Abstract: HMLS filaments consisting of a polyester, from 0.1 to 2.5% by weight of an incompatible, thermoplastic, amorphous, polymeric additive having a glass transition temperature of from 90 to 170° C. and a ratio of its melt viscosity to that of the polyester component of from 1:1 to 7:1, and from 0 to 5.0% by weight of conventional additives, where the polymeric additive is present in the filaments in the form of fibrils having a mean diameter of ≦80 nm. Process for the production of these HMLS filaments by static mixing with shearing of the polyester and of the polymeric additive and, optionally, of the additives, spinning of the mixture at a spinning take-off speed of from 2500 to 4000 m/min to give spun filaments which are stretched, heat-set and wound up, where the concentration of the polymeric additive is determined as a function of the pre-specified spinning take-off speed and the desired birefringence of the spun filaments.

Abstract: The invention relates to a spinning device in which liquid polymer is guided through a polymer line with a first heating jacket to a spinning pump with a second heating jacket. From said spinning pump, the polymer is transported through several lines to spinning packets and extruded through spinnerts to form filaments. The lines that are connected downstream of the spinning pump, the spinning packets and the spinnerets are located in at least one spinning housing through which heating fluid flows. There is a distance of 5 mm between the spinning housing through which the heating fluid flows and the first and second heating jackets and the spinning pump, to obtain thermal decoupling. According to a method for heating the spinning device, vaporous heating fluid is guided out of a first reservoir into the spinning housing, and heating fluid is guided out of a second reservoir into the first and/or second heating jacket.

Abstract: High strength polyester fibers comprising from 0.1 to 2.0 by weight of an incompatible, thermoplastic amorphous, polymeric additive.

Abstract: The invention provides a reheater door of a spinning device, which door is constructed so as to facilitate relatively easy access to the spinning nozzle plate as well as enable suction removal of vaporizable compounds and prevention of substantial cooling even when the door is open.

Abstract: A process for the improvement of the drawing ability of polyester, pellets of which are thermally post-treated in the solid phase in an inert atmosphere, containing a precise concentration of water vapor. The water vapor concentration is equal to the amount of water, plus 15%/minus 50%, which could theoretically be formed, at the polyester end viscosity, from the --COOH end groups and the excess --OH end groups of the polyester. An equimolar quantity of the vapor of the alkanediol, which serves as the diol reactant for the polyester, may be substituted for all or part of the water vapor.