These are both polyacetal grades, manufactured by companies such as Quadrant Engineering Plastics.

Acetal is a copolymer version;
Copolymer grades tend to be more resistant against hydrolysis, strong alkalis and thermal-oxidative degredation than the homopolymer grades.

Delrin is a homopolymer version;
The homopolymer grades have a higher mechanical strength, stiffness, hardness and creep resistance as well as a lower thermal expansion rate and often it also presents a better wear resistance.

Be wary of listings with both the words 'Acetal' and 'Delrin' in the title- they may be trying to sell Acetal at Delrin prices, which are usually slightly higher.

Look out for brand-names, Ertacetal for example comes in a number of forms- Ertacetal C is a copolymer Acetal, Ertacetal H is a homopolymer made from genuine DuPont Delrin resin.

Both products are usually available in Natural (White) and Black. Acetal is made in other colours, with Blue being a popular choice in the food industry.

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