What polymer limit applies to paper and board under the SUPD?

The Single-Use Plastics Directive names no figure. It asks whether plastic acts as a main structural component and leaves the assessment to the individual case. That is precisely the point of contention: paper and board always contain polymer-based additives such as sizing and wet-strength agents, without which they would not have their properties.

What the technical literature shows

Six technical sources average 0.93 per cent of dry weight as the technically necessary polymer content. Adding the scientifically recognised trace allowance of 0.1 per cent gives a derived overall threshold of 1.03 per cent. These additives are functionally necessary and do not form a plastic matrix of their own.

What follows from that

Without a threshold it remains open, four years after the directive took effect, whether a fibre-based cup falls under it. The flustix LESS PLASTICS PRODUCT mark works with 0.75 per cent and therefore sits below the derived value. The full derivation with all six sources is set out in the scientific derivation.