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. Acetal homopolymers are available in several viscosity ranges that meet a variety of processing and end-use needs. The higher viscosity materials are generally used for extrusions and for molded parts requiring maximum toughness; the lower viscosity grades are used for injection molding. Elastomer-modified grades offer greatly improved toughness.
A practical difference between the copolymer and the homopolymer is that the copolymer can accept reinforcement much better than the homopolymer. Thus. the strength of the copolymer can be increased far more easily than that of the homopolymer. Both types can be modified by additives such as PTFE (Teflon®) to increase the resistance to wear.