“Decades ago, the development of synthetic retanning chemistry has changed the leather industry. Now, we think the time has come for a next-generation innovation that once again opens the door to the future”, says Dietrich Tegtmeyer, Vice President of Product Development and Application at the Lanxess Leather business unit. Dr Tegtmeyer was speaking at an official launch of the product at the ACLE. A presentation of the new technology in a practical tannery application was given by Fernando Bellese of JBS Couros who are using the new technology.

To become increasingly independent from fossil fuel based raw materials, the incremental substitution of petroleum-based chemicals is one of the key challenges for the leather industry in the years ahead. Lanxess is a driving force behind the formulation of advanced leather chemicals derived from renewable resources.

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 functionalised 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.

No compromise on leather quality

With Levotan X-Biomer important performance characteristics for the production of high quality leather can be achieved. This has become possible through a production process where the biopolymer raw material is partly hydrolysed into small oligomers and then converted back into modified polymers with very specific characteristics. Thus, the performance properties with respect to dyeability, fullness, tightness, selective filling as well as heat resistance and light fastness can be exactly tailored to meet the needs of the retanning applications.

Clean wastewater

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% 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 one percent. Therefore, increased substitution of traditional syntans allows the tanners to reduce the amount of salt in the float and in the effluent.