Insights / Sustainability

Mechanical and Advanced Recycling: Moving Toward a Circular Economy

Empty plastic bottle in mechanical waste stream

Recycling plastic packaging employs a mechanical (physical) process or an advanced (sometimes called chemical) process to transform waste into raw materials for creating new packaging. While significantly different, the two processes are complementary strategies to achieve a circular economy for plastics.

Mechanical Recycling

Mechanical sorting of packaging waste

With decades of use, mechanical recycling involves several key steps: sorting the waste stream, grinding or shredding the material into flakes, washing and cleaning, color sorting, extrusion, and pelletizing. The resulting pellets of post-consumer recycled (PCR) content (typically PET or HDPE) can be used alone or combined with virgin resins to produce new packaging.

Recycling rates for both PET and HDPE approach 30% in the U.S. Canadians recycle 75% of PET beverage bottles. Material recovery facilities (MRFs), which receive waste from curbside and drop-off collection programs, value PET for its transparency and clarity.

However, PET recyclability can be impacted by color or opaqueness. While clear and light blue PET are easily recyclable, colored or opaque PET reduces its value, making it more suitable for non-packaging applications like carpets. MRFs prize natural HDPE (e.g., milk jugs) but will accept different colored materials.

Why Mechanical Recycling Matters

Research shows that PCR resins significantly reduce greenhouse gas emissions and energy usage compared to virgin plastic resins. Increasing consumer preferences for sustainable packaging, commitments from consumer packaged goods (CPG) companies to enhance recyclability and recycled content, and state legislation mandating minimum recycled content in packaging are all driving the demand for PCR resins in plastic packaging.

Mechanical recycling plays a vital role in diverting waste from landfills and reducing plastic pollutants in the environment. It also uses fewer natural resources than those required to produce virgin polymers.

At Berlin Packaging, we specialize in PCR materials sourcing, some with no additional cost, and seamlessly integrate them into your entire packaging portfolio. We create packaging solutions that optimize sustainability, brand impact, performance, cost, and material availability. Our customer-focused teams combine deep subject matter expertise with practical commercial experience to build circular strategies that strengthen your brand and grow your bottom line.

Mechanical Recycling Limitations

Mechanical recycling produces plastic with qualities approaching virgin resins. However, the grinding and extrusion (heating/melting) steps slightly degrade the material, limiting the number of times the plastic can be recycled and reused for packaging applications.

The existing infrastructure of municipal curbside and drop-off recycling programs works well for rigid plastic containers. However, most programs cannot handle flexible packaging and films. According to the Association of Plastic Recyclers, only about 5% of the 1.1 billion pounds of film recovered for recycling came from curbside recycling programs. Some retailers accept flexible packaging via in-store drop-off bins, but this method only accounts for 5% of film collection for recycling.

Advanced Recycling

Chemical recycling of plastics

Advanced recycling, or chemical recycling, is an umbrella term encompassing several technologies (e.g., pyrolysis, solvent-based, gasification, hydro-cracking) that can be grouped into three categories: purification, depolymerization, and conversion.

Purification uses solvents to dissolve the post-consumer plastic, separating the desired polymer from the liquid stream. Depolymerization (also referred to as decomposition) converts polymers into monomers, which can create new plastic. Conversion transforms plastic into hydrocarbons, which form a feedstock for new plastic.

In general, advanced recycling processes plastic waste (sorted and unsorted) into plastic feedstocks, monomers, or purified polymers that can create new plastic with identical properties to conventional virgin resins.

Why Advanced Recycling Matters

Some advanced recycling technologies can accept difficult-to-recycle plastics and packaging types (e.g., PP, PS, PVC, multi-material, and flexible packaging film) without sorting, diverting these challenging materials from landfills and incineration and boosting their recycling rates.

Unlike mechanical recycling, which degrades the material due to repeated shredding and melting, advanced recycling produces plastic indistinguishable from virgin plastic. Plastic made from advanced recycling can be infinitely recycled without any loss in quality or performance.

Advanced recycling also removes colorants, additives, and contaminants, enabling the production of high-quality and food-grade polymers.

Advanced Recycling Limitations


While advanced recycling offers many possibilities for improving the circularity of plastic packaging, it is still in its infancy with limited commercial operations and capacity. Some technologies are in development and undergoing scale-up. Capital costs for advanced recycling are higher than mechanical recycling.

Advanced recycling's multiple technologies and various stages of maturity make it hard to compare their economics, scalability, production capabilities/yields, energy requirements, efficiencies, and other factors. Collection systems for mechanical recycling need to expand to recover hard-to-recycle plastics for advanced recycling.

Some industry observers question whether advanced recycling technologies (i.e., conversion) are truly recycling since their outputs are hydrocarbons that may go into fuel or other chemicals rather than plastic production. In addition, these hydrocarbons are combined with fossil fuel-derived hydrocarbons, making it nearly impossible to differentiate between recycled hydrocarbons and petroleum-derived hydrocarbons. These concerns have brought scrutiny from regulatory bodies in North America and Europe.

Explore related topics: Life-Cycle Assessment, Ocean-Bound Plastic, PCR Content, Compostable Packaging, Container Deposit/Refund Programs, Refillable & Reusable Packaging, and Bioplastic

Robert Swientek

By: Robert Swientek
Date: October 9, 2023

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