Abstract: Spinning of a melt of water and an acrylonitrile polymer containing hydrophobic moieties through a spinnerette into a steam-pressurized solidification zone results in improved fiber when the amount of water in the melt is in the lower half of the range necessary to provide the melt under the conditions of extrusion, the amount of hydrophilic moieties contained in the polymer are sufficient to control the rate of release of water from the extrudate, the steam conditions in the solidification are sufficient to prevent formation of a separate water phase, and drying of the resulting extrudate under conditions of temperature and humidity to remove water therefrom while avoiding formation of a separate water phase.

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 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 a method of manufacturing shaped articles from crystalline or quasi-crystalline acrylonitrile polymers and copolymers, said method consisting in cooling down a solution of said polymer or copolymer in a mixture containing from 50 to 99.5% by weight of a solvent and from 0.5 to 50% by weight of a precipitant to a temperature below the gelation point of the solution until the same gelatinizes, without changing its composition, to the desired shape, whereafter the solvent is removed from the shaped thermoreversible gel thus obtained at temperatures lower than the gelation point of the solution, preferably using a liquid precipitant of polyacrylonitrile miscible with the solvent. It is advantageous to remove the solvent at a temperature which is at least 10.degree. C. lower than the gelation temperature of the polymer solution used. The shaping can be carried out in any convenient way, e.g. using a stationary or rotating mold.

Abstract: An improved process for spinning flame-resistant acrylonitrile polymer fibers wherein 33-43% by weight (preferably 35-40% by weight) of a chlorinated acyclic hydrocarbon containing 60-73% (preferably 66-70%) by weight chlorine and 57-67% (preferably 60-65%) by weight of an acrylonitrile polymer having an intrinsic viscosity of 1.6-3 (preferably 1.8-2.2) is dissolved in a suitable solvent to form a solution containing 25-31% by weight solids which solution is extruded under conventional dry spinning conditions to give fibers which are extracted, drawn and dried. Optionally, the spinning solution also contains 0.5-6% (preferably about 3%) by weight antimony trioxide based on total solids.

Abstract: A process is disclosed for producing plexifilament strands from an organic, synthetic substantially water-insoluble polymer having a selected melting point, by flash-extruding a dispersion of the polymer in water under specified conditions. The plexifilament strands produced are useful in preparing fabrics.

Abstract: A single phase fusion melt of an acrylonitrile polymer and water is extruded into a steam-pressurized solidification zone maintained under conditions such that the continuous filament resulting retains sufficient plasticity so that stretching can be effected at a stretch ratio of at least about 25 relative to the linear speed of the single phase fusion melt through the spinnerette.

Abstract: The invention relates to a process for the production of filaments and fibres having a moisture absorption of at least 7% and a water retention capacity of at least 25% by dry-spinning an acrylonitrile copolymer, containing more than 50 mval of carboxyl groups from a solvent, which contains 5 to 50% by weight of a compound with properties defined herein, washing the compound added to the solvent out of the freshly spun filaments and fibres and partly or completely converting the carboxyl groups into the salt form. The invention further relates to dry-spun filaments and fibres having a core and sheath structure, comprising a fibre-forming acrylonitrile copolymer having more than 50 mval of carboxyl and carboxylate groups and having a moisture absorption capacity of at least 7% and a water retention capacity of at least 25%.

Abstract: The invention relates to dry-spun polyacrylonitrile filament yarns having a tensile strength of at least 47 cN/tex and an individual filament denier of at most 1.5 dtex and preferably an overall denier of 20 to 145 tex as well as to a process for the production thereof by spinning, hot drawing and relaxing, wherein the spun filaments are drawn during spinning to such an extent that, after subsequent hot drawing in a ratio of from 1:6 to 1:10 and relaxation, the individual filaments have a denier of at most 1.6 dtex.

Abstract: The invention relates to dry-spun acrylic fibers and filaments having deniers of from 20 to 80 dtex and a strength of at least 1.5 cN/dtex; as well as to a process for their production.

Abstract: The invention relates to a process for the production of crosslinked fibres or filaments by spinning an acrylonitrile copolymer containing at least 20 mVal of carboxyl groups per kg of polymer together with a polyoxazoline in a polar organic solvent and thereafter crosslinking at temperatures of from 120 to 190.degree. C.The invention also relates to crosslinked acrylonitrile fibres and filaments obtainable by this process.

Abstract: The invention relates to gloss-stable modacrylic fibres and filaments comprising 50 to 84% of acrylonitrile, 15 to 48% of vinylidene chloride and 2 to 5% of an olefinically unsaturated sulphonic acid or salt thereof, all percentages being by weight, having a shrinkage in boiling water of at most 0.3%, a reduction in density on treatment with boiling water of no more than 0.015 g/cc and a scattered light component after boiling of at most 35 units compared with a BaSO.sub.4 standard of 1000 units, the increase brought about by treatment with boiling water amounting to no more than 30 units as well as to a process for their production.

Abstract: The invention relates to a process for continuously removing residual solvent from filaments of dry-spun acrylonitrile polymers to values of below 2% by weight of solvent by a multi-stage hot-wash with low quantities of water.

Abstract: The invention relates to a process for the production of bifilar fibres and filaments consisting of only one acrylonitrile polymer. The polymer is dissolved in a usual solvent and the resulting solution is divided up into two solution streams. After these solution streams have been brought to different temperatures they are spun by a conventional bifilar spinning technique.

Abstract: The invention relates to highly shrinkable fibres or filaments of acrylonitrile polymers or copolymers which have a shrinkability of at least 35% and a fibre strength of at least 2 p/dtex.The invention relates further to a process for the production of these fibres or filaments.

Abstract: Substantially single-phase compositions which are substantially partial or complete hydrates of an acrylonitrile polymer containing at least 40% acrylonitrile units can be shaped into filaments and films. The nitrile groups of the polymer are hydrated to a selected extent depending on the particular polymer used. Hydration occurs only within a certain elevated temperature range and under at least autogenous pressure. Also disclosed are films and filaments having novel structural features which are spun from the substantially single-phase compositions comprising polymers or copolymers of 80% or more acrylonitrile. The filaments are characterized by a sheath which has a density gradient in which the density increases toward the surface and, after drawing, by a unique luster source ratio related to reflective interfaces. Many of the filaments have surface striations and an optically microvoided core. The filaments contribute good hand and good water absorption properties to fabrics made therefrom.

Abstract: This invention relates to a process for the production of dyed filaments or fibres of acrylonitrile polymers, wherein carbon black pigments are added to the polymer before the spinning process and the filament containing carbon black pigments are dyed. By this process it is possible to save considerable amounts of dye-stuff.

Abstract: A process for producing carbon fibers by heat-treating an acrylonitrile fiber, containing or impreganted with an aminosiloxane, at a temperature of at least 150.degree. C for 0.1 second to 30 minutes so that the fiber contains 20 to 80 weight % undissolved matter upon immersing it in a 60% aqueous solution of sodium thiocyanate at 80.degree. C for 20 minutes, and then carbonizing the fiber, whereby the productivity throughout the whole process, including the step of producing the precursor fiber and the step of producing the carbon fiber, is increased and a carbon fiber having high tensile strength and high modulus of elasticity is obtained in an industrially advantageous manner.

Abstract: High-shrinkage acrylonitrile polymer fibers that shrink with unusually high shrinkage force are prepared by a process in which as-spun, dry-spun filaments are extracted to remove solvent by passing the filaments continuously through aqueous baths at 63.degree. to 75.degree. C., drawn between 1.5X and 3.5X during passage through the baths, and cooled to a temperature below 50.degree. C. while free of tension. The filaments are further drawn 1.1X to 1.5X while passing continuously through at least one aqueous bath at 70.degree. to 80.degree. C. and are then dried at a temperature no higher than 60.degree. C. The filaments may be crimped at 55.degree. to 65.degree. C. in a stuffer box prior to drying. The filaments may be cut to staple fibers for use in pile fabrics; they are particularly useful in preparing artificial furs.

Abstract: Process for producing an acrylonitrile polymer in a substantially melted state by polymerizing a monomer mixture composed mainly of acrylonitrile in the presence of water under a pressure above the autogenous pressure at a temperature of from 80.degree. to 120.degree. C so as to attain a polymerization rate of at least 45%.

Abstract: The invention relates to a new method for manufacturing shaped articles from multi-block copolymers of acrylonitrile with acrylamide and/or acrylic acid, using hot pressure molding, preferably in swelled condition.

Abstract: An improved splice is provided which is useful in joining segments of a substantially flat band (e.g., a flat tow) of an acrylic fibrous material in an end to end relationship. A fabric surrounds and is sewn to an end of each band segment and extends beyond the end of the band to form a fabric extension. A pair of fabric extensions are sewn in an overlapping opposing relationship in the absence of any substantial overlap of the acrylic fibrous material of each band segment within the splice. The resulting splice is substantially flat in configuration and the band may be continuously passed in the direction of its length through the thermal stabilization zone without impairment of movement resulting from the presence of the splice. The usual exothermic heat of reaction which is evolved during the cyclization portion of the thermal stabilization reaction effectively is dissipated from within the splice without harm.

Abstract: Dry semipermeable membranes of polyacrylonitrile or copolymers containing more than 65 wt. % of acrylonitrile are prepared by dissolving the polymer in a solvent in a solids concentration of 15-30% by weight; uniformly coating the solution onto a surface in a desired shape under an atmosphere whose relative humidity is 60-85% and dipping said coated surface into a non-solvent medium so as to remove the solvent which forms the membrane; heat-treating the membrane under moist conditions at 60.degree.-90.degree. C; and drying the membrane at a temperature less than the temperature of the heat treatment under conditions such that the coefficient of contraction is less than 1%, whereby a dried semi-permeable membrane having an open-celled structure with a pore size of a diameter less than 0.5 .mu. and a porosity of 0.40-0.7 is obtained.

Abstract: The invention relates to a process for the production of spontaneously crimping composite fibres of acrylonitrile polymers wherein the dry-spun-filaments which still contain solvent are stretched to at least three times their original length in a bath of hot water which contains from 12 to 30 % by weight of dimethyl formamide. The stretching operation may be carried out in one or two stages.

Abstract: High-shrinkage acrylonitrile polymer fibers that shrink with unusually high shrinkage force are prepared by a process in which as-spun, dry-spun filaments are extracted to remove solvent by passing the filaments continuously through aqueous baths at 63.degree. to 75.degree. C., drawn between 1.5X and 3.5X during passage through the baths, and cooled to a temperature below 50.degree. C. If the filaments are cooled while free of tension, the filaments are further drawn 1.1X to 1.5X while passing continuously through at least one aqueous bath at 70.degree. to 80.degree. C. If the filaments are cooled under tension, the further drawing step is unnecessary. In either case the filaments are dried at a temperature no higher than 60.degree. C. The filaments may be crimped at 55.degree. to 65.degree. C. in a stuffer box prior to drying. The filaments may be cut to staple fibers for use in pile fabrics; they are particularly useful in preparing artificial furs.

Abstract: There is disclosed an improvement in the continuous melt extrusion of a refractory polymer and its melt assistant by which a porous plug of the composition being extruded is formed between the compressing zone and the melting zone of the extruder so as to prevent loss of vaporized melt assistant by backward escape through the feed inlet.

Abstract: Substantially single-phase compositions which are substantially partial or complete hydrates of an acrylonitrile polymer containing at least 40% acrylonitrile units can be shaped into filaments and films. The nitrile groups of the polymer are hydrated to a selected extent depending on the particular polymer used. Hydration occurs only within a certain elevated temperature range and under at least autogenous pressure. Also disclosed are films and filaments having novel structural features which are spun from the substantially single-phase compositions comprising polymers or copolymers of 80% or more acrylonitrile. The filaments are characterized by a sheath which has a density gradient in which the density increases toward the surface and, after drawing, by a unique luster source ratio related to reflective interfaces. Many of the filaments have surface striations and an optically microvoided core. The filaments contribute good hand and good water absorption properties to fabrics made therefrom.

Abstract: A naturally crimped polyacrylonitrile fiber having an asymmetrical cross section, the cross section having at least two large oblong lobes, the angle between at least two of these lobes being less than 90.degree., the fiber having an outer structure which has a relatively high density and has a variable thickness, this outer structure enclosing an inner structure which is porous and less dense than the outer structure.The process for producing crimped polyacrylonitrile fibers comprises spinning a solution of a polyacrylonitrile polymer into a cold bath at a temperature of less than 30.degree.C.

Abstract: The invention relates to a process for the production of polyacrylonitrile tows containing from 7 - 15 % by weight, preferably from 10 - 12 % by weight, of comonomer components from which it is possible to produce yarns having low boiling-induced shrinkage values and yarns and dimensionally stable made-up articles with improved textile properties which comprises reducing the tow-shrinkage emanating from the spinning and stretching process by 80 - 95 % of the original tow shrinkage by heat-fixing and eliminating subsequently the residual shrinkage by fixing with saturated steam.

Abstract: A method is provided for fabricating asymmetric acrylic hollow fibers for use in separatory processes as a selective membrane. The fibers are highly permeable and exhibit a high degree of selectivity in discriminating mixtures into their various components. The fibers are formed by extruding an acrylic polymer solution through an annular orifice while simultaneously injecting a coagulating fluid into the bore of the fiber extrudate as it is formed. The extrusion may be directly into a coagulating bath maintained at a temperature of from 60.degree. to 80.degree.C. or alternatively the freshly extruded fiber may be first passed through an air space (evaporation zone) and thence into the coagulating bath. Following coagulation, the fibers are water washed to remove residual solvent.

Abstract: Process for dyeing substantially undrawn dry-spun filaments of acrylonitrile polymer which comprises extracting spinning solvent from moistened dry-spun filaments of acrylonitrile polymer to below 10% by weight of the filaments and at below 80.degree.C., dyeing the extracted filaments in a dye bath at below 80.degree.C. by initially contacting the filaments with the dye at nearly zero stretch, followed by stretching the filaments from 1.5.times. to 4.5.times. at between 60.degree. - 80.degree.C. while still contacting the dye solution.

Abstract: fibers of a polymer containing at least 40% by weight of acrylonitrile units, at least 15% by weight of vinyl chloride units and at least 1% by weight of units of an ethylenically unsaturated sulfonate salt compound which have improved dye yield and luster stability are prepared by dry-spinning fibers of the polymer in an organic solvent and wash-drawing the fibers at a draw ratio of at least 2.2X in an aqueous bath maintained at an elevated temperature, thereby reducing the solvent content of the fiber to less than 3.5% by weight of the fiber. The wash-draw step may be carried out in one or more stages and preferably in at least two stages, the first of which involves a draw of 1.15-1.5X at 40.degree.-60.degree. C. Drying is preferably carried out by subjecting relatively wet fibers (80% moisture) to a high temperature (about 150.degree. C).