by Jackie Johnson Jackie Johnson No Comments

The Illustrious History of PTFE

Spring Energized PTFE Seals

Today PTFE is one of the most widely used materials in the world. So, it may come as a surprise to learn that it was discovered entirely by accident!

How was PTFE discovered? In April of 1938, Dr. Roy Plunkett and his assistant Jack Rebok were working as chemists at DuPont’s Chemors Jackson Laboratory in New Jersey. On the night of the 6th, they stored the gas they were experimenting on (tetrafluoroethylene) in small cylinders where they were then frozen and compressed.

When the men returned the next day, they discovered that the gas they stored was gone. When they released the nozzle of the cylinders, no gas was released. Thinking this odd, they split the cylinders open to find the gas had turned into a solid, white, and waxy material.

This material would later become known as PTFE (polytetrafluoroethylene) or better known by its brand name Teflon.

The History of PTFE

Dr. Plunkett continued research on this strange new material and found that it was not only one of the slipperiest materials known, but that it also had several other incredible properties such as:

  • Non-Corrosive
  • Chemically Stable
  • Extremely High Melting Point

In 1941, Kinetic Chemicals Inc, a company founded by DuPont and General Motors, patented the new fluorinated plastic. In 1945 the name Teflon was trademarked. By 1948, Kinetic Chemicals was making over two million pounds of the Teflon brand PTFE.

PTFE-Coated Cookware

It wasn’t until 1954, when French-woman Collette Grégoire, wife of engineer Marc Grégoire, asked him to try the material he had been using on fishing tackle on her cooking pans. He subsequently created the first non-stick pans under the brand name Tefal (which is an amalgamation of “Tef” from “Teflon” and “al” from aluminum). The first PTFE-coated pan was introduced in the US in 1961 as “the Happy Pan”. Since then, non-stick cookware has been a staple in kitchens around the world.

Aside from cookware, PTFE has been used in a wide variety of applications, from food processing to the space industry. In fact, PTFE was used in the initial moon landing in 1969, as it was the only plastic that could withstand the extreme atmosphere of space.

Since then, PTFE has become a staple in our everyday lives and will continue to be so for many more years to come.

Need PTFE sealing solutions? Contact us today for more information!

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Spring Energized Seals for Use in Food Processing, Pharmaceutical, and Medical Applications

Spring-energized seals are a popular choice for applications that involve food, dairy, and medicinal applications, as well as medical devices. However, not just any polymer can be used for these seals because of the risk of contamination. In this blog post, we are going to review why FDA approved materials are so important, and then talk about the three most common engineering polymers that are used with spring-energized seals.

FDA Approved Materials

The FDA CFR 177 is contained in Title 21 of the Code of Federal Regulations and deals with indirect food additives in the form of polymers. The term indirect additive refers to something that inadvertently makes its way into food, pharmaceuticals, or inhaled substances (i.e., via an inhaler or oxygen machine).

Real-world applications where FDA approved materials are of concern include filling and mixing equipment for food and beverages as well as pharmaceutical products that can include pills, powders, caplets, tablets, liquids, oral suspensions, and inhalers. In the context of medical equipment, FDA approved materials are key to the design of devices that must be free of contamination.  For analytical equipment it is vital that samples are not contaminated; machines and devices for treatment, such as blood dialysis machines or ventilators, must not have any contaminants that can harm the patient.

Spring Energized Seals with FDA Approved Materials

When spring-energized seals are combined with FDA approved materials, the result is a durable, reliable seal that is safe for use in food processing, pharmaceutical, and medical applications. Three of the most common materials used are UHMW PE, Virgin PTFE, and mineral-filled PTE

UMHW PE

UHMW PE (Ultra High Molecular Weight Polyethylene) is an FDA and USDA engineering polymer with an extremely low coefficient of friction, low moisture absorption, and good chemical compatibility. In addition, it can withstand rigorous sterilization requirements that may involve hot water, steam, or aggressive chemicals. One of its key characteristics is its self-lubrication, which eliminates the need for lubricants that could cause contamination issues.

Virgin PTFE

PTFE (Polytetrafluoroethylene) often goes by the trade name Teflon. Virgin PTFE, which has no fillers added, has the lowest coefficient of friction of any material in existence. It is also one of the most chemically inert engineering polymers and handles extreme temperatures (both cold and hot) and is both thermally and dimensionally stable. Like UHMW PE, it is also FDA and USDA approved as well as self-lubricating.

Mineral-Filled PTFE

Mineral-filled PTFE takes the outstanding properties of PTFE and enhances them for improved wear performance and strength. It, too, is FDA and USDA approved, self-lubricating, a wide range of operating temperature, chemical inertness, and compatibility with even the most aggressive cleaning and sterilization regimens.

Conclusion

Spring-energized seals provide the often mission-critical reliability that is demanded in industries involving food, medicine, and medical treatment. However, they must be matched with an FDA approved polymers such as UHMW PE, virgin PTFE, or mineral-filled PTFE.