The demand for coatings with uniformly sized nanoparticle pigments has been increasing strongly in Europe because of their enhanced colors, resistance and durability.

At the same time, however, the European Union has introduced rules to ensure that manufacturers and users of  nanopigments and other nanocoatings ingredients give more information about the safety of the products.

“Data for hazard and risk assessment are not available for the vast majority of identified nanopigments,” said a report on the uses and risks of nano pigments in the EU issued in September 2018 by the European Union Observatory for Nanomaterials (EUON).

“It is clear that more information on the use of nano-sized pigments and their potential for release and exposure in occupational, consumer and environmental contexts is needed in order to derive comprehensive and realistic risk assessment,” added EUON, which is funded by the European Commission, the EU’s Brussels-based executive.

Under amendments to REACH, the EU’s chemicals safety legislation, companies will have to provide data to the European Chemicals Agency (ECHA) on nanopigments and other nanomaterials so that  regulatory authorities and customers know more about their characteristics, safe use and health and environmental risks. The safety information will have to be passed down the supply chain to coatings producers and their customers.

Nanopigment suppliers and their coatings customers will now have to focus their R&D on not only continuing to improve the properties and applications of their products but also on conducting tests to provide data to fill the information gaps in  REACH  registration safety dossiers.

At the moment, there are approximately 80 different identified  types of nanopigments on the European market, with titanium dioxide, carbon black, and iron and other metal oxides having the biggest volume, according to EUON estimates.  But due to the paucity of firm data, the numbers of  nanoparticles on the market is likely to be much higher. 

Ultimately the new registration requirements may work in favor of the coatings sector because more knowledge about the safety aspects of  nanomaterials in coatings will give users greater confidence that  nanopigments and other nanosubstances will not be a danger to health and the environment.

The  move  probably comes too late for suppliers of titanium dioxide in Europe to prevent the pigment from being classified as a suspected carcinogen. 

This will result in  health warning labels having to be put on paint containers under the EU’s Classification, Labeling and Packaging (CLP) regulation, ECHA, which administers both REACH  and the CLP legislation, has, in the face of fierce opposition from industry, successfully persuaded the European Commission that TiO2  be categorized as a suspected cause of cancer (category 2) through the inhalation of  the pigment’s dust. 

The Commission’s decision is due to be finally endorsed by a committee of expert representatives of EU member states at their next meeting in December 2018 or February 2019.

“The French regulatory authorities who made the original  TiO2 labeling proposal to ECHA due to the carcinogenic risk were unhappy about the lack of data on TiO2 nanoparticles, particularly in reference to their inhalation,” said Janice Robinson, product regulations director at  the European Council of the Paint, Printing Ink and Artists Colours Industry (CEPE), Europe’s coatings trade association.

“Now the decision on the cancer classification has gone too far down the road to be reversed,” she continued.  “Things could be different in future because safety information on nanoparticles and other nanomaterials will be available in REACH  registration dossiers.”

Currently, the biggest safety concern with nanoparticles is their danger to human health through inhalation. Inhaled insoluble nanopigments can interact with organisms at the cellular level and cause immunological effects, oxidative stress and chronic lung and liver inflammation, according to the EUON  report.

Coatings producers can lower risks from nanopigments to minimal levels by ensuring they are well locked into the coating matrix.

“Exposures to nanosized pigments that are integrated into polymer, paint or coating matrices are not thought to be significant,” said the report.

In the OEM automobile coatings sector, a lot of research has been directed at their integration with other coatings components.

PPG  Industries, a leader in automotive coatings, has, for example, developed a technology which encapsulates nanopigments in resin during the coatings production process.

The OEM car coatings sector is  among the most advanced in its application of nanopigments and other nanomaterials to provide properties like scratch resistance and  improved colors.

Nanoparticles help provide colors  enabling  OEM manufacturers  to differentiate their cars. The particles create color spaces unobtainable with conventional pigments and which can highlight the vehicle’s design by emphasising the shape  of the body.

Colors like reds, blues, yellows, and greens are made stronger on cars by nanopigments, which are more efficient at absorbing light waves and reducing scattering of light. With less scattering of light there is less haze, more purity and transparency in the colors.  Nanoparticles are accelerating a trend towards brighter colors on cars.

One of the biggest gaps in safety information about nanomaterials in coatings is the risks of  exposure to them among production and other staff and among consumers.

The new data requirements for REACH registrations of substances with nanoparticles will require not only information relating to toxicological profiles but also exposure patterns.  

Details of particle size, shape and surface patterns of nanoparticles are seen as being linked  to exposure  as well as  behavior in the environment, in addition to  toxicological characteristics.

However, the types of materials which will be covered by the new REACH registration rules could be changed by alterations to the current seven-year-old EU definition of what is  a  “nanomaterial.”

Presently, this is defined as a material with 50 percent or more of particles by number which has one or more dimensions between one and 100 nanometers.

The definition is being reviewed by the European Commission because of widespread complaints in the industry about its deficiencies, such as its narrowness, lack of clarity and difficulties with implementation.

It may be broadened to include particles of an elongated shape, such as a rod, fiber or tube, and of a plate-like shape where one external dimension is small than 1 nm.

Other nanomaterials covered by the existing definition may be excluded but overall the new definition is likely to result  in more types of materials, including pigments, being categorized as “nano.” 

Overall it will mean that suppliers of nanopigments  and other nanomaterials and their coatings customers will have to allocate additional resources to ensuring compliance with REACH rules in their production and use.