Abstract: The invention relates to filaments and fibers spun from at least 98% by weight of polyacrylonitrile and relative viscosities of between 2.5 and 6.0 which have tensile strengths of more than 50 cN/tex with an elongation at break of at most 15% and a shrinkage at the boil of less than 5% and to a process for their production which comprises at least 2 stretching stages with a minimum stretching ratio of 1:9 as well as a concluding setting stage in which the filaments are treated without shrinkage in dry heat at 170.degree. to 280.degree. C.Such filaments and fibers are distinguished by an increased resistance to swelling and hydrolysis and they are particularly suitable for reinforcing organic and inorganic materials.

Abstract: The invention relates to continuous processes for preparing dimethylformamide-insoluble acrylic filaments and fibers which incur a weight loss of at most 20, preferably 15% on being heated up to 400.degree. C., by spinning appropriate polymer solutions, treating the filament bundles obtained before the first drying or heating stage in a continuous manner with an aqueous solution containing copper(I) ions, thermally fixing the copper content, and heating the bundles to 200.degree. to 350.degree. C.

Abstract: There is disclosed a melt-spun acrylonitrile polymer fiber of improved dye intensity and reduced shade change due to hot-wet processing.

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: The invention relates to a process for preparing wet- or dry-spun filaments and fibers of polymers which consist to more than 50% by weight of acrylonitrile units and which are continually treated with an aqueous solution containing copper(I) ions during the fiber production process but before a first heat treatment above 100.degree. C. and the copper content in the fibrous material is fixed by heating to above 60.degree. C., preferably to above 100.degree. C. The filaments and fibers thus obtained can be dyed with acid dyestuffs, have bactericidal properties, and can be subjected to accelerated pre-oxidation.

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: Dry-spun synthetic fibers and filaments having an individual as-spun denier of 3 dtex are obtained by dry spinning a viscosity-stable spinning solution with a draft of at least 20.

Abstract: A process for preparing fibers from acrylonitrile polymer via melt spinning is disclosed wherein a slurry of polymer, water and surfactant are evaporated to form a single phase homogeneous melt of less than about 25 weight percent water and in the range from about 12 to 20 percent.

Abstract: Ready-for-despatch filaments and fibres made of acrylonitrile polymers which contain at least 40% by weight of acrylonitrile units can be prepared from a spinning solution 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 content of the filaments is at most 40% by weight, relative to the solids content of the fibre,(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 fibre, and(d) before the stretch the filaments have no contact with any other extraction liquid for the spinning solvent.

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: An acrylic fiber produced by the dry-spinning process having, as characteristic properties, a tensile strength of 1.2-2.5 g/denier, a knot strength (g/denier)-knot elongation (%) product of 25 or less and a boiling water shrinkage rate of 5% or less. Said fiber can be obtained by dry-spinning a spinning solution of acrylonitrile type polymer containing 85% by weight or more of acrylonitrile, stretching the resulting fiber in hot water at a stretch ratio ranging from 1 to 2, subjecting the stretched fiber to a drying and relaxing to give the fiber a shrinkage of 10-40% and then stretching it at a stretch ratio of 1.2-2.3 at a temperature of 180.degree.-210.degree. C.

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: High-shrinkage stretch-broken tows of acrylonitrile polymers are obtained by fixing with saturated steam at maximum temperatures of 140.degree. C. after drawing and before stretch breaking and stretch breaking at a draft of at least 30%.

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: In order to conduct thoroughly pre-mixed hot gas into a ring spinning nozzle by a rotational flow in such a manner that sufficient quantities of hot gas are available for drying the filaments situated on the inside without causing backflow and without any significant movement of the filaments by turbulence, an annular chamber with tangential inlet is placed around the ring spinning nozzle. The internal wall of the chamber is separated from a circular chamber by equalizers in its upper region while on its underside it is separated from the spinning chamber by equalizers and metal gauzes at the level of the lower edge of the spinning nozzle. The circular chamber is also separated on its underside from the spinning chamber by equalizers and metal gauzes.

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: High-strength filaments of dry-spun polyacrylonitrile are obtained by a process in which tension-reduced spun filaments are continuously stretched hydrothermally in one or more stages: where it involves several stages, stretching is carried out at a temperature of the stretching medium gradually increasing from stage to stage up to .theta.=.theta..sub.n and, in the final (n-th) stage, to a degree of at least 50% of the maximum degree of stretching; where it is carried out in a single stage, stretching is carried out at the optimal stretching temperature .theta..sub.n, after which the material is further treated in the conventional way, optionally with fixing of the stretched material to a pre-determined extent.

Abstract: Dry-spun synthetic fibers and filaments having an individual as-spun denier of 3 dtex are obtained by dry-spinning a viscosity-stable spinning solution with a draft of at least 20.

Abstract: A process for improving the comfort of garments made from acrylonitrile polymer filaments by incorporating in the filaments, a polymer obtained by cross-linking a polyether with an isocyanate.

Abstract: Use of special pin insert in the counterbore-orifice combination of a conventional spinnerette plate provides open structure fibers.

Abstract: The invention relates to flame-retarding filaments and fibers and a process for the manufacture thereof. The filament-forming substance is a mixture of from 20 to 70 weight % of an acrylonitrile copolymer A containing at least 80 weight % of acrylonitrile units and from 0.3 to 20 weight % of other units copolymerizable with acrylonitrile, and from 80 to 30 weight % of an acrylonitrile copolymer B containing from 50 to 75 weight % of acrylonitrile units, from 25 to 45 weight % of vinyl chloride and/or vinylidene chloride units and from 0 to 5 weight % of other units copolymerizable with acrylonitrile.The filaments and fibers have a boil-off shrinkage of at least 20% and a knot strength of at least 10 cN/tex and are obtained by spinning the turbid solutions of the copolymer mixture, which however do not separate into components, in an aprotic solvent, and drawing of the filaments in a moderate ratio.

Abstract: Extrusion of a single phase melt of acrylonitrile polymer and water directly into a steam-pressurized solidification zone and stretching the nascent extrudate in at least three stages while it remains within the solidification zone provides fiber which is readily relaxed.

Abstract: The invention relates to a process for the production of hydrophilic filaments and fibres from a filament-forming synthetic polymer by a wet- or dry-spinning process which comprises introducing into the spinning solvent from 5 to 50% by weight of a substance with special properties defined herein and from 0.05 to 5% by weight of at least one surface-active compound as well as to hydrophilic filaments and fibres produced by such process.

Abstract: Use of a high tenacity acrylonitrile polymer fiber in a reinforced plastic composition based on a thermosetting resin produces high tensile impact at low fiber usage.

Abstract: Using a conventional spinneret plate with suitable pins inserted in the counterbore-orifice combination thereof, hollow fibers are provided.

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: Continuous film production from a high pressure feed stream is achieved in a system which provides methods and means for maintaining pressurized gas in an extrusion zone wherein the extrudate may be cooled to form a solid polymeric film. The product film is withdrawn from the extrusion zone continuously through a standing liquid column in fluid communication with the extrusion zone. The film is passed downwardly into a liquid leg below the extrusion zone and upwardly through the liquid column, which has an upper exit end elevated above the pressurized zone thereby exerting super-atmospheric pressure. The product is recovered from the liquid sealing medium, advantageously water, at ambient pressure. Hot aqueous solutions of polyacrylonitrile may be extruded at elevated pressure onto a cooled casting drum in a gaseous environment wherein flashing of the hot solvent is prevented.

Abstract: A spinnerette assembly wherein tapered passageways and distribution chambers of diminishing length are so arranged as to provide equal back pressure over all orifices thereby providing extrudates of improved uniformity of diameter after stretching.

Abstract: Orientation stretching of acrylonitrile polymer fiber spun from a polymer-water melt directly into a steam-pressurized solidification zone is more readily accomplished when hot, liquid water is used to wet the fiber being processed at or before the stretch rolls.

Abstract: A self-crimping, melt-spun acrylonitrile polymer fiber comprising as the continuous fiber matrix a first polymer comprising from about 80 to about 99 weight percent acrylonitrile and from about 1 to about 20 weight percent of one or more monomers copolymerizable with acrylonitrile and heterogeneously dispersed within said fiber matrix a second polymer incompatible with said first polymer.

Abstract: Incorporation of an N-vinylamide and polymerization initiator into a single phase fusion melt of a hydrophobic acrylonitrile polymer and water and polymerization of said monomer in situ provides a stable, transparent acrylonitrile polymer shaped article when said melt is extruded directly into a steam-pressurized solidification zone in which it is stretched, followed by drying under controlled conditions of temperature and humidity.

Abstract: A process for preparing an acrylonitrile polymer fiber is disclosed wherein melt-spun acrylonitrile polymer filaments are maintained in a stretchable state as spun, stretched in at least two stages while maintained in such stretchable stage, the first stage being at a stretch ratio of up to about 5 and the subsequent stretch being at a stretch ratio greater than that of said first to provide a total stretch ratio of at least about 25.

Abstract: A fiber tow bundle passing from a high pressure zone through the passageway of a sealing zone to a low pressure zone provides an effective pressure seal when liquid water under pressure diffuses through the surface of the passageway as the fiber tow bundle passes therethrough.

Abstract: Use of a vertically disposed compression zone for providing a fusion melt of acrylonitrile polymer and water in conjunction with melt spinning provides reduced bubble count in the resulting fiber.

Abstract: Terpolymers of acrylonitrile, a hydrophobic comonomer, and a hydrophilic acrylate ester provide meltspun acrylonitrile polymer fiber of improved dyeing characteristics.

Abstract: By blocking part of a spinnerette orifice with a wire strand desirable cross-sectional shaped fibers of acrylonitrile polymer are obtained.

Abstract: Method of preparing films of acrylonitrile polymer exhibiting very high tensile strength, stiffness, optical clarity, and outstanding gas barrier properties. Method entails extruding a hot, concentrated solution of said polymer in a solvent therefor that is water-soluble, e.g., dimethyl sulfoxide, onto a film-supporting surface, e.g., a flat surface, or a drum, which, preferably, has a low energy surface such as provided by wetting the surface with aqueous dimethyl sulfoxide, or coated with polytetrafluoroethylene, or other suitable means to thereby form a film. The resulting film is then contacted with an aqueous medium, e.g., water to remove the solvent (e.g., dimethyl sulfoxide) and partially replace it with water, this treatment being effected under conditions that will prevent the film from curling or puckering. The resulting film is composed essentially of acrylonitrile polymer and water, and is ignition resistant.

Abstract: The invention relates to a process for the production of hydrophilic filaments or fibres having a sheath/core structure, a porosity of at least 10% and a water retention capacity of at least 10% and having a fibre swelling factor which is lower than the water retention capacity. The process is carried out by spinning a solution of a fibre forming synthetic polymer, especially an acrylonitrile polymer by the dry jet wet-spinning method wherein immediately on leaving the spinning jet and prior to coagulation in the precipitation bath the filaments or fibres are contacted with steam or with the vapor of another liquid which coagulates the filaments.

Abstract: A spinnerette plate having multiple capillaries per counterbore can be effectively used to melt-spin fusion melts of acrylonitrile polymer and water without sticking together of individual filaments.

Abstract: A process for producing a synthetic rush-like structure which comprises causing an acrylonitrile polymer composition in a substantially melted state (Polymer A or B or C) to flow down towards a spinning orifice; adjusting the pressure of the system in which the melt just before the orifice is present to within a specific range; extruding the melt to form a foamed product; and subjecting the foamed extrudate to heat treatment, thereby obtaining a synthetic rush-like structure resembling the natural rush plant in outer skin structure and internal structure and having excellent sensory and practical properties.

Abstract: The invention relates to a process for the production of hydrophilic filaments and fibers from filament-forming synthetic polymers by spinning a solution which, in addition to a suitable solvent, contains from 5 to 50% by weight, based on the solvent and solids, of a substance which is essentially a non-solvent for the polymer, has a higher boiling point than the solvent used and is readily miscible with the spinning solvent and with a liquid suitable as a washing liquid for the filaments, and subsequently washing this substance out of the filaments, wherein a suspension is initially prepared at room temperature from the solvent, the polymer and the substance, the suspension thus prepared is subsequently heated, left for at least one minute and at most 15 minutes at a temperature of at least 30.degree. C. and of at most 60.degree. C.

Abstract: Acrylonitrile polymers containing at least 91% by weight acrylonitrile are spun from solutions having a polymer concentration of 38 to 75% by weight. Useful polymers have an intrinsic viscosity of 0.6 to 2.0, most preferably 0.9 to 1.1, 7 to 23 .mu.eq./g. enolizable groups after mild acid treatment, 15 to 70 .mu.eq./g. thioether ends derived from a water insoluble mercaptan and less than 3 .mu.eq./g. oxidizable hydrolysis fragments.

Abstract: A process for preparing acrylonitrile polymer plexifilamentary strands comprises dispersing in water 25 to 45% by weight of an acrylic polymer containing at least 91% by weight acrylonitrile units and up to 9% by weight of one or more copolymeric units and having an intrinsic viscosity of 0.6 to 2.0, 7 to 23 .mu.eq./g. enolizable groups after mild acid treatment, 15 to 70 .mu.eq./g. thioether ends derived from a water insoluble mercaptan and less than 3 .mu.eq./g. oxidizable hydrolysis fragments, heating the dispersion to a temperature of 200.degree. to 300.degree. C. while maintaining the dispersion under sufficient pressure to maintain the water in the liquid state, the time of heating not exceeding about 30 minutes, and promptly flash-extruding the dispersion through an orifice into a region of substantially lower temperature and pressure to form a continuous strand of filbrillated plexifilaments.

Abstract: The melt spinning of acrylonitrile polymer hydrates is improved when the polymer used contains at least 91% by weight acrylonitrile units and up to 9% by weight of one or more copolymeric units and has an intrinsic viscosity of 0.6-2, 7-23 .mu. eq./g. enolizable groups after mild acid treatment, 15-70 .mu. eq./g. thioether ends derived from a water insoluble mercaptan and less than 3 .mu. eq./g. oxidizable hydrolysis fragments.

Abstract: An acrylonitrile polymer composition containing ethylene carbonate and optionally small amounts of water is an effective purge material for start-up and shut-down of melt spinning operations employing hydrated acrylonitrile polymer melts.

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: Melt-spinning of a fusion melt of an acrylonitrile polymer and water through a crowded hole spinnerette plate having small orifice diameters is achieved using low molecular weight polymer to provide fiber of desirable physical properties.

Abstract: Fusion melts of acrylonitrile polymer and water are effectively melt-spun through spinnerettes of high capillary density without sticking together of the individual filaments.

Abstract: Acrylonitrile polymers having number average molecular weights in the range of about 6,000 up to about 15,750 provide fiber of desirable properties when melt-spun as a fusion melt with water.