The ins and outs of using post-consumer resin in packaging

Image Credit: Nova Chemicals Corp.

Nothing is so powerful as an idea whose time has come, French author Victor Hugo once wrote, and the idea of using post-consumer resin (PCR) in packaging has arrived with a vengeance.

Consumers are now demanding sustainable packaging options, and a growing number of brand owners, retailers, product manufacturers, and food producers have mandates to incorporate more recycled content in plastic bottles and bags. And in some jurisdictions, it’s now the law. A European Union (EU) law enacted in 2019 mandates that plastic bottles be made of at least 25 per cent recycled plastic by 2025 and 30 per cent by 2030, and all 28 EU member countries now have to amend their national laws to comply. On this side of the pond, Canada’s federal government has set a 50 per cent recycled content target in plastic products – which includes all packaging – by 2030. And in the U.S., a new law in California requires that plastic bottles covered by the bottle deposit program contain at least 15 per cent post-consumer resin by 2022, and it could become a national model.

So, one way or another, this ship is sailing, and many Canadian packaging suppliers are already onboard. To name just a very few, Vegpro – said to be the largest fresh baby lettuces producer in Canada – has teamed up with Quebec-based packager Cascades to replace all Fresh Attitude salad containers, traditionally made from virgin plastic, with 100 per cent recycled and recyclable plastic containers; Ice Rivers Springs has become the first beverage company in North America to collect blue box materials to produce 100 per cent recycled plastic bottles, using no new plastic; and all Hellmann’s mayonnaise jars and bottles made by Unilever Canada are now made with 100 per cent recycled plastic.

SUPPLY AND DEMAND

But for the material and packaging product suppliers, going green isn’t without challenges, beginning with finding a steady source of high-quality PCR. In a nutshell, the problem is that consumers aren’t yet recycling enough plastic worldwide, which drastically impacts the supply. Amherst, N.S.-based flexible packaging supplier Emmerson Packaging was way ahead of the recycling curve, having started incorporating PCR into its films in the late 1980s, but moved away from the practice in the mid-1990s due to poor quality supplies. “Advancements in recycling technology over the last few years have improved the quality of PCR to a level that now enables us to incorporate FDA-compliant PCR for direct food-contact applications, but the sources for this material are still very limited,” said Dawn MacDonald, the firm’s innovation and R&D manager. “Many companies are working toward offering FDA-approved resin options, but they aren’t available yet.” Unlike sourcing virgin material, brands, converters and suppliers must work as a team and make the proper investments to build a viable infrastructure, and this is still a work in progress.

Although things are getting better, in part due to China’s 2018 Green Fence ban on importing a range of discarded plastic types. “In the short time since that decision from China, we’ve seen a growing focus to extract value from these streams that, historically, would have been exported in a mixed plastics bale,” said Domenic Di Mondo, vice president, technology and business development with Brantford, Ont.-based recycling technology firm GreenMantra Technologies. “Today, we see new capacity for the recovery and processing of resins like polypropylene [PP], and there are even buyers for PET thermoform bales. And importantly, we also see more North American opportunity for polyethylene [PE] films, both collected commercially as well as recovered at municipal recycling facilities. All of these developments are combining to accelerate the availability and consistency of high-quality post-consumer material, and the sourcing high-quality recycled materials has become less challenging every day.”

Another concern relates to a different kind of green: money. “The PCR market is transitioning from a mindset of recovery for the purpose of generating a low-cost feedstock – generally to offset higher virgin plastic prices – to one focused on value delivery, which accepts that some PCR prices may be higher than virgin plastic,” said Anna Rajkovic, circular economy market manager with Calgary-based Nova Chemicals Corp. And it’s getting worse. “The cost of PCR is considerably higher than virgin, and is increasing,” Dawn MacDonald said.

GREY MATTER

A hallmark of modern packaging is that it makes an impression on the consumer through unconventional designs, convenience features, brilliant colours, and more. And at least as far as the brilliant colours go, PCR doesn’t always deliver, and cost is a big reason why. Recycling gets sorted by plastic type and composition but usually not by colour, since this increases the cost significantly; which means that when plastics get recycled together, the colours mix and create grey granules, making the recycled plastic that results greyish as well. This can be a non-starter for package designers that have to meet very specific brand design standards.

But while colour can be a barrier at present, there are signs of an attitude change. “Looking forward, we see many new sustainable brands coming online which embrace the colour variations of recycled content,” said Domenic Di Mondo. “These brands also use specific darker colour palettes that enable more flexibility to use different recycled streams. This leads to the new quip that ‘grey is the new green’, but in all seriousness, this is the attitude we need to take our use of recycled content to the next level.”

A second aesthetic concern relates to imperfections in PCR blends that can cause minor product blemishes. Certain plastics just don’t mix well, and the contamination caused by their mixing – or, worse yet, the addition of other factors such as food, dirt, or other contaminants – can result in less-than-perfect visuals in the final product. This doesn’t mean that PCR can’t be used, just that brands and consumers need to have realistic expectations about the results. “We sometimes encounter unmelts or gels that don’t melt and flow uniformly, which creates small, hard particles in the film,” said Dawn MacDonald. “Generally, this is acceptable, as the customers wanting PCR understand that it comes with a compromise.”

The good news is, new technologies are being implemented to address this problem. “For contamination, near infrared sorting can detect polymer type and ensure a homogenous stream – i.e., PE PCR that’s free of PP contamination – while improved wash lines are better at removing labels which would otherwise appear as gels in the final product,” said Anna Rajkovic. And according to Domenic Di Mondo, GreenMantra has developed a line of new sustainable plastic processing aids designed to help overcome shifts in melt flow and other degradation that can occur with multiple melt cycles.

LETTER OF THE LAW

A critical step in replacing virgin plastic with PCR in any packaging application is making sure the recycled resin complies with applicable regulations, which can vary inter nationally and from region to region – and not every type of recycled resin works for every use case or complies with these regulations. In Canada and the U.S., the PCR material must meet all the same legal requirements as virgin material. Europe has more stringent guidelines: Under a regulation set over a decade ago, only food-contact materials and articles that contain recycled plastic obtained from an authorized recycling process may be used in the EU. Elsewhere, it gets even trickier: In several jurisdictions, such as India and Mercosur – an economic and political bloc comprising Argentina, Brazil, Paraguay, Uruguay, and Venezuela – recycled PET is permitted in food applications but not recycled PE.

What’s not tricky at all is the fact that it’s the responsibility of the supplier or manufacturer to ensure that a PCR material is suitable for the final application, wherever in the world it goes. “This is achieved through testing and by assurance from regulatory statements provided by plastic suppliers,” Anna Rajkovic said.

Another step is to match the properties of the PCR to the virgin resin that’s being displaced, the goal being to ensure that the processability, and ultimately the performance of the part, is similar. “Some resins can be used interchangeably for certain applications – for example, both PET and polystyrene can be used for thermoform clamshells – but most resins are selected for their functionality to do a specific job,” said Domenic Di Mondo. “PET has excellent barrier properties, for example, making it ideal for carbonated beverages, but you wouldn’t be able to put a carbonated beverage in HDPE. On the other hand, HDPE has superb dimensional stability and that makes it a great resin for large, heavy jugs of detergent or plastic pallets, while PET couldn’t hold that shape with such a large volume of liquid or weight.” In general, these same processing rules apply to the recycled versions of the resins, Di Mondo continued, so the performance requirements for each packaging application must be considered so that the correct recycled resin can be selected.

Current recycled resin technology also informs this decision. “At present, HDPE is the only PCR available for flexible food packaging and, depending on the application and package type, it can work very well,” said Dawn MacDonald. “For example, if the package already contains HDPE, then it’s relatively simple to substitute the virgin PE with the PCR. However, if it’s an LLDPE bag with no HDPE, the converter will be changing the properties of the package with the addition of the HDPE PCR.”

And even with more prosaic applications like bottles, post-consumer recycled PET (rPET) is not a drop-in equivalent material to virgin PET; the use of high percentages of rPET in the resin could change the material properties and affect the filling process, resulting in bottle structure shrinkage and deformation. As a result, lightweight, hot fill containers with a high percentage of rPET aren’t common.

CHOOSE WISELY

All of which is why the converter has to pick and choose which packaging applications can displace virgin resin with PCR. “Highly regulated applications like food-contact and pressure pipe will see the largest hurdles to adoption of PCR,” Anna Rajkovic said. “Some applications with specific performance and/or property requirements may need to look to closed-loop systems, where post-use material is returned to the producer for incorporation into the same types of applications.” For example, Nova just introduced a white rLLDPE PCR manufactured from closed-loop agricultural and irrigation film recyclate for use in agricultural film, heavy-duty shipping sacks, collation shrink, trash bags, and liners; the new grade is one of Nova’s first three grades of 100 per cent post-consumer PE resins targeted to flexible film applications.

Recycled plastics have come a long way as far as strength and durability, but – for now, at least – getting even more PCR into even more packaging applications will depend on designers, branding agencies, and consumers accepting some imperfections. The good news is, there’s a precedent. “Brown and grey paper towels and coffee filters have a characteristic dull colour and are proudly labelled as recycled,” said Domenic Di Mondo. “More brand owners and consumers need to make this shift, and understand that the colour of the packaging doesn’t indicate product quality or performance. And if they can’t, they have to be willing to pay a price premium for the costs that are built into high-quality PCR.”

It’s the price of an idea whose time has definitely come.