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Acetal is the common name for a family of thermoplastics with the chemical name “PolyOxy-Methylene”. Acetal is available in a general purpose copolymer grade, a homopolymer version (Delrin®), and several filled Delrin grades. Acetal provides high strength and stiffness, enhanced dimensional stability, and is easy to machine. As a semi-crystalline material, acetal is characterized by a low coefficient of friction and good wear properties.


  • High strength, stiffness, dimensional stability
  • Very low moisture absorption
  • Good wear and abrasion resistance
  • Wide range chemical resistance (including many solvents)



The copolymer grade offers excellent performance at a slightly lower cost than Delrin. Acetal copolymer may exhibit center line porosity, but porosity-free material is available. Certain grades are FDA, USDA, NSF, Canada AG and 3-A Dairy compliant. Low stress levels and high strength assure flatness and dimensional stability up to a maximum continuous service temperature of 180°F (80°C). Acetal copolymers are available in a wide variety of colors, including red, orange, yellow, green, blue, violet, black, white & natural.

DELRIN (unfilled)

Delrin acetal homopolymer offers slightly higher mechanical properties than acetal copolymer, but may contain a low density center (also known as “center line porosity”) especially in large cross-sections. The homopolymer also gives slightly less chemical resistance than copolymer acetal. For example, Delrin is ideal for small diameter, thin-walled bushings that benefit from the additional strength and rigidity of homopolymer acetal. Delrin is available in black & natural colors.


This material is manufactured from Delrin homopolymer resin which has been uniformly filled with a dispersion of PTFE (Teflon®) fibers. Delrin AF is a unique thermoplastic material for use in moving parts in which low friction and long wear life are important. It retains 90% of the mechanical strength of unfilled acetal homopolymer, while offering very low friction and almost no “slip-stick” behavior. Delrin AF is brown in color.

DELRIN and TEFLON are registered trademarks of DuPont.