Effects of fatliquor on vacuum drying of leather

The effect of fatliquor was not included in our previous vacuum drying studies for chrome-tanned leather. Therefore, a follow-up vacuum drying study was performed to evaluate the effect of fatliquor. By using the SAS statistical program, we have formulated the relationship between fatliquor concentration and drying rate. This study also focused on how fatliquor affects the strength, elongation, stiffness and toughness of the vacuum dried leather. A second order polynomial regression equation was derived to plot 3-D response surfaces that clearly illustrate the relationship between the fatliquor concentration and drying rate, as well as the resultant physical properties. Measurements showed the drying rate decreases as the fatliquor concentration increases by a factor of (1 - f)(1/2), where f is the fatliquor concentration fraction. Observation showed that the tensile strength, elongation, and toughness all increase steadily with an increased fatliquor concentration, whereas the Young's modulus decreased. A correlation was observed between elongation and Young's modulus.