The big cover-up

An essential component of today’s packaging designs, advancements in coating technologies afford brands and their design partners a flexible environment in which to develop new packaging form factors. Dave Howell investigates the current state of the coatings conversation.

Across packaging sectors, the development of coatings continues to support and drive innovation. Food packaging, in particular, has seen huge impact from new coating technologies. Paper and board continue to be the most desired and widely used forms of materials in food packaging, with research suggesting an annual market growth of 5% to 2020; the industry should expect coating technologies to see a growth in demand alongside this as brands diversify their product ranges and seek new solutions.

As these developments continue, brands must assess entire product ranges to review the impact of consumer behaviour on the ways in which packaging is realised and placed on their design roadmaps. Technologies that offer easier recycling, packaging minimisation and extended functionality – with shelf life and product integrity being of paramount importance – are driving brands’ outlooks, especially within the food sector.

 Natural barriers

High-barrier technologies are often used for the preservation of fresh food, preventing spoilage by reducing or eliminating oxidisation. As well as keeping oxygen and bacteria out, coatings can be used to contain natural oils or potentially unpleasant scents within a product’s shell. But today, coatings and other film technologies are advancing to the point where they can offer broader packaging options to companies than this.

Barrier coatings such as aluminium oxide and silicon oxide are offering new solutions for food brands, for instance, while recent research points to the possibility of replacing BPA in metal cans containing high-acidity products with a ‘natural’ alternative. The new material, derived from soy, has been developed by the Ohio Soybean Council with researchers from Battelle in Columbus, Ohio. The Soy-PK coating dries quickly, allowing aluminium-can production lines to be maintained, and may be a welcome solution to the potential strengthening of BPA regulations regarding chemical migration levels.

 Adding value to variety

‘Active packaging’ is becoming a vital component of new packaging design. This trend involves coatings being able to offer brands and their supply-chain partners a number of additional functions beyond the containment of a product, depending on companies’ demands for sustainability, convenience, recyclability, shelf life and so on.

In sustainability, for instance, the industry is seeing a rise in consumer demand for packaging that is widely and more easily recycled, that can be disposed of within their existing recycling streams, and that can be composted. Reacting to this, international standards organisation ASTM recently announced that it is looking closely at polymer coatings and the impact they have on the ability of packaging to be composted.

ASTM member John Kokoszka, vice-president of technical services and business development for Sustainable Fiber Solutions, said that the research will “afford testing laboratories the opportunity to evaluate aerobic mineralisation (or biodegradation) in compost of polymer coatings according to a standard test method”.

As well as paper and board, plastic plays an important role in how brands package and coat their products – most notably in their food ranges. Bioplastics have been in development for some time now, offering brands a plant-based substrate that can be used like plastic and – by creating oxygen-proof barriers – enhances shelf life.

 Intelligent packaging

Smart coatings are layers of materials – applicable to a number of substrates across packaging – that have one or more predefined characteristics enabling them to deliver useful benefits to brands and their supply chain partners. These characteristics can include reactions to heat and light, or stimulus by electric currents.

The use of nanotechnology in tandem with advanced coatings could deliver a new range of additives able to directly influence the food within a package. Focus is currently on the ability of nanotechnology coatings to slow oxygen ingress, which affects how long foods stay fresh, but, delivered with coatings, this nanotechnology could also be used to fortify foods with vitamins, or make food taste sweeter or saltier without the need to actually add sugar or salt.

Scientists in Israel have already shown how using silver nanoparticles, delivered as coatings, can reduce the instances of E coli in some foods and extend shelf life. Nano-encapsulation is also being investigated, which could see bread enhanced with Omega-3 fatty acids, for example, without customers suffering the fishy smell. The thought behind this particular idea is that the fish-oil particles are placed in a film coating that prevents the fish oil from reacting to the oxygen in the pack, which is what causes the fishy smell that brands would want to avoid. The nanocapsules only break open when digested in the stomach, delivering their health benefits without the assault on the nostrils. Such research is currently in the early stages.

 Stick it to the status quo

While consumers may understand the benefits of coatings that extend products’ shelf lives, they remain concerned about how coatings can alter the food they eat. Research into how nanoparticles may react with food will eventually lead to new kinds of coatings to address this, but Angus Blundell, marketing director EMEA at Sun Chemical, says that at the moment, “the fundamental issues when selecting coatings and barrier technologies are regulatory requirements, functionality and cost. Whatever barrier technology is used, it must perform to protect the product while addressing the cost concerns of the brand-owner”.

Blundell continues, “Low-migration inks and coatings compliant with [the Swiss Ordinance on food-contact materials and articles] are growing in popularity. Barrier coatings can also play a role in minimising the migration of certain undesirable materials, such as mineral oils, polyaromatic amines or plasticisers – or even simply blocking unpleasant odours.”

Coating technologies address myriad other trends in packaging development and design, too. “The trend towards more sustainable, more recyclable and, overall, ‘greener’ packages is supported by coatings – especially barrier coatings,” says Blundell. “And the demand for more organic products and the reduction or elimination of preservatives in food have created new opportunities for barrier packaging. Consumers’ desire to see a product through its packaging has also created a new market for high-performance transparent barrier packaging.”

 Drive on

Some of the more advanced coatings currently in development illustrate that brands have great ambitions in packaging design. While the convenience trend continues to flourish, demands for longer shelf lives are also coming to the fore and, as we have seen, consumers are increasingly looking for packaging with a purpose. Other key drivers of new coating technologies include lightweighting and higher recyclability levels.

Brands and their partners along the supply chain will need to work closely together to meet the changing needs of consumers and the ever-shifting landscape of packaging. Manufacturing processes will be simplified, however, by the development of more printable barrier coatings and advances in how packaging design is formulated.

BOXOUT

The legacy of the paper cup

With the UK alone discarding three billion paper cups every year, this innocuous packaging mainstay has been the focus of packaging developers for several years. Brands have seen their environmental credentials eroded by the difficulties involved in the disposing and recycling of their paper cups.

The plastic coating on a paper cup, which ensures that the cup is watertight, is bonded to the paper substrate. The separation of the plastic coating from the rest of the cup is where the problem lies: it requires specialised recycling techniques that are not widely available across the UK.

In January, however, papermaker James Cropper announced a trial of a new material with McDonald’s that could change the game.

Richard Burnett, market development manager at James Cropper, said of the launch, “The partnership with McDonald’s has been nearly two years in the making, and signifies an important step towards recycling used paper cups and, ultimately, reducing waste going to landfill. By collaborating with McDonald’s, we’re working towards an effective scheme that can recoup as many used paper cups as possible, which can then go back into the supply chain.”

Initiatives like this are aimed at the current supply chain and cup manufacturing processes, but brands are also looking towards the ability to place waste cups into standard and cheaper waste streams. Created by British entrepreneur Martin Myerscough, the frugalpac cup claims to resolve the recycling issue.

Made from recycled paper, the plastic layer that makes these cups watertight is only lightly bonded to the paper substrate, allowing the coating to easily separate from the paper backing in a standard recycling mill. This means the frugalpac cup can be disposed of within ordinary paper recycling bins.

The coating liner is rolled over the lip of the cup delivering identical performance from cups made with conventional manufacturing techniques.

Launched at the end of July, these new cups are already being put to the test by high-profile brands including Starbucks.