Abstract: This invention provides yarns of randomly crimped filaments which are associated together into a substantially cylindrical yarn. The filaments are made by extruding two different synthetic organic polymers simultaneously through the same elongated orifice and the polymers are fed to different orifices in different proportions or at different angles with respect to the axes of the orifices so that in some of the filaments the interface between the two polymer layers is along or parallel to the smaller axis of the cross-section thereof while the interface of other filaments is along or parallel to the larger axis.

Abstract: Bicomponent polyester filaments are disclosed, wherein the filaments are made of at least two different, substantially unmixed components, each present in an amount of at least 20% by weight of the total filament, one component being polyethylene terephthalate and the other component being polybutylene terephthalate which has been sparingly crosslinked with trimethylolpropane.The bicomponent polyester filaments of the present invention have excellent physical properties and especially improved permanency of crimping. The filaments may be used to manufacture woven and knit materials, and are especially useful in the manufacture of hosiery, wherein the resulting hosiery articles have excellent wear properties.