Abstract

The relation of shoe comfort to the mechanical properties of upper leathers is briefly discussed. The potential importance of behavior in the low strain (1–2% extension) region has been investigated using linear extension. Both leather and synthetic substitutes show a non-linear initial portion, and methods of estimating its magnitude have been developed. For leathers, there appears to be little relation between the extent of the departure from linearity and either fiber structure or overall load-extension behavior. Heat setting does not remove the initial curvature, and it remains unaffected by simple variations in liming, bating, or fat liquoring. Using a retannage involving ammonium dioleate addition followed by rechroming significantly reduced the load required for a given extension, as seen in previous work with this type of retannage.