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Life Cycle of Plastic: Impacts on Business and the Economy

By Protomold - Nobody's Faster In The Short Run®

Over the last sixty years, plastic has become one of the most common materials in the man-made world. As a result, we take it for granted, thinking little about its origins and less about its cost, especially since it costs less than most of the materials it has replaced. At the same time, aside from recycling our pop bottles, we don't think much about where our plastic goes once it has served its purpose. But, as the cost of petrochemicals skyrockets and concern with the environment continues to grow, we'll have to think more about plastic's origins and destinations, both as consumers and as producers of plastic components.

It wasn't long ago that we were alarmed by petroleum prices of $50 a barrel. As this is being written, that price is approaching $100 a barrel and still climbing. Ask most consumers how petroleum prices affect them and they'll cite transportation; not surprising, considering that half of our petroleum is refined into gasoline. But the cost of gas is still small compared to the cost of the cars we drive, and smaller still compared to the wages we earn at the jobs we drive to. Resin, on the other hand, typically represents three-quarters of the cost of a plastic part, making the cost of the part very sensitive to oil prices.

What's a resin user to do? First, we need to recognize that the problem isn't going away. As far back as 1956, geologist M. King Hubbert predicted a near-term mathematical peak in oil production, and while experts still argue over whether "Hubbert's Peak" is approaching or has already passed, few dispute its existence. Meanwhile, world demand continues to grow. We can assume that consumers will bus, carpool, or downsize their vehicles before they cut back on plastic purchases, but it's not too early to start thinking about controlling material costs.

Obviously, the purchasing department will do its share, but designers will have a role as well. Choice of materials will be more critical than ever. So will design as a means of achieving maximum performance using no more material than is absolutely necessary. And since per-piece material savings will be multiplied by thousands, or even millions, when parts go into production, careful performance testing in the prototyping stage will be critical.

Finally, while the technology is still young, chemists are beginning to produce plastics that do not rely directly on petrochemicals. Among the most promising petrochemical alternatives is polylactic acid (PLA), a thermoplastic aliphatic polyester derived from corn or sugarcane. The material is also of interest for its possible benefits at the back end of plastic's life cycle, where PLA shows some promise of biodegradability. While it can not yet be broken down in your backyard compost heap, it does have potential in that arena that traditional resins lack.

As always, engineering is an exercise in overcoming challenges, and anticipating the challenge is the first step in the process. The First Cut Prototype and Protomold divisions are here to help with design guidance you can use to maximize part manufacturability, as well as the prototype parts you can test to make sure you've achieved the required functionality.