Studies on the application of power ultrasound in fatliquoring

Fatliquoring experiments have been carried out with ultrasound under stationary conditions and compared with the process in the absence of ultrasound under stationary as well as dynamic drumming condition. Type of fatliquors such as vegetable, semi synthetic and synthetic fatliquors have been studied. Variation in process parameters like ultrasonic output power, amount of fatliquor, and temperature have also been studied. The results show improvement about 2.5, 1.8, 1.5 times in the fat uptake in leather due to ultrasound for vegetable, semi synthetic and synthetic based fatliquors respectively. The observed order of improvement, vegetable > synthetic fatliquor is in agreement with the hindrance generally expected for fatliquors during penetration as indicated by emulsion particle size and Gel Permeation Chromatography (GPC) data. Therefore, ultrasound is useful for more difficult fatliquoring conditions. The results also indicate that ultrasound under stationary conditions is comparable or better than dynamic drumming conditions. The effects of ultrasound due to pre-sonication and on the viscosity of the fatliquor have also been studied. Leather fiber stricture has been analyzed using Scanning Electron Microscopy (SEM) and found to be more regular and improved by ultrasound aided processing. The studies indicate ultrasound promotes effective emulsification of the fatliquor in water systems rendering better penetration and more uniform distribution through the leather matrix.