“One of our biggest applications is feminine hygiene products. These require a high-moisture-barrier plastic wrapping with good machineability, good heat seal and anti-static characteristics. An unexpected plus point with NatureFlex is that it naturally degrades through a waste water stream, so if the pack is thrown down the loo it will decompose.” This application won Innovia the best non-food award at the December 2006 Bioplastics Awards.

 

Sweetman agrees that the market for degradable flexible plastics is still developing and NatureFlex still accounts for a “reasonably small proportion” of Innovia’s sales. “But interest levels are very high and it’s certainly one of the fastest growing areas,” he adds. “The quest for us is how to include greater levels of moisture barrier in a degradable matrix.”

 

Sweetman says there are challenges to overcome with the structural properties of degradable materials. “Biodegradable materials inherently have a structure that allows biological elements to get in and break them down. We have to work on them to make them tougher. Cellulose is naturally absorbent in a chilled environment, so we have had to develop production techniques and get the right raw materials from our suppliers to make sure it remains clear and fresh for as long as possible in the chiller cabinet.”

 

Major changes have taken place and continue to take place today as newer and older materials compete for prominence in the flexible plastic packaging market. Flexible plastic is adapting to more packaging jobs than ever and nanotechnology, natural antioxidants, biodegradable materials and active structures should keep it even busier in the future.

 

 

Some futuristic ideas for flexible plastic

Producers don’t just think about the materials that make up the film when it comes to flexible plastics, says Plastic and Industrial Films Association (PIFA) chief executive David Tyson: “There are new ink technologies, and new uses for 2D barcodes that are beginning to make the pack do more than just its primary function of protect and deliver.”

 

Utilising nature and nanotechnology are just a couple of the ways flexible films producers might carve a niche for themselves in the future.

 

Active ingredients

Researchers at Spain’s University of Zaragoza Department of Analytical Chemistry and Laboratory of Food Technology last year published a report in the American Chemical Society’s Journal of Agricultural and Food Chemistry investigating the organoleptic properties and colour, texture and physical characteristics of fresh meat which was packed in active flexible plastic containing rosemary extract.

 

A new active film was developed from a polypropylene film – polyethylene is also now being considered for this purpose – in which some of the rosemary’s natural antioxidants had been immobilised.

 

Results showed that, compared to normal polypropylene, the active film containing natural antioxidants efficiently enhanced the stability of fresh meat against oxidation processes.

 

Slovenian firm Vitiva, which produces rosemary extract, plans to test the effect of the extract when added to packaging sometime in 2007. The UK distributor of Vitiva rosemary extract is Food Ingredient Technology (FIT) and managing director David Gray says the ability to include rosemary extract in a clear plastic film has been a recent development. “Rosemary extract used to be dark, thick and smelly, but in recent times there’s been much more work done on the extract so that is doesn’t impart colour, odour or smell.”

 

 

A small breakthrough

Professor Andrew Mills, of the Pure and Applied Chemistry Department at the University of Strathclyde, has been thinking small when it comes to flexible plastic finishes.

 

With other scientists at the university, Mills has developed a smart technology that could put an end to consumers paying for spoiled food.

 

 

An intelligent ink which changes colour when it detects the presence of oxygen in food packages if the package seal is broken could be used to warn consumers that the food is no longer safe to eat.

 

Professor Mills says: “Leaking food packages are not uncommon, and they’re more than just a nuisance. If the seal on the packaging is broken, then it means that oxygen is getting in, drastically reducing the freshness of the food so it may no longer be safe to eat.”

 

 

The ink was created with light-sensitive nanoparticles, which only detect oxygen when they are ‘switched on’ with UV light. Mills says producing the ink is inexpensive, making it suitable for use in large numbers of labels.

 

This nanotechnology could be included in a laminated, multi-layer film, says Mills, with a permeable coating on the side of the film in contact with food and an impermeable layer on the outside to prevent oxygen from the environment contaminating the results.