Packaging News

Nanotechnology: Micro science thinks big for future

Nanotechnology is one of those terms that is bandied about, but few actually know what it means. The term actually refers to the science of nanoscale materials, those measuring between one and 100 billionth of a metre. To put that into context, 80,000 nano particles in a row equate to the diameter of a human hair.

The opportunities for packaging companies to harness this technology are great, with applications including improved barrier films of potentially reduced weight, barcodes and traceability products and sensors to define end of life.

Nanoparticles already exist in nature. Milk and blood, for example are both classed as nanofluids. But the lack of information about new materials being developed using nanotechnology has raised questions in some quarters over the safety of using nanomaterials in direct contact with food.

In January 2010, the House of Lords Science and Technology Committee took evidence from many different groups and individuals and published a report describing the issues in and around using nanotechnologies in food and food-contact materials.

Chairman of Microflex Technologies Dr George Kellie predicted in the report that the next five years would be "an explosive period of development" for nanotechnology in food packaging. The report subsequently recommended that the Food Standards Agency create and maintain an "accessible list of publicly available food packaging products containing nanomaterials that have been approved by the European Food Safety Authority". Regular research into public attitudes towards the use of nanotechnologies in the food sector was also called for to inform debate on
the subject.

Dr Barry Park, theme manager for chemical and consumer products at the Nanotechnology Knowledge Transfer Network (NanoKTN) believes there is significant potential for nanotechnology to enhance the storage life and quality of packaged food.

"The consumer is used to absolute clarity in packaging materials for food and so use of nanosized additives to prevent gas and transport through the packaging and to prevent UV damage to the packaging and the food inside must not compromise the appearance of the packaging or the food within," he says.

Industry breakthroughs
At present, many packaging companies are exploring the opportunities offered by nanotechnology. Finnish paper manufacturer UPM Kymmene, for example, is currently investigating how cellulose-based nanofibres can be used to alter the structure of materials and create new products.

Cellulose fibres, which are 30 micrometres wide and 2-3mm long, are made from nanofibrils that are one-thousandth of the dimensions of a cellulose fibre. Nanofibrils can alter the properties of raw materials, particularly the strength and stiffness of packaging materials.

"Nanocellulose fibrils are not very close to commercialisation – we can estimate that some four or five years of research will be needed," admits UPM Kymmene corporate spokeswoman Sari Horkko. "The idea is to create new products and some of them look quite possible. Demand, of course, will depend on many things, but in the best cases it could be substantial."

Oxygen-intelligent ink is another breakthrough in packaging that harnesses nanotechnology (see box). These inks use nano-titanium dioxide, a biologically and chemically inert pigment often used in food, sunscreen and paint, but in this instance to indicate the amount of time a pack has been open.

However, not everyone is convinced of the benefits nanotechnology could afford packaging. Linpac Packaging’s director of innovation Alan Davey says his company has been part of a large consortium in Spain that is investigating nanotechnology opportunities in PET and barrier performance.

"There are still a number of issues of food contact that are unresolved," says Davey. "It needs some more research as it’s all very complex. What might be risky with one chemical might not be risky with another."

Faraday Packaging Partnership managing director Walter Lewis believes the packaging industry is in danger of falling behind in nanotechnology if it does not recognise the opportunities in front of it. "I think what [the packaging industry] needs is to invest in R&D; in particular R&D that enables it to understand what the end customer wants and will pay for."

Lewis likens nanotechnology to a "magic box" with endless possibilities. "Nanotechnology has been used for many things, like a material that doesn’t take stains," he says. "I think what it illustrates is perhaps not the connection to packaging, but that the world is using nanotechnology and packaging is allowing itself to be passed by."

The latest hot topics in terms of nanotechnologies are nanoclays and the use of silver nanoparticles, says nanotechnology expert and consultant Dr Alan Smith. "Clays are made up of millions of little platelets that slide across each other," he says. When these are put into a plastic, he continues, they create a "tortuous route" for gases to navigate.

According to Smith, the clays act in the same way as traditional fillers, like chalk, in plastic and using them can save up to 20% of the cost of plastic. "The other good thing about it is if you put that film around the food it keeps the odours out as well and keeps them fresher for quite a bit longer," he says.

Gleaming opportunity
Silver nanoparticles are another form of the technology. Leading skincare brand Nivea already uses silver citrate in one of its deodorant lines. Silver has known antibacterial qualities, which is why the Assyrian people used silver containers to carry their water as far back as 2,500 BC. Bedouins still keep silver coins in their drinking water pouches to keep the water fresher for longer.

The potential for using silver nanoparticles in packaging is an area that could be explored further.

Faraday’s Lewis encourages companies to do extensive testing of any products that contain nanoparticles so as to understand the properties of the product they are creating and whether it will react with food.

For those companies wishing to find out more, the government’s NanoKTN has a food focus group, which works in collaboration with Leatherhead Food Research to share views on nanotechnology and food. There is also a coatings focus group.

The NanoKTN organises seminars and workshops to bring together companies and share information on nanotechnologies related to the food industry. It is organising a series of seminars in response to the challenges outlined in the House of Lords report. The first of these, Nanotechnology and Food Contact Materials, was held last month.

Nanotechnology is a rapidly growing technology, which spans many industries. The potential for harnessing its benefits in the packaging sector is great and some companies will soon be at the point of commercialisation. As with all food-contact materials, safety is an issue and testing is a prerequisite, but this should not stop innovation. After all, the technology is in our blood.