Preventol U-Tec G is a fungicide formulation from the LANXESS specialty chemicals company that reliably preserves raw hides tanned using LANXESS’ new X-Tan technology. Only small amounts of the product are sufficient to ensure that these organically tanned hides and skins, known as “X-Whites”, can be stored for longer periods. This means that, like chrome-tanned raw hides (wet blues), they can be transported over greater distances, thus opening up new marketing opportunities.
To protect leather intermediates (wet blue, wet white, X-White) effectively against attack by fungi, it is essential to prevent fungal spores from growing both on the hides themselves. Hartmut Rehbein, Product Development in LANXESS’ Leather business unit, carried out extensive series of laboratory trials to investigate which fungicide provides the optimal protection.
Combination fungicide proves best
For their laboratory trials, he examined numerous common fungicides, including both membrane-active substances, such as o-phenylphenol (OPP), p-chloro-m-cresol (PCMC) and sodium pyrithione, and intracellular, nucleophilic substances, such as octylisothiazolinone (OIT) and (2-thiocyanatomethylthio)benzothiazole (TCMBT).
Four widespread strains of microorganisms, namely the mold fungi Aspergillus niger, Aspergillus repens, Homoconis resinae and Trichoderma viride, which are known to attack leather, were used for the benchmark study. All the tests were conducted on the basis of the standardized ASTM 4576-08 process.
The combination product Preventol U-Tec G, which contains both the membrane-active components OPP and PCMC and the intracellular, nucleophilic active ingredient OIT, proved efficacy in every case. Even additions of as little as 0.25 %, calculated on the X-White weight, were found to be sufficient to prevent mold infestation for more than 28 days. In practice, this means that the leather intermediate (X-White) could be stored for up to six months. Without a fungicide, extensive mold growth is visible after only 10 days of storing.
Preventol U-Tec G has a number of further advantages, too, that fit perfectly with the Sustainable Leather Management concept. For example, all the ingredients are readily biodegradable in wastewater treatment plants. Additionally, the aromatic ingredients OPP and PCMC are distributed uniformly in the leather and fixed there via hydrogen bridges without tanning the collagen.
X-Tan – a milestone in organic tannage
X-Tan from LANXESS is an organic tanning system that offers substantial improvements over conventional wet white manufacturing processes as regards both quality and ecology.
X-Tan is a sustainable tanning process that gives high-quality leather. It combines first-class performance with ecological advantages: for example, no reactive tanning materials remain in the leather or the effluent, and the salt load of the effluent is much lower than in conventional organic tannages.
A key feature of X-Tan is the relatively high whiteness of the leather, which makes it possible to obtain brilliant colors in the subsequent dyeing. The leather also has excellent physical fastness properties.
The new X-Tan technology is in keeping with the main goals of LANXESS’ Sustainable Leather Management initiative, which is designed to enhance and extend the company’s product portfolio for sustainable leather production. Detailed information on Sustainable Leather Management and on X-Tan technology can be found on the Internet at lanxessleather.com/.
The Leather business unit is part of LANXESS’ Performance Chemicals segment, which posted sales of EUR 2.13 billion in fiscal 2011.
LANXESS (lanxess.com) is a leading specialty chemicals company with sales of EUR 8.8 billion in 2011 and currently around 16,700 employees in 30 countries. The company is at present represented at 49 production sites worldwide. The core business of LANXESS is the development, manufacturing and marketing of plastics, rubber, intermediates and specialty chemicals. LANXESS is a member of the leading sustainable indices Dow Jones Sustainability Index (DJSI) World and FTSE4Good.