New research conducted by Aquapak Polymers highlights that ‘recycle ready’ adhesives and fully soluble barriers can replace plastics in fibre-based packaging, making it fully recyclable in high volume recycling mills.
The new technology is non-toxic, marine safe, dissolve and subsequently biodegrades, but still provides the much-needed functionality required for household product packaging, and food and drink packaging.
The study was commissioned as the move to replace conventional, hard to recycle and single use plastics has resulted in a wide variety of fibre-based packaging formats combined with alternative functional barriers being introduced into the recovered paper recycling streams.
However, the materials currently being used to give paper the packaging functionality required for products such as food, drink and household goods, are not easily recyclable and mean that the paperboard is rejected because paper mills cannot process the paper and plastic combinations. Instead, they are incinerated or go to landfill.
Numerous benefits for fibre-based packaging
The research focused on Hydropol, a commercially available fully soluble, bio-digestible barrier polymer, which can be adhesive- or extrusion-coated onto paper. Hydropol brings a number of benefits to fibre-based packaging, including oil and grease resistance together with a high gas barrier. It has also been shown to increase some paper strength properties (tear, burst, puncture and tensile strength), allowing coated or laminated papers to be heat-sealed for ‘form, fill and seal’ fibre packaging applications.
Hydropol is designed to solublise at the typical repulping temperatures and durations used by high volume recycling mills allowing fibre to be dispersed to make new paper. Independent tests reveal that once solubilised, even when Hydropol coated paper forms 20% of the fibre furnish, it is biodegraded in the mills’ anaerobic digestion and aerobic activated sludge treatments as part of its intended use. Hydropol is non-toxic and biodegradable in the marine environment should it be littered, forming no micro-plastics.
The results of the study confirm that most laminating adhesives can disrupt the recycling loop; they can ‘lock-in’ valuable fibre and, in some cases, result in more than a quarter of fibre associated with some adhesive laminated packs being lost from the paper recycling process. Using non-repulpable laminating adhesives could consign paper and board packaging to the ‘Don’t Recycle’ category – an undesirable outcome for producers, brands and retailers who are turning to paper fibre-based packaging as the ‘green’ alternative to plastic.
A goal of the circular economy approach
John Williams, chief technical officer at Aquapak and co-author of the whitepaper on the study, comments: “Maximising fibre recovery rates is the goal of a circular economy approach and the designing of recyclability in packaging should focus on the practicalities of fibre recovery in the mill and at eliminating all elements contained in packaging such as adhesives and conventional plastics, which impact on negatively on this process.
“The study illustrates the importance of designing and testing fibre-based packaging to confirm recyclability under the repulping conditions used by high volume recycling mills. In addition, the work demonstrates that ‘recycle-ready’ packaging adhesives and fully soluble, bio-digestible barrier systems are available to designers to manufacture recyclable fibre-based packaging.”
The full results of the study: ‘Designing recyclability into fibre-based packaging using fully soluble bio-digestible barrier systems’, are available online.
A closer look at Hydropol
Aquapak’s novel biodegradable, non-toxic and water-soluble polymer called Hydropol is said to be three times stronger than alternatives on the market and is designed to be used in existing thermo-processing equipment. This gives it a wider range of applications.
Hydropol enables up to 100% paper/board recovery whatever the percentage packaging makeup. The base plastic is currently used for dishwasher tablets, ingestible pill casings and soluble stitches.
Hydropol’s resistance to low temperature solubility and high barrier to elements adds functionality, providing a wider range of uses. Blown film products commercially available and made from Hydropol include garment bags, ESD bags, organic waste disposal bags and laundry bags for infection control. Its solubility makes it easy to separate from other materials, simplifying the confusing recycling options that exist for different packaging.
Extrusion coatings and laminates for paper/board applications are at customer production trial stage, including a number of home delivery and ecommerce applications, packaging for dried pet food, snacks, cooked meat and convenience food applications.
Other applications under development with customers and development partners include injection mouldings and injection moulded parts such as golf tees, non-woven fibre for applications such as wet wipes and cellulose combinations for thermoformed trays.