Acetal resin is a thermoplastic produced by the addition polymerization of an aldehyde through the carbonyl function, yielding unbranched polyoxymethylene chains of great length. Acetal resins are among the strongest and stiffest of all thermoplastics. They are characterized by good fatigue life, resilience, low moisture sensitivity, high resistance to solvents and chemicals, and good electrical properties. They may be processed by conventional injection molding and extrusion techniques, and fabricated by welding methods used for other thermoplastics.

Acetal is mainly used in industrial and mechanical products, such as: gears, rollers, and automotive applications which include door handles, ventilation and cooling system parts, and fuel system components. Acetal is also used in plumbing and irrigation systems because it resists scale buildup, and has excellent thread strength.