Abstract: The invention relates to a thread with a proportion of a basic-dyeable, texturized polyester filament which contains a metal sulphonate containing the structural unit ##STR1## where M is equal to Na or K and a compound A containing structural units --(CH.sub.2).sub.y -- and/or --O--(C.sub.x.sbsb.1 H.sub.2x.sbsb.1 O).sub.y.sbsb.1 -- where x.sub.1 .gtoreq.2, y.gtoreq.20 and x.sub.1 y.sub.1 .gtoreq.20.The basic-dyeable polyester filament contains 1.0 to 5.0 mol % of metal sulphonate units and between 0.5 and 12% by weight of compound A.

Abstract: The invention is directed to filament yarns made from synthetic polymers and having false-twist texture, comprising a core filament group and a sheath filament group wrapped around and partially covering the core. The sheath filament group comprises at least two filament groups 4 and 5 with different cross-sections, the smaller component of the sheath filament group including fibrils with the coarsest denier, and the larger component of the sheath filament group containing fibrils with the finer fibril denier, the finer fibrils in the filament group having a lesser fibril denier than the fibrils 3 of the core group 1.