Recycled content requests are arriving more often and they are reasonable. The question is not whether recycled polypropylene can be used, it is which recycled stream, at what proportion, and what that does to the properties the box actually depends on.
What changes with recycled material
Consistency, colour and, at higher proportions, impact behaviour. Virgin resin arrives with a specification and a batch number. Recyclate arrives with a specification that is real but wider, and the spread between batches is larger. For a box panel, that is usually acceptable; for a moulded component with a fine tolerance, it sometimes is not.
Which properties hold up
Stiffness holds up well. Moisture resistance holds up, which matters for a box that gets washed. Colour does not, unless the stream is controlled, and the result tends to be a darker or greyer shade that moves between batches. If the box colour is part of a customer’s visual standard, agree the colour range in writing rather than assuming a match.
Impact behaviour and the cold
This is where recycled content deserves attention. Impact resistance is the property most sensitive to the history of the material, and it is also the property a box depends on when it gets hit at a corner in a cold yard. Test at the lowest temperature the box will realistically see, not at room temperature, and test the corner rather than a flat panel.
Food, pharma and regulated routes
Some routes restrict recycled content, particularly where direct food contact or a cleanliness claim is involved. That is a customer and regulatory question rather than a technical one, and it should be answered before the material is chosen rather than after the box is made. Ask the customer’s quality team, not their purchasing team.
Proportion, and the honest way to state it
State recycled content as a percentage of the material by weight, and state which stream it came from: post-industrial, which is clean and predictable, or post-consumer, which is the more meaningful claim and the harder one to hold consistent. Both are legitimate; conflating them is not.
Closing the loop with your own boxes
The strongest claim available is a box made partly from boxes that have come back at end of life. It needs a take-back route and a recycler willing to process a defined stream, and it is a genuinely good story when it is real. The end-of-life arrangements that make it possible are described in end-of-life for a box fleet.
The properties to re-qualify
If a specification moves to recycled material, retest the load case, the corner impact at low temperature and the wash durability, and keep the first article process. Three tests, one approval sheet, and the box is requalified on evidence rather than on a supplier’s assurance.
What to tell a customer who asks for a number
Give the percentage by weight, the stream, and the property that was retested. Customers who have done their own homework will ask all three, and a supplier who answers only the first looks like somebody who has not tested anything. If the number is lower than the customer hoped, say what would be needed to raise it and what it would cost, rather than quoting the highest figure the resin market can supply on a good month.
Where a route is regulated, get the recycled content question answered by the customer’s quality function rather than their purchasing function. A buyer asking for more recycled material and a quality manager restricting it are a common pair, and discovering that after the box is moulded is an expensive way to find out who was right.
What we can do
We build PP honeycomb board boxes and can quote recycled content options with the stream stated and the impact behaviour tested at your service temperature. Tell us the content target and the constraints, and we will say what is achievable rather than what is convenient.