What if one could wrap wood pellets with a renewable and sustainable forest-based packaging with the same protective features as plastic and without changing the bagging equipment? Well with the new Mondi “SKOG” paper liner one can.
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Admittedly, as a bagged pellet user who receives two pallet deliveries that occasionally have been left on the driveway exposed to the elements for some length of time, it all first sounded rather counterintuitive – bagging pellets into 16 kg paper sacks instead of conventional plastic ones.
After all paper tears relatively easily and it does not do too well on exposure to moisture.
Quite so and yet your local supermarket dairy section is full of milk, fruit juices, and other wet products packed in barrier-coated paper- or carton packaging, countered Pär Dahlqvist, Business Solutions Manager Extrusion Coatings Mondi Örebro, immediately banishing any further unreasonable doubt from my mind.
Barrier coating is a key technical term that refers to lining a paper carrier with another material such as a polymer or different kinds of foil to provide specific properties. In other words, the packaging material itself is built in layers with properties tailored to the product that it is meant to contain and protect.
Here in Sweden, SKOG can even go straight into the same recycling category as milk cartons and cardboard, added Dahlqvist’s colleague David Karlsson, Supply Chain and Development Manager at Mondi Örebro.
Both Dahlqvist and Karlsson work for Mondi Örebro in Sweden, a facility that is part of the global packaging and paper Group Mondi. Mondi Örebro is one of the largest of five European production facilities in the “Extrusion Coatings” business segment of Mondi Europe and International’s Fibre Packaging Business Unit.
The Örebro facility is focused on the production of extrusion-coated materials for the paper and converting industry. In other words, it produces paper-based packaging materials for industrial clients in a wide range of industries such as food, consumer goods, pharmaceuticals, mill wrapping, and industrial packaging to mention a few.
Some of the consumer customers operate so-called Form Fill and Seal (FFS) machines to fill and package their products using packaging material supplied on a reel. As such the production plant itself comes under strict food and pharmaceutical hygiene restrictions.
The project was initiated about three years ago when we asked ourselves what other sectors use natural resources for their end-products to which we could apply ourselves to provide a renewable and sustainable forest-based packaging solution, explained Karlsson adding that Mondi also operates a kraft pulp and paper mill in Sweden that has an annual production capacity of 260 000 tonnes of specialty and sack kraft paper, Mondi Dynäs.
Mondi SKOG launched
Wood pellets came up on the short-list as a likely sector because it too is a forest product.
We really felt it would make sense to try and close the loop, keep it in the family so to say, by offering a sustainable forest-based product to package another forest product, said Dahlqvist.
After conducting market research, which included attending national and international pellet industry conferences and tradeshows, an internal project to develop an alternative paper-based packing material was set in motion.
Drawing on vast in-house barrier and packaging production expertise and experience within Mondi, the initial prototype was presented to a presumptive client in early 2015.
It was a very positive reception and together with the client, the prototype was honed into a finished commercial product, said Dahlqvist adding that the client is currently conducting a longer trial for its animal bedding pellets to gather end-customer feedback.
At the end of October 2015 the new first-of-its-kind paper liner “Mondi SKOG” was launched at a packaging trade fair in Sweden.
Another important group involved in the development discussions was the FFS equipment manufacturers. Since the usage of paper on such machines is completely new, they also needed to be able to verify that only a few minor adjustments are enough to run the new paper liner, highlighted Karlsson.
Although undisclosed Dahlqvist described the client as a “forest industry major colleague” with animal bedding and wood pellet production operations in the Nordics.
Our industry is actually highly specialized so partnership and cooperation is the way forward, said Dahlqvist.
In principle and somewhat simplified, production at Mondi Örebro consists of taking a roll of kraft paper of a specific quality, setting it up in an extrusion coating line, which unrolls it, prints if applicable any consumer information that is to appear on the package, applies the barriers on one or both sides and rolls it all up again before shipping it to the client.
Mondi SKOG is a kraft paper coated on both sides, the inside has good sealing properties and the outside has a barrier for moisture and sunlight protection. The barrier coating assures comparable protection in- and outside of the bag as well as good bag sealing properties as a conventional plastic one.
However, it has also some distinct advantages over plastic sacks such as stability during palletizing and transportation. This stability translates into the safer stacking and handling of pellet bags from the bagger as soon as it is sealed and flops onto the conveyor to the palletizer, during transportation of the pallets, and during unloading and bag removal from an opened pallet.
This was something we discovered during the trials with the client where the pallets were significantly more stable and well packed. The stability is due to friction and the very high dead-fold capacity of the paper meaning it readily adjusts to take on a new shape, explained Dahlqvist illustrating the point by scrunching a piece of paper in his fist.
According to Dahlqvist, the bag is highly convenient for the end user as well. It can be opened without tools, the contents are easy to pour and, thanks to its dead-fold capacity, can be folded again for storage taking up much less space than a plastic sack.
Although the polymer component in the new liner is far less than what is possible for a conventional bag to achieve, it is still fossil-based.
We’re actively looking at various sustainable bio-polymer alternatives to complete the last piece of the puzzle to achieve our goal for a 100 percent renewable, recyclable, and sustainable paper-based packaging material, ended Pär Dahlqvist.
Given the rate of development on the bio-polymer front, it is not a stretch to suggest this may be very soon indeed.