Solid Waste & Recycling

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The "Plastic Can"

Napthalate-based polyesters, or "PEN" for short, are a group of wonder materials from which beverage containers may be made which have aesthetic and performance characteristics similar to glass, but w...


Napthalate-based polyesters, or “PEN” for short, are a group of wonder materials from which beverage containers may be made which have aesthetic and performance characteristics similar to glass, but which offer the durability and convenience of cans. We could call these containers “plastic cans.”

The potential benefits from PEN are such that it would already have supplanted or augmented many PET plastic applications but for one catch: PEN is challenging to recycle (though not insurmountably so). Consequently, the U.S. FDA has delayed approval of certain uses for PEN/PET copolymers and blends out of concern for their potentially detrimental effect on the finances of recycling programs which currently rely on aluminum can revenues to offset the cost of collecting and processing PET bottles. Pending FDA approval, beverage producers have mothballed PEN/PET container production in North America. However, this is not the case elsewhere. Coca-cola’s market tests of its Bonaqua-brand bottled water in Uruguay were successful, and PEN container distribution proceeds apace in other countries, most notably Japan.

This is an extraordinary situation. What business does the U.S. FDA have stymying a market-ready packaging innovation that, if anything, will enhance the health and safety of spoilable contents? Clearly, the topsy-turvy world of recycling economics is beyond its jurisdiction, and it’s only a matter of time before the PEN proves that it’s mightier than the (regulatory) sword.

Here’s why.

In its homopolymer form, a PEN container can withstand high-temperature washing and filling with no shrinkage. It sparkles like glass and is highly scuff resistant but, unlike glass, is light and virtually unbreakable. High-speed processing lines in Germany (where reuse is mandatory) already wash and refill hundreds of millions of refillable PET soft-drink bottles with super-efficiency. Studies show refillable PEN can be processed on the same equipment, and the temptation to switch will not only be a function of the longer lifespan of PEN containers, but of the fact that they don’t absorb and transfer different flavors from one use to another (as PET does). More importantly for the North American context, PEN is resistant to UV light and offers four-fold superior “barrier qualities” to PET. The unfortunate tendency of CO2 to leach through the semi-porous surface of a PET container is remedied.

This is critical for the soft-drink industry where “no fizz” equals “no sales.” In North America, soft-drink companies would use PEN layers to boost PET performance, extend the shelf life of the popular 2-litre soft-drink bottles, and replace glass and metal in single-serve applications where porous PET never did the trick (because of technical issues related to the ratio of the surface area of a container to the volume of its contents).

The potential applications for PEN homopolymers (for refillable soft-drink, wine, spirits and milk containers, wide-mouth food jars, pharmaceutical and cosmetic bottles, etc.) and PEN/PET copolymers or blends (for recyclable beverage and other containers) are almost limitless. The international beer market, for example, will soon use more than 302 billion containers a year. (Laid end to end, they’d circle the earth more than 1,050 times!) PEN beer bottles are already in use in the United Kingdom, and a technical glitch has apparently been overcome (at least, in the lab). Focus groups routinely stated their preference for the “coldness” of refrigerated glass bottles and cans, as the PEN plastic containers always felt tepid. Now, technicians have apparently got the molecules to line up right and transport coldness to the outside of the bottle, leading to the desired exterior condensation.

The essential science of PEN has been known for decades, but the required raw materials kept costs prohibitively high. This changed when chemists devised a synthetic process to make PEN precursors from orthoxylene and butadiene, and Amoco Corp. in the United States and Mitsubishi Gas Chemical in Japan are positioned to use economies of scale to make PEN cost effective, especially after FDA approval of copolymers and blends.

If you think this approval will be held up forever, consider that historically every major packaging innovation has (eventually) overcome regulatory hurdles. The funds available to the soft-drink and petrochemical industries for lobbying and marketing are astonishing. (Amoco, for instance–which has constructed a 100-million pound per year PEN plant in Decatur, Alabama–has annual revenues in excess of $28-billion!) The market won’t stand still just because curbside recycling programs were established at a time when beverages were sold in pricey cans and clunky glass bottles. PET has already altered recycling programs forever, and PEN will do the same. In a 1996 press release, Professor Marvin Tung, a director of a partnership between the University of Guelph and the Guelph Food Technology Centre which tested PEN/PET,stated that such copolymers will be a familiar site in the Canadian marketplace “over the next two to five years” and that costs will be kept down by “piggybacking of the plastic on to the large and successful PET recycling program.”

Until the FDA road block is overcome, and with hundreds of millions of dollars at stake, industry is being very cagey about its plans for PEN (even denying it has any). But information is surfacing. Nashville-based Magnetic Separation Systems (MSS) has announced equipment that sorts out PEN, PET, and the various blends to enable their recycling. Also, the U.S.-based National Association for PET Container Recycling (NAPCOR) has merged with the Napthalate Polymers Council (NPC) to represent the interests of PEN manufacturers, and the group has opened a Canadian office.

With these developments, anyone operating a recycling program or MRF today on the assumption that the “plastic can” will never arrive would appear to be, at best, naive.


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