Flexible Packaging Recovery Collaborative

Curbside collection options as well as specialized collection systems are limited for MMFP. However there are pilot systems that show promise to be scaled. The Hefty Energy Bag project offers promise in aggregating the collection of hard-to-recycle plastics, and suggests that bagged plastics can be collected curbside, while the Materials Recovery for the Future (MRFF) report suggests that a loose automated collection process, similar to current single stream collection may have more potential to be scalable and cost effective than bagged films – particularly with large-scale MRFs. 

As we have seen with other recycling programs, engaging consumer participation is key to ensuring participation and quality. An increasing number of studies on recycling behavior for plastics and other materials, reinforces the need to provide clear and easy-to-understand messaging through multiple channels. Additionally, the use of images is highly recommended.

Collection and acceptance of compostable films still remains limited in most municipalities as a result of limited permitted facilities. Therefore, any design of compostable multi-layer films should be accompanied by investments in collection. Investment is also needed in general for collection of organics, which is a potential pathway for future collection of compostable packaging. 

Two-dimensional flexible plastic packaging has been known to flow with two-dimensional paper, clogging screens and contaminating paper bales at MRFs, Ejecting these materials from the paper stream is likely where the best solution for sortation may be found. Recent findings from the  MRFF pilot project show promise - which added several optical sorters and a paper magnet to a MRF creating a mixed flexible plastics bale. 

There are a variety of existing and emerging technologies which offer significant promise for sorting multi-material flexible packaging along the MRF sortation line. Recommendations for further testing are encouraged. Promising technologies include the use of:

• Near infrared (NIR) optical sorters to detect multi-material films

• Optical sorters to direct flexible plastics out of the paper stream

•  The use of innovations such as vacuum systems, ballistic separators, density-based air separators, robotic film grabbers, to help capture more film and clean paper bales 

• The use of a digital watermarks on packaging, which would be undetectable to the human eye, but could be read by optical sorters to better sort out more types of packaging

• The use of AI based robotic sorting for flexibles and films

Although these technologies offer potential promise for sortation, the economics of end market sales will dictate their long-term adoption.

Opportunities for reprocessing of multi-material flexible packaging are limited. Reprocessing  in general refers to operations that aim to recover sorted plastics received from MRFs via mechanical processes (i.e. grinding, washing, separating, drying, re-granulating and compounding) and production of recycled plastic flakes or pellets that can be reused to make new products. The technical capability does exist to reprocess polymers in polyolefin based multi-material flexible packaging, however there are also many limitations. Limitations are often caused by the different melting points of different polymers, which makes it challenging to get quality output from mixed polymers. It is generally considered important to know what the incoming resin composition is and keep it consistent and relatively clean so that equipment can be adjusted accordingly to get the best outputs based on the unique qualities of the incoming polymer mix..his makes it highly challenging to use multi-material flexible packaging collected at the curbside where much of this information is unknown and unpredictable. 

Most existing processes can typically use only a small percentage of MMFP, due to this variability of input, so MMFP represents a small percentage of the composition of the product produced (see example end markets from mixed flexible packaging on page 26 of the MRFF report). New technologies like compatibilizers (described above) and molding innovations for processing plastics with different melting points are emerging that might address some of these limitations. . 

New technologies are emerging that use chemical and water-based solvents to dissolve bonds between layers, separating them. These processes can be added onto existing mechanical recycling processes and can expand the markets to those of distinct polymers, rather than send the package to a mixed flexible plastics bale that could potentially be destined for less preferable forms of recovery like waste-to-energy. These technologies are very promising additions to the capabilities of mechanical recycling for MMFP, however have yet to be applied at scale. Often these technologies require pure streams of specific laminated packaging types, as different solvents work to separate different combinations of layers (i.e. PET/PET), and one solvent may not work for all varieties of MMFP in mixed plastics bales. 

Read about Mechanical recycling options for MMFP here. 

Reprocessing options for multi-material flexible packaging includes more than just mechanical recycling. For multi-material flexible packaging, so-called “Feedstock Recycling” technologies that  reconstitute plastic films to more basic hydrocarbons is an opportunity area for multi material film recovery. Feedstock recycling is achieved by heating the plastic at high temperatures in a chamber that is either void of oxygen (pyrolysis) or uses oxygen and steam (gasification), with many variations of these processes being developed. These processes simulate virgin feedstocks for plastics (e.g. oil and gas), and from these hydrocarbon outputs , a variety of end products may be created that have virgin-like properties. These outputs include many of the chemicals, plastics, waxes and other products made from virgin fossil fuel feedstocks today. The output can also be used in fuel applications.  

Exploration by the Multi-Material Flexibles Recovery Collaborative suggests that feedstock recycling may be one of the most viable options currently available for the end of life management of multi-material flexible packaging. Unlike other plastics like rigid PET or mono material PE, MMFP cannot be viably recycled mechanically. However, most of these recovery technologies are still in the pilot stage and the economics of the market are still emerging, with markets currently in favor of fuels instead of plastics outputs.  As sortation and collection of significant volumes is still a challenge, the processing of multi-material flexible packaging only is unlikely to produce sufficient volume, additional plastics to supplement processing demand is likely. So instead, mixed plastic waste inputs are preferred. 

Clarifying terms

“Chemical” or “Advanced” recycling processes cover a broad range of technologies.Polymer recycling maintains the polymer and can utilize chemical solvents as a complimentary add-on process in mechanical recycling to purify the polymer from inks, colors or additives. Monomer recycling breaks apart polymers into individual monomers through chemical depolymerization processes such as hydrolysis (which does not generally apply to mixed polyolefins). Feedstock Recycling technologies reconstitute plastics to more basic hydrocarbons which can be used to make a variety of outputs, including plastics, chemical intermediates and fuels, and represent the most suitable technology for chemical recycling of mixed polyolefin MMFP.

The term Feedstock Recovery is also sometimes used to broadly cover all of these outputs of these technologies (both plastics, chemicals and fuels). The process can be called Feedstock Recycling when its outputs are put towards non-fuel use, per ISO definitions which state “Material Recycling is defined as reprocessing, by means of a manufacturing process, of a used packaging material into a product, a component incorporated into a product, or a secondary (recycled) raw material, excluding energy recovery and the use of the product as a fuel.” Polymer manufacturers can use this output as feedstock to produce new products. When outputs are put towards fuels or burned as energy, this is called “Energy Recovery.”
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There is a hierarchy of preference for these technologies based on environmental footprint and end products. Feedstock-to-plastics are preferred to fuel outputs; however, there is still a place for non-plastic feedstocks in bridging the gap for flexible packaging recovery until plastics-to-plastics markets are scaled up. 
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Read more about examples of Feedstock recycling options for MMFP here. 

Waste-to-energy (WTE) is the process of generating energy in the form of electricity and/or heat from the combustion of mixed waste, including multi-material flexible packaging left for disposal. While waste-to-energy is a commonly accepted practice in many European countries, it is less popular in North America. However, it still represents a significant end market for MMFP in North America. As seen in our Technology Recovery Map, incineration represents the largest end market for pre-consumer MMFP waste, for example, used by cement kilns who burn and use this for energy. Another popular end market was for use as engineered fuel pellets, which are also set to be burned for energy/fuel.   

Currently, there are no large scale operations available to create end products from multi-material flexible packaging. While some pilots offer promise, further research estimating and understanding end markets for multi-material packaging would help develop interest and funding for end market development. Materials Recovery for the Future has started this process but more research is needed. One reason much of the current end markets are represented by fuel or energy is due to a lack of robust, alternative end markets.