Acetal Copolymer -vs- Homopolymer

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*Updated with additional information on 8/30/2016

Acetal, also known as poyoxymethylene (POM), is a very commonly used thermoplastic material that we are all familiar with. Everyone in the industry has a story of the time when someone ran some acetal at too high a temperature and had it degrade filling the plant with formaldehyde. However, not everyone is aware that there are actually two different versions of acetal on the market, copolymers and homopolymers.

I see a lot more copolymer being used than homopolymer at injection molders which puzzles me. This might be because the homopolymers tend to come at a premium price. Sometimes, however, you get what you pay for. A brief history of acetal might explain why homopolymer is more expensive and also why you should consider using it

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Relative Temperature Index is the Best Measure of Heat Resistance

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In specifying materials for certain applications, we might need to know what kind of heat resistance that the material has. This is a vague concept at best. What do we mean by heat resistance? Can the heat resistance of a material be altered with additives or fillers?

Let’s delve into a few of these issues and I will show you where to find the best indication of heat resistance of plastic materials as well as give you some guidelines that you can use for picking materials.

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Weekly News Digest-August 1, 2016

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BASF reports considerable decline in sales for 2016

Perhaps plastics are not so bad for the environment after all

Dyna Purge introduces new purging compound for polypropylene color changes

Great bargains are available in the PP/PE market

Star Plastics opening compounding facility in China

PolyOne acquires Gordon Composites and Polystrand

Chevron opens pilot PE plant in Oklahoma

Imports continue to drive down PP pricing

PP prices drop another penny

SABIC & Exxon Mobil plan major US complex

Ampacet expanding in Canada and consolidating in Australia

When Plastics Need Memory

 

Hard Drive
5 MB of memory in 1956

When we speak of memory in plastic materials, we are talking about a plastic parts ability to return to its original shape after it is deformed in some way. More specifically, we are talking about a part being able to return to its original shape after being held in a flexed position for an extended period of time.

The question is, what makes a material have good memory and what materials are best used for applications that require this property?

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