Abstract: Producer-colored nylon fibers which are stain-resistant to acid dyes are made by adding pigment to nylon copolymers containing 0.25-4.0 percent by weight of an aromatic sulfonate or an alkali metal salt thereof. In addition process advantages relating to the use of the same copolymers in making pigmented nylon fibers are also disclosed.

Abstract: Described is cobulked continuous filament yarn containing a first yarn and a second yarn having some special quality such as an electrically conductive yarn, a flame-retardant yarn, a yarn having soil release properties or a yarn having some aesthetic quality such as an unusual dye characteristic or unusual luster characteristic, in which the filaments of the second yarn are about 4 to about 20 percent longer than the filaments of the first yarn, whereby the effect of the second yarn is increased by an increase in the appearance of its filaments at the surface of the cobulked yarn.

Abstract: A cohesive yarn having latent twist, which is recoverable by relaxation of the yarn in heat and moisture, is composed of crimped and entangled continuous thermoplastic filaments. It provides good tuft definition and a lustrous appearance in pile fabric. Production of the yarn by hot jet-entangling crimped filaments throughout the length of a yarn bundle and heat-setting latent twist in the yarn bundle while false-twisted with an air-torque jet is illustrated.