Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0015—Electro-spinning characterised by the initial state of the material
  • D01D5/003—Electro-spinning characterised by the initial state of the material the material being a polymer solution or dispersion
  • D01D5/0038—Electro-spinning characterised by the initial state of the material the material being a polymer solution or dispersion the fibre formed by solvent evaporation, i.e. dry electro-spinning
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
  • D01D5/0069—Electro-spinning characterised by the electro-spinning apparatus characterised by the spinning section, e.g. capillary tube, protrusion or pin
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0015—Electro-spinning characterised by the initial state of the material
  • D01D5/003—Electro-spinning characterised by the initial state of the material the material being a polymer solution or dispersion
  • D01D5/0046—Electro-spinning characterised by the initial state of the material the material being a polymer solution or dispersion the fibre formed by coagulation, i.e. wet electro-spinning
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
  • D01D5/0076—Electro-spinning characterised by the electro-spinning apparatus characterised by the collecting device, e.g. drum, wheel, endless belt, plate or grid

Definitions

• the invention relates to a method of producing a linear nanofibrous structure in an alternating electric field on a spinning electrode from a polymer solution or melt, in which on the spinning electrode, a spinning area is formed with a supercritical alternating electric field intensity, in which are formed nanofibers which are carried away from the spinning electrode by the action of the electric wind in the direction of the maximum values of the electric field gradient.
• the invention also relates to a device for producing a linear nanofibrous structure in an alternating electric field from a polymer solution or melt on a spinning electrode mounted in a spinning chamber and connected to an AC voltage source of and coupled to a means for applying the polymer solution or polymer melt to the surface of the spinning electrode, wherein a spinning area with the supercritical intensity of the alternating electric field is formed on the spinning electrode.
• the invention relates to a device for producing a nanofibrous thread.
• CN111118677 discloses production of nanofibrous yarn by electrostatic spinning.
• the device comprises a cylindrical collector, which consists of a cavity and a throat which is rotatable about its axis, wherein the diameter of the upper opening of the throat is smaller than the diameter of the lower opening of the cavity.
• an electrostatic rotating spinning electrode connected to a high voltage source into which a solution to be subjected to electrospinning is fed.
• pressurized air inlets open into the inner space of the collector and above them is arranged a counter electrode which can be grounded or connected to a voltage source of opposite polarity to the rotating spinning electrode.
• Nanofibers formed on the rotating spinning electrode are carried by the action of the electrostatic field to the counter electrode and by the action of air flow, they are carried up into the throat of the cylindrical collector, which rotates, and due to its rotation and the supplied air flow, an air vortex is created, which twists the nanofibers into yarn, which is further withdrawn and wound on a bobbin.
• the nanofibers are twisted immediately after their formation due to the rotation of the spinning electrode and the subsequent action of the air vortex, so there is no parallelization of the nanofibers before twisting, the twisting is uneven and, as a result, their strength and appearance is variable.
• the aim is to twist the nanofibers as soon as possible after they are formed without achieving their parallelization.
• the disadvantages of electrostatic production of nanofibrous yarn are in both cases low yarn cohesion, irregular twist and poor orientation of the nanofibers.
• nanofibers are formed from a polymer solution in a jet head from which the nanofibers are drawn off by the action of high-speed air flow created in a Venturi tube and, through a funnel- shaped collection tube, enter a Venturi collection system, where they are straightened and oriented into oriented bundles of nanofibers using vacuum adsorption in the Venturi collection system.
• the oriented bundles of nanofibers are subsequently twisted and agglomerate by the action of the twisting device into a nanofibrous yam, which is in the next step wound on a bobbin.
• the twisting device comprises air jets for supplying the air flow in the tangential direction towards the yarn to be twisted.
• EP2931951 B1 discloses a method of producing polymeric nanofibers, in which polymeric nanofibers are formed by applying an electric field to a polymer solution or melt located on the surface of a spinning electrode, wherein the electric field for spinning is alternately formed between the spinning electrode to which an AC voltage is applied and the air and/or gas ions generated and/or supplied to the vicinity of the spinning electrode, without a collecting electrode, whereby, depending on the phase of the AC voltage on the spinning electrode, polymeric nanofibers with opposite electrical charge and/or with sections with opposite electrical charge are formed, which, after their formation due to the action of electrostatic forces, aggregate into a linear structure in the form of a cable or strip which moves freely in space away from the spinning electrode in the direction of the gradient of the electric fields.
• Spinning by the alternating high electrical voltage method is another way of producing nanofibers, alternative to electrostatic spinning.
• its yield is not yet at a level to produce purely nanofiber yarns by this method. Therefore, EP3303666 proposed a method of producing a core yam with a coating of polymer nanofibers enveloping a supporting linear structure forming the core during its passage through a spinning chamber.
• a spinning electrode connected to the inlet of a polymer solution and powered by alternating high voltage is arranged below the supporting linear structure on the face of which nanofibers are formed in a spinning space in the immediate vicinity of the face of the spinning electrode and above it, wherein the supporting linear structure rotates in the spinning space about its own axis.
• Nanofibers are formed around the circumference of the face of the spinning electrode and in the spinning space. They are formed into a hollow electrically neutral nanofibrous plume in which the nanofibers are arranged in an irregular lattice structure in which nanofibers in short sections change their direction, wherein the hollow electrically neutral nanofibrous plume is carried by the electric wind towards the supporting linear structure and change into a flat strip which is brought to the circumference of the supporting linear structure, wherein the strip created from a hollow electrically neutral nanofibrous plume wraps around the rotating and/or ballooning supporting linear structure in the shape of a helix, creating a nanofiber coating on it, in which the nanofibers are arranged in an irregular lattice structure, in which the individual nanofibers in short sections change their direction.
• the nanofibrous plume represents an ideal material for the coating of the core yam, because due to its electrical neutrality and irregular lattice structure, in which the individual nanofibers in short sections change their direction, it is capable of forming a solid coating enveloping the yam core, whereby the coating is inert to its surroundings when wound on a bobbin and during subsequent unwinding during processing.
• a pure nanofiber yam were to be produced from the nanofiber plume, there would be a problem both with an insufficient quantity of the nanofibers as well as with the lattice structure of the plume, which does not allow parallelization of the nanofibers.
• Classic yam with a permanent twist is produced, for example, on ring or rotor spinning machines, where at first, a ribbon of parallel fibers is formed and subsequently the ribbon is twisted, creating yam with high tensile strength and uniform twist.
• a ribbon of parallel fibers is formed and subsequently the ribbon is twisted, creating yam with high tensile strength and uniform twist.
• the object of the invention is to propose a method of producing nanofibers by AC electrospinning of a polymer solution or melt, in which nanofibers would be produced in sufficient quantity and carried away from the spinning area so as to form a ribbon of nanofibers at a certain location, in which the nanofibers would be at least partially parallelized, wherein the nanofibers would have sufficient strength allowing them to be drawn off and wound on a bobbin for subsequent use or processing into textile structures using known textile technologies.
• the object of the invention is to provide a device for performing this method and a device for producing nanofibrous yam.
• the object of the invention is achieved by a method of producing a linear nanofibrous structure from a polymer solution or melt in an alternating electric field on a spinning electrode, in which nanofibers are formed from the polymer solution or melt in a spinning area created on the spinning electrode and are carried away from it by the action of the electric wind, wherein the principle of the invention consists in that on the spinning electrode is formed at least one spinning area with a supercritical AC electric field intensity and a final length, from which the emerging nanofibers are carried away by the effect of the electric wind in the direction of the maximum values of the electric field gradient from the spinning area in a flat structure whose initial width is the same as the width of the linear spinning area, wherein as the electric field gradient decreases, the nanofibers lose their kinetic energy until, after losing their kinetic energy, they stop, gather and are compacted into a linear nanofibrous structure which is drawn off, with the linear weight of the linear nanofiber structure gradually increasing, while the nanofibers are at least partially parallelized and a ribbon of nanofibers is formed.
• the nanofiber ribbon created in this way has sufficient cohesion, which enables it to be wound on a bobbin for subsequent technological operations, such as twisting, elongation, heat fixation, etc.
• the nanofiber ribbon is formed into a nanofibrous thread.
• the spinning area of the belt and linear spinning electrode is straight and the nanofibers emerging therefrom move in a planar flat structure whose thickness corresponds to the width of the spinning area and whose length corresponds to the length of the spinning area.
• a double spinning area can be formed by increasing the width of the spinning electrode, wherein nanofibers emerging from both spinning areas move in planar flat structures which move away from each other in the direction of movement of the nanofibers. In this manner, two ribbons of nanofibers are formed on one spinning electrode, which can be further processed separately, or combined before processing.
• the created ribbon of nanofibers is wound on a bobbin, being capable of unwinding and further processing.
• the principle of the device for producing a linear nanofibrous structure in an alternating electric field from a polymer solution or polymer melt is that by setting the supercritical intensity of the alternating electric field, at least one linear spinning area is created on the surface of the spinning electrode, and above it, in the direction of the maximum values of the electric field gradient, a virtual collector is created in the area of force balance of electric and gravitational forces acting on the formed nanofibers, for stopping, collecting and compacting the nanofibers into a linear fibrous structure, to which a draw-off mechanism and winding device for winding the ribbon of nanofibers are assigned.
• the spinning area may be straight, with the maximum electric field gradient directed vertically upwards so that the formed nanofibers are carried vertically upwards as far as to the virtual collector.
• the spinning electrode can be formed by a strip spinning electrode, or a linear spinning electrode formed by a linear flexible structure, for example a string, a thin tape, or a thin strap, on which the polymer solution is only on the spinning area.
• the creation of two spinning areas near the edges of the linear flexible structure is achieved.
• These spinning areas can be formed by protrusions on the edges of the strip, or on the edge of this strip.
• the spinning electrode is formed by a narrow rotating disk spinning electrode, which with the lower part of its circumference extends into the polymer solution or the melt in a reservoir, and on the free part of the circumference of the disk spinning electrode, a spinning area is formed, which is formed by part of a circle, wherein the maximum gradient of the electric field is directed from the spinning area in the radial direction and the nanofibers are carried in a planar flat structure from which a ribbon of nanofibers is formed in a virtual collector.
• the rotating disk spinning electrode is mounted on a common shaft with at least one other rotating disk spinning electrode.
• An increase in the quantity of the nanofibers produced can also be achieved by arranging several rotating disk spinning electrodes one behind the other.
• the rotating disk spinning electrode has a larger disk width, and so two spinning areas are formed on its edges, which are formed by a part of a circle, and the maximum gradient of the electric field creates conical surface structures on the edges of the disk spinning electrode.
• the nanofibers in the conical surface structures are carried into virtual collectors, in which a ribbon of nanofibers is formed, wherein the conical surface structures of nanofibers move away from each other and create the letter "V" in cross-section.
• the spinning electrode is formed by an overflow spinning electrode, wherein the device comprises a reservoir of a polymer solution, in which the inlet of the polymer solution is placed vertically. At the upper end of the inlet, an overflow electrode is arranged, wherein the inlet is opened on its upper face and an overflow area is formed around its mouth, sloping slightly from the mouth of the inlet of the polymer solution to the edge of the overflow electrode and is terminated with a circumferential edge which forms the spinning area of the overflow spinning electrode on which nanofibers are elongated.
• the elongated nanofibers are carried by the action of the electric wind in the direction of the maximum electric field gradient through the spinning space in the radial direction from the circumferential edge of the overflow electrode and collected in the area of the virtual collector, where they are compacted into a material structure forming a ribbon of nanofibers, which is drawn off from the virtual collector in the tangential direction with respect to the virtual collector and further wound onto a bobbin or processed into a thread.
• Fig. 1a illustrates the distribution of the electric field intensity around the circumferential part of a narrow rotating disk electrode for the formation of nanofibers for conventional spinning
• Fig. 1b shows the distribution of the electric field intensity around the circumferential part of the narrow rotating disk electrode for the formation of nanofibers for producing a ribbon of nanofibers
• Fig. 1c shows the distribution of the electric field intensity on the narrow rotating disk electrode with a recess in the middle of its circumference
• Fig. 2a shows a diagram of the effect of the maximum electric field gradient on the circumference of the narrow rotating spinning electrode
• Fig. 2b shows a diagram of the effect of the maximum electric field gradient on a wider rotating spinning electrode
• Fig. 1a illustrates the distribution of the electric field intensity around the circumferential part of a narrow rotating disk electrode for the formation of nanofibers for conventional spinning
• Fig. 1b shows the distribution of the electric field intensity around the circumferential part of the narrow rotating disk electrode for the formation of nanofibers for producing a ribbon of nanofibers
• FIG. 7a represents a diagram of the production of nanofibers for a ribbon of nanofibers on a strip spinning electrode in side view
• Fig. 7b shows a diagram of the production of nanofibers for a ribbon of nanofibers on the strip spinning electrode in ground view
• Fig. 8a represents a diagram of the production of nanofibers for producing a ribbon of nanofibers on an overflow electrode in cross-section
• Fig. 8b shows a view of the production of nanofibers on the overflow electrode according to Fig. 8a
• Fig. 9a shows a diagram of the production of nanofibers for producing a ribbon of nanofibers on a linear spinning electrode in cross-section A-A of Fig. 9b, which represents this arrangement in front view
• Fig. 9a shows a diagram of the production of nanofibers for producing a ribbon of nanofibers on a linear spinning electrode in cross-section A-A of Fig. 9b, which represents this arrangement in front view
• Fig. 9a shows a diagram of the production
• the aim is to produce per unit of time the largest possible quantity of nanofibers, which are created over the entire working surface of a spinning electrode and are carried away from the spinning electrode by the electric wind, or possibly also by auxiliary air currents, to a collector which is neither grounded nor connected to an electric voltage source and which can be, for example, a flat textile or a linear fibrous structure which, after being coated with a nanofibrous plume, forms core composite nanofibrous yam.
• the formation of nanofibers begins at a critical value of the electric field intensity, which varies depending on the type of polymer solution being spun, voltage value, gas quality in the spinning chamber and other parameters.
• the distribution of supercritical intensity E of the electric field for the above-mentioned conventional spinning of polymer solution Z on a narrow rotating disk spinning electrode 11 is shown in Fig. 1a for a disk diameter of 300 mm, a disk thickness of 1 mm, a polymer solution layer thickness of 0.2 mm, and a voltage amplitude of 50 kV.
• the supercritical value of the intensity E of the electric field for PVB polymer solution is equal to or greater than 3000 V/mm 2 It is clear from the figure that the supercritical value of the intensity E of the electric field is achieved in a wide area around the circumferential part of the disk. Spinning of polymer solution Z therefore takes place on the entire circumferential surface of the disk and on the part of the disk faces near the disk circumference, and the created nanofibers are carried through the spinning space to the surface of an unillustrated collector.
• the spinning area 10 can be straight, for example in the case of a belt, strip or cable spinning electrode, or it can be formed by a part of a circle, for example in the case of a rotating disk spinning electrode 11.
• Taylor cones begin to form on the surface of polymer solution Z in the linear spinning area 10 of the spinning electrode 1_, from which, due to the effect of a sufficiently strong alternating electric field, nanofibers 5 begin to elongate and are carried away from the spinning area of the spinning electrode in the direction of the maximum values of the electric field gradient, i.e. in the plane of the greatest density of electric field lines, in one flat structure, whereas in the area in which the repeated natural slowing down to stopping of the nanofibers occurs, a virtual collector 7 is formed, i.e. a area where the nanofibers gather and are compacted to form a ribbon_6 of nanofibers and this ribbon 6 is drawn off.
• the flat structure of nanofibers 5 is planar, because all the forces acting on it act in the vertical direction.
• nanofibers 5 are created in the direction of the maximum values of the electric field gradient, i.e. in a plane inclined from the vertical plane, but by the action of gravitational forces and mutual repulsive forces of nanofibers with the same charge, the nanofibers 5 are deflected and, consequently, a virtual collector 7 is formed under the surface of the electric field gradient.
• the spinning process takes place by way of forming nanofibers in a conical surface, for example, on both edges of a wide rotating disk spinning electrode 11 , nanofibers 5 are formed in the direction of the maximum values of the electric field gradient.
• the distribution of regions of electric field intensity E is shown in Fig.
• the nanofibers 5 in this embodiment are carried in two conical flat structures that move away from each other in the direction of movement of the nanofibers 5.
• the movement of the nanofibers from each other is also aided by the fact that the nanofibers 5 formed on both protrusions 112 of one disk spinning electrode 11 have the same residual electric potential at a specific time, and so they repel each other.
• a gravitational force acts on the nanofibers, deforming the conical flat structures, and so a virtual collector 7 is formed under the surface of the electric field gradient.
• Electric forces represent the sum of all electric forces acting on the nanofibers 5, i.e., the force of the electric wind from the spinning electrode 1_, the force of the electric wind from other charged parts of the spinning device, the force from ionized air ions and the force from oppositely charged parts of the nanofibers 5 formed in the previous half-wave of the alternating electric field and the repulsive force from consensually charged parts of nanofibers 5.
• the virtual collector 7 is meant a narrow region terminating the planar structure of the nanofibers 5, being formed, where the nanofibers 5 being formed lose their movement speed when moving from the spinning area 10 of the spinning electrode 1_.
• the reason for their slowing down is the re-polarization of the spinning electrode 1. in the second half of the period of the supplied AC voltage.
• the already formed nanofibers 5 carried towards the virtual collector 7 or the nanofibers 5 collected in the virtual collector 7 are left with a residual electric charge of the polarity of the previous half-wave of electric voltage, and so they are now reversed charged relative to the current polarity of the spinning electrode 1_.
• the electric potential difference required for the initialization and progress of the spinning process in the alternating electric field is created.
• an electric potential is created between polymer solution Z in the spinning area 10 of the spinning electrode 1_ and the air ions in the vicinity of the spinning electrode 1_.
• the nanofibers slowing down to stopping in the region of the virtual collector 7 is due to the change in polarity of the supplied electrical voltage, wherein the distance of the virtual collector 7 from the spinning area 10 of the spinning electrode 1_ is determined by the frequency of the supplied electrical voltage.
• a suitable configuration of the spinning electrode 1_ and suitable setting of the amplitude, frequency and shape of the supplied electrical signal enables to create of a linear ribbon 6 of nanofibers and to ensure its uniform continuous withdrawal outside the spinning space 41 for further operations.
• the position of the virtual collector 7, i.e. , the area where the ribbon 6 of nanofibers is formed, is mainly determined by the frequency and amplitude of the supplied electric voltage.
• An important element in the formation of the ribbon 6 of nanofibers is the waveform of the applied AC electrical voltage.
• the magnitude of the intensity E of the electric field in the respective half-wave is constant, in the case of a sinusoidal waveform it changes.
• a major advantage of the proposed method of producing nanofibers for forming the ribbon 6 of nanofibers is the homogeneity of the ribbon 6 of nanofibers, because the formation of the ribbon 6 of nanofibers in the virtual collector 7 is not influenced by any frictional forces which would affect the homogeneity.
• the homogeneity of the formed ribbon 6 of nanofibers is ensured by the invariability in time and an adequate amount of Taylor cones on the surface of the polymer solution in the spinning area 10 of the spinning electrode 1, from which nanofibers 5 are formed by the action of the alternating electric field.
• the number of Taylor cones is constant, which leads to the formation of a constant quantity of nanofibers 5 and thus to obtaining a uniform ribbon 6_of nanofibers.
• the thin rotating disk spinning electrode 11 is shown in cross-section in Figs. 1b and 2a, and in a view in Fig. 3, from which it can be seen that the nanofibers 5 formed on the circumference of the electrode 11 are carried away from the electrode 11 in a radial direction, that is, perpendicularly to its axis of rotation in the direction of the maximum gradient of electric forces, which is indicated by an arrow.
• the wide disk spinning electrode 11 can be further improved by a recess 111 formed in the middle of the circumferential surface, so that the edges of the circumferential surface adjacent to the faces form protrusions 112 on which the intensity E of the electric field is concentrated, thereby creating two spinning areas 110. Since the intensity E of the electric field is concentrated at the protrusions 112, the spinning areas 110 with the supercritical electric field intensity are narrowed compared to the previous embodiment of the wide disk spinning electrode 11 . Also in this embodiment, the nanofibers 5 are carried away from the surface of the disk spinning electrode 11 in two conical flat structures in the direction of the maximum gradients of electric forces, which are indicated by arrows.
• Each of the disk spinning electrodes 11 works in the same way as a separate disk spinning electrodel 1 , as is shown in Fig. 1 and described above.
• the device produces two ribbons 6 of nanofibers that can be wound separately or combined and wound together. From the illustrated arrangement, it is apparent that the number of disk spinning electrodes 11 can be greater.
• FIG. 8a, 8b Another alternative of the device for producing a ribbon 6 of nanofibers by AC electrospinning is a device with an overflow spinning electrode 13 shown in Figs. 8a, 8b.
• the device comprises a reservoir 2 of polymer solution Z, in which an inlet 131 of polymer solution Z is vertically arranged.
• An overflow electrode 13 is arranged at the upper end of the inlet 131 of the polymer solution, and the inlet 131 opens into the upper face of the overflow electrode 13.
• the linear flexible structure which constitutes the linear spinning electrode 14 can be formed, for example, by a string, a strip, a strap, or a structure with a more fragmented surface composed of several mutually intertwined or interlaced parts, such as a cable, a cord, a multi-core structure, etc.
• a spinning area 140 having a finite length, which is open in the spinning direction.
• a narrow flat structure of polymer solution Z is formed, and the intensity E of the electric field is set to a supercritical value at which nanofibers 5_are formed.
• the shielding bar 142 prevents the creation of supercritical value E of the electric field outside the upper part of the linear spinning electrode 14, so that in some cases the shielding bar 142 also surrounds the side parts of the linear spinning electrode 14. All the formed nanofibers 5 then arise especially in the middle of the spinning area 140, which is straight, and are carried upwards from the spinning area 140 in the direction of the maximum gradient of the electric field in a planar flat structure in the vertical direction, wherein they gradually lose their kinetic energy and at a point with zero kinetic energy, the nanofibers 5 form a linear virtual collector 7, in which the nanofibers 5 stop, gather and are compacted into a linear ribbon 6 of nanofibers, which is drawn off. In Figs.
• the linear spinning electrode 14 is also formed by an endless linear flexible structure.
• one common reservoir_2 of the polymer solution is used, into which both pulleys 141 extend with a part of their circumference.
• the linear spinning electrode 14 moves in one direction and at the end of the spinning area 140 wraps around a return pulley 141 , returns to the reservoir 2 of the polymer solution and re-enters the spinning area 140 through a delivery pulley 141 .
• the shielding bar 142 can be used for some linear flexible structures. The part described above applies to linear spinning electrodes 14 formed by narrow linear flexible structures to which polymer solution Z is applied to their entire circumference.
• the linear spinning electrode 14 is formed by a wide strip 143 in the central part of which is formed a recess 1431 which creates protrusions 1432 on the edges of the strip.
• spinning areas are formed on the protrusions 1432. From both spinning areas 140, the nanofibers are entrained in the direction of the maximum gradient of the electric fields, in two flat planar structures that form the letter "V" in cross-section, to the areas of virtual collectors 7, the mutual distance of which is greater than the distance of the protrusions 1432.
• two ribbons 6 of nanofibers are created, which have the same properties and can be further wound separately, or they can be combined and wound together, or they can be fed to the device for producing thread.
• the linear spinning electrode 14 is formed by a flat strip 144, in which the spinning areas are formed on its edges 1441 . Since the thickness of the strip 144 is small in comparison to its width, the maximum electric field gradient is directed from the edges of the strip to the sides. Another reason is the fact that the environment above and below the flat strip 144 is the same, so there is no deviation of the maximum electric field gradient.
• planar flat structures are formed from the produced nanofibers which end in the corresponding virtual collectors (not shown), where two ribbons of nanofibers are formed and drawn off as in the previous embodiments. Due to the action of gravitational forces, the planar flat structures will be deformed by these forces, as in the other embodiments.
• the device for continuous production of a nanofibrous thread 60 from a ribbon 6 of nanofibers will be explained and described in combination with a rotating disk spinning electrode 11 for producing a ribbon of 6 nanofibers, as shown in Fig. 13.
• the ribbon 6 of nanofibers is conveyed from the virtual collector 7 of the disk spinning electrode 11 to the device 9 for producing a nanofibrous thread 60, which in the illustrated embodiment comprises a transfer pulley 91 downstream of which a first draw-off mechanism of the ribbon 6 of nanofibers is arranged in the direction of movement of the ribbon 6 of nanofibers.
• a twisting device 93 for creating a false twist is arranged downstream of a first draw-off mechanism of the ribbon 6 of nanofibers, downstream of which is arranged a second draw-off mechanism 94, downstream of which a drying and/or fixing unit 95 is included, downstream of which there is a third draw-off mechanism 96, downstream of which a winding device 97 is arranged.
• the ribbon 6 of nanofibers is drawn off from the virtual collector 7 of the disk spinning electrode 11 through the transfer pulley 91 by the first draw-off mechanism 92 and enters the twisting device 93, in which it passes through a twisting member 931 , for example, through a twisting pipe by which a false twist is imparted to it.
• the twisting device 93 From the twisting device 93, the twisted ribbon 6 of nanofibers is drawn off by the second draw-off mechanism 94.
• the twist is imparted to the ribbon 6 of nanofibers by the twisting member 931 of the twisting device 93 between two clamping points, formed by the first draw-off mechanism 92 and the second draw-off mechanism 94.
• the twist is formed and between the twisting device 93 and the second draw-off mechanism 94 the twist is untwisted, wherein due to the high specific surface area of the nanofibers 5 and the binding forces between the nanofibers 5, even after untwisting, a relatively high degree of twist is retained as a residual twist, thereby forming a nanofibrous thread 60.
• the nanofibrous thread 60 is withdrawn from the second draw-off mechanism 94 by the third draw-off mechanism 96 through the drying and/or fixing unit 95, in which the remaining solvent is evaporated and, if necessary, the nanofibrous thread 60 is thermally fixed. From the third draw-off mechanism 96, the nanofibrous thread 60 is led to the winding device 97, in which it is wound onto a bobbin by some of the known methods.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Dispersion Chemistry (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
• Nonwoven Fabrics (AREA)
• Artificial Filaments (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=86851543

Family Applications (1)

Country Status (3)

Family Cites Families (11)

• 2022
  • 2022-06-09 CZ CZ2022-248A patent/CZ310139B6/cs unknown
• 2023
  • 2023-04-28 WO PCT/CZ2023/050023 patent/WO2023237139A1/en active Application Filing
  • 2023-04-28 EP EP23731504.9A patent/EP4536877A1/en active Pending

Also Published As

Similar Documents

Legal Events