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Nano particles in inks

8 October, 2018 - 09:40 -- tbrunner

Amazing innovations are going on with inks as the graphics industry works to maintain its competiveness and improve environmental impacts. Nano inks are used for printed electronics, sensors and ceramics printing. For a few years now they have been used for commercial and packaging printing, on the basis that they can enhance colour gamut and overall print quality. We know relatively little about the effect of these inks on human health or the environment. One would like to think that impact on health has already been thoroughly researched and tested, but that appears to be the hope rather than the reality.

The problem is that nano particles are very, very small, so they do not do as normal molecules do. How molecules behave helps us to decide if something, such as an ink recipe, is toxic or not. With nano particles their toxicity depends on physical and chemical properties, including the particle’s crystalline structure, shape, size, purity and its surface electric charge. It also matters how the internal and shell components of the particle are constructed. The combination of all these factors determines how the nano particle behaves, for instance when it enters the bloodstream or is printed or printed and coated onto a barrier surface.

Nanopigments in inks are therefore a cause for concern. The European Chemicals Agency (ECHA) recently reported on a new study looking closely at the state of research into nanomaterials. The European Union (EU) Observatory for Nanomaterials (EUON) has published a list of the substances it has identified as nano-sized pigments (77) plus four filler pigments, used to bulk up inks and reduce their cost. The report also identifies “gaps in the current knowledge on the hazard and risk assessment of nano-sized pigments.”

The report bases its findings on what could be found in various nanomaterials inventories including nano materials listed in the EU’s Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulation, plus data from Belgian, Danish and French government sources. REACH regulates the use of chemicals and how they are produced, with restrictions based their environmental and human health impacts. REACH affects all industries throughout Europe that use chemicals and extends beyond the EU’s borders for goods sold into the region. REACH data is generally considered to be extremely robust and yet the EUON report concludes that “Data for hazard and risk assessment are not available for the vast majority of identified nanopigments”. This is more than worrying and could have a serious impact on existing and new ink technologies, especially those designed for packaging printing.

The problem of knowing how nanopigmented inks will impact human health is not just a concern for the EU. It has implications for all media markets around the world. The report found that the data that is available is often inconsistent to the point of being contradictory. EUON’s goal was to gather more information about the 81 nano-sized pigments used in the EU, but what they found is a lack of reliable information on toxicology data relating to nano-pigments. In other words we don’t really know if nano pigments are poisonous or not, or how they behave once printed.

– Laurel Brunner

This article was produced by the Verdigris Project, an industry initiative intended to raise awareness of print’s positive environmental impact. This weekly commentary helps printing companies keep up to date with environmental standards, and how environmentally friendly business management can help improve their bottom lines. Verdigris is supported by the following companies: Agfa Graphics, EFI, Fespa, HP, Kodak, Kornit, Ricoh, Spindrift, Splash PR, Unity Publishing and Xeikon.

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