Ecological Technology: NMP-free Leather Finishing

摘要

There were historically good reasons to use N-Methylpyrrolidone in leather finishing products, but compelling reasons to discontinue its use are now well known. Findings of reproductive toxicity lead to a new classification and labelling of NMP. This new knowledge led the state of California, in June 2001, to add NMP to the list of substances known to cause cancer or reproductive toxicity. This was the first toxicological listing of NMP but since then others have adopted legal restrictions, e.g. in the European Union. The current regulations of these compounds offer no limits. Even if a product contains minimum amounts of NMP it has to be labelled. So, for example, if a leather containing NMP in the finish is used for a car seat in California the instruction manual of the car has to include a warning label. When NMP is used in leather finishing almost 90% remains in the leather after drying, but is gradually released over a long period of time. This means that consumer products containing these leathers will release NMP and the end-user customer may be exposed to it.rnAt an early stage Clariant realised that the use and acceptance of NMP must come to an end and that it will be a big and time-consuming challenge to replace it. So in 2001 our company started a research project for the replacement of NMP in all leather finishing products.rnThere was no general possibility to replace NMP and fulfil all requirements. A lot of different specific solutions were necessary to surmount the production and application problems for NMP-free products. But, starting at the beginning of 2004, Clairant offered NMP-free finishing products that fulfilled even the high demands for automotive leather while meeting the new environmental requirements. By mid-2005 all of our standard products were free of NMP.