Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2006
Publication Date: 2/1/2007
Citation: Liu, C., Latona, N.P., Cooke, P.H. 2007. Effects of drying processes and fatliquoring on resiliency of leather. Journal of American Leather Chemists Association. 102(2):68-74. Interpretive Summary: Because of environmental and health concerns over the use and disposal of chrome-tanned leather, chrome-free leather has gradually gained commercial importance, particularly for automobile upholstery applications. Our research, however, has shown that the resiliency of chrome-free leather is inferior to chrome-tanned. Resiliency is very important to automotive upholstery makers because poor recovery from deformation, such as sitting on the car seat, will create bagginess in car seats made with upholstery leather. The drying operation is a critical leather-making step to attain the required physical properties for leather products. Therefore, we have conducted drying studies to identify the most favorable drying method to yield the best resiliency. Data from this research indicated that vacuum drying is best. We also observed a general trend that when leather has a higher resiliency it also has a greater toughness. In addition, our research also showed that the resiliency of leather is significantly affected by the amount of oil (fatliquor) added to leather during the leather-making process. The results of this research will benefit leather producers to make quality chrome-free leather with high resiliency.
Technical Abstract: Resiliency is the important quality characterizing the dimensional stability of leather. It expresses the ability of materials such as leather to recover from deformation after being subjected to a strain or stress. Resiliency is particularly important to automotive upholstery makers because poor recovery from deformation would create bagginess in car seats made with upholstery leather. We have designed a tensile method to characterize the resiliency of leather. Measurements showed that the resiliency of chrome-tanned leather is superior to chrome-free leather. Our studies also indicated that the physical properties of leather, particularly resiliency, were affected significantly by the drying and fatliquoring processes. Observations revealed that toggle drying may impair the resiliency of leather, while vacuum drying produced the best resilient leather in this study. In addition, data indicated that there is a close relationship between resiliency and fracture energy of leather.