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Compostable recyclable packaging

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Cullen Packaging has become the first UK company to get compostable packaging certification for a recyclable product. Paul Sanderson talks to Ken Blake


Over the last five or six years, a compostable and recyclable packaging product for fruit, veg and fungi has revolutionised the protection of these food groups.

Previously, these goods were almost always placed in plastic containers, and while this provided protection, it was not always breathable and easy to recycle.

Now almost all major supermarkets use paper-based packaging for these items following an initiative by Glasgow-based cardboard packaging manufacturer Robert Cullen Ltd, which trades as Cullen Packaging.

“To some degree we started doing this because the supermarkets wanted to work in a more green way,” says Cullen Packaging manufacturing, quality & systems manager Ken Blake.

“They wanted green packaging that was compostable and recyclable. Everyone assumes paper is compostable, but there wasn’t the evidence that it was when we started this. By compostable, we meant that if it was still paper after about three months then it wasn’t suitable.”

One of the first challenges that was looked at was whether the dyes used by some brands such as Marks & Spencer to make the packaging black, and therefore have a higher quality feel, would have an impact on the compostability of the packaging.

While another potential issue that was faced was with mushrooms, which have a high water content that can escape from the fungi.

If the water moistened the paper, then you would end up with a mushroom/paper mush.

But if waterproofing chemicals was put in it and the packaging wasn’t sufficiently breathable, then the mushrooms could end up in a pool of water reducing their shelf-life considerably.

Cullen Packaging also makes cardboard medical bedpans and used its waterproofing experience from that to come up with a solution using a mixture of paraffin waxing and paper waterproofing chemical alkyl ketene dimer.

Cullen compostable recyclable packagingTesting of the material under various guises found that the cardboard-based packaging worked, and best of all, it broke down.

“We exceeded our expectations,” he says. “In 12 weeks the material was composted, and we found that the waterproofing agent didn’t inhibit composting.

“It broke down quickly whether it was dyed black, was natural brown, waterproofed or not.”

Cullen Packaging spent €20,000 with a Belgian certification body to assess any negative environmental impact from the dyes and chemicals on the environment and none was found.

However, there was a particular concern about heavy metals in the paper and their potential impact on both ensuring the packaging was food grade, as well as them spreading more widely through the compost into soils.

The primary business of Cullen Packaging is making cardboard boxes, and there is inevitably an element of recycled fibre in these. As the food packaging is made from the manufacturing waste from the cardboard box process, there was a risk that inks containing heavy metals within the recycled materials could contaminate the food packaging.

As a result, to this day, Cullen Packaging maintains a testing regime to ensure heavy metals remain within safe levels.

“The initial testing in Belgium was very thorough,” says Ken Blake. “They would test the composting process to check there were no noxious vapours, and would grow plants in 100 per cent compost that included the cardboard packaging to check nothing serious went into the plants.”

In the five or so years since the product entered the market, it has virtually replaced the plastic container in supermarkets with around 20 million produced by Cullen Packaging alone.

While other competitors have also launched their versions, Cullen Packaging’s product is the UK’s first compostable product made from fully recycled material to be certified with the Seedling Logo on its soft produce trays, and one of only a handful in the world.

Working with the Renewable Energy Association subsidiary REAL, Cullen Packaging implemented the necessary procedures to comply with the European EN13432 standard given by Berlin-based certification body DIN CERTCO that allowed it to use the compostable Seedling Logo on the trays.

“Virtually everybody is using them now, and we are only happy to make more,” he says. “We are heading along the road of replacing plastic as this is nicer to handle. It is a package that is made out of waste, which is a sound thing to do.”

For a number of years, Cullen Packaging has wanted to be an environmentally sustainable company, and it is proud of its achievements, especially as it has taken the waste product from its cardboard box production, to create these food-grade trays.

“We are pretty much breaking even now on the use of our production waste, and at times we are having to buy in extra material from a local paper merchant that provides clean bales of waste paper, when we have extra demand,” he adds.

Suitable for both industrial and home composting, Cullen Packaging’s food tray made from recycled cardboard from its manufacturing process is a perfect example of resource efficiency in action.


Project facts:

Companies: Cullen Packaging, REAL, DIN Certco, supermarkets

What is it? Cullen Packaging has developed a soft food tray for fruit, vegetables and fungi made from 100 per cent recycled cardboard from its cardboard manufacturing process. It is the first recycled product in the UK that is also compostable, and this has enabled it to use the Seedling Logo on its packaging.

Other viewpoint: DIN CERTCO sales executive Antonia Striewski: “After a smooth certification procedure, DIN CERTCO is delighted to grant the Seedling logo to Cullens for its soft produce trays made from recycled cardboard. With this certification, and the Seedling Logo, Cullens are positioning itself more effectively in the market for biodegradeable and compostable packaging.

“The certification of these products demonstrates that there are effective routes for deriving best possible value from products at the end of their life.” 

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Category: Manufacturing
Recycling UKHanicke Robins Sanderson