As part of its Sustainable Leather Management initiative, specialty chemicals company Lanxess has come up with an effective way of preventing these problems: Preventol U-Tec G, a patented combination microbiocide that is specially formulated to protect leather. The product combines long-lasting effectiveness against a wide range of fungi and various bacteria that attack leather with an ecological and toxicological profile that is very favorable for a biocide. Preventol U-Tec G was specifically developed for preserving tanned hides (wet-blues, wet-whites, X-whites and vegetable-tanned leather) during storage and transport.
The microbicide also has economic advantages. It is supplied in the form of a highly concentrated, eutectic liquid and only relatively small amounts are required. That helps to cut transport and storage costs.
The secret of Preventol U-Tec G’s success is a specially developed formulation of the complementary active ingredients o-phenylphenol (OPP, 2-hydroxybiphenyl), p-chloro-m-cresol (PCMC) and octylisothiazolinone (OIT), whose ecological and toxicological properties have been studied closely over many years. "Tests carried out by independent laboratories have confirmed that, in the low concentrations required for this application, the main active ingredients OPP and PCMC are degraded quickly and easily in biological wastewater treatment plants," explains Christopher Tysoe, Director PD&A Wet End in Lanxess’ Leather business unit. "And residual concentrations of the active ingredients can even be biodegraded in normal water courses," he adds.
The special mechanism of action of Preventol U-Tec G is quite remarkable: it damages the cell membrane of the fungal cells irreversibly without reacting chemically with them. Once that has happened, the active ingredient is released again. In other words, it is not "used up" while it is taking effect and is "regenerated" to go on and on protecting leather efficiently. And as it is bound to the collagen fibers via hydrogen bridges, it stays in the leather for a long time. Applying the right preservation agent at the appropriate stage of processing in the right amount can reduce the likelihood of microbes getting a foot hold on the leather later in its useful life. This is good news for the consumer in two respects: on the one hand, it has been scientifically proved that, in the quantities recommended by Lanxess, the small amount of active ingredient remaining in the leather is safe for humans, and on the other hand, these small quantities are sufficient to effectively prevent microbial attack.
An independent and certified German institute recently carried out further tests on dermatological safety. Plasters impregnated with various concentrations of OPP, such as are used for preserving leather and also in various cosmetic products, and samples of leather treated with Preventol U-Tec G were applied directly to the skin of test persons with widely differing degrees of skin sensitivity. There was no evidence of primary skin irritation or of the product triggering skin reactions.
“Provided it is used correctly and for the intended purpose, Preventol U-Tec G is a safe and highly effective means of providing leather with long-lasting protection against mold fungi and various types of bacteria. The product not only satisfies the statutory provisions in many countries, but also meets the requirements of the restricted substance lists (RSL) of countless tanneries and processors," says Tysoe, summing up.
