September 2010 Additives for Polymers11

Perspectives for Mass Production of Graphene-Based Electronic Devices’, published in the American Chemical Society’s journal Nano Letters.

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ENVIRONMENT, HEALTH AND SAFETY ISSUES

Classification & labelling update required for melamine cyanurate flame retardant

The Brussels-based Phosphorus, Inorganic & Nitrogen Flame Retardants Association (PINFA)

reports that new tests on melamine cyanurate (MC) reveal that the flame retardant demonstrates stronger kidney toxicity than previously realized.

As part of the REACH registration process, MC (CAS 37640-57-6) was tested in 2010 according to certain envi-ronmental and toxicological aspects. As part of a pre-study, rats were fed melamine cyanurate for one week. The sub-stance revealed a greater toxic hazard to the kidney than was previously known. Therefore, the classification and labelling

of MC may need to be changed to ‘Xn; R48/22’, which indicates ‘harmful: danger of serious damage to health by prolonged exposure if swallowed’, according to Directive 67/548/EWG or 1999/45/EC; and to ‘STOT (RE) Cat. 2 (H373)’ or ‘specific target organ toxicity (repeated or long term exposure)’, according to regulation (EC) 1272/2008. Further testing is now being carried out to confirm the find-ings, PINFA says. A 90-day feeding study is ongoing at the National Center for Toxicological Research (NCTR) in the USA. Classification and labelling will be reviewed after the results of this study have been published.

MC is a solid white powder. As a flame retardant it is employed in unfilled and mineral-filled polyamides used for electric and electronic parts such as connectors and switches.

It is added to the polymer at a loading level of about 10–15% to achieve the necessary fire rating. MC is also often used as synergist in combination with phosphorus-based flame retard-ants. In addition, it finds minor use in formulations for poly-propylene and thermoplastic polyesters for cables.

Melamine and its derivatives show toxic effects on the kidney and sometimes the bladder, because salt crystals can form in the kidneys that clog the fine drainage tubes. The combination of melamine with cyanurate forms a particularly insoluble salt and therefore has a high tendency to cause this problem. MC is not genotoxic, it is not irritating and has no sensitizing properties. However, as a consequence of the new toxicity results, suppliers of MC have changed to the new labelling and are currently updating their safety data sheets.

Production and polymer formulation workers and others that handle MC as a pure chemical are the most affected and should upgrade their workplace safety precautions accordingly, PINFA advises. Since the substance is often used as a powder with low particle sizes, breathing the dust should be avoided. A particle filter with high efficiency for solid and liquid particles (e.g. EN 143 or 149, Type P3 or FFPE) should be used. In addition, gloves as well as local exhaust and ventilation in place are recommended.

Consumers and users of end products (e.g. electric and electronic equipment) that contain MC do not come into direct contact with the substance and ingestion is very unlikely, because it is firmly embedded in the polymer matrix. And there is no risk of evaporation because the vapour pressure of MC is extremely low.

PINFA is a sector group within Cefic, the European Chemical Industry Council. It represents the manufactur-ers and users of non-halogenated phosphorus, inorganic and nitrogen flame retardants. It also cooperates with national and supranational organizations (EU, OECD, United Nations) and other industry associations, consumer organizations and non-governmental organizations, and will ensure the development of scientific knowledge related to the whole life cycle of this group of flame retardants.

Contact:PINFA Secretariat, Avenue E. van Nieuwenhuyse, 4 (Box 2),

B-1160 Brussels, Belgium. Tel: +32 2 676 7286,

Fax: +32 2 676 7392, Email: pinfa@cefic.be, Web: www.pinfa.eu

HEALTH & SAFETY