LEATHER | High-performance biopolymers

Starting the future of retanning


The substitution of fossil fuel-based chemicals is one of the key challenges in the years ahead. With the Levotan® X-Biomer® new technology based on biodegradable polymers, LANXESS' experts have accomplished an innovative leap forward in retanning chemistry.

As an alternative to synthetic retanning agents the new patent-pending Levotan® X-Biomer® range includes a complete portfolio for all key steps of the retanning process. The chemistry behind it however, is completely different. All products are based on biodegradable polymers, which are produced from renewable raw materials and specifically functionalized for retanning applications in a biologically engineered process. Thus, the Levotan® X-Biomer® technology enables the production of wet blue leather that fulfills the high technical requirements demanded, e.g. for automotive leather or children's footwear. At the same time, tanners benefit from a significantly improved sustainability profile.

Clean waste water
One of the key features of the new X-Biomer® technology is the reduction of the retanning effluent load. Due to the amphoteric character of all products which contain both positive and negative charges a good fixation and exhaustion can be achieved. Compared to traditional retanning polymers the chemical oxygen demand (COD) is even up to 30 percent lower when using the corresponding Levotan® X-Biomer® product.

Another decisive advantage is the high biodegradability of X-Biomer® retanning agents which are based on organic components that can easily be degraded by microorganisms in the effluent treatment. Thus, tanners benefit from a more efficient COD elimination in their waste water. The high biodegradability has been confirmed by an independent testing laboratory which even classified two of three X-Biomer® products as “readily biodegradable” according to the OECD guideline 301F. The third one has also shown very good testing results with 52% being degraded in just 28 days.

Finally, the salt concentration is another important factor with an impact on both waste water treatment and the final leather quality. Reducing the saline freight in the float positively affects the efficiency of the whole retanning process especially with regards to fatliquoring and dyeing. Traditional retanning syntans considerably increase the salt freight. The salt concentration of the X-Biomer® alternative product is far below 1 percent. Therefore, increased substitution of traditional syntans allows the tanners to reduce the amount of salt in the float and in the effluent.