A Plastics Dichotomy – Durables versus Single Use

by Ronald Cascone (Nexant, Inc./Biofuels Digest) ... Durable items are those that are in use for a long time, even years, mostly are rigid, have substantial weight per item, generally are not littered, are typically of more expensive performance polymers (polyamides, polyesters, polycarbonate, etc.) and have high potential for recycling, including via manufacturer or retailer take-back. Single use plastics are dominated by blown and extruded film, often with relatively low performance indexes, such as polyolefins, but also polyesters, polystyrene, and PVC, with lower potential for recycling.

Rigid Single Use

Astride the dichotomy between rigid durables and film disposables are rigid single-use packages (bottles, jars, boxes, trays, etc.) like those used for retail beverages and food, personal care products, and household chemicals. PET and HDPE, with high potential for recycling, lead in this area. In fact, these are the two most recycled plastics, globally, both to original use and to other durable and disposable uses.

Optimizing Packaging

Most people do not realize that it’s not evil intent or even thoughtlessness behind the vast amount of plastics used in food and beverage packaging and handling. In most cases the aim is to optimize costs (and even carbon footprints) in considering spoilage, hygiene, logistics, refrigeration, and theft. These savings benefit the brand owner, retailer, society at large, and of course, the consumer. As much as 40 percent of the food that starts out at farms on its way to consumers never gets eaten due to spoilage and other losses. Without plastics packaging, much more would be lost.

Thermal and Chemical Recycling

The typical approach to re-use post-consumer plastics is to sort mainly rigid containers, make chips of them, clean them of other plastics and chemical contaminants, and make new products in extrusion processes. But other solutions are available, primarily:

The pyrolysis and gasification approaches are particularly relevant to “mixed plastic waste”, materials including much of the film in garbage, that are not PET (coded 1) or HDPE (coded 2), but the net of these not recovered, plus those coded 3 through 7, which are usually sent to landfill or incineration. Several US states have recently legislated in favor of these approaches. Alternatively, this mixed stream can be incorporated, together with certain amounts of paper and metal foils from multi-layer packaging into plastic lumber, pavers, and other construction materials where their weather-exposed surface area risking degradation to microplastics will be reduced by orders of magnitude.

From the outset of PET bottle manufacture, means to recycle the bottles and recover clean resin were sought. Recycling the resin into new bottles or other food or beverage packaging has always been challenging due to contamination, loss of clarity, etc. However, recycling this valuable resin into other, mostly technical and durable uses has been quite feasible. Over 2 billion pounds a year of PET are typically recycled. This “RPET” is used to make a variety of new end products such as:

Many small and medium businesses are involved in the value chains for these products. Nonetheless, in the religion of the Circular Economy of Plastics, there appears to be a distain for such RPET secondary use. Is this simply a case of Voltaire’s “Le mieux est l’ennemi du bien” (the better is the enemy of the good), or is there truly greater value in recycling to the original use? Likely, the “better” will always be more expensive than the “good”, both in money and in entropy (mess made in doing so), but diverting PET bottles from litter and from landfill or incineration is a goal that is increasingly valuable to society.

PET Chemical Recycling

Technologies are emerging that will allow PET found in a wide range of post-consumer items – contaminated recycled bottles, other packaging, and even in cotton-poly textiles – to be recycled into food and beverage-contact uses.

PLA and PHA, and even the competing bio-based polyester bottle resin PPE, have the potential to severely disrupt recycling systems. So far, biopolymers have achieved very limited market share. For durables and specialty applications, rigid or film, the generic drawbacks of biopolymers stated here might not be so relevant. The use of either in film packaging is also relatively low risk, primarily because film recycling has been so infeasible.

Relevant Nexant Reports

Nexant did a comprehensive report on thermal and chemical recycling, including PET chemical recycling, titled TECH: Plastics to Fuels and Chemicals (2017 Program). This report provides an overview of plastics to fuels and plastics to chemicals technologies that are used to convert so-called non-recyclable plastics into value-added products. Many of the technology providers and operators are profiled. Cost of production estimates for some processes were developed for the United States. The effect of oil price on process economics is explored. This is to be updated and supplemented later in 2019 by TECH: Recycling of Mixed Plastics Waste. Also available is a Special Report, Plastics Recycling: Impact on the Polymers Industry in Western Europe and the United States (December 2018), which analyzes the impact of the recycling of plastics on virgin plastics demand in Western Europe and the United States. It also provides insight into the recycling value chain, including an overview of the industry structure, key players and acquisitions. Recent changes in legislation, including China, are also highlighted in the report.

To better flesh out some of the themes of this blog is Nexant’s Special Report: Sorting through Plastic Waste – Is Chemical Recycling a Solution? This report, published in October 2019, provides a screening of selected chemical recycling technologies that target the largest/most difficult plastics waste streams. READ MORE