Collagen D-spacing and the Effect of Fat Liquor Addition

Abstract

The physical properties of leather are partly a result of the structure of the leather’s network of type I collagen fibrils. To achieve high strength and a soft, supple feel, penetrating oils(usually polyols) are added to leather during manufacture, and this process is known as fat liquoring. The modification of the collagen structure by fat liquoring (with a lanolin-based fat liquor) is investigated using synchrotron-based small angle X-ray scattering. The axial periodicity, or D-spacing, of the collagen changes as a result of fat liquoring. With no fat liquor, the D-spacing is 60.2 nm; spacing increases by 6% to 63.6 nm at 10% fat liquor. Pure lanolin results in a similar increase in D-spacing. We discuss mechanisms for fibril elongation brought about by fat liquoring. The observations of structural changes taking place within collagen fibrils as a result of fatliquoring provides new insight into the nature of fat liquoring and informs future processing developments.