Paper-thin protection – coating and laminating

6 April 2017

Ever thinner materials, decreasing manufacturing times and consumer-led requirements for efficient end-of-life disposal have propelled coating and laminating from a supporting role in packaging to a starring one. Making the right choice for a product is critical: Matthew Rogerson speaks with industry experts and suppliers about the thin line between success and failure.

In the first three months of 2017 there were more than 100 product recalls, safety notices and warnings from the Food and Drug Administration (FDA), with about 300 serious risk notices from the European Union. In the most serious cases – in which consumer safety had been threatened by contamination or poisoning – a failed coatings or barriers were invariably at the root of the problem. Given the scale of the issue, it is evident that coatings, barriers and laminating must work harder to protect products and improve the shelf life without reducing the capability or quality of packaging.

Increasing innovation means greater demands on packaging. In order to compete with alternative materials, barrier-coated boards and papers have been developed to guard against the penetration of moisture, gas and, depending on the product, light.

Barriers and coatings must enhance performance, and the right finish will drive custom, acceptance and growth; the better the barrier, the safer the product and the longer its shelf life. Since paper is biodegradable and recyclable, it is often preferred by consumers.

Improving paper’s barrier properties increases its viability, and, water-based technology is gaining acceptance.

The latest research from YouGov, commissioned by the Confederation of Paper Industries (CPI), found that half of supermarket visitors preferred their groceries and fresh produce packaged in paper-based materials.

CPI’s director of packaging affairs Andy Barnetson says: “The YouGov poll indicates that paper and corrugated remain the most popular forms of packaging for consumers in the UK. However, the corrugated industry must keep building on this public support by continuing to put the consumer at the centre of everything it does.”

Robert N Davison, chairman of BPIF Cartons, agrees with the poll results. “Consumers prefer cartonboard packaging to other media,” he says. “It stands out well on the shelf and portrays brand identity well, with the addition of space for ingredients and legal data.”

A study from the IVL Swedish Environmental Research Institute recently concluded that paper was decidedly less harmful than plastic. “The results of the study challenge a common misconception that the production of paper packaging is more energy-consuming and environmentally detrimental than the production of plastic packaging,” says project manager Lena Dahlgren. “An important reason why the production of the tested packaging materials emits less greenhouse gas is that their process is almost entirely run on renewable energy. Another is that the total energy consumption for production of these products is lower.”

Swell ideas

The Christian Doppler (CD) Laboratory for Fibre Swelling and Paper Performance in Graz, Austria, meanwhile, has begun to research the impact of swelling and de-swelling during production, printing and converting. “In modern high-speed inkjet printing presses,” explains team leader Ulrich Hirn, “less swelling means faster drying, but fibre swelling also has a positive impact on stability. The CD laboratory will develop simulation models of the different processes. We aim to find ways to improve the paper, the printing – including inks – and equipment, as well as the converting,.”

One of the fastest-growing markets for paper is convenience food. Whether it is for protecting coffee cups or the forming wraps for food, the right barrier not only protects against contamination or spoilage but also ensures grease is removed or prevented from building up, heat or cold is controlled and shelf life is extended.

As consumers have increasingly complex and busy lives, packaging and coatings used have had to evolve rapidly, as Linda Young, UK foodservice marketing manager at Huhtamaki UK, explains: “Double-wall products offer superior insulation, which is of paramount importance for services that offer ‘to go’ choices. The cups and containers should feel comfortable to hold and should retain the heat of the product within - without being too hot to handle by consumers.

“The aesthetics of takeaway packaging have also become more important. Consumers buy with their eyes, and if food and beverages look the part – in terms of the products themselves and the way in which they are being sold – then sales will be secured. Disposables that carry attractive designs or offer a tactile appearance can help increase the cost being charged for to-go options.”

Cascades Sonoco has introduced a water-based barrier coating to replace the polyethylene typically used on folding cartons for takeaway food. Incorporating the new FlexSHIELD barrier coating makes the boxes compostable when applied to recycled paperboard, without compromising barrier performance.

“Given the increasing demand for paper-based takeaway containers, and in light of many cities banning expanded polystyrene containers, this new barrier coating offers a unique, functional and viable option for making paperboard containers much more environmentally attractive, given their compostability,” says Sandy McArthur, director of sales and marketing at Cascades Sonoco.

Recent product launches suggest this is not an isolated trend, with major retailers increasingly moving food out of plastic packaging and into paper.

In Austria, Lidl has launched its hot Tarna falafel wrap. Consisting of a pillow-pack type carton made from recyclable, single-faced corrugated board with a film layer laminated to a white inner facing there is an outer (fluted) face of the board that is printed and a notched tear-strip running around the pack at one end for easy opening. The ends of pack are folded inwards to close.

It uses a single-faced corrugated board for hot food, which gives a natural feel and is eye catching. The board and its barriers provide insulation to keep the food warm and to protect consumers’ hands from heat, while preventing the meal or grease from migrating into the paper, which would affect quality and taste. The packaging is designed to hold the wrap while it is eaten, while the tear-strip enables just the end to be removed, so that the part being consumed can be enjoyed without any grease or product residue being left in the pack.

Think inside the box

Marks & Spencer (M&S) has launched a ‘bake in the box’ lemon meringue cube mix that enables consumers to mix the ingredients and cook them. The outer packaging is formed of corrugated board, with three flaps folded inwards, and a fourth forming a hinged lid. Two additional flaps match die-cut apertures on the box edge to keep the lid closed, with an opening point die-cut to form a finger recess.

Specialist barriers are required to enable baking without leaching or materials transferring from the packaging into the finished product. This type of approach offers a convenient means of preparing cakes at home, cutting down on washing up. It’s not entirely hassle-free (a baking tray is still required to make the meringues), but it is still quick, easy and efficient.

The development of intelligent coatings was a highlight at a recent Institute of Food Technologists conference. Julie Goddard an associate professor in the department of food science at Cornell University, said: “We have designed new polymer coatings that can be applied to food processing surfaces that resist microbial adhesion and can actually inactivate any microbes that do adhere, preventing them from growing and potentially contaminating our food supply.”

The coatings will initially find a market across the food preparation sector, but could be applied to customer-facing products from converters such as food containers at some point in the future.

All these developments illustrate that coatings and laminating technologies are crucial to success. With more bio-based packaging finding immense favour with environmentally conscious consumers, new forms of lamination in particular will be needed. 

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