The Packaging and Packaging Waste Regulation (PPWR) is raising the bar for compostable packaging across Europe. Among its technical requirements, one small but critical detail stands out for adhesives. This is the “1% rule” as defined in EN 13432. This rule may sound like a minor detail, but for converters aiming to certify compostable packaging, it can make the difference between a valid claim and a rejected application.
What the 1% rule means
Under EN 13432, any single packaging component that makes up more than 1% of the pack’s dry weight must be individually proven compostable. Adhesives are included in this definition.
That means if an adhesive contributes more than 1% of the total dry weight, it cannot simply be ignored in testing. It must meet the same standards of biodegradation, disintegration, and safety as the rest of the pack.
The rule also states that the sum of all non-compostable components in a pack cannot exceed 5% of its weight. This means adhesives below the 1% threshold still matter. If combined with other non-compostable elements (such as inks, coatings, or barriers), they could push a pack over the 5% allowance and invalidate the claim.
Why adhesives often cross the threshold
Although adhesives are often perceived as negligible, their contribution to overall pack weight is not always minor. Industry data shows that adhesives typically account for less than 2% of total packaging weight, but in more complex formats, such as laminated cartons, wraparound trays, or fibre-based packs with plastic windows, that figure can rise much higher. In fact, some reports note that in certain applications adhesives can contribute up to 5% of total pack weight.
Once adhesive content exceeds 1% of the pack’s dry weight, EN 13432 requires the adhesive itself to be certified as compostable. Without that certification, even an otherwise compostable pack risks failing compliance.
What EN 13432 requires of adhesives
For adhesives to comply with EN 13432, they must:
- Biodegrade by at least 90% within six months under industrial composting conditions (~58°C, with regulated oxygen and moisture)
- Disintegrate into pieces smaller than 2mm within 12 weeks
- Leave no harmful residues, such as microplastics, heavy metals, or ecotoxic effects on plant growth
If adhesives cannot demonstrate this through independent certification, the packaging claim will fail.
The documentation converters need
Under PPWR and EPR schemes, claims must be backed up by evidence. For adhesives, this means:
- EN 13432 or ASTM D6400 certification from accredited labs.
- Technical data sheets outlining composition and application details.
- Traceability documentation to prove consistent sourcing and performance.
Without this evidence, compostability claims risk being challenged by regulators, retailers, or NGOs (Non-Governmental Organisations).
Adhesives may once have been treated as a minor detail, but under the 1% rule they are front and centre in compostability compliance. For converters, this means adhesive choice is a strategic decision.
By selecting certified compostable hot melts, converters can not only meet regulatory requirements but also protect brand credibility, avoid compliance risks, and ensure packaging truly lives up to its sustainability promise.
The 1% rule makes it clear that adhesives are no longer just a background material in packaging. They can be the difference between compliance and rejection, between a credible sustainability claim and one that falls apart under scrutiny.
For converters, the safest path is to choose adhesives that are independently certified as compostable and supported with full documentation. Power Adhesives was the first to launch a certified biodegradable hot melt range and continues to expand it to meet the challenges of PPWR. By switching to proven solutions, converters can de-risk their packaging and demonstrate to customers and regulators alike that their sustainability claims are built on solid ground.
Explore Power Adhesives’ biodegradable hot melt range here.
Leave a Reply