Abstract: A process for dry spinning of synthetic polymers, in particular PAN threads containing more than 85 wt. % acrylonitrile in the PAN (co)polymer, with high spinning chimney capacities of at least 20 kg PAN solid per spinning chimney and hour, using superheated steam as the spinning gas and with in-chimney finishing with water or aqueous finishes.

Abstract: A process for the production of crimped filaments and fibers of acrylonitrile polymers of copolymers containing at least 40% by weight acrylonitrile units, by dry spinning from highly polar solvents, where the filaments are brought to extremely low solvent contents in the actual spinning tube by a minimum of superheated steam prepared in the absence of water at very high spinning tube temperatures and spinning gas temperatures, but are cooled to low filament temperatures in the spinning tube by application of water or aqueous finishes in a quantity equivalent to more than 10% by weight moisture. In this way, spun PAN filaments of good natural color are safely obtained, in which there is no washing stage and no drying stage. Acrylic fibers and filaments combining a vacuolestable structure with a very high degree of whiteness and gloss are thus obtained with densities of at least 1.180 g/cm.sup.3, giving shrinkage-free to high-shrinkage fibers, depending on the aftertreatment applied.

Abstract: A process for the dry spinning of synthetic polymers, in particular polyacylonitrile fibres, from solutions in high polar solvents, such as dimethylformamide, which are heated to 100.degree.-150.degree. C. shortly upstream of the spinneret and spun there by spinnerets having a certain shape, and in the spinning cell the specific energy supply is at least 0.090 kWh per m.sup.2 of heated cell area, the cell is charged with at least 70 m.sup.3 (S.T.P.) of hot air per hour, and the filaments are treated in the lower part of the cell with water or aqueous preparations, so that the temperature of the filaments which leave the cell is decreased below 110.degree. C. Under these conditions, the unexpectedly high spinning cell outputs of at least 20 kg of PAN solid per spinning cell per hour can be achieved without yellowing or self-ignition of the filaments occurring.

Abstract: In an improved crimping process, use is made of a stufferbox where(a) lid and/or floor are arranged movably and(b) in the working position, the distance between lid and floor at the inlet opening is smaller than the distance between lid and floor at the outlet opening.

Abstract: Thread bundles which are transported from top to bottom, can be wetted with liquids by means of a device consisting of a system releasing the liquid, conduits and a storage container as well as suitable transporting means for the liquid, whereby the system releasing the liquid has at least two slotted nozzles positioned one above the other and opposite each other, having a horizontal slot and whereby rods are attached at the slot ends which, seen from above, form an angle with the slot of from 100 to 170.degree., preferably from 115 to 160.degree..

Abstract: A process for the production of acrylonitrile fibers and filaments having a precise cross-sectional profile in which filament-forming synthetic polymers are dry-spun from a solution having a viscosity of at least 120 falling bass seconds, measured at 80.degree. C., or a viscosity of at least 75 falling ball seconds, measured at 100.degree. C. Such solution is dry-spun through one or more nozzles. The nozzle hole are of the profile nozzles being less than 0.2 mm.sup.2 and the lateral width being less than 0.17 mm.

Abstract: Threads, films or thread bundles which are transported from top to bottom, can be wetted with liquids by means of a device consisting of a system releasing the liquid, conduits and a storage container as well as suitable transporting means for the liquid, whereby the system releasing the liquid has at least two slotted nozzles positioned one above the other and opposite each other, having a horizontal slot and whereby rods are attached at the slot ends which, seen from above, form an angle with the slot of from 100.degree. to 170.degree., preferably from 115.degree. to 160.degree..

Abstract: Ready-for-dispatch highly shrinkable filaments and fibers made of acrylonitrile copolymers can be prepared in a continuous dry-spinning method in which:(a) the spinning solution spun has a viscosity at 100.degree. C. of 10 to 60 falling-ball seconds,(b) the evaporation of the solvent in the spinning cell is controlled in such a way that on leaving the spinning cell the solvent contact of the filaments is at most 10% by weight, relative to the solids content of the fiber,(c) before the stretch the filaments are treated with a spin-finish which contains a lubricant and an antistat and gives the filaments a moisture content of at most 10% by weight, relative to the solids content of the fiber, and(d) before or during the stretch the filaments have no contact with any other extraction liquid for the spinning solvent.

Abstract: Polyacrylonitrile filaments having a residual solvent content of less than 5% by weight and a total linear density of over 100,000 dtex can be prepared without contact with an extracting agent for the spinning solvent by a process in which(a) the spinning solution spun has a viscosity at 100.degree. C. of 10 to 60 falling-ball seconds,(b) the filaments are treated while still hot, directly at the end of the spinning cell, inside it or immediately outside the end of the cell, with a spin-finish which contains a lubricant and an antistat and which gives the filaments a moisture content of at most 10% by weight, relative to the solids content of the fibre, and(c) the filaments are immediately exposed to a heat treatment without cooling down first.

Abstract: Hollow acrylonitrile fibres and filaments are prepared by dry spinning the spinning dope through a nozzle having loop-shaped nozzle orifices, the solution having a viscosity equivalent to at least 120 falling ball seconds, measured at 80.degree. C., or at least 75 falling ball seconds, measured at 100.degree. C., wherein the nozzle orifice area of the profiling nozzle is smaller than 0.2 mm.sup.2 and the maximum width of the sides of the loop-shaped nozzle is 0.1 mm and the overlap between the two ends of the sides of the loop-shaped nozzle forms an angle of from 10.degree. to 30.degree. measured from the center of the nozzle and wherein the spinning air acts on the filaments in a transverse direction to the filament take-off and the air direction forms an angle of from 80.degree. to 100.degree. with a straight line passing through the opening between the sides.

Abstract: Hollow acrylonitrile fibres and filaments are prepared by dry spinning the spinning dope through a nozzle having loop-shaped nozzle orifices, the solution having a viscosity equivalent to at least 120 falling ball seconds, measured at 80.degree. C., or at least 75 falling ball seconds, measured at 100.degree. C., wherein the nozzle orifice area of the profiling nozzle is smaller than 0.2 mm.sup.2 and the maximum width of the sides of the loop-shaped nozzle is 0.1 mm and the overlap between the two ends of the sides of the loop-shaped nozzle forms an angle of from 10.degree. to 30.degree. measured from the center of the nozzle and wherein the spinning air acts on the filaments in a transverse direction to the filament take-off and the air direction forms an angle of from 80.degree. to 100.degree. with a straight line passing through the opening between the sides.

Abstract: Hygroscopic filaments or fibers with a core-jacket structure of hydrophobic, filament-forming synthetic polymers having a water retention capacity of at least 10% and having uniform round to oval cross-sectional profiles are obtained by a dry-spinning process which comprises addition of a substance to the spinning solvent which(a) has a higher boiling point than the spinning solvent used,(b) is readily miscible with the spinning solvent and with water,(c) is a non-solvent for the polymer to be spun,and addition of another substance which(a) is soluble in the non-solvent for the polymer to be spun,(b) is soluble in the solvent for the polymer(c) remains dissolved in the non-solvent for the polymer during solidification of the filaments,(d) is insoluble in water, and(e) does not evaporate to any significant extent during the spinning process,to the system in quantities of at least 1% by weight, based on polymer solids/spinning solvent/non-solvent carrying out the spinning process in such a way that the non-solv

Abstract: Hollow polyacrylonitrile fibers having a uniform closed cavity structure are obtained by dry-spinning filament-forming acrylonitrile polymers from a solution through a spinning jet comprising annular jet bores of the type shown in FIG. 1, the solution having a viscosity of at least 120 falling-ball seconds, as measured at 80.degree. C. or of at least 75 falling-ball seconds, as measured at 100.degree. C., the ring of the annular jet bores consisting of three, preferably equally large, ring segments at a distance from one another of at most 0.2 mm, the surface area of the jet bores of the profile jet amounting to less than 0.2 mm.sup.2 and the side width of the ring segments amounting to at most 0.1 mm, the spinning air acting on the filaments transversely of the direction in which they are taken off relative to the center of the spinning jet.

Abstract: The invention relates to a process for the continuous production of synthetic non-discolored filaments and fibers from a filament forming synthetic polymer being difficultly soluble in an organic polar solvent particularly polyacrylonitrile polymers which process comprises preparing a suspension of said polymer and said solvent at room temperature and subsequently heating the suspension thus formed for at least 3 minutes to at least 130.degree. C., and filtering the clear spinning solution formed without intermediate cooling, homogenizing and spinning it immediately afterwards into filaments.

Abstract: The invention relates to hygroscopic filaments and fibres of synthetic high polymers. The improved hygroscopicity compared with known synthetic fibres is due to the fact, that in a conventional dry-spun process a liquid is added to the spinning solvent which liquid has a higher boiling point than the spinning solvent used, which liquid is readily miscible both with the spinning solvent and water and which represents a non-solvent for the polymer to be spun.

Abstract: The invention relates to dry-spun hydrophilic core-jacket filaments or fibres of a hydrophobic filament forming synthetic polymer. The filaments or fibres having a porosity of at least 50%, a water-retention capacity of at least 100% and a mercury density of at most 0.7 g/cm.sup.3. The invention also relates to a process for the production of these fibres and filaments.

Abstract: The invention relates to a process for the production of hygroscopic filaments or fibers by dry-spinning a polymer solution wherein immediately they issue from the spinning jet or at the latest at a time when their solidification is still not complete, the filaments are brought into contact with water-vapour or with the vapour of another liquid which coagulates filaments.

Abstract: The invention relates to a process for the production of hydrophilic filaments and fibers which comprises wet- or dry-spinning a fibre-forming synthetic polymer from a spinning solvent containing from 5 to 50% of a substance which has a higher melting or boiling point than the spinning solvent which is miscible with the spinning solvent and with a liquid suitable for use as a washing liquid and which is a non-solvent for the polymer to be spun and from 0,1 to 20% by weight of at least one substance which decomposes into a gas under heating.

Abstract: The invention relates to hydrophilic fibers and filaments with good coloring response to dyes from filament-forming hydrophobic synthetic polymers having a sheath-core structure with a highly microporous core and a substantially compact sheath and having a water retention capacity of at least 10% wherein the pores in the core have an average pore diameter measured in the direction of the cross-section of the fiber, of at most 4000 A. The invention relates also to a process for the production of those filaments and fibers according to a dry-spinning process wherein a spinning solution is spun below the boiling point of the spinning solvent used.

Abstract: The wearing comfort of textiles produced from synthetic fibers which are normally hydrophobic, e.g., polyacrylonitrile, is improved by modifications in the spinning process whereby hygroscopic fibers having a sheath/core structure and a microporous core are obtained, which fibers are capable of absorbing considerably more water than conventionally dry spun fibers of the same synthetic polymer not having a sheath/core structure. Several suitable dry spinning processes for producing the improved fibers are disclosed.