Effect of Fatliquoring on Leather Comfort. Part III: Moisture Absorption-Desorption of Leather

Abstract

The comfort of tanned hide/skin is an added value, which is decisivefor the choice of leather in articles for footwear or clothing,compared to other alternatives whose design excludes thiscomponent. This comfort is related to the capacity of absorptionand desorption of moisture and with the physical, mechanical andorganoleptic characteristics of the leather. After tanning,fatliquoring and retanning are the operations that more intensivelymodify the characteristics of leather articles.This work is a continuation of two previous ones that have studiedthe influence of fatliquoring on softness and compressibility ofleather and on grain and corium quality of leather assessed by ballbursting and tearing tests. In this case, the effect of fatliquoring onmoisture absorption-desorption characteristics of leather is studied.The experimental work has been carried out in the pilot plant ofTrumpler Española S. A. and the moisture absorption-desorptiontests in the Laboratory of Thermal Analysis and Calorimetry of theIQAC. The behavior of non-fatliquored leather and that of leatherfatliquored with a combination of sulphited triglycerides of colza oiland fatty polymer (TCSi/PGR) or fatliquored separately with theircomponents TCSi and PGR, or with phosphoric ester ESF orsulphited fish oil Psi has been determined.The determination of the size of the moisture absorbing monolayer(Xm), the binding energy constants of the monolayer C and themultilayer K, the maximum absorption capacity at saturation X1and the hysteresis (Hyst.) between absorption and desorption,enabled us to classify the different fatliquoring agents according tostage (crust-blue, finished-red) by applying factorial analysis (seefollowing graph). Finishing is the factor that best explains thisbehavior. Finishing decreases the size of the monolayer andincreases the binding energy constants. Fatliquoring decreases themaximum absorption capacity and hysteresis, partially affectingthe reduction of the monolayer size.