Abstract: Hollow fibers, particularly useful as semipermeable membranes in separatory devices such as blood dialyzers, having a non-uniform cross-sectional area along the length thereof. The fibers have recurring points of maximum outside diameter and minimum outside diameter and such points may recur on a regular basis or at random. Fiber wall thicknesses may be substantially uniform or non-uniform. Methods and apparatus for making the fibers are disclosed.

Abstract: An ink reservoir element for use in a marking instrument is disclosed, which combines good ink holding capacity and good ink release properties with a wide variety of inks. The ink reservoir element is formed from a coherent sheet of flexible thermoplastic fibrous material, such as a spunbonded polyester fabric or a foam-attenuated extruded polyester fabric, which has been uniformly embossed with a series of parallel grooves. The embossed sheet is compacted and bonded into a dimensionally stable rod-shaped body whose longitudinal axis extends parallel to the embossed grooves. A method and apparatus is disclosed for continuous production of the ink reservoir elements from a continuous web of the fibrous sheet material.

Abstract: A semipermeable membrane made of a polyaryl ether sulfone comprised of recurring units represented by the general formula (I): ##STR1## wherein X, X', X" and X"' are non-dissociative substituents, and l, m, n and o are integers of from 0 to 4. The membrane, which is composed of a single continuous polymer phase, has pores of a diameter increasing progressively and continuously from the surface layers to the center portion thereof.The membrane is prepared by the process wherein:the polyaryl ether sulfone is dissolved in a mixed solution to form a dope of the polyaryl ether sulfone;the polyaryl ether sulfone dope is extruded to form a fiber or film and, then;both sides of the fiber or film are contacted with a liquid miscible with the mixed solvent but incapable of dissolving the polyaryl ether sulfone to remove substantially all the mixed solvent from the fiber or film.

Abstract: A method of manufacturing a hollow fiber in which a spinning solution of cellulose ester dissolved into an organic solvent is extruded from an annular slit, and simultaneously a core liquid is introduced into the inside hollow portion of the extruded spinning solution, the core liquid being selected from the group of hydroxycarboxylic acid, derivative of hydroxycarboxylic acid, monoterpene or these mixture, or consisting of a solution of the above-described compound or mixture.

Abstract: Tri- or tetra-locular oriented polymeric paintbrush bristles.

Abstract: Permselective membranes are provided consisting of lactam-polyol-polyacyl lactam block terpolymers having from 35 to 75% by weight polylactam blocks and 25 to 65% by weight polyalkylene ether blocks. The membranes are particularly suitable as blood dialysis membranes having improved permeability to solutes in the medium range of molecular weights while maintaining acceptable ultrafiltration rates and permeability to low molecular weight solutes. The membranes are provided both as planar films and hollow fibers, have high hydrolytic stability under hot wet sterilization conditions and good mechanical properties under hemodialysis conditions.

Abstract: This invention relates to a novel product, fibrils of crosslinked polyester resin having a vesiculated structure, and to a process of making them.Vesiculated fibrils of crosslinked polyester resin of length 50 .mu.m-5 cm, diameter 1 .mu.m-2 mm and aspect ratio of 10-50 are prepared by pouring into water with stirring a selected solution in unsaturated monomer of a carboxylated unsaturated polyester resin of acid value 10-90 mg KOH per g., the water containing both a base having a pK.sub.b value of 8 maximum and a dispersion stabilizer, and initiating polymerization. The polyester solution is selected for suitability for fibril formation by means of a buoyancy test.The fibrils are useful in a number of applications, for example, as fillers for paints and putties, viscosity modifiers in liquids and replacements in some applications for fibrous mineral extenders such as asbestos.

Abstract: A moldable article useful for making a form-stable article is described. The moldable article comprises a formable material that is a moldable polymeric or prepolymeric substance that can be cured to a form stable state and a curing agent, in close proximity to the curable substance but isolated therefrom, in frangible hollow fibers. In use, the frangible hollow fibers are ruptured to release the curing agent and the moldable article, in a first configuration, can be shaped to a second configuration in which it is maintained until the formable material is cured sufficiently for it to be form-stable in the second configuration. The moldable article can be used to make molds, casts, support for a portion of the human or animal anatomy, or other articles with diverse utilities.

Abstract: An article especially suited for use as a vibration isolating or shock absorbing structure comprising a multitude of short, resiliently compressible, elastic, tubular, rubbery bodies held together in closely-packed relationship by restraining means. The rubbery bodies comprise a cured thermosetting millable extrudable composition having in the cured state an elasticity in excess of 200% and an elongation at break in excess of 300%. The tubular bodies are characterized by having a length to diameter ratio from about 2:1 to about 8:1 and a wall thickness of at least 0.025 inch.

Abstract: There is described an ethylene-vinyl alcohol copolymer membrane comprising at least a skin layer on its surface and a porous layer supporting the skin layer. The porous layer, when the membrane is observed in the dry state with an electron microscope, contains vacuoles or voids, which present a mono- or multi-layer structure and have straight-line lengths corresponding to 20-99% of the whole thickness of the membrane. In addition, the polymer portion of the porous layer has micropores with an average pore diameter of 0.1-5 microns and the membrane has a porosity of 60-90%.

Abstract: A composite fiber or filament comprising a core or substrate coated with a cellular foam, and an outer circumference characterized by a substantially continuous, microcellular breathable and abrasion-resistant aspect.

Abstract: A method for the preparation of semipermeable membranes which comprises sulfonating porous membranes of acrylonitrile polymers containing acrylonitrile in an amount of 40% to 100% by mole.The resulting semipermeable membrane is very useful for separating substances by reverse osmosis or ultrafiltration.

Abstract: Polyimide fibers which have a porous, microcellular structure. Methods of making such fibers from a precursor under conditions which cause the precursor to foam and undergo imidization.

Abstract: Surface-modified cellulose acetate filaments having a microporous structure located in the peripheral surface layer thereof are prepared by bringing non-modified cellulose acetate filaments which have an average degree of acetylation of 50 to 62% into contact with an organic solvent which is capable of dissolving or swelling the non-modified filaments and by rapidly evaporating the solvent from the filaments. The microporous structure causes the surface-modified filaments to exhibit a desirable silklike touch and an increased intensity in dye exhaustion of from 1.1 to 2.0 times that of the non-modified filaments.

Abstract: Paper-making belts of hollow monofilaments of polyester, polyamide, or polycarbonamide.

Abstract: A hollow, stiff, one-piece filament-reinforced composite mandrel of nonuniform wall thickness for a wind turbine blade spar is comprised of bonded inner and outer filament-reinforced shells. The inner shell is fabricated by bonding together separately formed tubular halves. The outer shell is built up on the outer surface of the inner shell preferably by judicious winding of a plurality of turns of filament-reinforced epoxy resin material.

Abstract: High crimp, high strength, hollow rayon fibers or filaments which maintain their hollowness after being immersed in water and subsequently dried, and have a crimped configuration such that there is in excess of about 20 crimps per inch, preferably between about 25-30 crimps per inch, are provided by an in-line process whereby a viscose solution containing a blowing agent is extruded into an aqueous acid coagulating bath. The conditions of the process result in hollow filaments that are substantially irreversible since they remain hollow and do not collapse even after repeated washing and drying cycles. The hollow filaments possess high crimp, such as about 25-30 crimps per inch, which will permit ease in carding and blending with other fibers. The high crimp hollow fibers also possess high strength nearly equivalent to that of high wet modulus rayon fibers.

Abstract: Structural cores in the form of open-ended polyhedrons joined together al common edges or sides are generating high industrial interest because of the great strengths they possess relative to their weights. A structural core medium of interwoven fibrous filaments coated with plastic is highly satisfactory, but it has the disadvantage that it is very difficult, if not heretofore impossible, to produce in other than planar, sandwich or cylindrical form. A jig for the fabrication of such cores has not come into existance. This invention provides a jig which makes possible the fabrication of such polyhedral structural cores.

Abstract: A metallic substrate and a thermoplastic resinous coating are bonded to one another by a resinous hot melt adhesive. The method of applying the coating to effect the bond includes applying to the metallic substrate a resinous hot melt polyamide adhesive composition which has been found to adhere firmly to the metallic substrate and to form a secure bond with the molten thermoplastic resin extruded onto said hot melt adhesive at high rates of speed.

Abstract: Sticks of foamable thermoplastic material are provided with grooves in at least one surface. These grooves extend width-wise of the stick. In addition, the grooves are disposed in equi-spaced relation along one surface of the stick, or in spaced-apart series or groups on only one surface, or in series or groups on opposite surfaces and in spaced-apart relation. Upon foaming, the sticks form foamed elements of various shapes, each of which has at least one curvilinear portion such as, for example, a corkscrew shape, an annular shape or shapes with reverse bends.

Abstract: A small amount of SiO.sub.2 is added to the sodium borate solder glasses of the type previously used to make tubesheets in hollow fiber, high temperature battery cells. The modified glass is more easily ground and has a lower softening temperature. When the powdered glass is fused, to form the tubesheet and sealingly engage the fibers, the fiber-weakening fluxing action of the glass is considerably reduced.

Abstract: Process for the production of small tubing, e.g., hollow fibers comprising(a) preparing a solution of an organic fiber-forming polymer, containing, in a uniformly dispersed form, a sinterable inorganic material;(b) extruding the inorganic material-containing polymer solution through a hollow fiber spinneret;(c) forming a polymeric precursor hollow fiber, laden with the inorganic material;(d) treating the polymeric precursor hollow fiber to remove the organic polymer; and(e) sintering the resulting inorganic material in hollow fiber form.

Abstract: A dense hollow fiber cellulosic membrane which possesses outstanding permeability and strength characteristics and the method of preparation thereof is disclosed.

Abstract: The structure comprises more than four bundles each constituted by a plurality of regularly spaced, parallel, rectilinear elements, the directions of at least five of said bundles being oriented parallel to at least five of the ten directions defined by the lines connecting the non-contiguous vertexes of a parallelepiped in two's and the bundles taken in three's not constituting a system in which each bundle is perpendicular to the other two.

Abstract: A mat material suitable for use for reinforcing plastics, as an upholstery material, filter material and various other purposes is made by melt spinning a synthetic polymeric material onto a moving embossed surface where the filaments become melt fused together at mutual points of contact. A gas or gas producing substance is mixed with the melt prior to extrusion to produce a plurality of adjacent, separate, discontinuous cavities in the filament.

Abstract: In blood dialyzers in which hollow fibers are potted in plastic tube sheets and the tube sheets are then cut to form a manifold surface providing access to the interior of the hollow fibers, blood clotting at the manifold surface is greatly reduced by treating the surface to increase the radii of the microscopic sharp edges of the fiber ends which are produced by the cutting process. The smoothing of the fiber ends can be accomplished by momentary heating, flame polishing, etching, or coating of the manifold surface with a varnish.

Abstract: Cellular linear filaments are disclosed and include a substantially continuous, integral plastic hollow member having internal generally transverse partitions which divide the hollow member into cells. The wall of the hollow member can be continuous or can contain orifices, slits, windows and the like. The cells can be open or closed and uniformly or randomly spaced along the tubular member. The cells are defined by transverse partitions which can be integrally formed with the hollow member or they can be seals in the hollow member. Woven, non-woven and tufted materials including yarns made up in part or in total of the cellular linear element are also disclosed. The cellular linear element can be cut into discrete lengths to form pile-like elements which can be attached upright to a base to form a multi-element device.

Abstract: A textile multi-filament yarn having individual filaments cohered together at least in part by individual interfilamentary bridges, which bridges are disposed within the multi-filament yarn to join the filaments thereof so as to render the yarn structurally frozen so that at least a part of the individual filaments cannot be pulled apart without breaking at least in part the structure of the multi-filament yarn. The bridges are made of the same material as the filaments. Some of the segments of individual filaments between consecutive interfilamentary bridges can be of different length.

Abstract: There is disclosed a method of producing hydrogel tubes comprising partially hydrolyzing an acrylonitrile-containing polymer in an inorganic acidic solvent solution at temperature of about -10.degree. to 50.degree. C., extruding said hydrolyzed polymer solution through a circular nozzle into an aqueous coagulating bath, the same or similar coagulating bath simultaneously being fed through a central tube or pin of the nozzle.Preferably, the surface of the tube is made very slippery in wet condition, by treating it with chemical agents causing either a further hydrolysis or other reaction leading to carboxylic, sulfonic or sulfuric groups, or an esterification with polyols such as glycerol, glycols or polyvinyl alcohol, preferably with simultaneous sulfonation or sulfuration.

Abstract: Hollow fibers of acrylonitrile polymers having water-permeability greater than 0.2 ml/cm.sup.2.min.atm and useful as an inexpensive superior ultrafilter, comprising(1) a porous layer or layers existing on the outer or/and inner sides of said hollow fibers, the average sizes of pores contained in said porous layer or layers and existing on each of assumptive cylindrical surfaces concentric with the central axis of said hollow fibers, having such a gradient that the average sizes of pores contained in the porous layer existing on the outer side become smaller toward the outer surface of said hollow fibers while the average sizes of pores contained in the porous layer existing on the inner side become smaller toward the inner surface of said hollow fibers, and(2) a reticulate porous layer adjacent to said porous layer or layers (1) and containing therein at least one succession of voids having diameters of at least 10-50 .mu.

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.

Abstract: Essentially inorganic monolithic hollow fibers having a radially anisotropic internal void volume wall structure. Process for the production of such fibers. Apparatus and processes using such fibers.

Abstract: A tubular composite structure for transmitting forces comprises a metal tubular core, preferably of aluminum, having a layer of structural metal adhesive on the exterior surface of the core. On top of the structural adhesive layer are alternating laminae of resin impregnated unidirectional reinforcing fibers, particularly carbon or graphite fibers, and of woven fiberglass, beginning with a layer of woven fiberglass followed by a lamina of resin impregnated continuous unidirectional reinforcing fibers and continuing in alternating fashion but ending with a final layer of resin impregnated continuous unidirectional reinforcing fibers, each successive layer of resin impregnated continuous unidirectional fibers having the fibers oriented at an angle of between about 5.degree. to 12.degree. with respect to the longitudinal axis of the metal tube and in opposite orientation with respect to the next preceding layer. The fibers in the woven fiberglass layer are oriented at 0.degree. and 90.degree.

Abstract: This invention is directed to a novel fiberglass pole construction and the method for forming such. The pole is of composite construction and includes inner, outer and intermediate layers resin bonded together into an integral hollow elongated tapered form exhibiting lightweight and high strength characteristics. The intermediate layer includes individual sublayers in turn formed from a plurality of strips of non-woven, unidirectional glass fiber fabric. The strips of each sublayer are circumferentially staggered about the periphery of the pole and are disposed lengthwise therealong so that the orientation of the glass fibers forming such strips is parallel to the longitudinal axis of the pole. Several such sublayers are built up until the necessary strength characteristics have been imparted to the pole. An outer layer of generally spirally wrapped ribbon essentially completes the structure.

Abstract: A filament of a thermoplastic synthetic polymer having a plurality of adjacent, separate discontinuous cavities is made by a process wherein a silicone oil and an inert gas or gas-forming substance are dispersed in a polymer melt, and the melt is extruded into a filament. The melt contains up to and including 1% by weight of the silicone oil, based on the weight of the melt, at the time it is extruded and up to and including 10% by weight of an inert gas.

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: In a process for the production of fibre filters, the fibre material is sprayed electrostatically from the liquid state and deposited as a fibre fleece on a conductive support. The starting materials used are solutions of high polymers in readily volatile solvents. The filters obtained have substantially improved properties.

Abstract: A flexible element such as a small diameter filament or tubule comprising an outer body portion formed of a high molecular weight organic composition which protectively encloses therein polymerizable organic material in a pliable form and which is transformed into a rigid element when exposed to a source of wave energy having an intensity sufficient to effect substantial polymerization of said polymerizable material; whereby said element is adapted to be shaped into any desired configuration before exposure to said wave energy and rigidifiable while in said configuration on exposure to said wave energy without application of any surface coating to said element. Divisional application of U.S. Ser. No. 509,452, filed Sept. 26, 1974 now U.S. Pat. No. 3,990,437.

Abstract: A novel tubular composite structure for transmitting substantial forces comprising a metal tubular core having a layer of structural metal adhesive on the exterior thereof. On top of the structural adhesive layer are alternating laminae of resin impregnated unidirectional reinforcing fibers and of woven fiberglass, beginning with a layer of woven fiberglass followed by a lamina of resin impregnated unidirectional reinforcing fibers and continuing in alternating fashion but ending with a final layer of resin impregnated continuous unidirectional reinforcing fibers. All fibers are disposed at a predetermined angle of orientation with respect to the longitudinal axis of the tube. The number of layers disposed along the length of the tubular core varies such that the core thickness along the length of the tubular shaft has its greatest thickness at the mid section of the shaft.

Abstract: High strength hollow rayon fibers or filaments which will recover their hollow configuration after being immersed in water and subsequently dried are provided by an in-line process whereby a viscose solution containing a blowing agent is extruded into an aqueous acid coagulating bath of relatively high acid concentration. The conditions of the process result in hollow filaments that are substantially irreversible since they remain hollow and do not collapse even after repeated washing and drying cycles. The hollow filaments also possess high strength nearly equivalent to that of high wet modulus rayon fibers. Modifiers may be employed in achieving this effect, but are not necessary.

Abstract: Highly absorbent regenerated cellulose filaments have a collapsed hollow structure, a multi-limbed cross-section and a water imbibition of 170 to 345 per cent. They are made by a viscose process using sodium carbonate as an inflating agent.

Abstract: Blends of 55 to 97% by weight crimped hollow polyester fiber having a void content of from 8 to 30% by volume and 3 to 45% by weight of crimped lower-melting polyester binder fiber impart advantageous properties to bonded low density batts made therefrom, such as high filling power but low load bulk which makes the batt particularly useful as fiberfill for garments.

Abstract: Asymmetric hollow fibers useful for effecting separations are prepared by spinning a solution of a fiber-forming cellulose derivative through the outer tube of a double tube-type spinneret into an aqueous coagulating bath to form a hollow fiber and simultaneously injecting an aqueous salt solution through the inner tube of the spinneret to contact the interior of the hollow fiber. The hollow fibers are dipped in warm water, then the free water is removed and the fibers are frozen and dried under vacuum.

Abstract: The process of making an ingot for use as a feed stock for a coating process in which the ingot is vaporized to produce the coating material; the ingot being made by forming a billet of the alloy minus the reactive element with a rod of the reactive element of the alloy extending centrally through the billet and then shaping the billet to ingot size, the cross-sectional area of the rod having the same relation of the remainder of the area of the billet as the percentage of the reactive element in the alloy.

Abstract: A suede-like raised woven fabric which comprises: warp yarns; weft yarns, each being a single twist filament yarn or a loopy textured filament yarn consisting of a bundle of fine fibers; and an elastic polymer applied to the fabric. The bundle of fine fibers consists of a raised portion having an average monofilament denier of from 0.05 to 0.4 and an unraised portion having an average monofilament denier of above 0.4 but not exceeding 0.8.

Abstract: Porous fibers which are much preferred for having various functionalities such as ion exchangeability, catalytic activity, etc. can be produced by impregnating a mixed monomer liquid of at least one monovinyl monomer and at least one polyvinyl monomer which contains a polymerization initiator in substrate fibers capable of being swollen by 30 - 500 volume % with the mixed monomer liquid, polymerizing the monomers in the state of being absorbed in the fibers and then removing said substrate fibers.

Abstract: A fiber-reinforced plastic structure is obtained by weaving fibers in one direction about one or more spacing members located angularly to the fibers. The fibers may be either warp or woof stands, the spacing member serving as woof when the fibers from warp strands, and as warp when the fibers form woof strands. The removal of the spacing member leaves relatively large open channels forming, in effect, a multi-wall hollow structure. The resultant structure may be partially or completely treated with a plastic resin system prior to or after the removal of some or all of the members. The solidified resin reinforced structure may be filled with a foam-in-place plastic, and it may be stacked in layers to provide additional thickness with reinforcing fibers running in different directions for additional strength. Some fibers may extend from one ply into an adjacent ply or into more remote plies.

Abstract: Synthetic fibers capable of absorbing aqueous medium are manufactured by simultaneously extruding the fiber material and a second material in a core and sheath arrangement. Turbulence is produced in the zone where these two materials combine which results in undulations in their cross-sections. The second material is then dissolved away with a solvent to leave a fiber with an undulating surface. When the second material is extruded as the core, the fiber is hollow with undulations on the inside while when the second material is extruded as the sheath the solid fiber has an undulating outer surface.

Abstract: 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: A porous polytetrafluoroethylene tubing, useful as artificial internal organs or industrial filtering materials for, for example reverse osmosis, ultrafilteration, etc., having a microporous fibrous structure in which the fibrous structure is composed of fibers and nodes connected with each other and the microporous fibrous structure differs between the outer surface portions of the tubing and the inner surface portions of the tubing, and a process for producing the porous resin tubing comprising heating a tubing made of an unsintered polytetrafluoroethylene under conditions in which the tube is stretched at least in the longitudinal direction of the tubing and such that the outer surface of the tubing is heated above about 327.degree. C and the inner surface of the tubing is heated to a temperature below the temperature of the outer surface.