Aromatic polyamide fibers and process for stabilizing such fibers with surfactants

Yarn made from oriented, substantially amorphous, aromatic polyamide fibers containing a surfactant in an amount sufficient to enable the fibers to be dyed a deep shade, which amorphous fibers are crystallized by routine processing steps thereby to stabilize the fibers against progressive laundry shrinkage,

• wherein the aromatic polyamide is poly(meta-phenylene isophthalamide) and
• wherein such fibers contain from about 5 to 15%, by weight, of the surfactant.

An oriented, substantially amorphous, aromatic polyamide fiber containing a surfactant in an amount sufficient to enable the fiber to be dyed a deep shade, and whereby such fiber may be stabilized against progressive laundry srhinkage by a later routine processing step, by heating it in an aqueous dye bath, under pressure, at a low temperature of less than 130.degree. C., using conventional equipment, and wherein such stabilization is obtained, during this step, without requiring the use of a carrier,

• wherein the aromatic polyamide is poly(meta-phenylene isophthalamide) and
• wherein such a fiber contains from about 5 to 15%, by weight, of the surfactant.

An oriented, substantially amorphous, aromatic polyamide fiber containing a surfactant in an amount sufficient to enable the fiber to be dyed a deep shade, and whereby such fiber may be stabilized against progressive laundry shrinkage by a later routine processing step, by treating it with steam, under pressure, at a low temperature of less than 150.degree. C., using conventional equipment, and wherein such stabilization is obtained, during this step, in the absence of a carrier,

• wherein the aromatic polyamide is poly(meta-phenylene isophthalamide) and
• wherein such fiber contains from about 5 to 15%, by weight, of the surfactant.

In a process for making synthetic fibers which can be stabilized against progressive laundary shrinkage, which fibers are formed by extruding a solution of an aromatic polyamide polymer and a solvent through orifices in a spinneret to form amorphous fibers, which amorphous fibers are then moved into contact with an aqueous extraction bath to remove the solvent and during which such fibers become water-swollen, following which such water-swollen fibers are moved into contact with an aqueous solution containing a surfactant whereby such surfactant is imbibed into such water-swollen fibers, the improvement comprising:

• maintaining the water-swollen fibers in contact with the solution containing the sufactant until such surfactant is imbibed into such fibers in a high concentration amount and wherein a dye is imbibed into such amorphous fibers prior to imbibing the surfactant into the fibers,
• wherein the aromatic polyamide is poly(meta-phenylene isophthalamide) and
• wherein such fibers contain from about 5 to 15%, by wieght, of the surfactant.

An oriented, substantially amorphous, aromatic polyamide fiber containing from about 5 to 15% of a surfactant, by weight, whereby such fiber may be stabilized against progressive laundry shrinkage, in the absence of a carrier, by later routine processing steps, using conventional equipment.