MAY 2013 IN


Polypropylene has quietly become the new favorite plastic.

It is a surprising shift, given that polypropylene is about 50 percent more expensive to manufacture than any of its three predecessors, polyethylene terephthalate (PET), polyethylene, and polyvinyl chloride (vinyl). But it is preferred, I think, for two main reasons. First, it is lighter, so the savings in shipping costs might make up most or all of the added manufacturing costs. Second, it is more heat-resistant, so that you can use it in the microwave oven and dishwasher. In fact, dishwashers have mostly been made of polypropylene for the past 30 years.

Polypropylene has been around for ages. I first learned about it as the material in the floating rope preferred by boaters. But now, it is being used as the go-to material for containers. Besides the two main advantages I mentioned, it is strong, flexible, and apparently relatively non-toxic when compared to common forms of PET and vinyl — which means it is safe to reuse food containers made from it. And it is every bit as recyclable as these other plastics. You can identify a polypropylene container by its “PP” recycling mark.

As energy prices continue to increase, the light weight of polypropylene will ensure that it remains popular for some time to come.

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