Deciphering the Role of Individual Retanning Agents on Physical Properties of Leathers

In post-tanning different types of retanning agents are used incombination to improve the functional properties of leather andtherefore understanding the individual effect of each retanningagents on final properties is difficult. This work mainly focusestoward quantifying the individual effect of different weightpercentages (4, 8 and 16%) of phenol-formaldehyde resin (PFR),melamine-formaldehyde resin (MFR), acrylic resin (AR) andbiopolymers (BP) on physical properties of leather. It was foundthat the strength characteristics are greatly affected when theretanning agents offer increased above 8% where the effect ofphenol-formaldehyde resin is higher than other re-tanningagents. Melamine-formaldehyde resin and biopolymer ispredominantly affecting the belly region. It has also beenobserved that the phenol-formaldehyde resin improves thefullness whereas grain tightness and flatness are improved withincreasing the percentages of melamine-formaldehyde resinoffer. Biopolymer improves the grain smoothness and the abilityof improving the roundness of leather is similar for all kind ofretanning agents. A meaningful conclusion could not be drawnin the porosity results obtained due to the heterogeneous natureof leather matrix. Thus, a conventional triplicate method ofmeasurement as done in this study would not suffice to providea conclusive interpretation of results obtained using capillaryflow porometry technique.