Sustainable packaging: milking it - materials and design aid sustainability targets

Packaging Professional magazine
3 Sep 2013

For packaging to live up to its sustainability aspirations, the industry needs to be increasingly inventive with materials and design. Ashwin Moorthy, Head of Innovation and Engineering at Nampak Plastics, UK, explains how his company has done just that with the humble milk bottle, and how other manufacturers can adopt similar strategies and technologies for a greener future.

Right now, there is no bigger buzzword in the packaging industry than sustainability. Often derided as a sector that is detrimental to the environment, there has been a titanic effort over the past few years to improve packaging’s carbon footprint and ensure it is seen as the forward thinking, innovative industry that it truly is. No longer is it purely the role of packaging to protect, preserve and sell a product. The goalposts have moved and the onus is now on all of us to create packaging solutions that save on raw materials and reduce CO2 emissions.

These challenges are particularly pertinent to the dairy industry. Against a backdrop of high methane emissions from dairy cattle, and a complex supply chain, industry body Dairy UK and the Government’s Department for Environment, Food and Rural Affairs (Defra) came together in 2008 to launch the Dairy Roadmap – an industry-wide blueprint for creating a greener future.

Currently, 50,000 tonnes of resin is used in milk packaging in the UK for standard four-pint packs. And as plastic milk bottles are among the most widely used types of packaging in the country, with around four billion purchased every year, they create a lot of waste. As such, a strong focus of the Roadmap is the role of packaging, both in terms of reducing carbon footprint and increasing recyclability.

These targets are easy to identify, but not necessarily easy to achieve. As part of the Roadmap’s vision, we design Infini to help support and assist retailers when they signed up to the Roadmap’s targets. Redesigning a classic piece of packaging, which the four-pint plastic milk bottle undoubtedly is, was a tough brief that took more than four years to fulfil. We needed to reduce the overall amount of material used and include as much recycled high-density polyethylene (rHDPE) as possible, without compromising the aesthetics or the robustness of the pack.

The early stages involved looking at whether the bottle could be updated by simply using less material, an approach that other companies have used to tackle similar conundrums. In the case of the milk bottle however, this wasn’t possible, as there is a limit to how thin the walls can be while maintaining its strength. Simply reducing the amount of material would have left the bottle weak and unfit for purpose. It was a case of returning to packaging principles and considering other designs. After several other iterations, the end design – the Infini milk bottle – was finally reached, comprising a now iconic corner handle (a design aspect that independent research shows many consumers prefer). The final stages involved testing for suitability, for both producers at the dairies and consumers in their homes.

Cutting corners
The corner handle was the decisive factor that enabled a pack that is up to 25% lighter than a standard bottle (depending on size), as its octagonal structure allows for thinner walls and means the material doesn’t have to be pushed as far into each of the bottle’s corners, thereby reducing the weight of the pack. Since milk is not a product that can be concentrated into a smaller bottle in the same way that, say, washing up liquid can be, lightweighting is an ideal solution when it comes to reducing the overall carbon footprint. If lightweighting as a strategy can be successfully combined with the use of recycled material, it covers the three core requirements of modern packaging – reduce, reuse and recycle.

While the creation of the Infini bottle stemmed from dairy suppliers’ demand, the bottles have also been welcomed by the retail sector (170 million of the bottles have so far been sold in the UK to the likes of Marks and Spencer, Morrisons and Sainsbury’s), which has its own carbon reduction targets through the third Courtauld Commitment.

Over the last year, the bottle’s carbon footprint has been further reduced in a number of ways. February 2013 saw the creation of the world’s lightest four-pint HDPE milk bottle. Weighing in at just 32g, it offers a 20% material saving on the standard version and, if it were to become the bottle of choice, would reduce the overall amount of resin currently used in UK milk packaging for standard four-pint milk bottles by 20% to 10,000 tonnes a year.

In May 2013, the world’s first four-pint milk bottle containing 30% rHDPE was trialled, tested and supplied. Using this volume of recycled content had not previously been possible due to materials supply, because while the quality of material has improved, the amount available hasn’t.

Ensuring the bottles remained robust without compromising integrity involved extensive testing on-site at Nampak. This included physical performance tests, such as the 0.9-metre drop test, as well as organoleptic testing, which included a taste test to ensure that the recycled material had no effect on the milk itself. Independent research and trials were also undertaken in conjunction with Bradford University, UK, with multiple tests conducted in large dairy companies to ensure the bottle fulfilled their needs.

The result is a bottle with double the amount of recycled material than is present in most plastic milk bottles. This achieves the 30% target set by Dairy UK and Defra – something that could save the dairy industry around 25,000 tonnes of material – and its associated cost – each year.

The most recent development has been a range of smaller bottles, with one-litre, one-pint and two-pint versions, which will appear on supermarket shelves later this year. While this will be launched containing up to 15% rHDPE, this figure is expected to increase to up to 30% by 2014 – a factor that hinges on the required amount of suitable rHDPE available. Combined, these smaller bottles could herald a saving of 4,500 tonnes of material and 12,000 tonnes of carbon each year.

Milking the benefits
While these achievements are important steps forward for both dairy suppliers and the retail sector, such achievement can also prove beneficial to a manufacturer. To produce the new bottle design required an update in our manufacturing processes, which in turn has minimised waste.

Manufacturers can look to other ways to meet their own energy-reduction targets. Factors including staff awareness, air leakage surveys, sub-metering for accurate power consumption data, automated machines that shut off systems, and a focus on chilled water pipe installations (improved by increasing the efficiency of cooling systems and compressed air use) can all result in a steady year-on-year reduction in energy use – and the associated costs. For example, increasing the number of in-plants in operation can help reduce transportation costs.

Companies shouldn’t discount the contribution their staff can make towards making a greener business. For example, we organise regular training courses to provide everyone with an understanding of the company’s environmental concerns, and a scheme is in place that rewards staff who suggest ideas that drive environmental improvement.

Large businesses can also work with their customers to limit environmental damage – for example by adopting an in-plant arrangement, whereby manufacturing equipment is placed in a facility adjacent to the bottle filler rather than at a separate site. For us, this has two key benefits:

• It helps to reduce the requirement for bagging the bottles to be sent to the dairy and subsequent debagging at the dairy, thereby reducing the quantities of low-density polyethylene (LDPE) film required for the process.

• It eliminates road transportation of empty bottles, saving on average more than 1.5 million km a year and its associated CO2 emissions. At our Derbyshire in-plant facility, for example, bottles move between the two buildings on conveyor belts rather than wagons, resulting in reduced forklift truck emissions and diesel consumption.

A sustainable future?
Packaging manufacture in the UK is certainly at the forefront of the sustainability agenda. As an industry, dairy is one of the UK’s finest, but to keep it competitive on a global scale it needs carbon reduction practices that ensure sustainability – from the farm to the fridge. Innovations in packaging, both its design and manufacture, are helping to do just that. But while all packaging companies should be focused on minimising the carbon footprint of their products, it is important that this is done without compromising pack performance and integrity.

For further information, contact Ashwin Moorthy, email