As a component of multilayer packaging, our Durethan® C38 PA 6 IPD I product range is recyclable with the waste stream of flexible polyethylene (PE) packaging. The product range has been certified by the cyclos-HTP institute, ensuring that our customers will not have to pay charges for the sale of this packaging in Germany.
At first glance, packaging made from polyamide/polyethylene multilayer films seems to go against efforts to simplify the recycling of flexible packaging by reducing the variety of materials or using mono-material solutions. These multilayer systems have often been regarded as non-recyclable. However, this idea does not hold up when we consider holistic views, scientific studies and current recycling practices. Plus, this idea overlooks the additional benefits that polyamides provide to such packaging, like conserving material resources, reducing waste, avoiding food waste, and protecting the climate.
The recycling of PE multilayer films with polyamide content into PE recyclates is not new. It has been common practice for years and is technically possible without any problems, as proven by various studies, according to the report Mechanical Recycling of LDPE Films Containing PA6/66 by Three Different, Independent Testing Protocols, published by the Advanced Packaging Association (APA).
It can be done on existing equipment without costly retrofitting. This is because the multilayer systems only contains 10 to 30 percent polyamide. The polyamide content in the waste stream of flexible PE packaging is therefore only around one percent, and therefore hardly changes the properties of the PE recyclates. In some respects, the recyclates even have better properties than PE virgin material. One reason for this is that the multilayer systems contain tie layers that ensure good compatibility of polyamide with polyethylene in the packaging and also in the recyclate.
The discussion about multilayer systems, their advantages and the practical experience with their recycling enabled us to have the recycling compatibility of our polyamide 6 copolyamides in the Durethan® C38 product range tested and confirmed. We conducted detailed tests together with the independent cyclos-HTP institute. They confirmed the recycling compatibility of our copolyamides with the waste stream of flexible PE packaging. The associated certificates are a prerequisite for the next step, our product range will be included in the new minimum standard for assessing the recyclable design of packaging in accordance with Section 21 (3) of the German Packaging Act at the Central Agency Packaging Register (ZSVR).This is scheduled to happen in 2025.
The recycling compatibility of Durethan® C38F in the PE waste stream will also be formally stipulated, which will save our customers, who supply multilayer films to Germany, from potential charges. The ZSVR also has the task of ensuring a fair distribution of disposal and recycling costs. In the future, packaging that meets the minimum standard will result in better financial outcomes.
Our Durethan® C38F copolymers are made up of polyamide 6 chains in which isophthalic acid and isophorone diamine are incorporated as comonomers (IPD I). The latter reduce the number of hydrogen bonds between the polymer chains, so that the melting point of the copolymer falls and is closer to that of polyethylene.
In addition, the copolymer crystallizes more slowly and not completely compared to pure polyamide 6. This has advantages. For example, the blow-molded multilayer film does not curl up from the sides. It also tends to form less wrinkles. This results in a more stable and flexible production process for blown film. One of the strengths of our Durethan® C38F product grades in applications is that they allow for more precise corner formation and deeper walls in meat packaging trays.
The additional benefits that polyamide multilayer systems offer compared to pure PE packaging is enormous. They suppress the entry of oxygen and prevent aromas from escaping. Sausage, meat and cheese therefore have a long shelf life and keep their taste and appearance.
Packaging with polyamide helps to avoid food waste and makes an important contribution to climate protection because wasted food causes unnecessary greenhouse gas emissions, which contribute to global warming. Plus, the toughness of polyamide makes the film system puncture-resistant, so that it is not damaged by bones or sharp edges of bread and remains leak-proof.
Polyamide displays all these positive qualities in film thicknesses of just 20 to 40 micrometres (µm, 1 µm corresponds to 0.001 millimetres). Barrier packaging made of polyamide can therefore be more than half as thin as its PE-based counterparts and is typically only around 20 to 100 µm thick. This reduces material consumption, which saves resources and reduces packaging waste.
Currently, other European countries are considering similar certifications for the recycling of PE packaging films with polyamide content. One of the reasons for this is the new European Packaging & Packaging Waste Regulation (PPWR). We see the inclusion of our Durethan® C38F copolymers in the German minimum standard as a blueprint for further certifications in Europe and will actively support these regulatory processes for our customers.
To further this effort, we have recently co-founded the new, independent Advanced Packaging Association (APA). This non-profit organization aims to bring together stakeholders along the entire flexible packaging value chain. The goal is to raise awareness about the resource-saving, climate-friendly, and efficient qualities of multilayer packaging with polyamide. We aim to address the industry and legislators, and educate consumers about the sustainability of polyamide-containing film packaging.
Discover more about the Durethan® C38F product range and the cyclos-HTP certificates here.
Read the test report from Institut cyclos-HTP GmbH here.
Technical Marketing Manager, Envalior
Wolfram Littek is Technical Marketing Manager for PA 6 film grades at Envalior. He has overseen PA 6 film grades in this role since 2006, with his responsibilities expanding to include Pocan®, Durethan® base resins, glass fibers, caprolactam, and cyclohexanol. In this position, he serves as the interface between customers, and both product development and production departments.
11 March 2025
4 min read
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