The age of plastics began in 1907 with the creation of Bakelite, the first truly artificial manufacturing material. Although celluloids and casein (from plants and milk respectively) were already in use, they were volatile and degraded quickly so had limited applications.
Bakelite enabled the mass production of items and was used in a wide range of applications including household products and jewellery. According to the American Chemistry Council, in 1924 Time magazine predicted that Bakelite, a “material of a thousand uses”, would one day make up nearly everything we touch, see and use.
Fast-forward a hundred years and Bakelite has been largely superseded by other plastics such as polyethylene (PE, HDPE and LDPE) and polypropylene (PP) – a flexible transparent plastic film commonly used in sandwich bags.
Our history of experimenting with polymers has resulted in vast improvements for humanity, but these advances have at times been at the cost of the environment. John Williams, a former technical adviser to UK government on plastics regulations and well known in the European industry for a number of high-profile bioplastic innovations, is now business development director at Aquapak Polymers. Williams says: “Plastics recycling has never been easy. With so many polymers, additives and different materials attached to one another, the challenges are rife. Despite decades of experimentation and investment, we are still failing to recycle some of the most prolific polymers in the residual waste stream.”
According to WRAP, consumer film is one of the two largest untapped sources of recyclable plastic in the UK. A study by plastics recycling body Recoup found that plastic film – including carrier bags, pasta and rice bags, biscuit packets, single portion packets of pretty much anything, and the film on ready meals – is the worst offender, with a 2015 recycling rate of about 3%. Only one in five local authorities provides a recycling collection service for these materials.
Recoup’s UK Household Plastics Collection Survey identifies a number of practical barriers which prevent film from being compatible with many existing UK collection and materials recovery facility systems. It can contaminate established plastic bottle bales and paper lines, and clog sorting equipment.
Williams continues: “All of this adds up to a very poor recovery rate for flexible plastics, so although they remain popular from the perspective of a brand owner, retailer or consumer, for those of us responsible for driving society towards a circular economy, we need to look elsewhere for answers, and it needn’t be to futuristic new polymers.”
Flexible packaging is popular with brand owners and consumers because it requires less material for production, is lightweight and reduces product waste through better protection and portioning. Pouches are the fastest-growing flexible packaging segment, yet until now there has been no proper
closed-loop recycling system.
Aquapak Polymers has spent the last five years experimenting with polyvinyl alcohol (PVOH), a strong, flexible plastic that dissolves in warm water.
First patented in 1931 for using as surgical thread, by 2006 worldwide consumption was over one million metric tonnes, with contemporary uses including dissolvable laundry liquid tabs and contact lens fluid.
The team at Aquapak Polymers has developed a way to recover dissolved PVOH from water, so it can be repelletised at a waste sorting facility and sold straight back to plastics manufacturers. It’s a neat closed-loop recycling system, using chemical recycling instead of the mechanical recycling that has got us to a measly 3% recycling rate for the existing plastic films.
Made out of carbon, hydrogen and oxygen ([CH2CH(OH)]n), it biodegrades to a benign biomass, CO2 and H2O. Better still, if it’s in a compost heap or anaerobic digestion (AD) facility, it will actually break down in a timely and environmentally safe way. It won’t leave small flakes in the finished compost, or gunk up the workings of an anaerobic digester causing frequent costly maintenance closures (it dissolves when the warm seed digestate reaches the fresh feedstock). These characteristics make PVOH ideal for food waste bags, or even bread bags which could then be re-used as food waste bags (or recycled).
Mike Everard, Aquapak’s MD, says: “One of the single biggest costs for AD operators is the screening process, which Aquapak mitigates. Aquapak bags can be dissolved out at the de-packaging stage by using heated water from the spare heat given off from the generator. This spare heat also attracts a 4.5p/kW renewable heat incentive from the government, so in effect it pays for the removal of the bags. With the heat, Aquapak’s polymer turns into a gel which doesn’t contaminate the AD plumbing. So not only do we reduce the significant cost of maintenance to the AD operator, but they
also receive cash for removing the bag. It’s a different model altogether.”
The end-of-life options for PVOH are a circular economist’s dream. It can produce an uncontaminated recyclate stream that is ready to be fed back into the manufacturing process, or it can be composted or digested leaving no physically or chemically harmful residue.
Aquapak has developed a suite of PVOH-based materials that could replace plastic bags, food waste bags, flexible food packaging, and even the windows in sandwich boxes. An important feature is that it enables highly functional packaging to be made from one main material, so it’s a barrier film that extends the shelf-life of products, and that can also
But as Aquapak’s Julian Attfield points out, it’s not just easier to process and recycle. “What we’ve tried to do is to get a really high functionality from that one material, while maintaining the environmental advantage that our material is water soluble at a controllable range of temperature and hence naturally breaks down in the presence of water into harmless substances. The product can be assimilated into the environment without causing pollution, and you can even recover it via a very simple chemical process and recycle it completely.”
During performance tests the polymer came out as being superior to comparable plastic films, being both tear and puncture resistant and at least twice as strong as high-density polyethylene film of equivalent gauge. Laboratory tests also show that the Aquapak range is considered to be safe in the marine environment and is cheaper than bioplastics on the market.
The pellets can be fed directly into existing PE lines, and with a high level of interest from the packaging sector and full approval from Biffa, the future looks bright.
In some quarters there is the feeling that new materials will only complicate matters and should therefore not be helped onto market. The fact is that new materials are being produced all the time and waste managers are not able to influence the global product design and manufacturing worlds sufficiently to resist change.
Besides, one could argue that this is exactly the kind of change we do need. The plastics we’re using at the moment are preventing a circular economy from taking shape. If all the flexible plastic on the supermarket shelves was made from a single polymer, which could be recycled to an outstanding quality, or safely composted, wouldn’t it change things?
A 52,000 sq ft plant is in the final stages of construction in Birmingham where Aquapak Polymers will manufacture the specially formulated resin pellets for the polymer.
The facility is due to begin production in early 2017 and plans for all five production lines to be fully operational by the end of the year with capacity to produce 30,000 tonnes.