Method for producing linear nanofiber structures from polymer solutions or polymer melts in an alternating current (AC) electric field and apparatus for carrying out the method

Abstract

The present invention relates to a method for producing linear nanofiber structures from a polymer solution 21 or a polymer melt in an alternating electric field, in which nanofibers 5 are formed from the polymer solution 21 or the polymer melt in a spinning zone 110, 120, 130 formed on a spinning electrode 1, 11, 12, 13 and are carried away from the spinning zone by the action of an electric wind in the direction of the gradient of the generated electric field. The polymer solution 21 or polymer melt is transported to the spinning zone 110, 120, 130 by moving the spinning electrodes 1, 11, 12, 13 and exposed to a supercritical electric field E to form nanofibers 5, which move away from the spinning zone 110, 120, 130 and are deposited on the collection zone 40, 410, 420 of the moving electrically neutral belt collector 4, 41, 42, where they form fluffy bands 51 of nanofibers, which are then moved by the moving electrically neutral collector 4, 41, 42 to the drawing zone 401, 4101, 4201, where they are drawn out by the pulling force of the winding device 7 or drawing device and then wound up. The drawing of the fluffy band 51 from the electrically neutral collector 4, 41, 42 and subsequent twisting of the fluffy band 51 of nanofibers into nanofiber yarn 54 can be carried out before or after winding. Additionally, the invention relates to an apparatus for carrying out this method.

Description

[Technical Field]

[0001] The present invention relates to a method for producing linear nanofiber structures from polymer solutions or melts in an AC electric field, in which a spinning zone having a supercritical AC electric field strength is formed on a spinning electrode, in which nanofibers are formed and are carried away from the spinning electrode by the action of an electric wind in the direction of the maximum gradient of the generated electric field.

[0002] The present invention also relates to an apparatus for producing linear nanofiber structures from a polymer solution or melt in an AC electric field, wherein a spinning zone having a supercritical value of AC field strength is made on a spinning electrode mounted in a spinning chamber and connected to a high AC voltage source, and coupled to a means for applying the polymer solution or melt to the surface of the spinning electrode. [Background technology]

[0003] In nanofiber yarn preparation, oriented nanofibers are the basis for constructing nanofiber yarns. Currently, many methods have been developed in the field of DC electrospinning to obtain longitudinally oriented fiber bundles, which can be attributed to two main aspects: obtaining highly ordered nanofibers by improving the collection device, or obtaining highly ordered nanofibers by influencing the electric field using auxiliary electrodes.

[0004] Chinese Patent Application No. 111118677 discloses the production of nanofiber yarns by DC electrospinning. The apparatus comprises a cylindrical collector having a cavity and a throat rotatable about its axis, the diameter of the upper opening of the throat being smaller than the diameter of the lower opening of the cavity. A DC electrostatic rotary spinning electrode connected to a high-voltage DC source is attached to the inside of the lower opening of the cavity, and the solution to be electrospun is supplied into the DC electrostatic rotary spinning electrode. A pressurized air inlet opens into the interior space of the collector at the top of the collector cavity, and a counter electrode is disposed above the pressurized air inlet. The counter electrode can be grounded or connected to a voltage source of opposite polarity to the rotary spinning electrode.

[0005] The nanofibers formed on the rotating spinning electrode are carried to the counter electrode by the action of an electric field, and the nanofibers are carried up into the throat of a rotating cylindrical collector by the action of an air flow, and the rotation of the collector and the supplied air flow create vortices that twist the nanofibers into a thread, which is then drawn off and wound onto a bobbin.

[0006] The nanofibers are twisted together immediately after their formation by the action of the spinning electrode rotation and subsequent vortex, preventing the nanofibers from juxtaposing before twisting, and twisting occurs irregularly, resulting in variable nanofiber strength and appearance.

[0007] Chinese Patent Application No. 111286792 describes a horizontal arrangement of a DC electrospinning apparatus comprising a rotating jet spinning electrode and a collecting electrode formed by a hollow cylinder arranged coaxially with respect to the jet spinning electrode, where a DC electric field is formed between the spinning electrode and the collecting electrode. At least two air jets directed toward the axis of the collecting electrode are arranged around the rotating jet spinning electrode. The electric wind carries the nanofibers formed by the rotating jet spinning electrode to the hollow cylinder forming the collecting electrode, and the rotation of the jet spinning electrode and the airflow from the jet twist the nanofibers into a thread, which passes through the cavity of the collecting electrode before being drawn out and wound onto a bobbin.

[0008] In this solution too, the aim is to intertwine the nanofibers as soon as possible after they are formed without achieving parallelization of the nanofibers.

[0009] In both cases, drawbacks of DC electrostatic production of nanofiber yarns include poor yarn adhesion, irregular intertwining, and poor orientation of the nanofibers.

[0010] Currently, a method for continuously preparing nanofiber yarns is known, for example from Chinese Patent Application No. 110644080, in which nanofibers are formed from a polymer solution in a jet head, which is drawn out of the jet head by the action of a high-speed airflow generated in a Venturi tube, passing through a funnel-shaped collection tube into a Venturi collection system, where the nanofibers are straightened and oriented into an oriented nanofiber bundle by sucking the nanofiber bundle using the Venturi effect. The oriented nanofiber bundle is then twisted and agglomerated into a nanofiber yarn by the action of a twisting device, which in the next step is wound onto a bobbin. The twisting device is equipped with an air jet for supplying an air flow tangentially toward the yarn to be twisted.

[0011] In terms of the subsequent processing and use of nanofiber yarns, it is not enough to simply obtain oriented fibers to meet the current requirements for preparing oriented fibers; it is also necessary to continuously obtain oriented fibers or fiber bundles and to be able to uniformly impart a certain degree of twist to the oriented fibers or fiber orientation to ensure the length and degree of orientation of the oriented fibers or fibers. To optimize the strength of nanofiber yarns, it is advantageous if the nanofibers in the nanofiber bundle are already longitudinally oriented by the method of forming the nanofibers, i.e., if the nanofibers are aligned with the axis of the bundle. Existing DC electrospinning techniques for continuously producing nanofiber yarns result in low yields and poor quality of the nanofiber yarns produced. Therefore, core yarns are currently produced by DC electrospinning.

[0012] For example, Czech Republic Patent Application No. 2007-179 discloses a linear fiber structure comprising polymer nanofibers that form a coating on the surface of a core formed by a supporting linear fiber structure, with at least some of the nanofibers trapped between the fibers at the surface of the core. The nanofibers are produced by direct current electrospinning (i.e., using a high-voltage direct current source), in which the supporting linear structure is guided through a spinning space between a spinning electrode and a collecting electrode, and a false twist is imparted to the supporting linear structure outside the spinning space. Thus, the supporting linear structure in the spinning space rotates around its axis, and individual nanofibers transported through the spinning space to the collecting electrode are deposited on the collecting electrode. Not all nanofibers are trapped on the supporting linear structure; some nanofibers fly past the collecting electrode and are trapped only on the collecting electrode. This problem is not solved even in an embodiment in which the collecting electrode is formed by a conductive supporting linear structure. Even in this embodiment, the majority of the nanofibers fly past the linear supporting structure and are trapped on the wall of the spinning space.

[0013] The nanofibers are trapped between the fibers at the surface of the core, but during unwinding, the nanofiber coating is pulled away by the forces acting between the surfaces of adjacent fibers within the package, as these forces are greater than the cohesive forces between the nanofiber coating and the core.

[0014] The above-mentioned problems were partly solved by Czech Republic Patent Application No. 2009-797, in which the nanofibers are fixed to the core by at least one decorative thread. The wrapping by the decorative thread ensures a sufficiently strong and durable fixation of the nanofibers to the core for the majority of possible applications, and at the same time, this wrapping allows full utilization of the specificity of the nanofibers, since this wrapping does not hinder access to the nanofibers.

[0015] The actual fiber structure is produced by passing the supported linear structure through the spinning space multiple times. The supported linear structure, outside the spinning space, is returned through a portion of the circumference of at least one cylinder, where it approaches the cylinder at an angle, so that after returning, it faces the spinning electrode on its opposite side. In this embodiment, there is no false twist, so that the supported linear structure does not rotate around its axis when passing through the spinning space. Therefore, nanofibers are deposited on the side of the supported linear structure facing the spinning electrode during each pass. Due to the multiple passes of the supported linear structure through the spinning space, more nanofibers are deposited on the supported linear structure than in previous solutions, but some of the nanofibers fly off to the collecting electrode. The nanofibers are deposited randomly on the surface of the supported linear structure as layers of individual nanofibers, with low cohesion with the nanofiber core surface. The fixation of the nanofibers to the surface of the supported linear structure is then achieved by wrapping with at least one decorative thread.

[0016] EP 2931951 discloses a method for producing polymer nanofibers, in which polymer nanofibers are formed by applying an electric field to a polymer solution or melt placed on the surface of a spinning electrode, the spinning field being formed alternately between the spinning electrode to which an AC voltage is applied and air and / or gas generated and / or supplied in the vicinity of the spinning electrode, without a collecting electrode, whereby, depending on the phase of the AC voltage applied to the spinning electrode, polymer nanofibers with oppositely charged portions and / or polymer nanofibers with oppositely charged portions are formed, the polymer nanofibers agglomerating after the formation of the polymer nanofibers by the action of electrostatic forces into linear structures in the form of cables or belts, which linear structures are free to move in the direction of the electric field gradient in the space away from the spinning electrode.

[0017] Spinning by AC high voltage is another method for producing nanofibers that has replaced electrospinning. However, the yield of this spinning method is not yet at a level that would allow pure nanofiber yarn production by this method. Therefore, EP 3303666 proposed a method for producing core yarns by coating a supporting linear structure that forms the core with a polymer nanofiber coating while the supporting linear structure passes through a spinning chamber. In this method, a spinning electrode connected to a polymer solution inlet and powered by AC high voltage is placed below the supporting linear structure. Nanofibers are formed on the surface of the supporting linear structure in the spinning space immediately adjacent to and above the surface of the spinning electrode, which rotates around its own axis in the spinning space. Nanofibers are formed around the circumference of the surface of the spinning electrode and in the spinning space. The nanofibers are formed into a hollow, electrically neutral nanofiber plume, in which the nanofibers are arranged in an irregular lattice structure where the nanofibers within short sections change direction, in which the hollow, electrically neutral nanofiber plume is carried by the electric wind towards the supporting linear structure and turns into a flat strip, which is carried to the circumference of the supporting linear structure, and the strip made from the hollow, electrically neutral nanofiber plume wraps around the rotating and / or expanding supporting linear structure in a helical shape to create a nanofiber coating on the supporting linear structure, and in which the nanofibers are arranged in an irregular lattice structure where the individual nanofibers within short sections change direction.

[0018] Nanofiber plumes represent an ideal material for coating core yarns because their electroneutrality and irregular lattice structure, in which individual nanofibers within short sections change nanofiber orientation, allow them to form a solid coating that envelops the yarn core, making the coating inert to its surroundings when wound onto the bobbin and during subsequent unwinding during processing. However, if pure nanofiber yarns are produced from nanofiber plumes, problems arise from both the poor quality of the nanofibers and the plume's lattice structure, which does not allow for parallel nanofiber alignment.

[0019] Currently, there are no satisfactory methods for producing nanofibers with potential for industrial applications. Current methods for preparing nanofiber yarns are hampered by low productivity, low reliability, and limited material options. Nanofiber production is only achieved on a laboratory scale as part of research activities.

[0020] See, for example, Zhou B. et al., Developments in Electrospinning of Nanofibrous Yarns, Journal of Physics: Conference Series 1790 (2021) 012081 (DOI: 10.1088 / 1742-6596 / 1790 / 1 / 012081). [Prior art documents] [Patent documents]

[0021] [Patent Document 1] Chinese Patent Application No. 111118677 [Patent Document 2] Chinese Patent Application No. 111286792 [Patent Document 3] Chinese Patent Application No. 110644080 [Patent Document 4] Czech Republic Patent Application No. 2007-179 [Patent Document 5] Czech Republic Patent Application No. 2009-797 [Patent Document 6] European Patent No. 2931951 [Patent Document 7] European Patent No. 3303666 [Non-patent literature]

[0022] [Non-Patent Document 1] Zhou B. et al., Developments in Electrospinning of Nanofibrous yarns, Journal of Physics:Conference Series1790(2021)012081(DOI:10.1088 / 1742-6596 / 1790 / 1 / 012081) Summary of the Invention [Problem to be solved by the invention]

[0023] It is an object of the present invention to provide a method for producing nanofiber yarns by AC electrospinning of polymer solutions or melts, in which the nanofibers should be produced in sufficient quantities, be partially parallelized before twisting, and be strong enough after twisting to allow them to be wound onto bobbins and subsequently used or processed into woven structures by known textile techniques.

[0024] Additionally, it is an object of the present invention to provide an apparatus for carrying out this method. [Means for solving the problem]

[0025] The object of the present invention is achieved by a method for producing linear nanofiber structures by spinning a polymer solution or melt in an AC electric field, and the principle of the present invention is that at least one spinning zone is created on a spinning electrode having a supercritical AC electric field strength and a finite length, and the nanofibers emerging from the spinning electrode are carried by an electric wind away from the spinning zone towards a moving electrically neutral collector in the direction of the maximum value of the electric field gradient, and are deposited on the circumferential surface of the electrically neutral collector, the circumferential surface of which is arranged opposite the spinning zone, forming a collection zone of the moving electrically neutral collector, in the form of a fluffy band of nanofibers, and the fluffy band is moved by the movement of the electrically neutral collector into a drawing zone, in which the fluffy band is drawn from the surface of the electrically neutral collector by a pulling force and subsequently wound onto a bobbin of a winding device, and the nanofibers are at least partially parallelized by the pulling force.

[0026] In a preferred embodiment, the fluffy band of nanofibers is rolled up while moving to the drawing region on the surface of the electrically neutral collector, thereby tapering the fluffy band so that it can be wrapped directly or more easily form twisted triangles when twisted without risk of damage to the edges of the fluffy band of nanofibers during tapering.

[0027] The tension force for drawing the fluffy band of nanofibers is generated by the winding device or by a drawing device arranged between the drawing area and the winding device, which separates the technical tension force from the winding force and thus allows the selection of an appropriate tension force for winding relative to the bobbin structure.

[0028] Before winding or drawing, the fluffy band of nanofibers is acted upon by a twisting device that tapers the fluffy band of nanofibers into a twisted triangle and then imparts a twist to the twisted triangle, thereby forming a nanofiber yarn.

[0029] An important feature of the method is that a twist is imparted to the fluffy band of nanofibers between two clamping points, i.e., the drawing area of ​​the electrically neutral collector and the winding or drawing point of the nanofiber yarn on the bobbin, and the residual twist imparted to the fluffy band of nanofibers by the twisting device is taken up and retained after the nanofibers exit the twisting device.

[0030] An important feature of the method according to the invention is also that the spinning area of ​​the spinning electrode is formed on the circumference of a disk spinning electrode or at the bending point of a belt spinning electrode, where the spinning area is arranged transversely to the direction of movement of the spinning belt or on a linear flexible structure of a linear spinning electrode.

[0031] To carry out the method, an apparatus for producing nanofiber yarns by AC electrospinning of a polymer solution or melt is provided, the principle of which is that an electrically neutral collector coupled to a drive is placed above the spinning electrode in the nanofiber path, the area of ​​the electrically neutral collector surface relative to the spinning electrode forms a nanofiber collection area for continuous deposition of nanofibers in the form of a fluffy band of nanofibers, a drawing area for the fluffy band of nanofibers is formed downstream of the collection area on the surface of the electrically neutral collector in the direction of collector movement, and a winding device is placed downstream of the drawing area in the drawing direction of the fluffy band of nanofibers, which serves to generate a tensile force for drawing the fluffy band of nanofibers from the surface of the electrically neutral belt collector.

[0032] The tension can also be generated in a drawing device arranged between the drawing area and the winding device. In this way, it is possible to separate the technical tension, i.e., the tension and drawing strength associated with expanding the yarn, from the winding tension, i.e., the winding tension. The appropriate winding tension can then be selected for the bobbin configuration.

[0033] In a preferred embodiment, the twisting device is arranged upstream of the winding or drawing device in the drawing direction of the fluffy band of nanofibers, so that the nanofiber yarn is fed into the winding device.

[0034] The spinning electrode can be formed by a disk spinning electrode, a belt spinning electrode or a linear spinning electrode, or by another type of spinning electrode.

[0035] The electrically neutral collector may comprise an electrically neutral drum collector or an electrically neutral belt collector.

[0036] When the electrically neutral collector is formed by an electrically neutral drum collector, a collection area for the nanofibers is formed on the drum collector, which is electrically neutral with respect to the spinning electrode in a preferred embodiment, and a drawing area of ​​the drum collector is formed in the area of ​​the surface of the drum collector facing away from the spinning electrode for drawing out a fluffy band of nanofibers.

[0037] In this embodiment, a rolling means is advantageously assigned to the fluffy band of nanofibers between the collection area and the drawing area of ​​the electrically neutral drum collector, which reduces the width / thickness of the fluffy band of nanofibers and thus simplifies twisting and / or winding of the fluffy band.

[0038] When the electrically neutral collector is formed by a belt collector, this collector is an endless conveyor belt surrounding two upper and two lower cylinders, at least one of which is a drive cylinder. The lower branch of the endless conveyor belt forms a collection area for the nanofibers, which are deposited on the collection area in a fluffy band of nanofibers.

[0039] In a preferred embodiment, the nanofiber fluffy band is fed into the upper branch of the endless conveyor belt by the movement of the endless conveyor belt, and the end of the upper branch in the direction of movement of the endless conveyor belt forms a drawing area for drawing the nanofiber fluffy band from an electrically neutral belt collector. This embodiment makes it possible for a rounding means to be assigned to the nanofiber fluffy band on the upper branch of the endless conveyor belt, which rounds the nanofiber fluffy band to taper and improves the properties of the nanofiber fluffy band for drawing and subsequent twisting.

[0040] In another preferred embodiment, a drawing zone is formed at the lower branch of the endless conveyor belt to draw a fluffy band of nanofibers from an electrically neutral belt collector in the direction of movement of the endless conveyor belt, the fluffy band being connected to a collection zone formed by the lower branch of the endless conveyor belt, on which the nanofibers are deposited in the form of a fluffy band.

[0041] The device according to the invention is represented diagrammatically in the enclosed drawing. [Brief explanation of the drawings]

[0042] [Figure 1] FIG. 1 is a side view of an apparatus with a rotating disk spinning electrode and an electrically neutral drum collector. [Figure 2] FIG. 2 is a front view of the device of FIG. 1. [Figure 3] FIG. 2 is a top view of the device of FIG. 1. [Figure 4] FIG. 10 is a diagram showing the distribution of electric field strength on the circumference of a disk electrode. [Figure 5] FIG. 1 is a side view of an apparatus with a rotating disk spinning electrode and an electrically neutral belt collector. [Figure 6] FIG. 6 is a front view of the device of FIG. 5. [Figure 7] FIG. 6 is a top view of the device of FIG. 5. [Figure 8a]FIG. 1 shows a side view of the apparatus with a belt spinning electrode and an electrically neutral belt collector, along with the drawing region of the fluffy nanofiber band in the upper branch of the collector. [Figure 8b] FIG. 8b is a front view of the device of FIG. 8a. [Figure 8c] FIG. 1 shows a side view of the apparatus with a belt spinning electrode and an electrically neutral belt collector, along with the drawing area of ​​the fluffy nanofiber band in the lower branch of the collector. [Figure 8d] FIG. 8c is a front view of the device of FIG. [Figure 9a] FIG. 1 shows a side view of the apparatus with a linear spinning electrode and an electrically neutral belt collector, as well as the drawing region of the fluffy nanofiber band in the upper branch of the collector. [Figure 9b] FIG. 9b is a front view of the device of FIG. 9a. [Figure 9c] FIG. 1 shows a side view of the apparatus with a linear spinning electrode and an electrically neutral belt collector, as well as the drawing region of the fluffy nanofiber band in the lower branch of the collector. [Figure 9d] FIG. 9c is a front view of the device of FIG. 9c. DETAILED DESCRIPTION OF THE INVENTION

[0043] The apparatus for producing nanofibers by AC electrospinning of a polymer solution or melt comprises a spinning electrode 1, which in the embodiment of Figures 1 to 7 consists of a rotating disk spinning electrode 11, which is mounted with its lower circumferential part in a polymer melt 21 or a melt reservoir 2 and is connected to a known, not shown, device. Since the spinning of a polymer melt is performed in the same way as the spinning of a polymer solution 21, only the spinning of the polymer solution 21 will be described below. The polymer solution usually consists of PVB, PCL, PVA, or other spinnable polymer solutions. The spinning electrode 1 and the polymer solution reservoir 2 are mounted in a spinning chamber 3.

[0044] The spinning electrode 1 is connected to a high-voltage AC source (not shown), for example with an effective voltage of 32 kV and a frequency of 50 Hz. The polymer solution to be spun may be connected to the AC voltage source, and the spinning electrode 1 and the AC voltage source are interconnected via the polymer solution. According to a first exemplary embodiment, the spinning electrode 1 is formed by a rotating disk spinning electrode 11 with a horizontal rotation axis. The rotating disk spinning electrode 11 is mounted with the lower part of its circumference immersed in the polymer solution in the reservoir 2. The rotating disk spinning electrode 11 is coupled to a known rotation drive (not shown), so that during rotation of the rotation drive, the spinning electrode 11 carries the polymer solution 21 to the circumferential part of the surface of the spinning electrode 11. The amount of polymer solution 21 is usually regulated by a known wiping device (not shown). In the spinning chamber 3, near and above the upper part of the circumference of the disk spinning electrode 11, there is a spinning space 31. Above the spinning electrode 1 in the spinning chamber 3, an electrically neutral collector 4 is rotatably mounted, which is coupled to a known drive (not shown). The top of the disk spinning electrode 11 forms the spinning area 110, where the nanofibers 5 are formed, which are transported through the spinning space 31 to the electrically neutral collector 4, which is covered with a suitable coating, for example a flat fabric made of a material that allows easy pulling of the nanofibers from the surface of the electrically neutral collector 4.

[0045] In the embodiment of Figures 1 to 3, the collector 4 is formed by an electrically neutral drum collector 41. The axis of the electrically neutral drum collector 41 is parallel to the axis of the disc spinning electrode 11. The area of ​​the surface of the electrically neutral drum collector 41 facing the disc spinning electrode 11 forms the collection area 410 of nanofibers, on which the nanofibers 5 are deposited in the form of a fluffy band 51 of nanofibers. The area of ​​the surface of the electrically neutral drum collector 41 facing away from the disc spinning electrode 11 forms the drawing area 4101 of the fluffy band 51 of nanofibers.

[0046] Outside the spinning space 31, a twisting device 6 is arranged tangentially to the circumference of the electrically neutral drum collector 41 and in the flow direction of the nanofibers 5 being drawn off, and it consists, for example, of a rotary guide eyelet arranged outside the rotation axis of the twisting device 6 or the rotation axis of another known twisting device. A winding device 7 with a bobbin 71 is arranged downstream of the twisting device 6 in the flow direction of the drawn nanofibers 5 and in the direction of drawing off the yarn 54. In an exemplary embodiment not shown, a drawing device is arranged between the drawing zone 4101 and the winding device 7, which serves to create a pulling force for drawing off a fluffy band 51 of nanofibers from the surface of the electrically neutral collector.

[0047] The effective value of the voltage, for example 32 kV, the waveform of the voltage function, for example sine wave, sawtooth wave, step wave, and the frequency, for example 50 Hz, are not limiting, and a wide range of other suitable values ​​can be used.

[0048] During rotation, the disk spinning electrode 11 carries the polymer solution 21 from the reservoir 2 on its circumference and on parts of its surface near its circumference. During spinning in an AC electric field, the objective is to produce the maximum possible number of nanofibers 5 per unit time; the nanofibers 5 are formed over the entire spinning area 110 of the disk spinning electrode 11 and carried away from the disk spinning electrode 11 by an electric wind in the direction of the gradient of the generated electric field, optionally also by an auxiliary air stream, to an electrically neutral collector 41, which is not grounded or connected to a voltage source. The formation of nanofibers 5 begins at a critical value of the electric field strength E, which depends on the type of polymer solution 21 to be spun, the waveform, the frequency of the AC voltage, the quality of the gas in the spinning chamber 3, and other parameters. Below the critical value of the electric field strength E, nanofibers 5 do not form or the formation of fibers 5 stops.

[0049] The critical value of the electric field strength E for the purposes of AC electrospinning means the minimum value of the electric field strength E that results in a sufficient amount of nanofibers for further technological processing for a given geometry of the spinning electrode, type of polymer solution, and values ​​of frequency and waveform.

[0050] Therefore, during conventional spinning in an AC electric field with a detailed design of the spinning electrode 1, an electric field strength E higher than the critical strength, i.e., supercritical strength E, is used for the selected frequency of the electric field and the waveform of the electric field, which creates a high-intensity electric field E on the spinning electrode 1 to ensure sufficient evaporation of the solvent from the emerging Taylor cone of the polymer solution and to supply a sufficiently strong electric wind to the formed nanofibers 5 to the electrically neutral collector 4 in order to prevent the risk of interrupting the spinning process.

[0051] The distribution of electric field strength E for the above-described conventional spinning of polymer solution 21 on the disc spinning electrode 11 is shown in Figure 4 for a disc diameter of 300 mm, a disc thickness of 1 mm, a polymer solution layer thickness of 0.2 mm, and a voltage amplitude of 50 kV. The supercritical value of electric field strength E for PVB polymer solution is greater than 3000 MV / m. From the figure, it is clear that the supercritical value of electric field strength E is obtained within a wide area around the circumferential portion of the disc spinning electrode 11. Thus, spinning of polymer solution 21 occurs over the entire width of the circumferential surface of the disc spinning electrode 11 and on a portion of the surface of the disc spinning electrode 11 near the circumference of the disc spinning electrode 11. The formed nanofibers 5 are transported away from the disc spinning electrode 11 in the direction of the generated electric field gradient through the spinning space 31 to the surface of the electrically neutral drum collector 41 and to the collection area 410 of the drum collector. If necessary, the effect of electric wind is assisted by flowing air in the required direction. Considering the size of the region of supercritical field strength E, it is clear that a sufficient amount of nanofibers 5 is produced for further processing of the nanofibers.

[0052] Nanofibers 5 are deposited on the circumferential collection area 410 of the electrically neutral drum collector 41, becoming a narrow fluffy band of nanofibers 51. By rotating the drum collector 41, the fluffy band of nanofibers 51 is carried to the top of the electrically neutral drum collector 41, i.e., to the drawing area 4101, where the fluffy band 51 is drawn. The fluffy band of nanofibers 51 produced by AC electrospinning consists of a three-dimensional layer of nanofibers 5 that are deposited on the surface of the electrically neutral drum collector 41 by the action of an electric wind and the attractive forces between oppositely polarized portions of the nanofibers 5, and are partially paralleled during deposition, so that the fluffy band of nanofibers 51 represents a linear nanofiber structure. The nanofiber fluffy band 51 can be drawn in a three-dimensional shape from the surface of the drawing area 4101 of the electrically neutral drum collector 41, and then the fluffy band 51 can be drawn and twisted to form intertwined triangles 52 and nanofiber yarns 54 from the fluffy band 51 in a manner similar to that used when processing fiber strands to impart a permanent twist to the yarn.

[0053] When nanofibers are produced by DC electrospinning on a similar device, a drum collector acts as a collecting electrode connected to the opposite polarity of the DC voltage as the spinning electrode, and the nanofibers are deposited on the collecting electrode in a flat, very thin band that, after being pulled from the drum, behaves as a solid, flat structure that is subsequently twisted into the helix formed by the band.

[0054] The circumferential speed of the electrically neutral drum collector 41 is adjusted so that the fluffy band 51 of nanofibers produced on the drum collector 41 is mechanically sufficiently resistant when the band 51 is pulled from the surface of the electrically neutral drum collector 41 in the pulling area 4101 of the band 51, for subsequent twisting or for direct winding onto the bobbin 71 of the winding device 7.

[0055] The fluffy band of nanofibers 51 is drawn from the rotating electrically neutral drum collector 41 and guided to the twisting device 6, whereupon the fluffy band 51 tapers into a twisted triangle 52. From the twisted triangle 52, under the action of the twisting device 6 and the force moment transmitted from the twisting device 6 by the partially twisted nanofibers 5, the fluffy band of nanofibers 51 tapers and simultaneously twists into a nanofiber yarn 54. Because the nanofibers 5 of the fluffy band of nanofibers 51 are deposited on the electrically neutral drum collector 41 with a certain degree of adhesion, tension is generated in the nanofibers 5 when they are released from the surface of the electrically neutral drum collector 41 in the drawing region 4101, and this tension must be used to parallelize the nanofibers 5 before they can be twisted. As a result, the formation of twists, and therefore nanofiber yarns 54, occurs only after the nanofibers have been partially parallelized. In addition, the drawing of the fluffy band 51 of nanofibers from the surface of the electrically neutral drum collector 41 occurs due to drafting between two clamping points, i.e., between the surface of the collector 41 and the winding point on the bobbin 71, causing the nanofibers 5 to be stretched and partially parallel to the nanofiber flow direction, which facilitates helical arrangement of the nanofibers 5 when they are subsequently twisted together and therefore ensures sufficient strength of the produced nanofiber yarn 54.

[0056] During twisting, the nanofibers are no longer parallel but twist into a spiral. If the drawing is done at a speed faster than the collector speed, the nanofibers straighten / stretch at the moment of drawing, but then immediately start twisting into a triangular spiral.

[0057] After drawing the nanofibers 5 from the drawing region 4101 of the electrically neutral drum collector 41, the fluffy band 51 of nanofibers being drawn is formed into twisted triangles 52 by the twisting device 6, from which the twisted triangles 52 become nanofiber yarns 54, which expand before entering the twisting device 6. The twist propagates from the twisting device 6 towards the electrically neutral drum collector 41 against the technological direction of flow of the nanofibers 5, thus aiding in the drawing of the fluffy band 51 of nanofibers from the drawing region 4101 of the drum collector 41.

[0058] The twisting device 6 imparts a twist to the nanofiber yarn 54 between two clamping points, i.e., between the draw zone and the winding or withdrawal point, which would result in a false twist in a yarn made from conventional fibers that would be canceled out after passing through the twisting device. This is not the case with the twisting of nanofiber yarns 54, because due to the high surface area of ​​the nanofibers 5, the cohesion between the individual nanofibers 5, and the low twist coefficient, a relatively high degree of twist is retained as residual twist on the nanofiber yarn 54 downstream of the twisting device 6. Experiments performed on nanofibers made from different types of polymers have shown that the residual twist is 10-60% of the twist, and therefore the residual twist is permanent. In certain tests, at a twisting device speed of approximately 10,000 rpm, the residual twist was approximately 1,400 twists per meter of yarn length. The nanofiber yarn 54 is then wound onto a bobbin 71 in a winding device 7 in a known manner.

[0059] To increase the strength and uniformity of the produced nanofiber yarn 54, it is advantageous to roll the nanofiber fluffy band 51 on the drum collector 41 before drawing it from the electrically neutral drum collector 41, thereby narrowing the nanofiber fluffy band 51, achieving a more uniform application of the force holding the nanofibers on the surface of the electrically neutral drum collector 41, easier drawing of the nanofibers 5 within the drawing region 4101 of the electrically neutral drum collector 41 across the entire cross section of the nanofiber fluffy band 51, and a smooth transition of the nanofibers 5 into twisted triangles. At the same time, the rolling reduces the base of the twisted triangle 52, thereby reducing the tensile forces within the circumferential portion of the nanofiber fluffy band 51 and therefore the risk of the nanofiber fluffy band 51 breaking during drawing from the drawing area 4101 of the electrically neutral drum collector 41. The linear structure formed by rolling the nanofiber fluffy band 51 can also be used for winding directly onto the bobbin 71 of the winding device 7 without twisting on the twisting device 6.

[0060] Further strength of the nanofiber yarn 54 produced can be achieved, for example, by twisting the nanofiber yarn 54 with a permanent twist on a suitable device (not shown).

[0061] The amount of nanofibers 5 formed, the circumferential speed of the electrically neutral drum collector 41, and the drawing speed of the fluffy band of nanofibers 51 determine the linear mass of the nanofiber yarn 54, which is crucial to the resulting strength of the nanofiber yarn 54.

[0062] In another alternative embodiment of the device according to the invention, the electrically neutral drum collector 4 is formed by a belt collector 42 arranged in the spinning chamber 3 above the rotating disk spinning electrode 11, as shown in Figures 5 to 7. The belt collector 42 comprises an endless conveyor belt 421 surrounding two upper cylinders 422 and two lower cylinders 423, at least one of which is a drive cylinder. The rotation axes of all cylinders 422, 423 of the belt collector 42 are parallel to the rotation axis of the disk spinning electrode 11. 5-7, the endless conveyor belt 421 moves counterclockwise, and the lower branch 4211 of the belt 421, located between the lower cylinders 423, is positioned against the spinning zone 110 of the rotating disk spinning electrode 11, so that the nanofibers 5 formed in the spinning zone 110 of the rotating disk spinning electrode 11 are deposited on the lower branch of the endless conveyor belt 421 into a fluffy band of nanofibers 51. The lower branch 4211 of the endless conveyor belt 421 thus forms the collecting zone 420 of the electrically neutral drum collector 42. Due to the direction of movement of the endless conveyor belt 421, in this embodiment, the fluffy band of nanofibers 51 transferred to the upper branch 4212 of the endless conveyor belt 421 forms the drawing area 4201 of the electrically neutral drum collector 42 at the end of the upper branch 4212, from which the fluffy band of nanofibers 51 is drawn and guided to the twisting device 6, which imparts a twist to the fluffy band 51. After drawing, the fluffy band of nanofibers 51 tapers into twisted triangles 52 due to the twisting action, as described in the previous variant of the device with an electrically neutral drum collector 41, and is subsequently formed into nanofiber yarns 54. This arrangement allows a larger amount of nanofibers 5 to be deposited on the electrically neutral belt collector 42, thereby making it possible to form a fluffy band of nanofibers 51 with a greater thickness and weight.In addition, this arrangement provides sufficient space above the upper branch 4212 of the endless conveyor belt 421 for rolling the fluffy band of nanofibers 51 with known rolling means not shown. When the endless conveyor belt 421 moves in the opposite direction, the drawing-out area 4201 is again formed at the end of the upper branch 4212 of the endless conveyor belt 421, but according to the figure, the drawing-out area 4201 is on the right side.

[0063] In an alternative embodiment of this arrangement, not shown, by changing the direction of rotation of the drive cylinder of one of the cylinders 422, 423 around which the endless conveyor belt 421 is wound, it is possible to change the position of the drawing area 4201 of the fluffy band of nanofibers 51 and to position the drawing area 4201 of the fluffy band of nanofibers 51 at the end of the lower branch 4211 in the direction of movement of the endless conveyor belt 421. Thus, the deposition of nanofibers 5, the formation of the fluffy band of nanofibers 51 and the drawing of the nanofibers take place on the lower branch 4211 of the endless conveyor belt 421 of the electrically neutral belt collector 42, while the upper branch 4212 is empty.

[0064] In the arrangement of the device according to Figures 5 to 7, the rotating disk spinning electrode 11 can be replaced by a spinning electrode with a direct spinning area, which can consist of a belt spinning electrode 12 or a linear spinning electrode 13 formed of a linear flexible structure, as will be explained below.

[0065] An apparatus with a belt spinning electrode 12 is shown in Figures 8a-8d. The apparatus comprises a reservoir 2 of polymer solution 21 and an unwinding shaft 8 connected to a drive 81, with part of the circumference of the unwinding shaft 8 extending into the polymer solution 21. On top of the unwinding shaft 8, a blade 121 is fixedly mounted in the spinning chamber 3 on the apparatus frame, for example by a strut 82. The unwinding shaft 8 together with the blade 121 is wrapped around a spinning belt 122, which extends from the polymer solution 21 and curves over the blade 121 on the unwinding shaft 8. The spinning belt 122 carries the polymer solution 21 out of the reservoir 2, and the curve of the spinning belt 122 forms the spinning region 120 of the belt spinning electrode 12, which is connected to an AC voltage source. Above the spinning area 120 of the belt spinning electrode 12, at least along the entire width of the spinning area 120, the lower branch 4211 of the endless conveyor belt 421 of the electrically neutral belt collector 42 is arranged, as shown in Figure 8b.

[0066] The electrically neutral belt collector 42 is constructed in the same manner as in the embodiment according to Figs. 5 to 7. The belt collector 42 comprises an endless conveyor belt 421 surrounding two upper cylinders 422 and two lower cylinders 423, at least one of which is a drive cylinder. The rotation axes of all cylinders 422, 423 of the belt collector 42 are perpendicular to the rotation axis of the unwinding shaft 8. In the embodiment according to Figs. 8a and 8b, the endless conveyor belt 421 moves counterclockwise, and the lower branch 4211 of the belt 421, located between the lower cylinders 423, is positioned relative to the spinning zone 120 of the belt spinning electrode 12. The nanofibers 5 formed in the spinning zone 120 of the belt spinning electrode 12 are deposited on the lower branch of the endless conveyor belt 421 to form a fluffy band 51 of nanofibers. The lower branch 4211 of the endless conveyor belt 421 represents the collection area 420 of the electrically neutral belt collector 42. In this embodiment, with respect to the direction of movement of the endless conveyor belt 421, the fluffy band of nanofibers 51 is transferred to the upper branch 4212 of the endless conveyor belt 421, the end of which forms the drawing area 4201 of the electrically neutral drum collector 42, from which the fluffy band of nanofibers 51 is drawn off and guided in the direction of the arrow to the twisting device 6, which imparts a twist to the fluffy band 51. After drawing off, the fluffy band of nanofibers 51 is tapered by a twisting action into twisted triangles 52, from which nanofiber yarns 54 are subsequently formed, as described in the previous variant of the device with an electrically neutral drum collector 41. As already mentioned above, the direction of movement of the endless conveyor belt can be reversed, the arrangement described above being merely turned sideways.

[0067] An alternative embodiment of this arrangement of the apparatus for producing nanofiber yarns is shown in Figures 8c and 8d. In this embodiment, the rotation direction of the drive cylinders 422, 423 around which the endless conveyor belt 421 is wound is such that the endless conveyor belt moves clockwise, as shown in Figure 8d. The other parts of the apparatus and their functions remain the same as those in the embodiment of Figures 8a and 8b. As a result, the deposition of nanofibers 5, the formation of the fluffy band of nanofibers 51, and the drawing of nanofibers take place on the lower branch 4211 of the endless conveyor belt 421 of the electrically neutral belt collector 42, while the upper branch 4212 is empty. Therefore, the drawing area 4201 of the electrically neutral belt collector 42, where the fluffy band of nanofibers 51 is drawn from the endless conveyor belt 421, is at the end of the lower branch 4211 of the endless conveyor belt 421. The fluffy band 51 of nanofibers is fed from the drawing area 4201 in the direction of the arrow to a twisting device where, as described above, the fluffy band 51 is twisted into a yarn 54. As already mentioned above, the direction of movement of the endless conveyor belt can be reversed, the arrangement described above simply being turned sideways.

[0068] In the embodiment with a linear spinning electrode 13, the linear spinning electrode 13 consists of an endless linear flexible structure, which in the embodiment shown in Figures 9a-9d is mounted on two rotatably mounted pulleys 131 which are coupled to a drive, not shown. At least one of the pulleys 131 has a part of its circumference extending to a reservoir 2 of polymer solution 21. In the embodiment shown, each pulley 131 has its own reservoir 2 of polymer solution 21.

[0069] The linear flexible structure consisting of the linear spinning electrode 13 can be formed by a string, belt, strap or structure with a more fragmented surface consisting of a plurality of intertwined parts, for example a cable, cord, multi-core formation, etc. As in the previous embodiment, a spinning area 130 of finite length is formed on the linear spinning electrode 13 between the pulleys 131. The spinning area 130 is connected to an AC voltage source by one of the known methods.

[0070] An electrically neutral belt collector 42 is arranged above the spinning area 130 of the linear spinning electrode 13, and the lower branch 4211 of the belt collector 42 is arranged over at least the entire length of the spinning area 130 of the linear spinning electrode 13, as shown in Figures 9b and 9d. The electrically neutral belt collector 42 is constructed similarly to that of the previous embodiment and comprises an endless conveyor belt 421 surrounding two upper cylinders 422 and two lower cylinders 423, at least one of which is a drive cylinder. The rotation axes of all cylinders 422, 423 of the belt collector 42 are parallel to the axis of the pulley 131. 9a and 9b, the endless conveyor belt 421 moves counterclockwise, and the lower branch 4211 of the belt 421, located between the lower cylinders 423, is positioned relative to the spinning area 130 of the linear spinning electrode 13, so that the nanofibers 5 formed in the spinning area 130 of the linear spinning electrode 13 are deposited on the lower branch of the endless conveyor belt 421 into a fluffy band of nanofibers 51. The lower branch 4211 of the endless conveyor belt 421 therefore represents the collecting area 420 of the electrically neutral belt collector 42. In this embodiment, with respect to the direction of movement of the endless conveyor belt 421, the fluffy band 51 of nanofibers is transferred to the upper branch 4212 of the endless conveyor belt 421, the end of which forms the drawing area 4201 of the electrically neutral belt collector 42, from which the fluffy band 51 of nanofibers is drawn off and guided in the direction of the arrow into the twisting device 6, where the fluffy band 51 is twisted to form nanofiber yarn. As mentioned above, the direction of movement of the endless conveyor belt can be reversed, the above-mentioned arrangement being merely reversed on its side.

[0071] An alternative embodiment of this arrangement of the apparatus for producing nanofiber yarns is shown in Figures 9c and 9d. In this embodiment, the direction of movement of the endless conveyor belt 421 is changed, so that it moves clockwise, as shown in Figure 9d. The other parts of the apparatus and their functions remain the same as in the embodiment according to Figures 9a and 9b. As a result, the deposition of nanofibers 5, the formation of the fluffy band 51 of nanofibers, and the drawing of nanofibers take place on the lower branch 4211 of the endless conveyor belt 421 of the electrically neutral belt collector 42, while the upper branch 4212 is empty. The drawing area 4201 of the electrically neutral belt collector 42 is therefore at the end of the lower branch 4211 of the endless conveyor belt 421. The fluffy band 51 of nanofibers is fed from the drawing area 4201 in the direction of the arrow to a twisting device, which twists the fluffy band 51 to form nanofiber yarns. As mentioned above, the direction of movement of the endless conveyor belt can be reversed, the arrangement described above is simply turned sideways.

[0072] In an embodiment with a linear spinning electrode 13, the endless linear flexible structure can be replaced by a finite length linear flexible structure wound around pulleys 131. Both pulleys 131 extend in this embodiment with the lower part of the circumference of the pulley extending to the polymer solution 21. The pulleys 131 are coupled to a known, not shown, reciprocating drive and rotate alternately in both directions, with the linear flexible structure held in tension between the pulleys. [Industrial Applicability]

[0073] Fiber-made yarns and threads are the most commonly used structural elements in the textile industry for the production of various types of textiles, such as fabrics and knitwear. The use of 100% nanofiber yarns in conventional methods of textile production means the possibility of producing so-called nanotextiles, which exhibit excellent optical, electrical, mechanical, and biological properties due to effects related to the extremely large specific surface area and low flexibility (bending modulus) of nanotextiles.

[0074] Nanofiber yarns have applications as structural units in surgical braids, tissue carriers for repairing nerves, tendons, bones, and blood vessels, and have the potential to be structural elements for energy harvesting and storage, for actuators in mechatronic devices, and for sensors and filters. [Explanation of symbols]

[0075] 1. Spinning electrode 11. Rotating disk spinning electrode 110 Spinning area of ​​rotating disk spinning electrode 12 Belt spinning electrode 120 Belt spinning electrode spinning area 121 Blade 122 Spinning Belt 13 Linear spinning electrode 130 Spinning area of ​​linear spinning electrode 131 Pulley 2. Polymer solution reservoir 21 Polymer Solution 3. Spinning chamber 31 Spinning Space 4. Electrically neutral collector 40 Electrically neutral collector collection area 401 Electrically neutral collector extraction region 41 Drum Collector 410 Drum Collector Collection Area 4101 Drum collector extraction area 42 Belt Collector 420 Belt Collector Collection Area 4201 Belt collector pull-out area 421 Endless Conveyor Belt 4211 Endless conveyor belt lower branch 4212 Endless conveyor belt upper branch 422 Upper Cylinder 423 Lower Cylinder 5 Nanofiber 51 Nanofiber fluffy band 52 Twisted Triangle 54 Nanofiber Yarn 6. Twisting device 7 Winding device 71 Bobbin 8 Rewind shaft 81 Drive unit 82 Pillar E field strength

Claims

1. A method for producing linear nanofiber structures from a polymer solution or melt in an alternating current electric field, in which a spinning zone (110, 120, 130) having a supercritical alternating current electric field strength E is formed on a spinning electrode (1, 11, 12, 13), in which nanofibers (5) are formed in the spinning zone (110, 120, 130), and the nanofibers (5) are carried away from the spinning electrode by the action of an electric wind in the direction of the maximum value of the gradient of the generated electric field, the method comprising: forming at least one spinning zone (110, 120, 130) having a supercritical alternating current electric field strength (E) and a finite length on a linear spinning electrode, and carrying the emerging nanofibers (5) from the spinning zone (110, 120, 130) away from the spinning zone towards a moving electrically neutral collector (4, 41, 42) in the direction of the maximum value of the electric field gradient, by the action of an electric wind; The nanofibers are carried by the air current and deposited on the circumferential surface of the electrically neutral collector (4, 41, 42), which circumferential surface is positioned relative to the spinning area, forming a collection area (40, 410, 420) of the moving electrically neutral collector (4, 41, 42), in the form of a fluffy band (51) of nanofibers, which is drawn out together with the movement of the electrically neutral collector (4, 41, 42). and the nanofibers (5) are continuously moved to a drawing zone (401, 4101, 4201) in which the fluffy band (51) is drawn from the surface of the electrically neutral collector (4, 41, 42) by a pulling force and subsequently wound onto a bobbin (71) of a winding device (7), the nanofibers (5) being at least partially parallelized by the pulling force.

2. 2. The method of claim 1, wherein the fluffy band (51) of nanofibers is rolled up during its movement to the drawing region (401, 4101, 4201) on the surface of the electrically neutral collector (4, 41, 42) and thereby narrowed into a ribbon of nanofibers.

3. 3. A method according to claim 1 or 2, characterized in that during drawing of the fluffy band (51) of nanofibers, a tensile force is generated by the winding device (7).

4. 3. The method according to claim 1 or 2, characterized in that during the drawing of the fluffy band (51) of nanofibers, a pulling force is generated by a drawing device arranged between the drawing area and the winding device.

5. 5. The method according to claim 1, wherein upstream of the winding device (7) or the drawing device, a twisting device (6) acts on the fluffy band of nanofibers (51), which twists the fluffy band of nanofibers (51) into twisted triangles (52) and subsequently imparts a twist to the twisted triangles (52), thereby forming a nanofiber yarn (54).

6. 6. The method of claim 5, wherein the residual twist imparted to the fluffy band of nanofibers (51) by the twisting device (6) is maintained after exiting the twisting device, thereby forming a nanofiber yarn (54).

7. 10. An apparatus for producing linear nanofiber structures from a polymer solution or melt in an AC electric field using the method according to any one of claims 1 to 6, wherein a spinning zone (110, 120, 130) with a supercritical value of the AC field strength (E) is created on a spinning electrode (1, 11, 12, 13) mounted in a spinning chamber and connected to a high-voltage AC source and coupled to a means for applying the polymer solution or melt to the surface of the spinning electrode, in which above the spinning electrode (1, 11, 12, 13) an electrically neutral collector (4, 41, 42) coupled to a drive is arranged in the path of the nanofibers (5), and on the surface of the electrically neutral collector (4, 41, 42) The device is characterized in that the area for the spinning electrode (1, 11, 12, 13) forms a collection area (40, 410, 420) of nanofibers for continuous deposition of nanofibers in the form of a fluffy band (51) of nanofibers, and a drawing area (401, 4101, 4201) of the fluffy band of nanofibers (51) is formed downstream of the collection area on the surface of the electrically neutral collector (4, 41, 42) in the direction of movement of the collector, and a winding device (7) for generating a pulling force for drawing the fluffy band of nanofibers from the surface of the electrically neutral collector is arranged downstream of the drawing area in the drawing direction of the fluffy band of nanofibers (51).

8. 8. The device according to claim 7, characterized in that a drawing device is arranged between the drawing area (401, 4101, 4201) and the winding device (7), the drawing device serving to generate a pulling force for drawing the fluffy band of nanofibers from the surface of the electrically neutral collector (4, 41, 42).

9. 9. Apparatus according to claim 7 or 8, characterized in that a twisting device (6) is arranged upstream of the winding device (7) or the drawing device in the drawing direction of the fluffy band (51) of nanofibers.

10. 10. Apparatus according to any one of claims 7 to 9, characterized in that the spinning electrode is formed by a rotating disk spinning electrode (11).

11. 10. Apparatus according to any one of claims 7 to 9, characterized in that the spinning electrode is formed by a belt spinning electrode (12).

12. 10. Apparatus according to any one of claims 7 to 9, characterized in that the spinning electrode is formed by a linear spinning electrode (13).

13. 13. Device according to any one of claims 7 to 12, characterized in that the electrically neutral collector is formed by an electrically neutral drum collector (41).

14. 14. The device according to claim 13, characterized in that on the electrically neutral drum collector (41) a collection area (410) of the nanofibers (5) of the electrically neutral drum collector (41) is formed in an area relative to the spinning electrode (1, 11, 12, 13), and in an area of ​​the surface of the drum collector (41) facing away from the spinning electrode (1, 11, 12, 13) a drawing area (4101) of the drum collector is formed for drawing out the fluffy band (51) of nanofibers.

15. 15. The device according to claim 14, characterized in that a rolling means is assigned to the fluffy band (51) of nanofibers between the collection area (410) and the drawing area (4101) of the electrically neutral drum collector (41).

16. 13. Device according to any one of claims 7 to 12, characterized in that the electrically neutral collector is formed by an electrically neutral belt collector (42).

17. 17. The apparatus according to claim 16, characterized in that the electrically neutral belt collector (42) comprises an endless conveyor belt (421) surrounding two upper cylinders (422) and two lower cylinders (423), at least one of which is a drive cylinder, and a lower branch (4211) of the endless conveyor belt (421) forms a collection area (420) of nanofibers (5) for depositing the nanofibers in the fluffy band (51) of nanofibers.

18. 18. The device according to claim 17, characterized in that the endless conveyor belt (421) has an upper branch, the end of which in the direction of movement of the endless conveyor belt (421) forms the drawing area (4201) for drawing the fluffy band (51) of nanofibers from the electrically neutral belt collector (42).

19. 19. Device according to claim 18, characterized in that on the upper branch (4212) of the endless conveyor belt (421) the fluffy band (51) of nanofibers is assigned a rolling means.

20. 18. The device according to claim 17, characterized in that at the end of the lower branch (4211) of the endless conveyor belt (421) in the direction of movement of the endless conveyor belt (421), the drawing area (4201) is created for drawing the fluffy band (51) of nanofibers from the electrically neutral belt collector (42), and the fluffy band (51) is connected to the collection area (420) formed by the lower branch (4211) of the endless conveyor belt (421) for depositing the nanofibers (5) in the form of a fluffy band (51).

Images