Abstract: In the case of the method for the production of polyester granulate or molded articles from a melt which is discharged from a polycondensation (1), the melt in the discharge region (2) of the polycondensation is kept at a temperature between 270-285° C. in communication with a gas chamber at a reduced pressure in order according to the invention to achieve a low acetaldehyde content. With respect to the granulate, within the scope of the method according to the invention, a standard crystallization (5) and drying (6) with air as drying gas suffices. The molded articles can be produced directly from the melt, e.g. with an injection molding machine (9). The device according to the invention comprises a polycondensation, at least the last stage of which is configured as a disc reactor in which, with extensive avoidance of a sump, the melt is transported directly from disc to disc by a combination of rotating disc and static strippers fitted on the circumference of the reactor.

Abstract: Disclosed is a method of producing a non-adhering granulate above the glass-transition temperature comprising a polyester material, in which the polyester material is introduced into a cooling water flow as a melt and is separated from the cooling water after passing through a cooling stretch. The dwell time of the polyester material in the cooling stretch is 0.2-5 sec, and the cooling water has a pressure of at least 2 bar along the cooling stretch. For the thus obtained granulate, post-crystallization is not required, at least not in every case. It has been shown that the granulate does not adhere, even without post-crystallization and mechanical movement if no additional external input of energy takes place. Even during heating under pressure, no adhesion could be observed.

Abstract: In the case of the method for the production of polyester granulate or moulded articles from a melt which is discharged from a polycondensation (1), the melt in the discharge region (2) of the polycondensation is kept at a temperature between 270-285° C. in communication with a gas chamber at a reduced pressure in order according to the invention to achieve a low acetaldehyde content. With respect to the granulate, within the scope of the method according to the invention, a standard crystallisation (5) and drying (6) with air as drying gas suffices. The moulded articles can be produced directly from the melt, e.g. with an injection moulding machine (9). The device according to the invention comprises a polycondensation, at least the last stage of which is configured as a disc reactor in which, with extensive avoidance of a sump, the melt is transported directly from disc to disc by a combination of rotating disc and static strippers fitted on the circumference of the reactor.

Abstract: Disclosed is a method of producing a non-adhering granulate above the glass-transition temperature comprising a polyester material, in which the polyester material is introduced into a cooling water flow as a melt and is separated from the cooling water after passing through a cooling stretch. The dwell time of the polyester material in the cooling stretch is 0.2-5 sec, and the cooling water has a pressure of at least 2 bar along the cooling stretch. For the thus obtained granulate, post-crystallisation is not required, at least not in every case. It has been shown that the granulate does not adhere even without post-crystallisation and mechanical movement if no additional external input of energy takes place. Even during heating under pressure, no adhesion could be observed.

Abstract: The invention relates to a method for melt-spinning polyester microfilaments having a maximum dtex of 0.7 and to microfilaments that can be produced according to this method. According to the invention, the filaments, according to their titer, are spun from a melt with a solution viscosity lower than that of the prior art.

Abstract: A method for the production of melt-spun fibers comprising polyethylene terephthalate as a fiber-forming polymer, through polycondensation or melting of the fiber-forming polymer forming a melt and subsequently melt spinning, comprises mixing 0.1-4 wt %, relative to the fiber-forming polymer, of polymethyl methacrylate with the fiber-forming polymer before the melt spinning and dispersing the polymethyl methacrylate in the fiber-forming polymer to form unoriented melt fibers. During the melt spinning, the spinning speed of the fibers is set at up to 8000 m/min, whereby through the inclusion in the unoriented melt fibers, extruded from a sincerest, rod-shaped inclusions of the polymethyl methacrylate with a lateral particle size of less than 800 nm are obtained.

Abstract: The invention relates to fibers or filaments, consisting predominantly of polyethylene terephthalate as a fiber-forming polymer, that contain 0.1-4 wt %, relative to the fiber-forming polymer, of polymethyl methacrylate as another polymer, predominantly in the form of rod-shaped inclusions, whereby in the unoriented melt fibers under the spinneret, the mean lateral diameter of the rods is less than 800 nm and the polymethyl methacrylate has, a weight average molecular weight of between 20,000 and 200,000 g/mol, and whereby the spinning speed of the spun fibers in the production is up to 8000 m/min. Furthermore, the invention relates to a method for the production of these novel polyester fibers and filaments.

Abstract: The present invention pertains to a process for the production of a polyester multifilament yarn having at least 90 mol % ethylene terephthalate with a single filament titer of 1 to 20 dtex, using a central quenching system, characterized in that the method has the following steps: Extrusion of a polyethylene terephthalate polymer melt through a spinneret that has a number of capillaries between 150 and 1500, adjusting a spacer length between 5 and 150 mm, cooling of the obtained threads by means of a constant blown-air speed profile defined in the thread transit direction in that it initially rises very quickly in the region facing the spinneret, then reaches a maximum and subsequently drops off initially very quickly, then more slowly, with the average blown air speed in the vicinity of the threads being between 0.15 and 1.5 m/sec, in such a manner that the undrawn yarn produced from the process has a birefringence of between 0.050 and 0.

Abstract: A method for producing polyester bi-component threads on the basis of only one type of polyester is carded out by an "in line" modification of a partial stream with a co-monomer from the substance class of lactones, spinning of the unmodified and modified partial melt stream by means of a bi-component spinneret pack to form bi-component threads, and their further processing and use,

Abstract: A method for self-crimping of S/S bi-component fibers on a fiber line includes the steps of main drawing, post-drawing on a cold drawing unit, water application in the tensed state and relaxation at the dryer inlet in the compact closed state, which results in fibers with a novel .OMEGA.-shaped crimping structure.

Abstract: A process for producing bottle preforms from the melt of polyethylene terephthalate and/or its copolyesters, includes selectively introducing an inert gas into the continuous flow or partial flow of the polyester melt from a poly-condensation having an intrinsic viscosity between 0.5 and 0.75 dl/g, subsequently bringing the melt to an acetaldehyde content below 10 ppm in a melt after-condensation reactor and to an intrinsic viscosity of 0.75 to 0.95 dl/g and thereafter guiding the melt into an injection molding tool and processing same.

Abstract: A process for preparing linear copolyesters which contain omega-hydrocarboxylic acid units, from polyesters that contain at least 90 mol % polyethylene terephthalate units, as well as the usual amount of diethylene glycol units and possibly the known catalysts and stabilizers, includes adding to the already prepared polyester melt at least one compound of the group of lactones, optionally along with further additives but without additional catalysts in a system sealed off from gas exchange and at a higher pressure than the lactone vapor pressure in a proportion of up to 10 mol %, referred to the final melt, and mixed intensively with the melt. The resultant copolyesters, after a total dwell time of less than 30 minutes and a temperature in the range of 265.degree. to 310.degree. C.

Abstract: A process and an apparatus for the direct, continuous and flexible modification of polymer melts by branching off a branch melt stream from the main melt stream to be modified, dispersing the initially introduced additive in the melt in a specially designed twin-screw extruder, and subsequent recycling of the additive melt concentrate to the melt stream to be modified.

Abstract: A process and an apparatus for the direct, continuous and flexible modification of polymer melts by branching off a brand melt stream from the main melt stream to be modified, dispersing the initially introduced additive in the melt in a specially designed twin-screw extruder, and subsequent recycling of the additive melt concentrate to the melt stream to be modified.

Abstract: A method of spinning filaments from a melt which comprises flowing said melt through openings in a nozzle plate to form a stream of said filaments, directing a coolant radially outwardly from the center of said stream through a porous wall of a dispersing head provided with a downstream baffle adjusted to partially reduce the inside pressures of the coolant adjacent to the baffle to a value lower than the outside pressure, the resistance of said coolant caused by the wall porosity satisfying the relationship1.43.times.10.sup.6 m+2222 m.sup.2 =p=-96.96 m+20202 m.sup.2wherein m is the rate of flow of said coolant across the area of said porous wall in kg/h-cm.sup.2, and p is the pressure drop in Pa.

Abstract: An apparatus for spinning filaments from a melt has a nozzle plate with a plurality of passages through which the melt flows to form a stream of filaments, a downstream dispersing head in the stream in the form of a cylinder with its axis parallel to the stream of filaments and having an upstream end and a downstream end, a coolant source connected to the dispersing head having a porous wall parallel to the filament stream whereby coolant passes through the wall and impinges on the filaments and a baffle in the dispersing head to reduce the coolant pressure adjacent to the baffle, a resistance to the coolant flow satisfying a specific formula which avoids the prior art problems.