If printing is to expand well beyond its traditional strongholds, particularly in areas like electronics, it will have to rely a lot on advances achieved with the use of nanoscale particles and materials in inks.
“Nanotechnology is no longer new,” Barry Park, theme manager for manufacturing and processing at the UK government-funded Nanotechnology Knowledge Transfer Network (KTN), told a recent London conference.
“It is already providing the basis for exciting new products, with industry watchers forecasting sales of nanotechnology-based products in the trillions (U.S. dollars) by 2015,” he added.
Printing is well positioned to take at least a small share of this massive increase in sales because of the scope for printing to apply at a low cost and in high volumes nanoscale components in inks and coatings on a wide variety of substrates.
Currently, most of the range of materials used to make nano ingredients – like carbon, silver, iron, titanium dioxide, aluminum oxide, cerium oxide, zinc oxide, silicas, silicon dioxide, dendimers and nano clay – can be included, although not necessarily efficiently at the moment, in ink and coating formulations for printing.
However, nanotechnology in printing – as well as other sectors – still has to overcome formidable challenges. The biggest is health and safety concerns, especially in Europe where legislators and regulators have been taking a tough stance on nano materials.
“(Safety) information on nanomaterials currently on the market is incomplete,” Steve Hankin, a senior consultant at the Edinburgh-based Institute of Occupational Health, told the London conference, sponsored by the UK government and the Chemical Industries Association.
“There are important knowledge gaps in the toxicology, physico-chemical characteristics and exposure data,” he said. This made proper risk assessment and risk management of nanomaterials difficult.
As a result, many companies in Europe are insisting that their suppliers inform them about the presence of nano ingredients in their products, particularly in packaging.
In addition to safety matters, another major hurdle is the rising cost of research and development in nanomaterials and their applications. It now tends to require highly qualified research staff and expensive equipment. To keep up with the pace of innovation, small companies, in particular, require investment funds, which are scarce at the moment.
“The technology is moving from one requiring only simple materials and solutions to one needing complex technologies,” said Paul Reip, founder and director of Intrinsiq, a UK-based SME which has developed nano inks for printed electronics.
A combination of a necessity for strict health and safety compliance in the manufacturing of nano particles and materials and increasing R&D costs is tending to make nanotechnology a specialist activity which is beyond the capacity of many established ink producers.
Even some large players in the ink markets cannot afford the investment needed to set up an in-house team with expertise in the area.
Instead nanotechnology specialist businesses, some of them spin-offs from universities and research institutes in Europe, are expanding into the ink sector by either manufacturing their own inks or providing dispersions of nano particles which comprise a large proportion of the final formulation.
For several decades, ink producers have been using milling processing to produce nano pigment particles in order to improve their processability and color quality in ink formulations.
Nanotechnologies applied in conventional coatings to achieve properties such as scratch resistance have also been introduced into printed coatings, such as varnishes.
Inks with nano particles and structures can be used by most printing processes, especially with the emergence of printed electronics applied by a variety of printing equipment.
Nanomaterials are at present being printed on a range of substrates for making RFID labels and tags, luminescent displays using organic light emitting diodes (OLEDs), flexible batteries, sensors and solar energy cells.
One of the biggest applications of nanotechnology in printing is with inkjet inks, because of the need for small particles in their formulation, particular for dyes and pigments.
“Inkjet has developed side-by-side with nanomaterials,” Kay Yeong, a scientist at Xennia, a developer of inkjet equipment and ink systems, told a recent UK meeting on nanomaterials organized by NanoCentral, a UK government-funded technology development body. “Exciting areas of development of nanomaterials fully complement the maturity of inkjet printing technology.”
Examples of nano and micro materials which have been inkjet printed now extend to photochromic and electrochromic visual effects and markers, antimicrobials, flame retardants, conductive graphites and metals, magnetic materials, enzymes and other biomaterials and liquid crystals.
Nanomaterials in conventional and inkjet inks are increasingly being used for security, brand protection and anti-counterfeiting purposes, which is one of the main markets for nanotechnology in printing.
Derek Illsley, chief scientist for Sun Chemical in the UK, provided details at the NanoCentral meeting of an exfoliated nanocomposite of silicates in a polymer solution which can be printed as a barrier coating for products like foodstuffs. The company claims it has lower oxygen transmissions levels than many conventional packaging barrier materials.
“Composite oxygen barrier coatings enable transparent barrier packaging with exceptional barrier properties,” Mr. Illsley said. “The coatings can be applied by conventional printing methods.”
Providers and developers of existing and new printable nanotechnologies are increasingly having to keep a close eye in Europe on the regulators, both at the European and national levels.
One problem for legislators is the lack of a clear definition of what is an engineered or manufactured nanomaterial to differentiate it from natural or ambient nano particles.