricants for paints include:
Matte-based paints that are traditionally difficult to clean become easier with PTFE micropowders.
Marine coatings exhibit excellent anti-fouling properties.
Gloss coatings have a smoother surface and fewer imperfections due to the small particle size.
Lubricants are added to elastomer formulations to improve the coefficient of friction and wear properties versus solid lubricants, waxes, stearates, soaps, plasticizers and oils.
Adding lubricant powders to natural rubbers and synthetic elastomers during processing gives finished moldings many of the surface slip characteristics of PTFE. These characteristics include: improved mold release, lower static and dynamic coefficients of surface friction, abrasion resistance, elimination of stick slip and improved tear strength.
Oil and Grease
PTFE micropowders are ideal for improving lubrication in applications that experience extreme pressures, temperatures and environments. They are also used in applications where conventional additives such as graphite and molybdenum are unsuitable.
In addition, PTFE additives offer cleanliness, an important characteristic for greases used in food, pharmaceutical and dairy equipment. Because PTFE is not flammable, it is ideal for applications where the lubricants are exposed to gases and other potential fire hazards.
PTFE micropowders provide benefits to a wide range of applications for various industries.