TAGS: Sustainability / Natural Solutions Additives for Packaging
An Interview with Dale McCormick, Business Manager for Proprietary Products at Ingenia Polymers
The use of post-consumer resin (PCR) has increased with the increasing demand for sustainable packaging. Yet, it remains difficult for film producers to get a consistent supply of high-quality PCR for new plastic packaging.
Ingenia Polymers has developed and commercialized novel solutions for the recycler industry. INCIRCLE® product range includes:
- Compatibilizers
- PCR stabilizers
- Rheology modifiers
- Moisture/odor control agents
The INCIRCLE® brand promotes the circular economy of plastics. They improve the processability and quality of PCR resins. They also support increased PCR supply and improved quality for converter markets.
In this interview, we asked Dale McCormick, Business Manager of Proprietary Products at Ingenia Polymers to explain the challenges and opportunities in this space and update us on new product development efforts to support the circular economy for plastics.
#1. What limits the use of post-consumer resin (PCR) in new plastic packaging?
The biggest challenge is the supply of high-quality PCR! The supply of PCR with the quality attributes needed for packaging applications can be quite challenging. The bulk of the post-consumer stream is from FMCG (fast-moving consumer goods) packaging. This requires:
- Collection to be in place – various schemes from depot and store drop-off to curbside collection.
- Sortation facilities (Material Recovery Facilities – MRFs) that can manage the separation of current packaging formats and provide baled materials of the same resin type with minimal contamination.
- Recyclers with additional sorting capability who grind or flake the incoming plastic bales, wash and separate different polymer types. These firms often also extrude the cleaned flake into a pellet format for easy transportation to their customer, who will typically use an extrusion process, displacing a portion of virgin resin using the PCR and producing new packaging, closing the loop so to speak.
Any breakdown or lack of infrastructure to support each of these steps limits the supply of PCR. Upgraded equipment assists with the removal of contaminants and improves the supply and the quality of PCR, so investment and availability of capital to support recyclers are also very important.
Separate from collection, sortation, and prevention of contamination, the initial package design stage has a tremendous impact. Following design rules (see various national Plastic Pacts to learn more
1) assists sortation by avoiding multiple material types in a package’s construction which are often difficult to separate, leading to contamination and/or lower yields.
Heavily printed or colored plastic packaging reduces the availability of PCR for use in transparent/translucent packaging. Additional sorting capabilities at recyclers support further differentiation of natural, white, and mixed-color streams. Separating white PCR from the colored stream allows for a greater PCR supply for white packaging, so this is a good development.
Multi-material Recyclate Sources
#2. What quality and regulatory considerations can reduce the use of PCR back in new packaging?
Odor and moisture are two typical concerns when using PCR.
- If the extrusion process at the recycler does not remove odors that come from residues and degradation of the polymers, inks, and adhesives, through the washing and extrusion processes mentioned earlier, then the percentage of PCR that can be used may be limited. The packaging application itself may be very sensitive to odors, for example in pet food packaging any odor emanating from the packaging may dissuade animals from eating the pet food and will lead to costly returns of the packaged product.
- If moisture in the PCR is not kept to a low level, the water will convert to steam in the converter extrusion process and generate lensing or even blow holes in films and cause poor part finish in rigid packaging.
Ingenia offers both moisture and odor absorbers that can be added during the recyclers’ extrusion step, however, advances in equipment from companies such as Erema, NGR, and Starlinger have minimized the need for these solutions, as they provide improved odor and moisture removal during processing.
From a regulatory perspective, letters of non-objection from the
FDA in the US for recyclers’ products are allowing for expanded end-use applications for PCR. However, most of the highest quality Grade A food grade r-HDPE is being consumed into packaging for the cosmetics/personal care industry, so again there is more demand than supply.
#3. What are some of the special considerations when using PCR in film and flexibles?
Film and flexibles tend to be one of the most difficult applications for the use of r-PE from PCR streams. There are several challenges that the film producer is up against. First, the base stabilization packages in polyolefin resins are not designed to protect the polymer against degradation from repeated extrusion steps. At a minimum, post-consumer polyolefins are subjected to four extrusion steps if they are recycled and reformed for use in FMCG packaging for example.
- STEP 1: The first extrusion step is after polymerization, the reactor fluff is extruded to convert it into pellets for easy transport.
- STEP 2: Second, the initial forming into a film for example through blown or cast film extrusion.
- STEP 3: At the end of package life, the PCR is shredded, washed, dried, and extruded back into a pellet form.
- STEP 4: Finally, the PCR is extruded once more into a new film to be used again.
Resin producers typically do not include the required level of antioxidants and other stabilizers to prevent the degradation that occurs at each extrusion step mentioned. This leads to yellowing of the resin. Multi-pass extrusion studies simulate the effect of heat and shear histories on the PCR and can be used to evaluate the performance of PCR stabilizer packages.
Example of the effect on PE color, often measured as yellow index change in multi-pass study:
Multi-pass Extrusion Study Depicting the Effect on PE Color as Yellow Index Change
Beyond color generation, melt flow rates of PE recyclate are typically reduced due to repeated extrusion cycles, as the degradation of the polyethylene leads to cross-linking of adjacent polymer chains. This reduction in melt index can impact the ability to generate stable film extrudates in both blown and cast film extrusion. Melt instabilities can be created when the PCR is mixed with virgin resin, careful use of
multi-layer film structures can help to mitigate this problem.
The most significant challenge with the use of PCR in film and flexibles is gels that form due to localized cross-linking. The gels have many deleterious effects on the quality of the film. In extreme cases, causing holes in the film, and in less extreme cases impacting clarity and preventing good print quality. Large gels can also damage printing equipment and in general, gels are potential failure points reducing the mechanical properties of the film and the security of the package, which is its primary function.
Gels also can appear due to contaminants and the presence of other polymers. Paper labels and adhesive contamination are often the root cause of gels, again package design is critical! Multi-material barrier films also can contaminate the PE film recycle stream leading to gels as polar polymers such as polyamide and ethylene vinyl alcohol tend to coalesce in the non-polar polyethylene matrix and reveal themselves as gels.
This micrograph reveals the formation of polyamide gels in a polyethylene matrix. Gel sizes can be in the 10-20 μm range, which is a big problem with films that are less than 1.5 mil (36 μm) thick.
Micrograph Showing the Formation of Polyamide Gels in a Polyethylene Matrix
#4. So now we understand the dual challenges of availability and quality of recycled polyolefins hoping to go back into packaging, improving the circularity, but how is Ingenia helping with the availability of r-PE PCR?
Multilayer, multi-material films are a widely used format for food packaging requiring barrier properties. These structures prevent food waste by increasing shelf life from days to weeks/months for many of the foods that we enjoy each day. However, as mentioned previously this can have a negative effect on the quality of the PE recycle stream.
Through the use of Ingenia’s compatibilizer solution, the negative effects of polyamide and EVOH “contamination” are prevented. At the design stage, the inclusion of Ingenia’s
INCIRCLE® IP1601 compatibilizer MB allows film structures containing these barrier polymers to be compatibilized when they are extruded by the recycler. This compatibilization step prevents the formation of gels as the polar polymers are bonded to the polyethylene matrix, preventing them from coalescing.
Micrograph of 20% PA6 in LLDPE with 2% INCIRCLE® IP1601 showing no evidence of gel formation in the polyethylene matrix, allowing for higher quality film to be produced:
Micrograph Showing No Gel Formation in PE Matrix with 20% PA6 in LLDPE and 2% INCIRCLE® IP1601
Ingenia’s INCIRCLE® IP1601 masterbatch can also be added by the recycler during their extrusion step leading to the same gel-free recyclate with mechanical properties that are by and large similar to 100% PE:
Ingenia’s INCIRCLE® IP1601 Leads to Gel-free Recyclate Similar to PE
#5. Does Ingenia have any additional pathways to improve r-PE PCR quality?
As mentioned earlier, the lack of adequate stabilization of polyolefins leads to significant degradation which manifests itself in poor color, reduced melt flow, and gel formation. Ingenia has a range of traditional phosphite-phenol AOs that provide protection during reprocessing, however, a higher-performing solution was required to support recyclers.
Ingenia looked to liquid phosphites, which have higher activity and solubility than solid phosphites such as AO168. Ingenia overcame the challenges in feeding and handling of liquid phosphites, allowing patent-pending production of highly loaded liquid phosphite masterbatches that are not prone to hydrolysis. INCIRCLE® IP1417 masterbatch contains a liquid phosphite antioxidant in combination with other stabilizers, providing best-in-class performance and improving PE PCR recyclate quality.
The improved performance of
INCIRCLE® IP1417 vs. traditional phenol-phosphite blends (IP 1415) is demonstrated in multipass studies showing color development (yellow index) and gel counts in film measured by optical control systems camera:
Improved Performance of INCIRCLE® IP1417 vs. Traditional Phenol-phosphite Blends (IP 1415) Demonstrated in Multipass Studies Showing Color Development (Yellow Index) and Gel Counts in Film
#6. What has the market response been to these new solutions offered by Ingenia? Are you developing other products for additional polymer types?
Both products are fully commercialized and in use in the recycler and film producer markets. Adoption has been swift as the benefits are apparent and supportive of the need for higher quality PCR to support increasing recycle content goals and government mandates.
Growth of EPR in North America will continue to drive the collection and supply of PCR and our solutions are well-positioned to support recyclers in their efforts to generate high-quality products. Ingenia will continue to develop novel solutions to support the circular economy for plastics as we partner with all members of the supply chain.
About Dale McCormick
Dale McCormick is the Business Manager for Proprietary Products at Ingenia Polymers. His focus is to develop and grow the company’s masterbatch business with advanced technology products, supporting the growth of more sustainable plastic products through the INCIRCLE® and INBIO® branded solutions that Ingenia offers. Target applications include the key market segments of food and consumer goods packaging, while he also has responsibility for all masterbatch products, across a variety of end markets.
Together with the Ingenia R&D, sales, and manufacturing teams, Dale brings Ingenia’s proven strengths to the market, combining Ingenia’s deep and specialized application knowledge with proven manufacturing capabilities and best-in-class customer service support to provide efficient, cost-effective, and sustainable solutions for each customer application.
Through his background at Amcor, Spartech, and Ingenia, Dale has developed broad commercial and technical expertise in R&D, technical service, manufacturing, sales, and product and market management. He holds a Bachelor of Science Degree in Applied Chemistry from Brock University and resides in Ontario, Canada.
DISCLAIMER: All images and graphs used in this article are copyright of Ingenia Polymers.