PROCESS FOR PRODUCING SHEATH-CORE STAPLE FIBERS WITH A THREE-DIMENSIONAL CRIMP AND A CORRESPONDING SHEATH-CORE STAPLE FIBER

摘要

The invention relates to a process for producing sheath-core staple fibers with a three-dimensional crimp and to a sheath-core staple fiber of this type. In this case, the fiber is extruded with a symmetrical sheath-core arrangement consisting of two different polymer melts with a first polymer component for the core and with a second polymer component for the sheath. In order to generate an as far as possible intensive three-dimensional crimp in the fiber, the cooling of the fiber takes place by means of a sharp cooling air stream with a blowing air velocity of at least 3 m/sec., after the combining of the fibers into a tow the multistage treatment in a fiber line taking place under a maximum temperature load which lies below the glass transition temperature of the second polymer component in the sheath of the fiber. A high degree of three-dimensional crimping can consequently be achieved after the multistage treatment and before the cutting of the fiber.