Articles - Leather Technology Magazine Nº74

New Micro-sphere Application in the Leather Industry

New Micro-sphere Application in the Leather Industry

Work presented at the 2nd National Technical Symposium of the Tanning Industry, Buenos Aires, November 21st, 2008

ABSTRACT

The upgrade of lower quality hides or skins in order to produce a good quality leather article with acceptable yield and performance is one of the most value adding opportunities for a tanner. A new, innovative wet end technology based on expandable Micro-spheres is being introduced to the leather industry. Tanned leather is treated during the retanning step with a customized penetrating polymer dispersion containing compact micro-spheres. These Micro-spheres have a diameter of 5 - 20 µm and are small enough to migrate into the collagen structure; they are filled with a liquid gas, and can expand through a heat treatment process, up to 40 times of their original size to a much larger, resilient Micro-cell. During the wet end process the polymer together with the micro-spheres penetrate into the leather. After a conventional retanning and drying process the dried crust is then be subjected to a special steam treatment where the Micro-spheres inside the leather are expanded and transformed into larger Micro-cells. This operation results in a dramatic upgrade of the internal structure of the leather, and in turn the grain surface appearance and uniformity, too. The loose areas, blood vessels and other voids in the corium layer are selectively and permanently filled while keeping the leather light and soft. Several applications have already been studied and the feasibility of the technology has been proven, but this new system further opens up a variety of completely new opportunities for the leather industry.