1,034,401. Melt-spinning. SNIA VISCOSA SOC. NAZIONALE INDUSTRIA APPLICAZIONI VISCOSA S.p.A. April 13, 1964 [April 17, 1963], No. 15110/64. Heading B5B. Filaments of linear synthetic polymers are melt-extruded into a gaseous enclosure containing steam at 30‹-200‹ C., forwarded in such a way that they are in contact with the steam for at least 1 second, e.g. 1 to 6 seconds, then passed through a heated space in which every part of the yarn remains for at least 1 second, e.g. 1 to 6 seconds, and finally stretched. The steam treatment may be carried out in presence of air. the proportions of steam and air being such that the air has a relative moisture of at least 85%. The heated space may be a tubular passageway maintained at 20-95‹ C., and the stretching may be effected in one or more stages to a total draw ratio of 1: 4-5. Specified polymers are polyesters, e.g. polyethylene terephthalate, and nylons, e.g. polycaproamide. In one embodiment (not shown) filaments 18 extruded from spinneret 10 into an enclosure 11 are treated with a mixture of air (from fan 14) and steam (from perforated pipe 13) passing through perforated wall 17. The steam-treated filaments are then passed through tube 19 heated by jacket 20, stretched in two stages by pairs of skew cylinders 21, 22, 23 and wound up at 26. The yarns may have a tenacity of 5-9 g./den.