What are the properties of Delrin® and Acetal?

Compare these strong, durable materials

We’re often asked this question: Are Homopolymer Acetal and Acetal Copolymer the same thing? While it may seem like a simple question, the answer is a bit complex. The reason is because Delrin® (Homopolymer Acetal) and Acetal Copolymer are two materials that are very similar but also quite different.

The most popular name for Homopolymer Acetal is DuPont™ Delrin®, which is a premium type of Homopolymer Acetal and is produced by DuPont. Many of the physical properties of the Homopolymer exceed that of Acetal Copolymer, and there are many suppliers for the Acetal Copolymer resin.

What is Delrin® Plastic?

Delrin® is a tough, durable plastic that has excellent wear properties. It’s a thermoplastic used for making both moldable grade and machinable grade components for durable, high performance parts. Delrin® plastic can be blended with other compounds to improve its mechanical properties and comes in various colors. It’s used in gears, door system components, ski bindings, and zip fasteners. Delrin® maintains its toughness, rigidity, and dimensional stability, even at extremely high temperatures. Along with excellent wear resistance, Delrin®’s unique properties make it one of the most widely used thermoplastics in existence today.

What is Acetal Plastic?

Acetal plastic, also called polyacetal and polyoxymethylene (POM), is a general purpose, semicrystalline, engineered thermoplastic. Acetal is often used for parts that require strength, stiffness, low surface friction and excellent dimensional stability, or the ability of a plastic part to maintain its original dimensions when it is exposed to changes in temperature and humidity. A few examples of items that are often made of acetal plastic include sports materials, musical instruments, and vehicle tanks.

Delrin vs. Acetal: What’s the main difference?

Although Delrin plastic is a type of acetal and they are both used for similar applications, there are some key differences between the two. Because Delrin has a uniform crystalline structure rather than one with multiple subunits, it offers higher stiffness, flex fatigue resistance, and creep resistance (resisting being deformed over time due to stress) compared to other types of acetal plastic. One of its drawbacks, however, is that it is less resistant to chemicals than other forms of acetal plastics.

How acetal and Delrin are used

Due to their similarities, both of these plastics are used in a lot of the same applications. They are found in the automotive, construction, consumer goods, electronics, and food processing industries. Because of its greater stiffness and creep resistance, Delrin is more common in components like gears, bearings, bindings, and fasteners. Acetal, on the other hand, is more often used in food processing equipment parts, nozzles, tanks, and other components where greater chemical resistance is important.