Dr. Monika Tönnießen, Hartmut Büsching I October 2016 Plasticizers in Food Contact Materials and Adhesives

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1 Dr. Monika Tönnießen, Hartmut Büsching I ctober 2016 lasticizers in Food Contact Materials and Adhesives Europespecific content

2 02/11 lasticizers in Food Contact Materials and Adhesives Why are plasticizers used and where do we find them? lasticizers are additives that increase the plasticity or fluidity of a material. The use of plasticizers allows improved compound processing characteristics. At the same time it provides flexibility in the final product. Some technical effects of plasticizers are: Brittle materials become flexible, soft, stretchable or sticky Improved workability and elasticity Decrease of the elastic modulus and the glass transition temperature Swelling or dissolving of the polymer lasticizers can be found in many products we use frequently in our daily life. This includes toys, gaskets, floor coverings, window profiles, varnishes and lacquers, cigarettes, chewing gum and tablet coatings. lasticizers are also used in adhesives. As adhesives play an important role when it comes to food packaging they should be chosen with particular focus on the risk of migration of plasticizers into the foodstuff.

3 03/11 lasticizers in Food Contact Materials and Adhesives Definition of plasticizers Typically we differentiate two types of plasticization that are characterized by the use of either internal plasticizers or external plasticizers. Internal plasticizers Internal plasticizers cause a chemical modification of a rigid polymer (copolymerization). The molecular weight is > 1000 Da. As a result of the (internal) chemical reaction of the plasticizer with the polymer chain, the intermolecular attractive force is reduced. The polymer beeing of crystalline structure before now shows an amorphous structure. An internal plasticizer is chemically bonded. Therefore it cannot move outside of the adhesive film. n these grounds the common understanding in the adhesive world is that internally plasticized products are considered plasticizer-free. External plasticizers External plasticizers are added to a polymer. There is no chemical reaction with the polymer chain. The molecular weight of an external plasticizer is < 1000 Da. This relatively low molecular weight leads to a relatively high molecular mobility. External plasticizers are liquid or solid organic substances with a low vapor pressure and a high boiling point (> 250 C). They are indifferent substances that show no chemical reaction but a physical interaction. External plasticizers break up the interaction of the polymer chains and widen their separation from each other and thus raising the polymer chain mobility. Even though the external plasticizers are not chemically bonded, they are supposed to remain in the final product and therefore also in the adhesive film after drying. Figure 1 Effect of plasticizers igid VC Strong dipole-dipole interaction Crystalline structure lasticizer Internally plasticized VC Incorporation of co-monomers (e.g. vinyl acetate) with large side groups chemical bonding eduction of the intermolecular attractive force Amorphous structure Externally plasticized VC Incorporation of plasticizer physical interaction Breaking-up of the polymer chains Amorphous structure

4 04/11 lasticizers in Food Contact Materials and Adhesives Difference between plasticizers and solvents Both plasticizers and solvents are used in adhesives but with different characteristics and functions. Solvents Influence the production process of the final product. Low boiling point. Should not remain in the final product (e.g. the adhesive film). lasticizers Influence the properties of the final product. High boiling point. Are supposed to remain in the final product and (therefore) also in the adhesive film after drying. Internal plasticizers remain in the final product because they are chemically bonded. External plasticizers are critical to migration as there is no chemical bonding which leads to a high tendency of migration. Types of external plasticizers Today there are more than 300 known external plasticizers. Approximately 100 of them are commercially important. lasticizers based on ester In this documentation we focus on external plasticizers that are based on ester. lasticizers based on ester qualify for the use in water-based adhesives because of their dipole character. Examples of ester-based external plasticizers are: hthalates, Adipates, hosphates, Benzoates, Citrates and Acetates. The most commonly added ester-based plasticizers for the use in water-based adhesives are either a mixture of benzoates or Triacetin. Especially Triacetin has been much used recently due to its good performance and very low impact on human health. roperties of an ideal external plasticizer If we wanted to list the properties of an ideal external plasticizer, it would look like this: dorless Colorless esistant against light, cold and heat Low volatile Not harmful elatively large size (i. e. extended separation of the polymer chains for a good plasticizing effect) With polar and non-polar groups (to enable interaction with both polymer parts) Very effective at low amount No migration (which is impossible to realize) Figure 2 lasticizers based on esters hthalates Diisobutyl phthalate (DIB) Dibutyl phthalate (DB) Dioctyl phthalate (= Di(2-ethylhexyl) phthalate, D, DEH) H hosphates Citrates Triacetin Adipates Benzoates Acetates Dioctyl adipate (DA) Diisononyl adipate (DINA)

5 05/11 lasticizers in Food Contact Materials and Adhesives External plasticizers and migration In a typical packaging profile for a food packaging two materials are bonded by an adhesive to protect the foodstuff inside the packaging. Migration is the transfer of molecules from the adhesive layer into the foodstuff causing a contamination. At the same time there is also the tendency that substances from the foodstuff migrate into the packaging. This leads to a loss of the foodstuffs' composition, i. e. to a possible quality degration. All parts of the packaging materials contribute to the migration of the whole packaging, not only the adhesive layer! In case the adhesive contains an external plasticizer, the small plasticizer molecules quickly migrate (definately in both directions) causing a massive contamination of the foodstuff with the plasticizer. ossible effects of the migration of plasticizers: Incipient dissolution of contact materials Corrosion of contact materials Swelling of contact materials Adhering/sticky on the surface Contribution to windscreen fogging Contamination of foodstuff Figure 3 Migration of plasticizers from adhesives ackaging material 1 Adhesive lasticizer Migration ackaging material 2 Food Impact of external plasticizers on human health In many chemicals different external plasticizers are used. According to their toxicological assessment they may or may not be used for adhesives for food contact materials. lasticizers like hthalates have been commonly used for many years until critical health concerns have been raised. Today, hthalates should not be used. They are marked as SVHC (Substances of very high concern), i. e. their use must be authorized in the EU. For us at Henkel the SVHC is reason enough to ban hthalates as plasticizers! ther types of plasticizers are under evaluation by the European Chemicals Agency (ECHA) under the Community olling Action lan (CoA). As there is still no sufficient data available for a severe evaluation and complete assessment, the use of these alternative plasticizers is currently restricted to certain application. Finally there are two external plasticizers that can be declared as suitable for the use with food contact material. Acetyltributylcitrate is not classified according to CL. Anyway its use for FCM can be justified due to the toxicological assessment. However, citrates are not likely to be used in adhesives. Triacetin represents no risk according to its toxicological assessment. It is permitted as an additive for food in the EU under the E-Number E 1518 (explicitly for chewing gum; EU No 1129/2011).

6 06/11 lasticizers in Food Contact Materials and Adhesives Toxicological assessment of external plasticizers Figure 4 Toxicological assessment of external plasticizers lasticizer CAS No Harmonized C&L Toxicological assessment hthalates Adipates hosphates Benzoates Diisobutyl phthalate (DIB) H360Df Dibutyl phthalate (DB) H360Df Dioctyl phthalate (= Di (2-ethylhexyl) phthalate, D, DEH) Dioctyl adipate (= Di(2-ethylhexyl) adipate, DA, DEHA) H H360FD Diisononyl adipate (DINA) Tri-2-ethylhexyl phosphate (T, TEH) Ethylhexyl diphenyl phosphate Diethylene glycol dibenzoate (DEGB) Triethylene glycol dibenzoate Dipropylene glycol dibenzoate Citrates Acetyltributylcitrate (ATBC) Acetates Triacetin (E 1518) Should not be used, SVHC-substance: use must be authorized in the EU Should not be used, SVHC-substance: use must be authorized in the EU Should not be used, SVHC-substance: use must be authorized in the EU Some uncertainty due to lack of data, under further evaluation by ECHA (CA), current use might be justified Some uncertainty due to lack of data, use might be justified Some uncertainty due to lack of data, use might be justified Some uncertainty due to lack of data, use might be justified Some uncertainty due to lack of data, under further evaluation by ECHA (CA), current use might be justified Some uncertainty due to lack of data, use might be justified Some uncertainty due to lack of data, under further evaluation by ECHA (CA), use might be justified for some applications Use in FCM justified Food additive (permitted in chewing gum according to regulation (EU) No 1129/2011)

7 07/11 lasticizers in Food Contact Materials and Adhesives lasticizers in food contact legislation Looking at external plasticizers in food contact legislation we focus on the following legislations / restrictions: (EU) No 10/2011 (on plastic materials and articles intended to come into contact with food) Bf XIV, XXI or XXXVI (recommendations of the German Federal Institute for isk Assessment) FDA (legislation of the U.S. Food and Drug Administration) None of the below listed plasticizers is in compliance with the Bf XIV recommendation due to the fact that Bf XIV deals only with plasticizer-free dispersions. Figure 5 lasticizers in food contact legislation lasticizer hthalates Adipates hosphates Benzoates CAS No (EU) No 10/2011 Bf XIV Diisobutyl phthalate (DIB) no no no Dibutyl phthalate (DB) Dioctyl phthalate (= Di (2-ethylhexyl) phthalate, D, DEH) Dioctyl adipate (= Di(2-ethylhexyl) adipate, DA, DEHA) FCM: 157 SML = 0.3 mg/kg plasticizer in repeated use materials and articles contacting non-fatty foods no no no FCM: 207 SML = 18 mg/kg SML (T) = 60 mg/kg no Legislation / estriction Bf XXI Bf XXXVI FDA no max. 10 % max. 10 % max. 0.3 mg/kg foodstuff sum of DB and DIB max. 0.3 mg/kg foodstuff max. 0.3 mg/kg foodstuff sum of DB and DIB max. 0.3 mg/kg foodstuff max. 1.5 mg/kg foodstuff no Diisononyl adipate (DINA) no no no no Tri-2-ethylhexyl phosphate (T, TEH) 2-Ethylhexyl diphenyl phosphate no no no no FCM: 392 SML = 2.4 mg/kg no no no Diethylene glycol dibenzoate (DEGB) no no no no Triethylene glycol dibenzoate no no no no Dipropylene glycol dibenzoate no no no no Citrates Acetyltributylcitrate (ATBC) Acetates Triacetin (E 1518) FCM: 138 SML (T) = 60 mg/kg FCM: 40 SML = ML no no no no no no Acetyltributylcitrate and Triacetin as the most recommended substances under the toxicological point of view are listed in (EU) No 10/2011. For Triacetin the specific migration limit (SML) equals the overall migration limit (ML) meaning that this acetate is allowed to migrate up to the maximum permitted amount of non-volatile substances released into the food, the ML value of 60 mg/kg. ecycling You always meet plasticizers twice! lasticizers are not eliminated during the paper recycling process. Looking at recycled cardboard, plasticizers rather enrich during the manifold recycling steps leading to a high risk for food contact contamination when using the recycled cardboard in food packaging. You always meet plasticizers twice first in the original packaging and again in the recycled material.

8 08/11 lasticizers in Food Contact Materials and Adhesives History of improvements for food packaging adhesives Looking at the common use of external plasticizers there has been a number of improvements during the last decades. Henkel reacted whenever a substance became evaluated and/or considered as critical with respect to consumer health. Henkel does not use DB, DIB or other hthalates in its products. The very high concern these plasticizers cause has made Henkel looking for alternatives from the very beginning. Already in 2007 important associations in Germany committed themselves to stop using the hthalate DIB. As a result of the aligned actions of the involved industries, DIB in recycled cardboard dropped significantly. Figure 6 History of improvements for food packaging adhesives containing plasticizers DB DIB Benzoates Triacetin Low Migration (LM) lasticizer Migration potential EU Bf XIV FDA DB DIB Benzoates Triacetin internal plasticizer high high high high low SVHC SVHC x x x x

9 09/11 lasticizers in Food Contact Materials and Adhesives lasticizer-free with Henkel Since many years Henkel has developed and promoted a low migration product range without external plasticizers. Henkel's development focuses on internally plasticized products as these are commonly considered plasticizer-free, and therefore also these Henkel products are free of plasticizers. lasticizer-free and low migration by Henkel LM (Low Migration) shows the highest advantage for food contact with the best criteria. AQUENCE LM for the ackaging Industry Adhesives play a key role in the manufacturing of food packaging. Adhesives of Henkel s AQUENCE LM line provide the full range of low migration water-based adhesives. All AQUENCE LM adhesives use a plasticizer-free formulation with a minimum content of critical substances compared to traditional adhesives and a significantly higher efficiency through lower adhesive consumption. Safe Food ackaging with AQUENCE LM adhesives AQUENCE LM offers a complete water-based product range for the use with packaging from bags and sacks to folding boxes. AQUENCE LM adhesives Full range of low migration water-based adhesives lasticizer-free formulation with minimum content of critical substances Easy and clean processing Equal or better adhesive strength compared to traditional adhesives Significantly higher efficiency through lower adhesive consumption

10 10/10 rimary aromatic amines Key take aways Adhesives could contain internal or external plasticizers. Internal plasticizers are chemically bonded. They cannot migrate into the foodstuff. Adhesives with such plasticizers are considered plasticizer-free. External plasticizers are small molecules with a high migration potential. They show different toxicological behavior, some species are classified as SVHC, Triacetin is allowed as a food additive. Water-based adhesives containing external plasticizers cannot comply with the XIV. Bf recommendation. Henkel can offer plasticizer-free adhesives as low migration products. These products are in compliance with the relevant food contact legislation (FDA, (EU) No 10/2011 and Bf recommendation). Literature and useful links D. F. Cadogan, Ch. J. Howick, Ullmann s Encyclopedia of Industrial Chemistry, Wiley-VCH Verlag, Vol. 27, p , 2012 ömpp nline Lexikon Chemie, Thieme-Verlag, Datenbank Bf-Empfehlungen zu Materialien für den Lebensmittelkontakt Database Bf ecommendations on Food Contact Materials lastics egulation (EU) No 10/2011

11 11/11 rimary aromatic amines Meet your experts Dr. Monika Tönnießen is a chemist by profession and works in the roduct Safety Department of the Henkel Adhesive Technologies division. Since 2006 she deals with customer inquiries and is an expert on all food contact related questions. She is member of the paper & packaging group of the European Adhesive Association FEICA. Hartmut Büsching works in the product development for water-based paper converting adhesives with more than 35 years of experience. His main application fields are adhesives for packaging and consumer goods. A major part of his product development projects are adhesives for food packaging. Further information Visit the Food Safe ackaging remium Area offering webinars, white papers, FAQs, videos and more: Contact us! Many options available. Webinars ur webinars allow you to directly communicate with our Henkel food safety experts. Check our website for the dates of upcoming webinars. Henkel AG & Co. KGaA Düsseldorf, Germany The information provided herein, especially recommendations for the usage and the application of our products, is based upon our knowledge and experience. Due to different materials used as well as to varying working conditions beyond our control we strictly recommend to carry out intensive trials to test the suitability of our products with regard to the required processes and applications. We do not accept any liability with regard to the above information or with regard to any verbal recommendation, except for cases where we are liable of gross negligence or false intention. The information is protected by copyright. In particular, any reproductions, adaptations, translations, storage and processing in other media, including storage or processing by electronic means, enjoy copyright protection. Any exploitation in whole or in part thereof shall require the prior written consent of Henkel AG & Co. KGaA. Except as otherwise noted, all marks used in this document are trademarks and/or registered trademarks of Henkel and/or its affiliates in the US, Germany, and elsewhere. Henkel AG & Co. KGaA, 10/2016