{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,8]],"date-time":"2026-06-08T18:36:00Z","timestamp":1780943760726,"version":"3.54.1"},"reference-count":42,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2020,12,15]],"date-time":"2020-12-15T00:00:00Z","timestamp":1607990400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Lacking recyclability of multilayer packaging can be overcome by using a thermoreversible crosslinking adhesive consisting of maleimide- and furan-functionalized polyurethane-(PU-)prepolymers, reacting in a Diels\u2013Alder-reaction. Here, the furan-functionalized PU-prepolymer carries furan-side-chains to avoid the usage of an additional crosslinking agent. Thus, N\u2011(2\u2011hydroxyethyl)maleimide and furfurylamine are the only two chemicals contained in the adhesive that are not listed in the appendix of EU Regulation 10\/2011. Using migration modelling, it could be shown that, at 23 \u00b0C, both chemicals have lag-times of only a few minutes if 45 \u00b5m PE is used as a barrier. However, if the residual content is below 30 mg\/kg, the legally specified maximum amount of 0.01 mg\/kg food is not reached. After determining the diffusion coefficients and the activation energy of diffusion through ethylene-vinyl alcohol copolymer (EVOH), it could be determined that the lag-time of the migrants can be extended to at least 9 years by the use of 3 \u00b5m EVOH. From a food law point of view, the use of the described adhesive is possible if the above\u2011mentioned measures are complied.<\/jats:p>","DOI":"10.3390\/polym12122988","type":"journal-article","created":{"date-parts":[[2020,12,15]],"date-time":"2020-12-15T09:12:57Z","timestamp":1608023577000},"page":"2988","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Recyclable Multilayer Packaging by Means of Thermoreversibly Crosslinking Adhesive in the Context of Food Law"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9810-3416","authenticated-orcid":false,"given":"Katharina M. A.","family":"Kaiser","sequence":"first","affiliation":[{"name":"TUM School of Life Sciences Weihenstephan, Technical University of Munich, Weihenstephaner Steig 22, 85354 Freising, Germany"},{"name":"Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Strasse 35, 85354 Freising, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Johann","family":"Ewender","sequence":"additional","affiliation":[{"name":"Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Strasse 35, 85354 Freising, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7529-6799","authenticated-orcid":false,"given":"Frank","family":"Welle","sequence":"additional","affiliation":[{"name":"Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Strasse 35, 85354 Freising, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,12,15]]},"reference":[{"key":"ref_1","unstructured":"Wagner, J.R. (2016). Multilayer Flexible Packaging, Elsevier. [2nd ed.]."},{"key":"ref_2","unstructured":"Morris, B.A. (2017). The Science and Technology of Flexible Packaging. Multilayer Films from Resin and Process to End Use, Elsevier William Andrew."},{"key":"ref_3","unstructured":"Nonclercq, A. (2020, February 12). Mapping Flexible Packaging in a Circular Economy, Available online: https:\/\/ceflex.eu\/resources\/."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Singh, P., Wani, A., and Langowski, H.-C. (2017). Food Packaging Materials, CRC Press.","DOI":"10.1201\/9781315374390"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1016\/j.wasman.2017.07.044","article-title":"Mechanical and chemical recycling of solid plastic waste","volume":"69","author":"Ragaert","year":"2017","journal-title":"Waste Manag."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Kaiser, K., Schmid, M., and Schlummer, M. (2018). Recycling of Polymer-Based Multilayer Packaging: A Review. Recycling, 3.","DOI":"10.3390\/recycling3010001"},{"key":"ref_7","unstructured":"Dixon, J. (2011). Packaging Materials, ILSI."},{"key":"ref_8","unstructured":"(2018). A European Strategy for Plastics in a Circular Economy, European Commisson."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"49230","DOI":"10.1002\/app.49230","article-title":"Recycling of multilayer packaging using a reversible cross\u2014Linking adhesive","volume":"137","author":"Kaiser","year":"2020","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"33","DOI":"10.7569\/RAA.2019.097304","article-title":"Debonding on Demand of Adhesively Bonded Joints: A Critical Review","volume":"7","author":"Banea","year":"2019","journal-title":"Rev. Adhes. Adhes."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Hopmann, C., and Dahlmann, R. (2020). Photoluminescent Tracer Effects on Thermoplastic Polymer Recycling. Advances in Polymer Processing 2020, Proceedings of the International Symposium on Plastics Technology, Berlin, Heidelberg, 10 March 2020, Springer.","DOI":"10.1007\/978-3-662-60809-8"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1002\/cite.201900126","article-title":"Kunststoffidentifikation und-sortierung in der Circular Economy durch Fluoreszenzmarker","volume":"92","author":"Woidasky","year":"2020","journal-title":"Chemie Ingenieur Technik"},{"key":"ref_13","unstructured":"Letcher, T.M. (2020). Chapter 6\u2014Current industry position on plastic production and recycling. Plastic Waste and Recycling: Environmental Impact, Societal Issues, Prevention, and Solutions, Academic Press."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1016\/j.wasman.2014.12.006","article-title":"Automated sorting of polymer flakes: Fluorescence labeling and development of a measurement system prototype","volume":"38","author":"Brunner","year":"2015","journal-title":"Waste Manag."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1143","DOI":"10.1080\/09593332508618380","article-title":"A new technology for automatic identification and sorting of plastics for recycling","volume":"25","author":"Ahmad","year":"2004","journal-title":"Environ. Technol."},{"key":"ref_16","unstructured":"(2020, February 12). Pla.to GmbH. Die Pla.to GmbH und die Hochschule Zittau\/G\u00f6rlitz entwickeln ein innovatives Recyclingverfahren f\u00fcr die Trennung von Folien aus Altverpackungen. Available online: https:\/\/www.plato-technology.de\/downloads\/."},{"key":"ref_17","unstructured":"National Center for Biotechnology Information\u2014PubChem (2020, November 09). Furfuryl Alcohol, Available online: https:\/\/pubchem.ncbi.nlm.nih.gov\/compound\/Furfuryl-alcohol."},{"key":"#cr-split#-ref_18.1","unstructured":"(2011). The European Commission, COMMISSION REGULATION"},{"key":"#cr-split#-ref_18.2","unstructured":"(EU) No 10\/2011 of 14 January 2011 on plastic materials and articles intended to come into contact with food. OJ, L12, 1-89."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Stepanski, H., and Leimenstoll, M.C. (2016). Polyurethan-Klebstoffe. Unterschiede und Gemeinsamkeiten, 1. Ed. 2016, Springer.","DOI":"10.1007\/978-3-658-12270-6_1"},{"key":"ref_20","unstructured":"National Center for Biotechnology Information\u2014PubChem (2020, November 19). 1-(2-Hydroxyethyl)-1H-pyrrole-2,5-dione, Available online: https:\/\/pubchem.ncbi.nlm.nih.gov\/compound\/1-_2-Hydroxyethyl_-1H-pyrrole-2_5-dione."},{"key":"ref_21","unstructured":"Institute for Occupational Safety and Health of the German Social Accident Insurance (2020, October 23). GESTIS Substance Database\u2014Furfurylamine. Available online: http:\/\/gestis.itrust.de\/nxt\/gateway.dll\/gestis_en\/000000.xml?f=templates&fn=default.htm&vid=gestiseng:sdbeng."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"5261","DOI":"10.1002\/adfm.201400299","article-title":"Self-Healing Polyurethanes with Shape Recovery","volume":"24","author":"Heo","year":"2014","journal-title":"Adv. Funct. Mater."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1353","DOI":"10.1021\/acs.macromol.6b02370","article-title":"An Investigation of the Selective Chain Scission at Centered Diels\u2013Alder Mechanophore under Ultrasonication","volume":"50","author":"Duan","year":"2017","journal-title":"Macromolecules"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"770","DOI":"10.1039\/C3NJ01245J","article-title":"Synthesis of linear polyurethane bearing pendant furan and cross-linked healable polyurethane containing Diels\u2013Alder bonds","volume":"38","author":"Du","year":"2014","journal-title":"New J. Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"963","DOI":"10.1002\/pts.2085","article-title":"Determination and Prediction of the Lag Times of Hydrocarbons through a Polyethylene Terephthalate Film","volume":"27","author":"Ewender","year":"2014","journal-title":"Packag. Technol. Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"277","DOI":"10.1002\/pts.2203","article-title":"Functional Barrier Performance of a Polyamide-6 Membrane towards n -Alkanes and 1-Alcohols","volume":"29","author":"Ewender","year":"2016","journal-title":"Packag. Technol. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Ewender, J., and Welle, F. (2019). Diffusion Coefficients of n-Alkanes and 1-Alcohols in Polyethylene Naphthalate (PEN). Int. J. Polym. Sci., 2019.","DOI":"10.1155\/2019\/2748649"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"945","DOI":"10.1080\/02652030500323997","article-title":"Application of Finite Element Analysis (FEA) for the simulation of release of additives from multilayer polymeric packaging structures","volume":"22","author":"Roduit","year":"2005","journal-title":"Food Addit. Contam."},{"key":"ref_29","unstructured":"Oertel, G., Becker, G.W., and Braun, D. (1993). Polyurethane; mit 126 Tabellen, Hanser. [3rd ed.]."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1080\/02652030400028035","article-title":"Evaluation of migration models that might be used in support of regulations for food-contact plastics","volume":"22","author":"Begley","year":"2005","journal-title":"Food Addit. Contam."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1845","DOI":"10.1002\/app.38885","article-title":"A new method for the prediction of diffusion coefficients in poly(ethylene terephthalate)","volume":"129","author":"Welle","year":"2013","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_32","unstructured":"Kaushiva, B.D. (1999). Structure-Property Relationships of Flexible Polyurethane Foams, Virginia Tech."},{"key":"ref_33","unstructured":"The Dow Chemical Company (2016). Laminating Adhesives for Flexible Packaging. Science that Connects, The Dow Chemical Company."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Da Silva, L.F., \u00d6chsner, A., and Adams, R.D. (2011). Handbook of Adhesion Technology, Springer.","DOI":"10.1007\/978-3-642-01169-6"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Kinloch, A.J. (1987). Adhesion and Adhesives. Science and Technology, Springer.","DOI":"10.1007\/978-94-015-7764-9"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"202","DOI":"10.1080\/02652030500373661","article-title":"Typical diffusion behaviour in packaging polymers\u2014Application to functional barriers","volume":"23","author":"Dole","year":"2006","journal-title":"Food Addit. Contam."},{"key":"ref_37","unstructured":"Buschow, K.H.J. (2001). Networks: Diffusion. Encyclopedia of Materials: Science and Technology, Elsevier."},{"key":"ref_38","unstructured":"Dunn, T. (2015). Manufacturing Flexible Packaging. Materials, Machinery, and Techniques, William Andrew."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1023\/B:JPOL.0000021796.41800.e9","article-title":"Morphological, Thermal, Barrier and Mechanical Properties of LDPE\/EVOH Blends in Extruded Blown Films","volume":"11","author":"Huang","year":"2004","journal-title":"J. Polym. Res."},{"key":"ref_40","unstructured":"PlastEurope (2020, September 03). New Guidelines for Barrier Polytheylene Film\/\u201cRecyClass\u201d Tests Show EVOH Concentrations Compatible for Recycling. Available online: https:\/\/www.plasteurope.com\/news\/RECYCLING_t243864\/."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1156","DOI":"10.1111\/1541-4337.12556","article-title":"Multilayer packaging: Advances in preparation techniques and emerging food applications","volume":"19","author":"Anukiruthika","year":"2020","journal-title":"Compr. Rev. Food Sci. Food Saf."}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/12\/12\/2988\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:45:13Z","timestamp":1760179513000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/12\/12\/2988"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,12,15]]},"references-count":42,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2020,12]]}},"alternative-id":["polym12122988"],"URL":"https:\/\/doi.org\/10.3390\/polym12122988","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,12,15]]}}}