There is often some confusion about the difference between the most common grades of PTFE, often called Teflon: virgin grade and mechanical or reprocessed grade. This information will help you understand these two types and their different applications and thus save you time researching the information.
materials and applications
PTFE (polytetrafluoroethylene) is a type of plastic better known by the brand name Teflon®. PTFE resins have a continuous temperature rating of 500°F (260°C). The mechanical properties begin to degrade above this point.
Both virgin and mechanical grades are 100% PTFE material and have similar chemical properties. Both are unfilled types of PTFE. Other types are available with fillers such as carbon, bronze, or glass to improve performance in certain applications.
Mechanic PTFE is an economical reprocessed PTFE with slightly lower physical properties than virgin grade. It is also known as “recycled” or “reclaimed.” Reworked material is added during the manufacturing process; usually a small percentage but varies. It is cheaper than virgin. This is the grade used for most applications, for less demanding uses where high purity materials are not required, such as non-critical chemical, electrical and mechanical applications. It has better wear resistance and compressive strength than the virgin grade. Not suitable for contact with food.
Virgo PTFE is a higher quality pure material and is more expensive. It is made with no added recycled material. It is chemically inert up to 500ºF, the best chemically resistant material available. Virgin has better physical properties and retains flexibility at low temperatures. It is a good electrical insulator, with high dielectric properties. It is FDA approved and is used in the pharmaceutical, food and beverage, and cosmetic industries. Often used for medical or electrical applications. Virgin has better friction characteristics, which can be important in some applications.
How do you know if you have Virgin or Mechanical PTFE?
Distinguishing between the two grades with the naked eye is certainly not easy! To the naked eye, the two grades may appear identical.
The virgin grade is usually a purer white when compared side by side, and should feel smoother and slipperier.
Additional Information
PTFE is commonly referred to as Teflon®, which is actually a registered trademark of DuPont for their brand of PTFE resin. Other manufacturers use different brands, such as Fluon® or Dyneon®.
For the ASTM standard, see ASTM D1710 Standard Specification for Extruded Polytetrafluoroethylene (PTFE) Rods, Heavy-Wall Tubing, and Basic Shapes.
