In order to prepare a softener, alkyl imidazoline salt, fatty carbamide salt, and fatty polyamide salt were synthesized first, and then the synthesized salts were blended. The prepared softeners were applied to acrylic fibers, and then several properties were tested. As a result, the prepared softeners show good softening and lubricating properties, and they also show a little antistatic property. Through bending resistance tests and measurements of feeling change of acrylic fibers treated with the softeners, it was proved that the prepared softeners are durable softeners.

Fatty polyamide that gives softness, lubrication and bulky property and alkyl imidazoline that gives durable softness and antistatic property were synthesized. then, an O/W-type durable softener (DSN) was prepared by the emulsion of the synthesized fatty polyamide and alkyl imidazoline. Emulsion stability of the DSN was good, and the mixed HLB value was 11.2. From the measurement of softness, lubrication, antistatic property, bending resistance, and color fastness, it was proved that the prepared DSN was a good durable softener for nylon.