Plastic fantastic

3 September 2007

Plastic is workmanlike in the supply chain, a designer’s flexible friend and gives packaging material technologists a superb “toolbox” for stretching the potential for lightweight and imaginative packaging. Joanne Hunter investigates

The ability of plastic to “morph”, its exceptional structural strength and adaptability, give packaging designers huge scope for ideas. Clever chemical engineering endows traditional plastics and new-generation bioplastics with ever more functional properties. All of which gives consumer and industrial product supply chains ample reason to choose plastic, which is also light in weight and price-competitive, for rigid and flexible packaging.

Yet another retail grocery category has succumbed to seductive plastic.

A PET wine bottle is being trialled by Sainsbury’s for an own label New Zealand Sauvignon Blanc and Australian Rosé. The markedly lighter bottle weighs 54g compared with a typical glass bottle weight of about 400g. Sainsbury’s claims that using PET does not affect the taste of the contents, offers energy savings in distribution operations and provides easily recyclable containers at end-of-use.

The traditional-shaped 75cl bottle from Amcor PET Packaging UK is manufactured using special barrier technology and filled in the UK by Corby Bottlers in a project funded by the UK Government Waste & Resources Action Programme (WRAP).

“Plastic is an exemplary problem solver – adaptable and willing,” says Martin Bunce, design consultant Tin Horse Design, and “rarely is it off any list of potential packaging options.” But there is a catch to its popularity, Bunce points out. “Arguably this ubiquity is beginning to damage its reputation. For such a versatile material, it is surprising how little imagination goes into its application. Commercial realities may drive increasingly commoditised solutions but the designer can help to alleviate this trend by ensuring we seize every slither of opportunity plastic offers to enable and empower our ideas.”

A Tin Horse case study shows how one “slither of opportunity” seized, and a timely reality check, nailed the success of a new plastic paint pot.

Who needs men? Not a particularly positive or probable start to a discussion on breaking into a busy market with an innovative paint container for the amateur painter decorator.

But for Tin Horse and its client ICI, asking the “innovation question” was a curtain-raiser to a big hit on the DIY stage.

It was a perception problem, not a technical one, that hindered innovation in the DIY paint sector. Knocking down that barrier gave a “consumer-relevant” container for Dulux Once gloss paint. The perception that painting is a difficult, messy job and therefore associated with men no longer held true. In reality, “women don’t just shop for paint, they actually do the painting”, says Bunce.

A brush-wiping place away from the closure invisibly improves the functionality of the pack. The plastic container opens without need for a screwdriver, it has a comfortable grip and shows the actual paint colour inside.

“PET technology through injection blowmoulding simultaneously delivers engineered screw threads, solvent barrier, radical shaping and clarity”, says Bunce. “Replacing tinplate could be interpreted as a conscious, deliberate move to leave behind the negative associations of lever lid tins; but our motivation was more forward-looking in intent: we were not leaving behind ‘outmoded’ metal, we were moving towards the modern and contemporary facilitation of plastic.”

Better design will raise public esteem for plastic – and so will enhancing its environmental credentials.

Alcan claims to have developed the world’s first biodegradable flexible barrier film derived from renewable natural resources – Ceramis-PLA. The transparent thermoplastic polymer packaging film offers combined barrier protection against gases, water vapour and aromas. The company says it is “ideal for technical and industrial applications, snacks, petfood, fresh food, dairy products, and household and personal care items”, and can be laminated to other substrates such as paper to create differing visual effects.

Made from corn, the films are then Ceramis coated in a high vacuum. No solvents or other chemicals are used during the production process, so no accompanying emissions are produced. The SiOx (Silicon Oxide)-coated films are also free of chlorine and other “unwanted elements”, so there is no detrimental effect on the environment when they are recycled.

The SiOx coating barrier performance makes it a viable packaging material for food products that require a long shelf life. Alcan claims that until now the poor barrier properties of uncoated biodegradable materials have prevented their use in such applications.

Using Ceramis-PLA, Alcan has devised the Bio-Pack for snack foods, which it says offers “the seal integrity and barrier properties required for many snack products”. It is currently being trialled predominantly in the crisp and savoury snack market.

Innovation in plastics “for the good of the environment” is a goal of

Rohm and Haas, which has introduced new additives to toughen polylactic acid (PLA) polymer material so that bioplastics can be used more widely. The impact modifier is said to achieve a stronger product without sacrificing clarity. It complies with food contact requirements in Europe and with room temperature food contact requirements in the USA, adds Rohm and Haas.

Similarly, DuPont Packaging recently extended its Biomax Strong family of polymer additives for PLA packaging to include a US FDA-compliant food-contact grade. This opens the way for food marketers to offer fresh produce in stronger, clearer and more environmentally-friendly clamshells, says DuPont.

Meanwhile, Now Plastics has introduced a new degradable BOPP film to complement its existing range of BOPP and CPP film and bags. The film is said to be 100% degradable and to offer the same strength, clarity, sealability and printability as standard BOPP film. The company says: “Disposed of in a landfill site the film will degrade in the presence of oxygen, heat and stress within 12-24 months and even if dropped as litter it will degrade in sunlight and wind due to mechanical stress. The film can also be recycled both prior to or after use.” It is also claimed to be substantially cheaper than compostable films as well as being 25% lighter by weight when comparing like for like gauges. The film complies to both the EU 2002/72 EC and FDA legislation concerning plastic in direct contact with food.

Now Plastics has also successfully trialled a cast polypropylene film on both HFFS and VFFS machines packing products such as carrots, parsnips and herbs up to a weight of 1 kg. The trials were conducted using 30 and 40mu film compared with the 47 and 52mu that is currently used in many applications, “thus offering considerable cost savings and reducing packaging in the environment”.

New-generation plastics are in their infancy, but evolving fast. Belgian company Denico Green Products has a range of compostable packaging designed for the food industry’s fresh and frozen sectors as well as non-food uses.

“We work together with our customers on tailor-made and customised projects,” explains Dirk Wens, sales and marketing manager at Denico. “We produce a high-value compostable packaging product from non-used agricultural residues and/or natural waste streams as raw material, especially, and in the first place, fibres of bamboo and sugar cane. They are the basis for the production of organic food packaging as well as catering products and a perfect alternative for the actual foamed PS trays.

“Denico continuously pays attention to improve the chemical and mechanical properties of those products. This results in a practical and high-end range of products like thermoformed trays and thermoforming films but also barrier films for the packaging of fresh meat, fish and cheese.”

All commercialised products of Denico Green Products are certified in compliance with EN 13432.

Following on from the launch of its degradable bubble-wrap earlier this year PH Flexible Packaging has expanded its eco-friendly range with the introduction of Compost-a-Bubble, a compostable bubble-wrap product. Produced using compostable film from BPI, Compost-a-Bubble meets EN13432, the European composting standard which is used as a reference point for public authorities, industrial composting operators and consumers.

Compost-a-Bubble is said to offer the same protective properties as traditional bubble-wrap and is currently available in a 1500mm width, but PH is now reviewing the production of smaller sized reels.

Among an ever-growing list of biodegradable and compostable material introductions is the development whereby starch is mixed with PVOH – polyvinyl alcohol, which is water-soluble – to create products that will degrade over a relatively short time. Varying the thickness of the finished pack can help control the process says RPC Container’s Ashley Salter, general sales manager at RPC Market Rasen in the UK.

Salter continues: “Selecting the most appropriate forming method for these new materials – injection moulding by single, multishot or 2K moulding, injection blowmoulding, extrusion blowmoulding and thermoforming – is of course a critical factor in the successful development of a new container.

“The 2K moulding process is where two different materials are combined in a single injection moulding process to produce the finished product. This allows manufacturers to mould sealing parts from TPE (thermoplastic elastomer), incorporate company logos, create products in various colour combinations or make multi-layered products.

“It offers aesthetic advantages and greater freedom in terms of product shape. Probably the most striking example of the 2K process is the cap produced for the famous Grolsch swing-top bottle, which has moved from porcelain to plastic,” Salter notes.

Cost-effective luxury packaging in the beauty market is also thanks to new plastic materials and techniques, adds Gerald Martines, of RPC beauté based in France. He says that, despite a slowing trend to source from countries with lower costs, “forward-looking western manufacturers have continued to refine and further automate their processes, enabling them to become more competitive”.

Ongoing developments are bringing plastics, more and more, into the premium sector. For example DuPont Surlyn material, in Martines’ opinion, offers excellent transparency “with the kind of thickness usually associated only with glass”. Surlyn can be used to create a variety of special effects and finishes; it can be co-injection moulded with a number of colours that have different melt flow characteristics; and its translucence allows for a depth of colour “difficult to recreate using alternative methods”. Surlyn can also be used with overmoulding and electroplating for cost-effective eye-catching finishes.

A spark of creativity in plastic has given beverage manufacturers in nutraceuticals and organics a new concept to help shake up sales of bottled products in the water, juice, dairy, tea, coffee and health drink markets.

The Pop N' Shake closure technology from US company Erie Plastics allows the consumer to blend and fortify drinks on demand with a flavouring, vitamin or mineral of their choice. Ingredients dispense with the turn of a tamper-evident dust cover and subsequent "pop" of an inner-cap chamber.

The PET chamber works with both liquid and powder. It boasts a “first-of-its-kind, patent-pending moisture and oxygen barrier providing secure separation from active and inactive ingredients”.

“Erie Plastics’ long term plan would be to also produce Pop N' Shake via its Hungary plant, but the programme is initially being launched in the USA,” a company spokesperson tells Packaging Today. Erie Plastics is in talks with “several category leaders” in the beverage industry regarding Pop N' Shake and it is they who will drive where Pop N' Shake is distributed. That said, Erie Plastics expects Europe will be a market for Pop N’ Shake in the future. A 38mm and 26mm Pop N' Shake are now available.

With such big strides happening in the industry it is a shame there is a blot on the plastic packaging landscape. In the UK at least it has a blemished environmental image due partly to thoughtless consumer behaviour but also to do with non-standardised schemes for collection and recycling nationally. Packaging professionals can only do what they are doing: using the positives of plastic to meet the needs and demands of retail and industrial products, supply chains and consumers. Plastic is workmanlike in the supply chain, a designer’s flexible friend and gives packaging material technologists a superb “toolbox” for stretching the potential for lightweight and imaginative packaging. Joanne Hunter investigates