Polyoxymethylene, better known as acetal plastic, is a thermoplastic that has high stiffness, excellent dimensional stability, high flow, and a low coefficient of friction. It is commonly used for gears and bearings, structural automotive parts, and some applications that you might not expect such as lids for food containers and automotive speaker grills.

Acetal resins provide a well-balanced set of properties including a hard self-lubricated surface and excellent chemical resistance, fatigue resistance, high strength stiffness, moisture absorption, and wear resistance over a broad temperature range.

Acetal plastic is available in two primary forms, copolymer and homopolymer. Homopolymer acetal has higher tensile strength than copolymer but copolymer offers better flexibility and is significantly less expensive. It is commonly reinforced with glass fiber or glass beads which increases the strength and dimensional stability further. Acetal copolymers tend to respond to glass fillers and reinforcements better than homopolymers making them preferred.

It is available in a wide variety of melt flows to accommodate profile extrusion to injection molding of very intricate parts.

The typical brands of acetal plastic resin offered by Midwest Resins are: