Optimizing methods applied to sheepskin degreasing with non-ionic surfactants

Woolskins from Australia and New Zealand, etc. have a very high content of natural fat, possibly 40-50% on dry skin weight. The high content of natural Fat, if not reduced during the degreasing proce ss, causes problems during the manufacturing process which can confer undes irable characteristics to the leather: hard handle, reduced mechanical prop erties, difficulty in the fixation of the finish base coats, dyeing spots, fat spue, etc. Depending on the final leather article, a very thorough degr easing process will be required. Of the existing degreasing processes, that one which uses non-ionic surfactants in an aqueous medium is well known. In this work, a comparative study has been performed between different non- ionic surfactants: ethoxylated nonylphenol and ethoxylated fatty alcohols. By means of a 3(3) factorial design optimizing method, the efficiency of de greasing of glutaraldehyde pre-tanned sheepskins has been studied as a func tion of the following variables: non-ionic surfactant type, non-ionic surfa ctant offer and degreasing process temperature.