Abstract: In order to solve the alkali swelling of pelt with enzyme unhairing，a special swelling auxiliaries was developed. By reducing by the isoelectric point of the polypeptide solution, increasing swelling weight of pelt, and dissolving out hydroxyproline,total protein and proteoglycan,the functions of swelling auxiliaries were characterized. The appearance of swelling pelt and fiber structure of chrome leather all proved that 2% swelling auxiliaries could satisfied pelt swelling and and the machining requirement, while the fiber structure characteristics of chrom leather are close to that of enzyme unhairing and swelling by alkali method.

Key words: enzyme unhairing, swelling, auxiliaries, pelt, machining