Clariant prepare tanners for NMP-free future

One of the leading suppliers of leather finishing chemicals, Clariant were among the first to begin research and development into the challenge to replace NMP. The solvent, which was previously valued for its beneficial effects for example on levelling and jet blackness, was reclassified by the State of California in June 2001 following toxicology reports and added to the list of substances known to cause cancer or reproductive toxicity. When NMP is used in leather finishing, almost 90% remains in the leather after drying. However the solvent is released over a long period of time, exposing the end consumer to its potentially harmful effects.

In California, even minimum amounts of NMP in a product have to be labelled. For example, a vehicle instruction manual must include a warning label if a leather containing NMP has been used on the car seats.

At the end of the transitional period in December 2010, NMP will be reclassified within the EU. Mixtures containing 5% or more of NMP must be labelled as toxic with all the consequences for the customers in handling and regarding the emission limits by law. Even 0.1% of NMP must be listed in the safety data sheet. So leather processing companies are asking and will ask more and more for NMP-free leathers.

‘Clariant realised at an early stage that the use and acceptance of NMP would come to an end and that it would be a major challenge to replace it’, comments Dr Ralph-Gunther Blach, head of marketing & application development of BU Leather Services of Clariant.

‘So in 2001 Clariant started a project for the replacement of NMP in all leather finishing products. A lot of different solutions were necessary to surmount the production and application problems for NMP-free products, but since 2005 our standard finishing products have been free of NMP and fulfil even the high quality demands and environmental requirements for automotive leather.’

Clariant’s Aqualen topcoat range meets strict customer performance and processing requirements without the use of phthalates, alkylphenolethoxylates (APE’s), and NMP, and with very low VOC levels. The high-performance topcoats, with low impact to the environment, are suitable for all kinds of applications, from glazed kid imitation to high-wear-resistant automotive leather.

As a result of Clariant’s proactive stance on NMP removal and its on-going commitment to advancing sustainable leather finishing, the company have become a recognised specialist in this field. Clariant representatives presented in-depth lectures at congresses at the LGR Gerberschule Reutlingen in Germany (March 2010) and the ALCA conference in the US (June 2010).