Abstract: An improved method of molding articles from air-laid webs wherein resin is deposited in a dry process onto cellulose fibers prior to air-laying. Cellulose material and a resin-containing airstream are simultaneously fed into a comminuting means such as a hammer mill. The cellulose particles thereby produced have a coating which adheres to the surface of the cellulose particles. The cellulose particles retain substantially all of the dry resin coating when pneumatically conveyed and air-laid into a web. The fiber web produced with the resin-coated particles is suitable for use in a conventional molding process whereby the web is molded under sufficient heat and pressure into a molded article having a uniform resin distribution resulting in improved strength and improved structural integrity.

Abstract: A system for forming an air laid web of fibers and/or particles on a moving foraminous carrier. Fibers and/or particles are blended, and while supported in an air stream, introduced into a distributor unit. The distributor unit includes a rotatable cylinder formed with classification apertures of a predetermined shape, number, and size as specifically related to the types of fibers and/or particles utilized. A rotatable shaft with radially extending wire-like members agitates the fibers and/or particles and throws them outwardly through the apertures. Downwardly directed air flow transports the refined fibers and/or particles so as to form a homogeneous, still further refined, web on the surface of the carier. A variety of adjustments and alternations can be made to the system and its components to control the composition and thickness of the end product, and to attain maximum capacity for any combination of fibers and/or particles.

Abstract: An apparatus for the manufacture of fibrous webs comprises a forming wire and a distributor for depositing dry fibers on the wire. The distributor comprises at least one cylindrical chamber having its axis extending transversely of and in a plane parallel to the wire. The lower semicylindrical wall of the chamber is perforate for distributing fibers on the wire and the upper semicylindrical wall includes a fiber inlet. A helically bladed rotor in the chamber has its axis substantially coincident with the chambers axis of curvature, and upon rotation operates to drive fibers through the screen while evenly distributing them across the wire. Disposition of a pair of chambers in tandem with a common central fiber inlet operates further to create a racetrack fiber distribution across the wire.

Abstract: An apparatus for depositing a uniform web of dry fibers on a foraminous wire moving at speeds greater than 500 feet per minute including offset suction and air deflecting means within a fiber distributor for imparting a horizontal velocity component to the deposited fibers in the direction of the moving wire, also a method for depositing a uniform web of dry fibers onto a moving foraminous wire including imparting a horizontal velocity component to fibers deposited onto the wire in the direction of the wire by inducing a pressure gradient and baffling the air flow within a fiber distributor.

Abstract: A two-step process for producing microspherical pitch or green coke particles having an average diameter of 30-200 .mu.m from finely divided petroleum or coal pitch having a softening point of 60.degree.-220.degree. C. and a fixed carbon content of 40-75 wt %. In the first step the material pitch is fluidized in the stream of a gas substantially inert to the pitch at a temperature of 100.degree.-800.degree. C., the mixed stream is rapidly cooled to 30.degree.-400.degree. C., and microspherical pitch particles are recovered with or without separate recovery of an oily product. In the second step the pitch spheres are further subjected to thermal cracking and polycondensation by use of a fluidized bed at a temperature of 350.degree.-520.degree. C. for a retention time of 1 min. to 3 hours, and microspherical green coke particles and a light cracked oil are recovered. In both steps a pressure between the ordinary level and 10 kg/cm.sup.2 is used.

Abstract: The invention relates to a method and an apparatus for producing layers of dry fibres and/or particles on a forming surface pervious to air. According to the invention, the material is distributed in air and passed to a forming unit where a turbulence with high intensity is effected in that air is injected through separate nozzles.

Abstract: A method for the preformation of a cushion for a seat, characterized by feeding an aggregate of three-dimensional curled short-fiber filaments to conveyor means, causing said conveyor carring thereon said aggregate of filament to be advanced under a rotary member provided on the outer surface thereof with a multiplicity of raised needles and kept in rotation and allowing said needles to come into contact with said aggregate of filaments thereby scraping part of the filaments from said aggregate and giving to said aggregate of filaments a prescribed shape.

Abstract: Polyester fiberfill having spiral-crimp that is randomly-arranged and entangled in the form of fiberballs with a minimum of hairs extending from their surface, and having a refluffable characteristic similar to that of down on account of the low cohesion between the balls. A process for making such fiberballs by repeatedly air-tumbling small tufts of such fiberfill against the wall of a vessel.

Abstract: In a method of making a fibrous thermally insulating layer of coherent structure, a quantity of fibers is treated with a binder, whereby prior to or during the treatment with the binder, fibers are formed into a quantity of particles each having a substantially rounded periphery and consisting of a number of short fibers and the particles treated with the binder are conveyed by means of a gas as conveying medium via an inlet piece 11, 13 to within a container 3, the particles being blocked by an outlet piece 8 for the container, the outlet piece 8 being formed with gas outlet apertures 10.The particles are formed by vigorously agitating a number of flakes in a vessel, each flake consisting of arbitrarily arranged short fibers, and simultaneously applying pulsating forces to at least part of the volume of flakes, so that the flakes are converted into particles having a substantially rounded periphery and having a higher density than that of the flakes.

Abstract: Hydrogen bonding between cellulosic fibriles can be improved in an air-laid process by injecting ammonia or organo-amine catalysts and steam into the cellulosic fibrile mass after such fibers have been reduced to fibrile form and prior to their dispersion in air to form a fibrous mat. Prior to and subsequent to the injection of the catalytic bearing steam, the fibers may be combined with other paper forming material, resins, additives and processed in an air-laid paper making process to form a felted fibrous product with a minimal amount of water content and with acceptable strength and density. Suitable catalysts include gaseous ammonia, ammonium hydroxide, or the organo-amines such as triethanol amine, methyl amine, ethyl amine, cyclohexyl amine, or aniline and the homologous series derivatives thereof.

Abstract: An apparatus for making airlaid articles such as discrete absorbent cores for catamenial napkins and disposable diapers and the like. Apparatus embodying the invention preferably comprises a laydown drum having a plurality of formation cavities having foraminous bottom walls, which cavities are circumferentially spaced around the perimeter of the drum. The apparatus also preferably includes means for directing a high velocity stream of air-entrained matter such as, for example, fibers or particulate matter, substantially radially towards a relatively short circumferential span of the perimeter of the drum; and a hood having sufficient circumferential span of the drum to enable excess entrainment air to be drawn by vacuum through the foraminous bottom walls of substantially empty cavities, and to enable recirculation of the excess scarfed fibers.

Abstract: A process of preparing a fast reacting, light stable, sprayable or injectable polyester-modified polyurethane polymer reaction product to prepare coatings or molded products, which process comprises admixing and reacting together: a trimerized or biuret aliphatic polyisocyanate, such as a trimerized or biuret hexamethylene diisocyanate prepolymer; a polyamine to react as a chain extender for the prepolymer, such as for example, a diethyltoluene diamine, in an amount sufficient to react substantially with the free NCO groups of the trimerized or biuret prepolymer; an unsaturated polyester subject to cross linking by the use of a metal salt promotor, such as a cobalt salt promotor, and a peroxide initiator; the cobalt salt and the peroxide initiator present in an amount to provide for the curing of the unsaturated polyester.

Abstract: Thermoplastic polymer solutions in organic solvents are converted to granules of relatively uniform sizes and a narrow distribution range by passing the polymer solution through a jet nozzle to form a high velocity stream, injecting super heated steam into the high velocity stream to form a suspension of fine polymer particulates in a gas stream, passing the particulates into a heated agglomeration tube having a series of adjoining circular turns of at least 180.degree. wherein the particulates are substantially completely agglomerated into granules and the granules are recovered from the gas stream.

Abstract: A method and apparatus for granulation in which particulate feed material is charged into a rotary cylindrical vessel (12) having its axis disposed horizontally, and respective cover plate (16,18) at each end for retaining the feed material, and a treatment gas and a process liquid is passed into the vessel during rotation of the latter.

Abstract: A synthetic vascular graft is made by electrostatically spinning an organic polymeric material or a precursor thereof and collecting the spun fibres on a rotating mandrel (13), the method comprising the step of controlling the speed of rotation of the mandrel (13) such that a desired degree of anisotropy is present in the synthetic vascular graft.

Abstract: The invention relates to a process for preparing flat articles which are moulded in any desired shaped in dry moulds from defibrated components of wood. In this process, the moisture required to give good felting remains a constituent of the wood fibres until the moulding stage. These wood fibres are mixed with fibre- and/or moisture-reactive binders and, if appropriate, auxiliaries, are metered by means of a gravity-compensating air stream onto a preform sieve, and are then compression-moulded without a cooling cycle in sieve-free moulds between two surfaces which are smooth or embossed in any desired pattern.

Abstract: A method of manufacturing a highly porous refractory material by feeding raw material in discrete particle form into the hot zone of a furnace chamber, the method including the initial step of making a slurry of the raw material and feeding the slurry into a spray drier to produce particles of refractory material with very little fines.

Abstract: A method for making an air-laid batt of fibers which utilizes a plurality of scarfing rolls to remove material from the surface of the batt, wherein the batt is reformed between at least two of the scarfing rolls in order to produce a more homogeneous web.

Abstract: In a method of manufacturing dry-pressed molded articles from essentially dry, pourable ceramic metal or carbon-containing molding compound in a mold of one or more parts, it is proposed to generate a negative pressure through the mold wall in the hollow space of the mold and, by means of the pressure difference generated as a result, to propel molding compound which is under pressure, for example, atmospheric pressure, through an injection opening into the hollow space of the mold and to precompress the molding compound in the mold while deaerating the molding compound, and that subsequently, the pneumatically precompressed molding compound is compression molded into a molded article having the desired final density.

Abstract: The invention relates to high pressure decorative laminates containing an air-laid web of fibers, filler and resin as a core and to a method of preparing such a decorative laminate from an assembly comprising said substrate and a thermosetting resin impregnated decor sheet.

Abstract: A method for producing a porous plastic molded product of uniform, predictable porosity throughout. A fluidized airstream of moldable plastic powder is formed. Water may be injected into said fluidized powder airstream for maintaining said powder in a uniform, fluidized dispersion. The moisturized, fluidized, powder airstream is injected into a cavity of a closed mold to fill said mold cavity with said powder. The mold is maintained at a temperature and for a time sufficient to at least partially fuse said powder particles together without melting said particles, thereby to form a porous, plastic molded product. The mold is partially separated for cooling the product which is then discharged from the mold. The product may be further cured by heating the molded product in an oven at a temperature and for a time sufficient to cure said molded product without melting said plastic or glazing said product.

Abstract: Disclosed herein is a process for manufacturing ceramic or ceramic oxide hollow bodies and a method for its manufacture. The ceramic hollow bodies of the present invention does not require the use of a binder or adhering substrate or any type of internal embedded supports. The hollow body is capable of being manufactured for any desired diameter and length and is especially suited for thick walled pipes. The ceramic hollow body is homogeneous, free of internal cracks, and highly heat stable and shock insensitive. It is produced in a continuous quasi-isothermal thermal spray process in which hot atomized ceramic or ceramic oxide particles are sprayed as a plasma onto a non-adhering highly thermally conductive internally cooled mold core. The mold core is mounted on a rotating lathe which in turn is mounted on a longitudinally movable carriage to accomplish the uniform layer thickness of the hollow body.

Abstract: A method of increasing the caliper and bulk of air laid dry fibrous webs, particularly such webs intended for use as napkin, tissue, and absorbent paper towel products by partially drying the loose formed fibrous webs to a degree of dryness of less than 4% prior to consolidation. In the preferred embodiment uniformity of the product web caliper in the machine direction is obtained by measuring the caliper downstream of the bond curing drier and before take-up on the parent roll, output signals therefrom being transmitted to the drier for adjustment of one or more of the drier parameters. Uniformity of caliper in the cross machine direction can be optimized by providing multisectional driers in the cross machine direction, a series of output signals from the caliper sensing means being transmitted to the respective drier sections for individual adjustment of the drier parameters.

Abstract: The invention relates to high pressure decorative laminates containing an air-laid web as a substrate and to a method of preparing such a decorative laminate from an assembly comprising said substrate and a thermosetting resin impregnated decor sheet.

Abstract: In the manufacture of low density air laid webs of predominantly ligno-cellulosic material, the method and apparatus for bonding the dry web with binder and compacting the web with a wet, fabric covered surface so as to increase tensile strength and delamination resistance while reducing binder content and cost is described. Wet compaction of the binder laden web enables controlled penetration of the web with a smaller amount of binder than is possible without wet compaction, and also reduces energy consumption in drying due to the use of less binder.

Abstract: A method and an apparatus for manufacture of moulded mineral wool objects which are bound by a binder and which have a substantially constant cross-section along their entire lengths, whereby mineral wool in the form of flocks and/or granules which are impregnated or mixed with a binder and which are collected in a feeding chamber to which a mould channel is connected. The mineral wool is continuously or stepwise pressed by a compressing device into and through the mould channel and during the movement therein it is subjected to a heat treatment to cure the binder of the mineral wool, whereupon the continuous body of bound mineral wool is expelled from the channel. If desired it is subjected to a surface treatment or any subsequent treatment and is cut into intended lengths. The channel may include one or more cores providing one or more axial bores through the mineral wool body.

Abstract: Improved air laid papermaking is disclosed in which the fine particles which pass through the forming wire are, after collection by a baghouse separator, delivered back to the papermaking machine for incorporation in the web being formed by the machine. A plurality of individual separator units within the baghouse are sequentially discharged so that a substantially constant feedback of fines to the papermaking machine is obtained. The fines are fed back to a selected one of the distributors of the papermaking machine to be distributed to the surface of the web being formed at a position downstream of the position at which fibers are initially laid on the wire, thereby trapping the fines on the surface of the previously laid mat of fibers such that very little of the fines pass through the forming wire at this position.

Abstract: A method of forming an air-laid web or sheet of wood pulp fibers suitable for tissue and toweling applications comprising airlaying a web of wood pulp fibers, applying water containing a chemical softening agent to the web, pressure bonding the water-treated web to provide dry stength, preferably drying the pressure-bonded web, applying an adhesive containing solution to the dried web to provide increased wet strength, and drying the web to form the finished product. By adding a chemical softening agent to the water applied to the air-laid web ahead of the pressure bonding rolls, the strength and softness of the finished web can be controlled. Alternatively, the chemical softening agent can be added to the printing adhesive solution.

Abstract: Methods for pre-forming and feeding a lightly compacted batt of individualized fibers having a controlled cross-directional profile directly to a rotary fiber orienting and screening mechanism across the full width thereof so as to maintain a controlled cross-directional profile in an air-laid web of dry fibers formed in a high speed dry web forming system.

Abstract: A method therefor for forming an air-laid web of dry fibers suitable for use in a wide variety of products ranging from bath and facial tissues to towels having basis weights on the order of 13 lbs./2880 ft..sup.2 to 50 lbs./2880 ft..sup.2 on a high-speed production basis, wherein the web is characterized by random array of individualized fibers substantially undamaged by mechanical action and having a controlled cross-directional profile, and by its freedom from nits, pills, rice and the like, thereby improving both the appearance and the tensile strength of the web. The full-width feeding of dry fibers to a 2-dimensional flow control and fiber screening system is described wherein substantially no cross-flow forces are created in the system, ensuring a uniform cross-directional basis weight profile.

Abstract: Apparatus for producing a porous plastic molded product of uniform, predictable porosity throughout. A fluidized airstream of moldable plastic powder is formed. Water may be injected into said fluidized powder airstream for maintaining said powder in a uniform, fluidized dispersion. The moisturized, fluidized, powder airstream is injected into a cavity of a closed mold to fill said mold cavity with said powder. The mold is maintained at a temperature and for a time sufficient to at least partially fuse said powder particles together without melting said particles, thereby to form a porous, plastic molded product. The mold is partially separated for cooling the product which is then discharged from the mold. The product may be further cured by heating the molded product in an oven at a temperature and for a time sufficient to cure said molded product without melting said plastic or glazing said product.

Abstract: Method for improving fiber throughput in a high speed production system for forming an air-laid web of dry fibers and wherein individual fibers are separated from aggregated fiber masses in an enclosed, pressurized rotor chamber comprising forming a segment of the chamber wall with a plurality of closely spaced, elongated, narrow slots oriented parallel to the axis of the rotor chamber.

Abstract: Method for the deposition of a uniform layer of dry fibers on a foraminous forming surface which comprises passing the fibers through a perforated wall having zones of different aperture sizes in order to provide an even cross-direction basis weight profile.

Abstract: An apparatus for producing fibrous sheet material comprises a slot nozzle having side walls normal to converging frontal walls, its inlet opening communicating with means for dispersing fibers in a gas stream, while its outlet opening communicates with a chamber. A flat screen adapted to form a fibrous layer thereon is mounted under the chamber, and a suction box is arranged underneath the flat screen, wherein the side walls of the slot nozzle are parallel with respect to each other, and means for removing part of the gas from the gas-fiber stream are provided in the chamber under the outlet opening of the slot nozzle, the chamber being provided with branch pipes for gas exhaust, mounted substantially in the upper portion of the chamber.

Abstract: Method for improving fiber throughput in a system for forming an air-laid web of dry fibers wherein individualized fibers and soft fiber flocs are separated from aggregated fiber masses by means of mechanical action in a system employing a plurality of fiber disintegrating rotors mounted for rotation in a horizontal plane about vertical axes and disposed over a generally planar sifting screen wherein the sifting screen comprises a plurality of closely spaced, elongated, narrow slots.

Abstract: A method of forming an air laid web of hydrogen bonded wood pulp fibers is disclosed. More specifically, a paper producing method is disclosed wherein microencapsulated hydrogen bond promoting material is thoroughly premixed with wood pulp fibers. The mixture is then air laid on a moving screen to form a three dimensional continuum. The microcapsules may then be ruptured by heat and/or pressure to release the hydrogen bond promoting material evenly throughout the continuum. The continuum may then be heated or pressed to further consolidate the web.

Abstract: Method of producing fiberboard products according to the so-called dry method from lignocellulosic fiber material in which the fiber material discharged from a defibrating apparatus in an environment of steam is propelled in a stream of heated air to remove substantially all moisture therefrom. The thus dried fibers are deposited on an underlying moving perforated screen to form a mat in which the fibers are oriented at random while propellant air is evacuated therefrom. The thus formed mat is wetted by adding water thereto while it is being advanced by the screen into a hot press where the wetted fibers are compressed and bonded in their random orientation, with consequent removal of water. The amount of water added in the wetting step is proportioned to be effective in itself to bond the fibers without use of extraneous bonding or adhesive substance.

Abstract: An especially high strength, high temperature, economical material useful for insulation is preferably made by making up a mix having the following proportions in parts by weight: 20-50 parts expanded perlite; 0.5-4 parts sodium fluosilicate; 0.2-5 parts fiber material; a water solution having 9.5-19 parts total of solids content of sodium or potassium silicate; 2-9 parts zinc oxide; and water which, along with the water in the sodium silicate solution totals 21.5-67 parts; thereafter storing the mix under cover for less than 21/2 hours, compressing or blowing the mix to a desired form, and curing and drying it by heating.

Abstract: A method and an apparatus for distributing loose fibres or particles onto a moving web in an even layer thereon preparatory to production of a non-woven sheet of the fibre or particle material. The material is filled into a container having a generally V-shaped screen bottom extending crosswise over the moving web, and whipping members are rotated in the bottom space so as to whip the material adjacent the interior surface of the screen by a whipping movement causing the fibres or particles to be slung against the screen and the material to move in a flow lengthwise along the bottom surfaces, whereby when suction is applied to the outside of the screen bottom through the web the fibres or particles will get dispensed through the screen and deposited on the web. The combined whipping and slinging of the material contributes to a high capacity of the distribution.

Abstract: This invention relates to methods for forming a nonwoven fibrous web on a foraminous forming surface moving at a velocity in excess of about 500 feet per minute. In forming satisfactory uniform webs, the fibers are conveyed to the forming surface in a gaseous stream whereby the relative surface-to-fiber velocity along the moving surface is maintained within a critical ratio relative to the fiber velocity normal to the moving surface.

Abstract: A thermally-insulating, non-flammable, air-permeable insulation for installation in the field, for example, in closed cavities between the walls of a house. A multitude of individually preformed, foamed plastic particles are initially entrained in a carrier stream, and thereupon drenched with a settable film-forming, non-flammable, liquid substance, such as a sodium silicate solution. The liquid substance sets to form a film which covers and adheres the particles to one another to form a thermally-insulating dense structural aggregate mass having structural integrity, resistance to fire, and venting capability. A method of making and installing the insulation, and a preferred apparatus therefor, are disclosed.

Abstract: A web is formed from particulate material, for example, wood fibers, by depositing the fibers on a conveyor surface in a distribution chamber. The particulate material is introduced into the distribution chamber at its top by a carrier air stream which is caused to oscillate across the surface by impulses from separate control blow boxes on the opposite sides of the stream. The particulate material is thoroughly dispersed in the air stream by passage through a transition zone where the carrier air stream is deflected into a zigzag path and its flow velocity is reduced. The effect of static electricity on the particles in the carrier stream is reduced by lining the transition zone with nonconductive material and providing ionizing devices in the blow boxes for the air flow passing through the control boxes, or in the chamber adjacent the boxes.

Abstract: The present invention relates to the manufacture of fibrous wool by the rotary process. In the rotary process heat softenable material, such as molten glass, is supplied to a centrifuge wherefrom streams of said heat softenable material emanate and are acted upon by a fiber attenuating high velocity gaseous medium located about the periphery of the centrifuging means. As a result thereof, a cylindrically shaped veil of high velocity gases having attenuated fibers contained therein flows axially away from the centrifuging means to a suitable collecting means. By the present invention improved method and apparatus are provided for distributing the entrained fibers upon the collecting means. The cylindrically shaped veil is intermittently acted upon by finite planes of high velocity gas thereby interrupting the otherwise columnar flow of the cylincrical veil and establishing diverging flows of fibers.

Abstract: A fiber-reinforced cementitious sheet is formed by first co-mixing in an air current reinforcing fibers such as glass fibers, and cementitious mineral materials in finely particulate form such as calcium sulfate hemihydrate, both in substantially dry form, depositing the mixture on a moving foraminous surface by means of the air current to form a sheet, applying water as by spraying in at least an amount which is stoichiometrically sufficiently to hydrate the calcium sulfate hemihydrate to the dihydrate form and to provide the necessary degree of plasticity to the mixture, densifying the sheet by compression, and setting and drying the sheet. A pair of sheets may be utilized as face sheets and, prior to setting, combined with a core formed of for example a calcium sulfate hemihydrate slurry, and the sheets and core then set and dried to form a paper-free gypsum board having excellent strength, surface hardness, and fire-resistant properties.

Abstract: A device having at least one, preferably a plurality of air turning foils situated upstream of and at the level of the region between a fiber distributor and an underlying moving forming surface. Terminal edge portions of the foils direct ambient air in the direction of forming surface movement to impart to fibers in transit between the distributor and forming wire a uniform velocity component of movement in said direction. Each foil preferably is convex from upstream of the foil when viewed in cross section, is parallel to and equidistant from the other, and has its terminal edge portion parallel to the forming surface.

Abstract: A method for producing fibrous sheet material comprising dispersing fibers in a gas stream to obtain a gas-fiber stream, supplying the gas-fiber stream onto a flat screen, removing gas from the gas-fiber stream through said screen to form a fibrous layer thereon, removing part of the gas from the gas-fiber stream prior to supplying it onto the flat screen, simultaneously damping transversal pulsations induced in the gas-fiber stream during the course of its movement. The fiber concentration is increased to 20-500 g/m.sup.3. The fiber concentration is chosen in accordance with the specific fiber and its properties. An apparatus for carrying out this method comprises a slot nozzle having side walls normal to converging frontal walls, its inlet opening communicating with means for dispersing fibers in a gas stream, while its outlet opening communicates with a chamber.

Abstract: A method and apparatus for purifying waste product emissions from the manufacture of glass fiber products, including a system in which an electrostatic precipitation may or may not be employed, and in which separate, and easily controlled, forming air and oven air scrubbing systems are employed.

Abstract: A method of manufacturing reinforced elements includes the steps of providing a lattice-like mesh of threads lying in a first plane, applying a plurality of reinforcing fibers so that they extend in planes located at angles to the first plane in which the mesh of threads lies, and embedding the lattice-like mesh with the thus-applied fibers into a bulk of cement. A reinforced concrete element includes a bulk of cement and a reinforcing structure comprising a lattice-like mesh of threads and a plurality of fibers located in planes which are inclined to the plane of the mesh. The reinforcing fibers may extend normal or be inclined to the plane of the mesh of threads. They may be prefixed to the same before the embedding step.

Abstract: Apparatus for making a fibrous element includes an elongate foraminous former provided by at least one foraminous belt, with a foraminous forming chamber through which said belt passes and which is formed to a hollow shape thereby. The belt is driven through the forming chamber, and fluid is extracted in a fluid extraction zone which surrounds at least part of the forming chamber and formed by a closed drainage casing. An injection nozzle injects a fibrous dispersion into the former within said forming chamber with the injection nozzle being dimensioned so as to substantially exclude the ingress of air around an interface with the walls of said belt so that the apparatus produces an elongate fibrous element having an outer core of greater density than the inner core which it surrounds.

Abstract: Strong, low basis weight, spontaneously dispersible sheets of modified cellulosic fibers. The sheets are prepared from modified cellulosic fibers such as cross-linked carboxymethyl cellulose or essentially acidic sodium carboxymethyl cellulose. Mixtures of modified fibers with unmodified fibers are also disclosed. The process of preparing the sheets comprises the steps of airlaying the fibers to form an airfelt, increasing the moisture content of the airfelt, and compacting the moisturized airfelt.