Biopolymer Supply Chains To Reduce Toxic Exposures


In response to Lloyd's recent post on toxins in plastics, a commenter remarked "I too look forward to some solutions". Challenge accepted; we're all on the trail. Lloyd followed up right away with some good rules of thumb . Now here's what we're talking about. From the distance, closer by the day, comes the sound of the Biopolymer Calvalry, charging down the supply chain to offer biodegradable water bottles made of polylactic acid, a.k.a. "PLA" or "corn plastic". Once the supply chain is set up with the right raw materials (PLA), the necessary tools (like Norland's blow molding equipment offerings to the bottling industry, shown below the fold), and consumer recognition, solutions will proliferate for many applications.Paraphrased from the PRLEAP press release: ' Norland introduces the first small-bottle blow molders capable of producing bottles for bottled water or other uses from corn-based plastics (PLA) for use by small to medium-sized bottling operations. The compostible bottles are produced by using pre-forms made of PLA, a 100% corn-based plastic developed by NatureWorksLLC , a wholly-owned Cargill company, in Minnetonka, Minnesota'.

Readers please note: TreeHugger's Kyeann Sayer's excellent post on the pictured Biota product is worth reading to see the full life cycle context for PLA-based bottles and other single use plastic items.

Per the Kayeann and Lloyd posts, reducing toxic exposures by switching to PLA biopolymers offers a "tentative" win-win-win for the environment (toxic exposure reduction, biodegradability, reduced petroleum consumption). We qualify with a "tentative" because we do not have complete knowledge of the hazards of plastic additives that may be used in this and other PLA applications. Additives may range from fire retardants, to softeners, to anti-oxidants, to impact modifiers, depending on the application. But, we can be reasonably certain that none of the RoHS-banned substances, especially the brominated fire retardant, will be present.

More from the release: "The Norland blow molders, designed originally for blowing PET (petroleum-based) plastics, have been specifically adapted to handle the PLA plastics. Preforms made of PET and PLA have different characteristics. For PET, preforms must be preheated to 100-C, while PLA preforms must be heated to just 75-C".

The reduced molding temperature requirement demands our attention. We've all heard the debates about the relative fuel efficiency of growing corn for production of fuel compared to just gasoline. When it comes to PLA blow molded products, yes we see that growing corn takes fossil fuel and that energy savings at the basic raw material level may not be that great. But, further down the supply chain, energy savings start to accumulate at point where monomer is made into polymer (plastic). Further energy savings accumulate when you account for the fact that spent bottles can be simply composted instead of being re-ground into a techical "food" for chemical recycling or "down-cycling. Now back to the release:

"PLA bottles offer a significant advantage to producers of bottled water, juices, oils and other liquid products—they are environmentally friendly. While it is estimated that petroleum-based plastic products require thousands of years to decompose, PLA products are compostible within 45-90 days. This compost material can then be used to fertilize the next year's crop of corn, completing the cycle of a totally renewable resource. PLA plastics contain no petroleum, and require 20-50% less fossil fuel to create than PET plastics".

For those of you wondering whether biopolmers can ever make it into high performance equipment applications like bicycles, roller-blades, snow boarding boots, and climbing equipment, the answer is "yes". Because TreeHugger is not the place for technical epics, we'll hold off for now on the details. But here are a few hints for you Google divers: -- Not PLA; Castor Beans; Athletes Foot; and Air Brakes. If anyone guesses the exact biopolymer we're hinting at we'll do a full post.

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