Plastics have become a ubiquitous workhorse in the modern economy. The use of plastic has increased 20-fold in the last half century and is expected to double again in the next 20 years. While bringing a lot of benefits, the drawbacks of the plastic economy are becoming increasingly obvious. After a short use cycle, the economic value of plastic packaging materials has lost 95%. Another report said that 32% of plastic packaging escapes the collection system and enters the ocean and urban infrastructure, which brings huge governance costs. The process of overcoming these shortcomings also represents new opportunities: enhancing system effectiveness to achieve better economic and environmental outcomes, while continuing to take advantage of the many benefits of plastic packaging. The "New Plastics Economy" offers a new vision consistent with circular economy principles to seize these opportunities.

     Three different types of recycling
  The key principle of the circular economy is that products and materials always circulate at the highest value. This means that plastic packaging will be reused where possible (recycled packaging products) and then recycled (recycled packaging materials).
  1. Closed-loop mechanical recycling. This is the most valuable cycle. Mechanical recycling keeps the polymer intact and retains a higher value than chemical recycling, which destroys the polymer, and closed-loop mechanical recycling keeps the material quality at a similar level by cycling the material into the same application process (such as from PET bottle to PET bottle) or into an application process that requires a material of similar quality. Mechanical closed-loop recycling preserves not only the value of the material, but also the value that may be applied to other cycles in the future.
  2. Open loop mechanical recycling. Due to the inherent quality loss in the mechanical recovery process, closed-loop mechanical recovery cannot be continued indefinitely, and open-loop recovery also plays an important role. In open-loop mechanical recycling, the polymer also remains intact, but the corresponding application requirements are lower because the quality and/or material properties are reduced.
  3. Chemical recovery, chemical recovery can break down the polymer into monomers or other hydrocarbon products, which can then be used as a base material or feedstock to produce the polymer again. Its value is low compared with that of machinery. For most common packaging plastics, chemical recycling technologies are not yet widespread and/or economically viable. However, because they allow used plastics to be upgraded again to a prime-quality polymer, they may be an option for materials that cannot be mechanically recycled (for example, most multi-material packaging or plastics that cannot be further degraded for recycling).

      Multi-material packaging: Definitions, advantages and post-use challenges
   Multi-material packaging consists of a variety of materials that cannot currently be easily separated mechanically (PET bottles with PP caps are not considered multi-material packaging). Such packaging items can be a mixture of surprises or a product that combines different layers of material.
   The advantage of multi-material packaging products is that they can combine the functional properties of different materials into a single packaging item.       Therefore, multi-material packaging is today's rapidly growing market, and the most typical applications include multi-layer film bags, vertical bags, tube packaging (such as teeth) and aluminum-plastic paper composite packaging boxes.
   Because current technology cannot economically separate multiple materials into different plastics, recyclers are increasingly turning to compatibilizer technology. In the recycling process, this injection can be used to blend resins that are usually incompatible (multi-material packaging or non-separable materials, such as mixtures found in sorted residual materials), so that previously hand-only materials can also be mechanically recycled into low-value applications.
   In the future, as long as the technology is further developed, chemical separation or chemical recycling can be used as a solution for multi-material product recycling.