Monomers
Mechanical recycling of polyamide-containing multilayer structures
Recycling of polyethylene/polyamide composite packaging is already state-of-the-art.
Multi-layer packaging combines the best properties of different materials and thus achieves the best product protection with minimal material use. Polyethylene/polyamide packaging is used in applications with high mechanical and thermal demands (such as sausage, cheese or meat packaging).
BASF welcomes reclassification of recyclability of coextruded polyethylene/polyamide film structures
The „Stiftung Zentrale Stelle Verpackungsregister” (Central Agency Packaging Register) has reclassified the recyclability of polyamides in the minimum standard for assessing the recyclability of packaging subject to system participation pursuant to Section 21 (3) VerpackG: Since September 1, coextruded polyethylene (PE)/polyamide (PA) film structures have been recognized as mechanically recyclable.
Institute cyclos-HTP GmbH has proven and certified the recyclability of polyamide 6 (PA6, Ultramid® B) as well as Polyamide 6/6.6 (PA6/6.6, Ultramid® C) in coextruded polyethylene (PE)/PA6-multilayer film structures for the PE film stream. This was analyzed for PA contents of up to 30 percent in the original packaging based practice-relevant conditions.
The research details and results related to this work have been summarized in an updated publication to provide detailed answers to a wide range of questions on this issue. This publication is available for download here.
Cyclos HTP certificates
Since September 2022, the recyclability of coextruded polyethylene/polyamide films has been officially recognized in Germany in the minimum standard for the assessment of the recyclability of packaging subject to system participation in accordance with Section 21 (3) of the Packaging Act. Thanks to new independent studies conducted by cyclos-HTP institute together with BASF, it is now possible to certify polyamide-containing packaging that has not yet been covered as recyclable.
Regarding recyclability considerations, PE/PA composite films have been divided into three categories:
- Coextruded Polyethylene/Polyamide Composite Films
- Coextruded Polyethylene/Polyamide/Ethylene Vinyl Alcohol High Barrier Composite Films
- Laminated Polyethylene/Polyamide Films
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Coextruded barrier packaging (with tie layer)
PE/tie/PA
Certified:
up to 30% PA6 / PA6/66 with PE-g-MAH: recycling compatible
With additional PE-g-MAH (compatibilizer): 100% recyclable
(Already accepted in German minimum standard on recyclability)
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Coextruded high barrier packaging (with tie layer)
PE/tie/PA/EVOH
Certified:
up to 30% PA6 and 5% EVOH with PE-g-MAH: recycling compatible
With additional PE-g-MAH (compatibilizer): 100% - % EVOH recyclable
(Individual certification possible)
Laminated barrier packaging with adhesives
BOPA//PE with PE-g-MAH (BOPA = biaxially oriented PA laminated on PE Film)
Certified:
up to 23% PA6/ 2% compatible adhesive/3,5% PE-g-MAH: recycling compatible
(Individual certification possible)
Films that meet the following requirements can be certified as recycling compatible by cyclos-HTP based on the available tests.
- Coextruded PE/PA films with up to 30% polyamide 6 or polyamide 6/66 containing at least 0.5 g PE-g-MAH compatibilizer per g of polyamide.
- Coextruded PE/PA high-barrier films with max. 5 wt% EVOH and up to 30% polyamide 6 containing at least 0.5 g PE-g-MAH per g of polar polymers (PA+EVOH).
- Laminated PE/PA films with up to 23% polyamide 6 with adhesives tested as recyclable (e.g. LA7825/LA6230) if a compatibility promoter based on PE-g-MAH (3.43 wt% of the total film) has been incorporated into the PE layers.
The cyclos-HTP protocol analyzes the recyclability on the basis of the original packaging under practical conditions.
For PE/PA films, the PE/PA recyclate can be considered as a recyclable material according to cyclos-HTP classification (100% recyclability) if an additional compatibility promoter (0.15 g/g polyamide 6) is installed.
Why is this topic important?
Due to the currently very pronounced focus on the mechanical recycling of packaging waste from households and here on the so-called "monomaterials" desired by the recycling industry and politics, the advantages of polyamides for high-performance and flexible packaging are being pushed into the background. Certain criteria, such as the reduction of the used plastic due to lower material thicknesses ("downgauging"), the associated reduction in plastic waste volumes or the improved utilization of foodstuffs due to extended shelf life in barrier packaging with polyamide, are not adequately taken into account. Yet these criteria play an important role when it comes to supplying food to a continuously growing world population and reducing packaging waste and food wastage.
The currently realized update concerning compatibility of coextruded PE/PA multilayer films in the category “LDPE and films” of “Minimum standard for determining the recyclability of packaging subject to system participation pursuant to section 21 (3) VerpackG of ZSVR in Germany is a first and extremely important step to consider the advantages of PA containing packaging structures as well as the latest state-of-technology in terms of recyclability of Polyamides into legislation basics. Due to the fact, that there are a lot of things to do, especially with focus to the still ongoing finalization of EU legislation, we as BASF will continue to work and argue for a serious categorization of Polyamides in flexible packaging structures.
“Film-to-film” approach for PE/PA waste blends is a real recycling option including manufacturing of “new” monolayer films:
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