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Paper and board contain polymer-based additives such as sizing agents and wet-strength agents, without which they would not have their properties. Six technical sources average 0.93 % of dry weight. Adding the scientifically recognised trace allowance of 0.1 % gives an overall threshold of 1.03 %. These additives are functionally necessary but do not form a plastic matrix of their own.
0.93 %
average of the mean values from six technical sources (dry weight)
+ 0.10 %
scientifically recognised trace allowance
1.03 %
derived overall threshold
0.75 %
limit of the flustix LESS PLASTICS PRODUCT mark
The full document
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The question is how high the technically necessary polymer content in fibre-based packaging is according to the technical literature, and which threshold can be considered appropriate in regulatory terms if the recognised understanding of trace substances is also taken into account. The reference point is the Single-Use Plastics Directive (EU) 2019/904.
These are functional additives: polymer-based sizing agents for hydrophobicity such as alkyl ketene dimers (AKD) or alkenyl succinic anhydrides (ASA), wet-strength agents such as polyamide-epichlorohydrin resins (PAE), plus optical brighteners. They are added to the stock suspension or applied at the surface and are an integral part of established manufacturing processes.
Francolini et al. (2023) 0.3–1.0 %, Bajpai (2015) 0.1–0.5 %, Hubbe (2006) 0.2–1.0 %, KTH (2023) 0.5–2.5 %, Gullichsen & Paulapuro (2000) 1.0–2.5 % and the Taschenbuch der Papiertechnik 0.4–1.2 %. The arithmetic mean of these mean values is 0.93 %.
In environmental analysis, proportions below 0.1 % count as traces, a threshold found at the BfR (2018), the German Environment Agency (2020) and in the REACH Regulation. Add to that process variation and analytical uncertainty at very low polymer levels. The allowance is therefore a conservative addition, not leeway.
Recital 11 of the SUPD states that paints, inks and adhesives do not fall under the definition of plastic in Article 3(1). The European Commission’s guidelines confirm that functional additives such as adhesives, binders and paints are excluded from the scope. Polymer-based binders and additives in paper, board or cardboard that perform no structural function are therefore not covered by the SUPD.
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In more detail
Six sources, each giving the amount of polymeric additives relative to dry weight: Francolini et al. (2023) 0.3 to 1.0 per cent, mean 0.65. Bajpai (2015) 0.1 to 0.5 per cent, mean 0.30. Hubbe (2006) 0.2 to 1.0 per cent, mean 0.60. KTH (2023) 0.5 to 2.5 per cent, mean 1.50. Gullichsen and Paulapuro (2000) 1.0 to 2.5 per cent, mean 1.75. Taschenbuch der Papiertechnik, eighth edition, 0.4 to 1.2 per cent, mean 0.80.
For each source the arithmetic mean of the lower and upper limit is taken, then the arithmetic mean of those six means. The result is 0.93 per cent. The approach summarises heterogeneous but comparable literature data and follows the usual statistical treatment of technical ranges.
In environmental analysis, shares below 0.1 per cent count as traces. That threshold appears at the German Federal Institute for Risk Assessment (2018), the Federal Environment Agency (2020) and in the REACH Regulation. Because polymeric additives in paper technology regularly sit in the range of tenths of a per cent, and because process variation and analytical uncertainty add to that, the trace value is included as a conservative allowance. 0.93 plus 0.10 gives the threshold of 1.03 per cent.
The legal reading matches the derivation: paints, inks and adhesives, that is polymer-based binders and additives, are expressly outside the definition of plastic under Article 3(1) of Directive (EU) 2019/904. In addition, stilbene-based optical brighteners are as a rule low-molecular organic compounds and do not meet the definition of a polymer under Article 3(5) REACH at all.
The analytical work uses combined, standard-compliant procedures to DIN, EN and ISO, including DIS methods. These include thermal analysis, TED-GC/MS, PY-GC/MS, extraction procedures and other internationally established methods of polymer analysis.
Source: Six technical sources on paper technology (Francolini 2023, Bajpai 2015, Hubbe 2006, KTH 2023, Gullichsen/Paulapuro 2000, Taschenbuch der Papiertechnik 2021); BfR 2018; UBA 2020; REACH; Directive (EU) 2019/904, recital 11
As of: March 2026
Editorial responsibility: Malte Biss, Managing Director of flustix GmbH
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