Abstract: The preparation of dimethyl carbonate by reaction of methanol, carbon monoxide and oxygen in the presence of Cu compounds is carried out in distillation units and the water of reaction is removed at least partially from the stripping region or the bottom phase.

Abstract: Glass fibres which are distinguished by their greatly reduced carcinogenicity have an average fibre diameter of <8 .mu.m, preferably <3 .mu.m, with more than 10% of the fibres having a diameter of <3 .mu.m. The types of glass used for producing these fibres are characterized by containing the following compounds in the proportions shown in mol %:______________________________________ SiO.sub.2 55-70 B.sub.2 O.sub.3 0-4 Al.sub.2 O.sub.3 0-1 TiO.sub.2 0-6 Iron oxides 0-2 MgO 0-5 CaO 12-20 Na.sub.2 O 10-20 K.sub.2 O 0-5 fluoride 0-2.

Abstract: The invention relates to a process for the production of low-gel spinning solutions-surprisingly stable in their solution viscosity-of segmented polyurethane urea elastomers in highly polar solvents, such as dimethyl formamide or dimethyl acetamide, characterized by the use of multistage jet reactor, and to a multistage jet reactor.

Abstract: A process and device for manufacturing ultrafine fibers and ultrafine-fibre mats from thermoplastic polymers with mean fibre diameters of 0,2-15 .mu.m, preferably 0,5-10 .mu.m, by a melt blowing technique. The polymer melt (12) flows through at least one bore (15) in a melt blowing nozzle (18). Immediately on emerging from the bore, gas is blown against the extrusion from both sides of the bore exit (15), thus breaking up the melt to form fibers. To this end, the gas is accelerated to supersonic speed in Laval nozzles (25, 26; 31, 32), disposed in mirror symmetry round the bore exits (15), and decelerated to just below the speed of sound in channels (27) with constant cross-section, or a cross-section which decreases in the direction of flow, fitted downstream of the Laval nozzles, and the melt (12) fed into the gas stream emerging from the channels (27).

Abstract: This invention relates to processes for the production of mono- and multifilaments and also staple fibers of multifilaments based on polyarylene sulfides, preferably substantially linear polyarylene sulfides and, more preferably, substantially linear poly-p-phenylene sulfide by melt spinning, multistage stretching and optionally crimping and setting.As a result of the treatment by blowing of air onto the stabilized spun filaments in the first stretching stages at temperatures .ltoreq.100.degree. C. (preferably in stretching baths, more particularly in boiling water), the chain molecules are oriented; the orientation and crystallinity required for high strengths is achieved by afterstretching (in hot air) at elevated temperature.

Abstract: Fibres, fibre webs or fibre aggregates made of polyphenylene sulphide (PPS) or of mixtures of PPS with other polymers are produced by a melt-spinning process where the melt filaments are drawn out and cooled down to below the melt temperature by a gaseous medium flowing essentially parallel thereto at sonic or supersonic speed, this simultaneous deformation and cooling giving rise to amorphous fine or extremely fine fibres (17) of finite length which are deposited to form a fibre web or fibre aggregate.

Abstract: Processes for the production of mono- and multifilaments and also staple fibers of multifilaments based on polyarylene sulfides by melt spinning, multistage stretching and setting. As a result of the treatment by blowing of air onto the stabilized spun filaments in the first stretching stages at temperatures .ltoreq.100.degree. C., the chain molecules are oriented; the orientation and crystallinity required for high strengths is achieved by afterstretching at elevated temperature. The residence times in the first stage required for effective stretching can only be varied within relatively narrow limits in order subsequently to achieve the calculated orientations and effects. Overly long residence times at temperatures above 100.degree. C. result in elongation of the material with no additional orientation and hence with an inadequate increase in strength.

Abstract: The polymer granular melt (1) is whirled out of a rotating nozzle head (6) through a plurality of exit holes (24) with fibre formation (32) and the fibres formed (9) are deposited on a collecting surface (12) in web form (15). This polymer melt is introduced into the nozzle head (6) under a preliminary pressure of 1 bar to 200 bar, preferably 1 bar to 50 bar. Furthermore, the fibres (32) are deflected by a high-speed gas stream (7, 8) in a radial direction at a radial distance of 10 mm to 200 mm from the exit holes (24) and, in the course of being deflected, are simultaneously drawn and stretched. The melt streams (32) exiting from the exit holes (24) can be additionally drawn by gas streams (26, 34) exiting in the vicinity of the exit holes (24) at the nozzle head (6) with a predominantly radial component before coming under the influence of the axial deflecting gas stream (7, 8).

Abstract: A compressing chamber (7) for directed crimping consists of step-shaped bars (8) by way of increasing outwards in length.

Abstract: For the purpose of conveying slivers the latter are fed over constructional units (15) which are situated behind each other in a staggered maner from injector (8), in a pipe (16) including a guide means (17) by means of an air supply, and subsequently carried further by mechanical means.

Abstract: Filament cables are crimped and the crimp cake of the filament cable obtained is passed over a gas permeable screen plate while gas flows to the bottom of the cake from flow through the screen plate so that the cake can be moved over the plate without making contact therewith or with reduced contact force and can be treated during its residence over the screen plate.

Abstract: The streams of melt issuing from the melt outlet apertures (18) at the bottom of a melting crucible (14) are broken up into fibers in a drawing nozzle by means of a blast medium directed substantially parallel to the streams of melt. The blast medium is produced by a pressure gradient in the drawing nozzle and sucked in at the drawing nozzle inlet (7). In the drawing nozzle (16), the flow velocity is reduced in a downstream diffuser after the drawing process. The blast medium is supplied in the form of a hot gas between the underside of the crucible and the top edge (15) of the drawing nozzle from opposite broadsides of the melt distributor (14) in excess to the total quantity of gas stream sucked in at the drawing nozzle inlet (7). The hot gas consists of a mixture of combustion gases and air and is at a temperature from 600.degree. C. to 1500.degree. C., preferably from 800.degree. C. to 1400.degree. C.

Abstract: A method for sealing a passage (2) in a wall (3) for the unsupported transport of continuously accumulating tows (1), in which the pressure difference on both sides of the wall (3) is compensated by an additional gaseous medium (5).

Abstract: The conditioning of synthetic fiber material to produce perfect products with a low residual solvent content using comparatively small quantities of steam is carried out in a steam-tight conditioning apparatus consisting of several zones with a rotating perforated belt, using steam which has been superheated to temperatures of from 105.degree. to 150.degree. C., and the material having a residence time in the apparatus of more than 3 minutes.

Abstract: The treatment of a filament cable in a device into which it is introduced, in which it is crimped, treated with a gas, and withdrawn, characterized by the fact that the cable is crimped using a crimping device which is operated gas-dynamically, which has been mounted into the front face of a device for the treatment of the cable with a gas, and is thus introduced into this device in the manner of a sluice, and is folded using a slide with an S-shaped section onto a gas-permeable, horizontally transporting base as a crimping cake, is treated there with the gas, and is finally withdrawn from the device.

Abstract: The conditioning of synthetic fiber material to produce perfect products with a low residual solvent content using comparatively small quantities of steam is carried out in a steam-tight conditioning apparatus consisting of several zones with a rotating perforated belt, using steam which has been superheated to temperatures of from 105.degree. to 150.degree. C., and the material having a residence time in the apparatus of more than 3 minutes.

Abstract: An improved method for the after-treatment of washed and dried fibre cable having a minimum mass of 250 ktex by crimping, fixing, cooling and optionally cutting or tearing is achieved in that the band width of the cable issuing from the drier with a covering density of at most 5 ktex/cm is reduced by at least 50% of the original band width with a corresponding increase in the packing density, is crimped in a stuffer box crimping means at a stuffer box pressure of from 4 to 10 N/cm and a stuffer box temperature of from 80.degree. to 95.degree. C., the crimping is fixed in or immediately after the stuffer box, the cable is deposited on the surface of an air-permeable conveyor belt, air is blown or sucked there through fibre package or conveyor belt and the cable is then optionally supplied to a tearing converter or a cutting machine.

Abstract: A fluid which flows through a distributing pipe and is distributed into several outlets branching from the distributing pipe may be displaced more rapidly by another fluid, for example when changing the color of spinning solutions, if the entire layer of fluid adjacent to the wall and located upstream of a chosen outlet is caused to flow out through this outlet.

Abstract: Filaments of a molten material issue from a plurality of openings in a heated melt crucible and are further fiberized in a draw nozzle by means of a blowing medium. The diameter of the outlet openings (3) at the base of the melt crucible (1) is very small and is 0.2 to 1.5 mm, so that very fine primary filaments (12) are already formed at this point. These primary filaments are grasped by a very turbulent current at the entrance of the draw nozzle (5). The transverse component of the current decreasing in favor of the longitudinal component as the axial distance from the outlet openings (3) increases. The draw nozzle also has an inlet portion, which has a sharp outer edge and widens in the direction of flow, so that air blows against the primary filaments at a high speed and they are exposed to a strong pressure gradient in the longitudinal direction before entering the inlet portion.

Abstract: Polyacrylonitrile filaments and fibers may be obtained without interruption by spinning the spinning solution into a hot-air spinning duct, washing, drawing, crimping, preparing, steaming, drying cooling and, optionally, cutting at a take-off rate kept at 150 to 400 m/minute and for a tow weight of from 10 to 100 g/m when(a) the washing process is carried out in several stages on the countercurrent principle and a vibrating duct is used for transporting the spun tow through the washing process,(b) drawing is carried out before and/or after washing in a steam atmosphere at 100.degree. to 120.degree. C.,(c) crimping is carried out in an aerodynamic crimping unit using a hot, gaseous medium under a pressure of from 5 to 16 bars and at a temperature in the range from 50.degree. to 210.degree. C.