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This post was last edited by Xin Ruifangxiao on 2025-6-13 08:50. Click the blue text to follow us. Polytetrafluoroethylene (PTFE) gaskets are widely used in various situations that require high corrosion resistance and chemical stability due to their excellent chemical resistance and unique physical properties to meet the needs of different applications. From the initial PTFE sealing material to later, scientists have developed sPTFE, ePTFE, rPTFE sealing materials and so on. / 1. Molded Sintered PTFE/ Molded Sintered PTFE Sealing Materials Molded Sintered PTFE sheet is the earliest product launched on the market. They are made from virgin or reprocessed PTFE resin without any added fillers, which is first molded, then compressed and sintered. Like any plastic product, PTFE exhibits creep properties when subjected to compressive forces. This characteristic is very detrimental to the performance of the gasket as it requires frequent retightening to avoid and reduce leaks. Creep behavior increases significantly with increasing temperature. The main advantages of molded PTFE are low cost, sufficient market supply and high chemical resistance. / 2. Turned PTFE / Skived PTFE Sealing Materials Turned PTFE (sPTFE) sheets are made by scraping sintered PTFE blanks to overcome the manufacturing defects of the molding process. However, scraper PTFE products still suffer from the same creep issues. To reduce the creep behavior of molded or scraped PTFE sheets, mineral fillers or fibers are added. However, due to the manufacturing process (molding or scraping), this reduction is not sufficient to produce a long-term effective seal. / 3. Filled molded or turned PTFE / Molded or Skived Filled Sealing Materials In order to reduce the creep behavior of molded or turned PTFE sheets, filled molded or turned PTFE sealing materials have also been developed. Try to solve the creep problem by adding mineral fillers or fibers. However, due to the manufacturing process (molding or scraping), this reduction is not sufficient to produce a long-term effective seal. / 4. Expanded PTFE/ePTFE Sealing Materials Before sintering, PTFE undergoes special treatment to give it the ability to overcome creep. Expanded PTFE sealing materials manufactured through special processes are available in uniaxial stretch (strip) and multi-directional stretch (strip/sheet). Expanded PTFE (ePTFE) has high chemical resistance and very high compressibility, making it ideal for fragile or glass-lined flanges. Most expanded PTFE products on the market do not contain fillers. Its main disadvantage is that it is difficult to install without being able to separate the flange. / 5. Restructured modified PTFE/Restructured Filled PTFE Sealing Materials In order to reduce the creep phenomenon, a new type of reinforced filled PTFE sheet has been developed, also called rPTFE. Through the lamination process, a highly fibrous structure is formed before sintering, * * Reduces creep phenomena at room temperature and high temperature. To meet the needs of chemical services, a variety of mineral or artificial fillers are used, such as barite, mineral and synthetic silica, barium sulfate or hollow glass beads, etc. Each filler has specific applications, but there may be overlap in many applications. Although traditional PTFE sealing materials have certain limitations, these problems have been overcome through the development of advanced processes such as ePTFE and rPTFE. By adding fillers or fibers and using special processes, traditional PTFE sealing materials can achieve better creep resistance. With a variety of filler options, they can be tailored to meet specific chemical service needs, ensuring long-term and effective sealing performance in a variety of harsh applications.