Process for self-crimping acrylic fiber from a melt of two non-compatible polymers

Claim 1

A process for producing a self-crimping acrylonitrile polymer fiber which comprises preparing a fusion melt of water and (1) a first polymer comporising from about 80 to about 99 weight percent acrylonitrile and about 1 to about 20 weight percent of one or more monomers copolymerizable with acrylonitrile and (2) a second polymer incompatible with said first polymer and having thermal and/or hydrophilic properties which differ from those of said first polymer by an amount sufficient to provide self-crimping properties in said fiber, said first polymer constituting the major weight proportion of polymer and said fusion melt being free of any separate phase of water and/or unmelted polymer, dispersing the second polymer melt heterogeneously within the first polymer melt, extruding the resultant dispersion through a spinneret directly into a steam-pressurized solidification zone maintained under conditions which control the rate of release of water from the nascent extrudate, enable the extrude to solidify and maintain the solidified extrudate in plastic state and subjecting the plastic extrudate to stretching to provide desirable textile properties therein.