Abstract: In this paper, considering the contact mode of the fabric and the dye liquor, the paper analyzed the dye mobility and retarding performance of the acid leveling agent, studied the main application performance of the acid leveling agent in the dyeing process of the nylon jigger, and explained the application mechanism model of acid leveling agent in the process. In doing so, the paper put forward the basic principle of leveling agent selection, that is, in the jig dyeing process of nylon fabrics, dye mobility has been weakened obviously,therefore, acid leveling agent with outstanding retarding ability can better ensure the leveling of dyeing.

Key words: nylon; jig dyeing machine; acid leveling agent; dye mobility; retarding ability