Leather that smells nice

Bayer's Euderm Aroma will aid manufacturers in producing leather which not only feels and looks good but also has an appropriate fragrance. Euderm Aroma consists of tiny (one to ten micrometer), perfume-filled polyurethane microcapsules which are applied on the leather and release their fragrance when the leather is subjected to mechanical strain. The idea for Euderm Aroma originated from repeated requests from customers for that typical leather smell. With the modern tanning and finishing processes used today, the end product has very little inherent odour, and so leather manufacturers asked Bayer to look for a way of reproducing the characteristic leather smell which end-users so often want. The result was Euderm Aroma CV, which smells of pure leather. But this is not the only fragrance offered by Bayer. There is also Euderm Aroma BL, which is described as neutral and fresh, and further selected fragrances are to be added to the range in the near future. From the purely technical point of view, virtually any fragrance can be produced. According to Dr Martin Kleban, a leather research scientist at Bayer: 'We will gladly process any fragrance a customer wants into Euderm Aroma microcapsules, so that he can give his leather products an exclusive perfume.' This new development opens up hitherto unheard-of possibilities for the automotive, furniture and clothing industries. Sports-shoes that smell of lemons, leather armchairs that surround you with the fragrance of spring meadows when you sit down and relax after a hard day at work, convertibles whose leather interior emits a fresh, sporty aroma or leather jackets with a decidedly masculine scent - there is virtually no limit to the creativity of designers. The fragrance is enclosed in patented polyurethane microcapsules which are largely impermeable to diffusion. Encapsulation is carried out by means of interfacial polymerisation on the surface of finely dispersed droplets of fragrance oil in an aqueous phase. The size of the microcapsules can be controlled by varying the conditions. The microcapsules are supplied in the form of a 50% aqueous dispersion which can be freely diluted with water before use. They are generally applied by simply spraying the diluted dispersion onto the flesh side of the finished leather. Dr Kleban explains: 'Euderm Aroma basically works according to the same principle as copying paper which is coated with a microencapsulated colour pigment. When pressure is applied by a ballpoint pen, some of the capsules release their dyestuff. This is known as release-on-demand technology.' Similarly, if a leather article finished with Euderm Aroma is subjected to pressure or moved - for example, if somebody sits down on a treated armchair or car seat or walks in treated leather shoes - some of the microcapsules in the leather rupture and release their content, ie their fragrance. The great advantage is that the fragrance really is only released when the leather is subjected to mechanical strain. Thanks to this release-on-demand principle, the fragrance can be released again and again. So the characteristic and pleasant smell of new leather that greets you when you first get into a new car with a leather interior is still there many drives later. Details can be found on the website [http://www.bayerleather.com]