Mono-material pouches, two years on

Mono-material flexibles were the clear answer in 2024: a pouch made entirely of polyethylene can go into a store drop-off stream, where a laminate of three polymers cannot. We moved six clients onto them.

Two years later, four are still there and two came back.

What held

The recyclability claim held. Barrier performance held for dry goods. Sealing windows were narrower than the laminates they replaced, but within what the lines could hold once they had been trimmed.

What did not

The two that came back had the same problem: oxygen ingress at the seal over a long shelf life. Both were products at 14+ months. The material was not the issue; the seal geometry was, and neither line could hold the tolerance consistently at speed.

We should have caught it. Our line trials at the time ran for a shift; the failure appears over a production week when tooling warms and drifts. Trials now run across a full week as standard, which came directly out of this.