EP4225982A1 - Method of spinning a polymer solution or melt using alternating electric voltage and a device for performing the method - Google Patents

Method of spinning a polymer solution or melt using alternating electric voltage and a device for performing the method

Info

Publication number
EP4225982A1
EP4225982A1 EP22712796.6A EP22712796A EP4225982A1 EP 4225982 A1 EP4225982 A1 EP 4225982A1 EP 22712796 A EP22712796 A EP 22712796A EP 4225982 A1 EP4225982 A1 EP 4225982A1
Authority
EP
European Patent Office
Prior art keywords
spinning
spinning electrode
reels
melt
polymer solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22712796.6A
Other languages
German (de)
French (fr)
Inventor
Jaroslav Beran
Jan Valtera
Martin BILEK
Josef SKRIVANEK
Petr Zabka
Ondrej BATKA
Martin Diblik
David Lukas
Pavel Pokorny
Eva Kuzelova Kostakova
Vera Jencova
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Technicka Univerzita v Liberci
Original Assignee
Technicka Univerzita v Liberci
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Technicka Univerzita v Liberci filed Critical Technicka Univerzita v Liberci
Priority claimed from PCT/CZ2022/050016 external-priority patent/WO2022174846A1/en
Publication of EP4225982A1 publication Critical patent/EP4225982A1/en
Pending legal-status Critical Current

Links

Classifications

    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
    • D04H1/72—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged
    • D04H1/728—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged by 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
    • 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
    • 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
    • D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
    • D01D5/0092—Electro-spinning characterised by the electro-spinning apparatus characterised by the electrical field, e.g. combined with a magnetic fields, using biased or alternating fields

Definitions

  • the invention relates to a method of spinning a polymer solution or melt using alternating current voltage.
  • the invention relates to a device for performing this method.
  • DC voltage of one polarity is supplied to at least one spinning electrode formed by a tube, a capillary tube or a nozzle, or by a moving body, e.g., a cylinder (see, e.g., CZ 294274), and DC voltage of opposite polarity is supplied to at least one counter electrode, so-called collecting electrode, arranged opposite the spinning electrode/electrodes.
  • some of the electrodes or of groups of electrodes may be grounded.
  • an electrostatic field is created between the collecting electrode/electrodes and the spinning electrode/electrodes, which acts by the electrostatic force on the polymer solution or melt which is fed into the field through a cavity in the spinning electrode or on the surface of the spinning electrode, the electrostatic force forming on the surface of the polymer solution or melt the so-called Taylor cones, from which polymer nanofibres are subsequently elongated.
  • the polymer nanofibres are then carried by the force of the electrostatic field towards the collecting electrode/electrodes and are usually captured on the surface of a static or moving collector, most often a textile fabric, before coming into contact with the collecting electrode/electrodes.
  • CZ patent 304137 discloses a method of producing polymer nanofibres by the electrospinning of a polymer solution or melt in which alternating current (AC) voltage is used, which is supplied to the spinning electrode/electrodes.
  • AC alternating current
  • An electric field is created between the spinning electrode and a so-called virtual counter- electrode formed by oppositely charged air and/or gas ions, which are generated in the vicinity of the spinning electrode/electrodes by the ionization of ambient air or gas and/or which are supplied to the vicinity of the spinning electrode from an ion source, and/or by oppositely charged nanofibres formed in the preceding moment.
  • the individual nanofibres or even different sections of the individual nanofibres carry opposite electric charges, as a result which, almost immediately after their formation by electrostatic Coulomb forces, they aggregate to form a voluminous structure in the form of a plume, in which individual polymer nanofibres change their direction in segments with a length in the order of micrometres forming an irregular grid structure of densely interconnected nanofibres with repeating points of contact between them.
  • This grid structure can be used, for example, for covering various surfaces, including threads - see, e.g., CZ 306428, etc.
  • the advantage of this method is that it does not require the use of a physical counter electrode and the formed structure consisting of nanofibres is not electrically charged, which makes it more advantageous for many applications than electrostatic spinning using DC voltage; for the same reason, the formed structure is also easier to manipulate.
  • CZ 306772 discloses a method of producing polymer nanofibres by electrospinning a polymer solution or melt using alternating current (AC) voltage, in which excess of polymer solution or melt is fed to a spinning surface formed on an extended face of a capillary-shaped spinning electrode, part of the polymer solution or melt is spun and the rest washes the spinning surface of the spinning electrode and flows by action of gravity from the spinning surface onto an adjoining drainage surface, where spinning no longer occurs.
  • AC alternating current
  • CZ 306772 also discloses several embodiments of a spinning electrode with an extended face designed for the above-described method of electrospinning, whose common feature is that a spinning surface is formed around at least a part of a mouth of a conduit of the solution or polymer melt, the spinning surface being rounded downwards below the mouth.
  • the disadvantage of currently known methods of electrospinning a polymer solution or melt using AC voltage and of the spinning electrodes designed for these methods is especially the fact that the spinning electrode is completely separated from a reservoir of the polymer solution or melt and the spinning material is fed into the spinning electrode cavity by a conduit formed by hoses or tubes.
  • This arrangement not only increases the volume of the polymer solution or melt that must be available in the spinning device any time and the pressures required to transport it, but also the volume of the polymer solution or melt that is not spun eventually, which in the case of some types of polymers significantly increases the cost of the preparation of nanofibres.
  • Another disadvantage is also the fact that a larger volume of polymer solution or melt usually also has a larger surface area or larger area of the interface between the solution/melt and the tube/hose wall, which may result in faster solidification or degradation of the polymer solution or melt - in the case of a solution caused by faster solvent evaporation, in the case of the melt caused mainly by its faster cooling.
  • a fundamental disadvantage of the existing devices for electric and electrostatic spinning is also the fact that in order to transport the polymer solution or melt from the reservoir to the spinning surface of the spinning electrode, the peristaltic pumps are typically used, which cause “pulsation” of the solution or polymer melt flow on the spinning surface of the spinning electrode, which, due to the change in the volume of the solution or melt currently present on this spinning surface, the movement of the level of the polymer solution or melt and the change in its shape, significantly worsens the uniformity of the spinning process and of the nanofibres formed.
  • nanofibres are formed on a relatively small spinning area of the spinning electrode, so that in order to increase productivity and to form a planar layer of nanofibres, it is necessary to use a larger group of mutually suitably arranged spinning electrodes.
  • the layer of polymer nanofibres being formed is not completely homogeneous.
  • the objective of the invention is therefore to propose a method of spinning a polymer solution or melt using AC voltage and a device for performing the method, which would not suffer from these disadvantages and allow to fully exploit the potential of electrospinning a polymer solution or melt using AC voltage.
  • the objective of the invention is achieved by a method of spinning a polymer solution or melt using AC voltage supplied to a spinning electrode and/or to the polymer solution or melt, whose principle consists in that the spinning electrode formed by a linear flexible structure is wound during spinning between two driven reels which are around their circumference provided with a spiral groove, whereby this spinning electrode is unwound from the spiral groove of one reel and simultaneously wound into the spiral groove of the other reel, wherein the part of the spinning electrode wound on any of the reels does not extend beyond its circumference, at least one of these reels with the part of the spinning electrode wound in its spiral groove wades in the polymer solution or melt stored in the reservoir, whereby the solution or melt of polymer is deposited on the surface of this part of the spinning electrode and is spun therefrom in the space between the reels during subsequent rewinding from the spiral groove of this reel to the spiral groove of the other reel.
  • Spinning takes place along the entire circumference of the spinning electrode and, preferably, also along the entire length of its active part, whereby the nanofibres formed by the action of Coulomb forces aggregate into a voluminous structure which moves away from the spinning electrode due to the action of an electric wind driven by ions generated by corona discharges of the electric field in the vicinity of the spinning electrode.
  • This process makes it possible to form uniform planar layers of nanofibres with high spinning output. These planar layers can be used, among other things, for the formation of linear structures - e.g., yarns, etc.
  • the entire active part of the spinning electrode when performing the additional reciprocating movement, moves in the same direction or the opposite ends of the active part of the spinning electrode move in mutually opposite directions.
  • the reels perform reciprocating rotary movement during spinning, changing the sense of their rotation as well as the sense of movement of the active part of the spinning electrode in the direction of its longitudinal axis.
  • the reels perform rotary movement during spinning, whereby the sense of rotation and the sense of movement of the active part of the spinning electrode in the direction of its longitudinal axis preferably remain the same during spinning; however, they may also change in this variant during spinning, if necessary.
  • the drive of one of the reels slows down the movement of the spinning electrode when it is wound, thereby keeping it tensioned.
  • the drive that slows down the movement of the spinning electrode is the drive of the reel from which the spinning electrode is currently being unwound.
  • the reel drives are interconnected in a master-slave manner, changing their roles depending on which reel currently serves as winding and unwinding.
  • an air flow is created in the space in which the voluminous structure moves after its formation, which supports the movement of the structure away from the spinning electrode.
  • this air flow is generated by an electric wind driven by ions generated by corona electric field discharges in the vicinity of an auxiliary electrode mounted in the vicinity of the spinning electrode to which AC voltage is supplied during spinning.
  • the formed voluminous structure formed by nanofibres is mechanically deposited on the collector or guided away, e.g., sucked into a suction nozzle.
  • the excess polymer solution or melt is removed from the sides and circumference of the reel which wades in the polymer solution or melt during its rotation by at least one wiping means. This helps to ensure that the optimum amount of polymer solution or melt remains on the surface of the spinning electrode for spinning and to prevent unwanted spinning, e.g., from the surface of the reels, etc.
  • a device for spinning a polymer solution or melt using AC voltage which comprises at least one spinning electrode, whose principle consists in that the spinning electrode is formed by a linear flexible structure mounted on two rotatably mounted reels which are coupled to a drive, wherein the section of the spinning electrode which is situated between the reels constitutes the active part of the spinning electrode, which is intended for spinning the polymer solution or melt.
  • Both reels are on their circumference provided with a spiral groove where the spinning electrode is temporarily wound, whereby the length of the groove of each reel corresponds at least to the length of the active part of the spinning electrode, the depth of the groove is equal to or greater than the diameter or height of the spinning electrode and a part of the spinning electrode with a length corresponding to at least the active part of the spinning electrode is placed altogether in the grooves of both reels, wherein at least one of the reels intervene with part of its circumference into the reservoir of the polymer solution or melt.
  • an auxiliary electrode is arranged in the space of the active part of the spinning electrode along at least part of its length, to which AC voltage is supplied, preferably the same as to the spinning electrode.
  • At least one wiping means for wiping excess polymer solution or melt from the sides and circumference of the reel is assigned to the reel that intervenes into the reservoir of polymer solution or melt.
  • two wiping means are assigned to each reel, each of which being assigned to the opposite side of the reel.
  • At least one collector for collecting the formed nanofibres is arranged in the space above or next to the spinning electrode.
  • a collector is, e.g., a rotatably mounted cylindrical body, a planar textile material, a thread or fibre cable, a suction nozzle, etc.
  • both reels intervene with part of their circumference into the reservoir of polymer solution or melt. In this case, they may intervene into a common reservoir solution of polymer solution or melt, or a separate reservoir can be assigned to each of them.
  • the spinning electrode can be closed in an endless loop.
  • the device according to the invention may comprise two or more spinning electrodes arranged next to each other.
  • the active parts of at least some of the spinning electrodes lie in one active plane.
  • the reel drives are preferably interconnected in a master-slave manner with the possibility of interchanging their functions, which allows one of the motors to slow down the movement of the spinning electrode during spinning, thereby keeping it tensioned.
  • Fig. 1 schematically shows a cross-section of a first variant of the device for spinning a polymer solution or melt using AC voltage according to the invention
  • Fig. 2 shows a cross-section through a second variant of the device for spinning a polymer solution or melt using AC voltage according to the invention
  • Fig. 3 shows a cross-sectional view of a third variant of the device for spinning a polymer solution or melt using AC voltage according to the invention.
  • Fig. 4 schematically shows a view of the circumference of a reel carrying the spinning electrode of the device.
  • Fig. 5 schematically represents one variant of guiding the spinning electrode in the spinning space and of its additional movement
  • Fig. 6 shows a second variant of guiding the spinning electrode in the spinning space and of its additional movement.
  • the device 1 for spinning a polymer solution or melt using AC voltage comprises in its spinning space at least one spinning electrode 2 consisting of a linear flexible structure (e.g. a string, a strip, a strap, a chain, etc.), preferably in particular a structure with a rugged surface composed of several interlaced and intertwined parts, such as e.g. a cable, a cord, a multi-core structure, etc.) of electrically conductive or non-conductive material which is mounted on two reels 3.
  • the reels 3 are arranged in/on an unillustrated frame of the device 1 rotatably around their horizontally oriented axis and each of them is coupled to an unillustrated drive, e.g., a servomotor.
  • the drives of the two reels 3 are interconnected via unillustrated bus in a master-slave manner and at the same time constitute the tensioning means of the spinning electrode 2.
  • the functions of the individual drives alternate, with each drive acting alternately as master and subsequently as slave. This arrangement makes it possible that at each moment the drive of one of the reels 3 slows down the movement of the spinning electrode 2, thus keeping it tensioned.
  • the section of the spinning electrode 2 that is situated between the reels 3 constitutes the active part 20 of the spinning electrode 2, i.e., the part of the spinning electrode 2 on which the polymer solution or melt 4 deposited on its surface is spun.
  • the grooves 30 of the two reels 3 together is preferably placed a part of the spinning electrode 2 with a length which corresponds at least to the length of the active part 20 of the spinning electrode 2, whereby during spinning, the spinning electrode 2 is wound from one reel 3 to another and a new part of the spinning electrode 2 with fresh polymer solution or melt 4 is constantly entering the space between the reels 3.
  • the length of the groove 30 of each reel 3 corresponds to at least the length of the active part 20 of the spinning electrode 2 and the spinning electrode 2 is preferably placed into these grooves 3 in one layer.
  • each reel 3 is provided with at least one wiping means 6 - e.g., an obliquely arranged bar with a U-shaped recess to receive the body of the reel 3, wherein the bar wipes during its rotation the excess polymer solution or melt 4 both from the sides and from the circumference of the reel 3, thereby ensuring the desired, predetermined amount of the polymer solution or melt 4 on the surface of the spinning electrode 2.
  • each reel 3 is provided with two wiping means 6 - an outer wiping means 61 and an inner wiping means 62 (see Fig. 2 and Fig. 3), each of which is arranged on the opposite side of the reel 3.

Abstract

The invention relates to a method of spinning a polymer solution or melt (4) using AC voltage, which is supplied to the spinning electrode (2) and/or to the polymer solution or melt (4). The spinning electrode (2), formed by a linear flexible structure, is during spinning wound between two driven reels (3), which are provided with a spiral groove (30) on their circumference, wherein this spinning electrode (2) is unwound from the spiral groove (30) of one reel (3) and at the same time is wound into the spiral groove (30) of the second reel (3), wherein at least one of these reels (3) with the part of the spinning electrode (2) placed in its spiral groove (30) is submerged in the polymer solution or melt (4) stored in a reservoir (5), whereby the polymer solution or melt (4) is deposited on this part of the spinning electrode (2) and is spun from it in the space between the reels (3) during the subsequent winding from the spiral groove (30) of this reel (3) into the spiral groove (30) of the other reel (3). Spinning takes place around the entire circumference of the spinning electrode (2) and the nanofibres formed, due to the action of Coulomb forces aggregate into a voluminous structure which due to the action of an electric wind driven by ions generated by corona discharges of the electric field in the vicinity of the spinning electrode (2) moves away from the spinning electrode (2). The part of the spinning electrode (2) which is currently situated in the space between the two reels (3) and constitutes the active part (20) of the spinning electrode (2), on whose surface spinning takes place, performs, as a result of winding and unwinding the spinning electrode into/from the spiral grooves (30) of the reels (3) in addition to the movement in the direction of its longitudinal axis, additional reciprocating sliding movement in a direction perpendicular to the longitudinal axis of the active part (20) of the spinning electrode (2). In addition, the invention also relates to a device for performing the method.

Description

Method of spinning a polymer solution or melt using alternating electric voltage and a device for performing the method
Technical field
The invention relates to a method of spinning a polymer solution or melt using alternating current voltage.
In addition, the invention relates to a device for performing this method.
Background art
Currently, a method is known for producing polymeric nanofibres (i.e., fibres with diameters less than 1000 nm, typically about 400 to 800 nm) by electrostatic spinning of a polymer solution or melt, which is based on the use of direct current (DC) voltage. In this method, DC voltage of one polarity is supplied to at least one spinning electrode formed by a tube, a capillary tube or a nozzle, or by a moving body, e.g., a cylinder (see, e.g., CZ 294274), and DC voltage of opposite polarity is supplied to at least one counter electrode, so-called collecting electrode, arranged opposite the spinning electrode/electrodes. In some variants, some of the electrodes or of groups of electrodes may be grounded. In either case, an electrostatic field is created between the collecting electrode/electrodes and the spinning electrode/electrodes, which acts by the electrostatic force on the polymer solution or melt which is fed into the field through a cavity in the spinning electrode or on the surface of the spinning electrode, the electrostatic force forming on the surface of the polymer solution or melt the so-called Taylor cones, from which polymer nanofibres are subsequently elongated. The polymer nanofibres are then carried by the force of the electrostatic field towards the collecting electrode/electrodes and are usually captured on the surface of a static or moving collector, most often a textile fabric, before coming into contact with the collecting electrode/electrodes.
CZ patent 304137 discloses a method of producing polymer nanofibres by the electrospinning of a polymer solution or melt in which alternating current (AC) voltage is used, which is supplied to the spinning electrode/electrodes. An electric field is created between the spinning electrode and a so-called virtual counter- electrode formed by oppositely charged air and/or gas ions, which are generated in the vicinity of the spinning electrode/electrodes by the ionization of ambient air or gas and/or which are supplied to the vicinity of the spinning electrode from an ion source, and/or by oppositely charged nanofibres formed in the preceding moment. Due to regular change of phase and polarity of the AC voltage on the spinning electrode, the individual nanofibres or even different sections of the individual nanofibres carry opposite electric charges, as a result which, almost immediately after their formation by electrostatic Coulomb forces, they aggregate to form a voluminous structure in the form of a plume, in which individual polymer nanofibres change their direction in segments with a length in the order of micrometres forming an irregular grid structure of densely interconnected nanofibres with repeating points of contact between them. This grid structure can be used, for example, for covering various surfaces, including threads - see, e.g., CZ 306428, etc. The advantage of this method is that it does not require the use of a physical counter electrode and the formed structure consisting of nanofibres is not electrically charged, which makes it more advantageous for many applications than electrostatic spinning using DC voltage; for the same reason, the formed structure is also easier to manipulate.
CZ 306772 discloses a method of producing polymer nanofibres by electrospinning a polymer solution or melt using alternating current (AC) voltage, in which excess of polymer solution or melt is fed to a spinning surface formed on an extended face of a capillary-shaped spinning electrode, part of the polymer solution or melt is spun and the rest washes the spinning surface of the spinning electrode and flows by action of gravity from the spinning surface onto an adjoining drainage surface, where spinning no longer occurs. As a result, no solidified residues of unspun solution or polymer melt or nanofibres formed during the previous spinning process adhere to the spinning surface of the spinning electrode and the spinning process can take place with unchanged intensity for a substantially unlimited time.
In addition, CZ 306772 also discloses several embodiments of a spinning electrode with an extended face designed for the above-described method of electrospinning, whose common feature is that a spinning surface is formed around at least a part of a mouth of a conduit of the solution or polymer melt, the spinning surface being rounded downwards below the mouth.
The disadvantage of currently known methods of electrospinning a polymer solution or melt using AC voltage and of the spinning electrodes designed for these methods is especially the fact that the spinning electrode is completely separated from a reservoir of the polymer solution or melt and the spinning material is fed into the spinning electrode cavity by a conduit formed by hoses or tubes. This arrangement not only increases the volume of the polymer solution or melt that must be available in the spinning device any time and the pressures required to transport it, but also the volume of the polymer solution or melt that is not spun eventually, which in the case of some types of polymers significantly increases the cost of the preparation of nanofibres. Another disadvantage is also the fact that a larger volume of polymer solution or melt usually also has a larger surface area or larger area of the interface between the solution/melt and the tube/hose wall, which may result in faster solidification or degradation of the polymer solution or melt - in the case of a solution caused by faster solvent evaporation, in the case of the melt caused mainly by its faster cooling.
A fundamental disadvantage of the existing devices for electric and electrostatic spinning is also the fact that in order to transport the polymer solution or melt from the reservoir to the spinning surface of the spinning electrode, the peristaltic pumps are typically used, which cause “pulsation” of the solution or polymer melt flow on the spinning surface of the spinning electrode, which, due to the change in the volume of the solution or melt currently present on this spinning surface, the movement of the level of the polymer solution or melt and the change in its shape, significantly worsens the uniformity of the spinning process and of the nanofibres formed.
Another drawback is that nanofibres are formed on a relatively small spinning area of the spinning electrode, so that in order to increase productivity and to form a planar layer of nanofibres, it is necessary to use a larger group of mutually suitably arranged spinning electrodes. However, even in this case, the layer of polymer nanofibres being formed is not completely homogeneous.
The objective of the invention is therefore to propose a method of spinning a polymer solution or melt using AC voltage and a device for performing the method, which would not suffer from these disadvantages and allow to fully exploit the potential of electrospinning a polymer solution or melt using AC voltage.
Principle of the invention
The objective of the invention is achieved by a method of spinning a polymer solution or melt using AC voltage supplied to a spinning electrode and/or to the polymer solution or melt, whose principle consists in that the spinning electrode formed by a linear flexible structure is wound during spinning between two driven reels which are around their circumference provided with a spiral groove, whereby this spinning electrode is unwound from the spiral groove of one reel and simultaneously wound into the spiral groove of the other reel, wherein the part of the spinning electrode wound on any of the reels does not extend beyond its circumference, at least one of these reels with the part of the spinning electrode wound in its spiral groove wades in the polymer solution or melt stored in the reservoir, whereby the solution or melt of polymer is deposited on the surface of this part of the spinning electrode and is spun therefrom in the space between the reels during subsequent rewinding from the spiral groove of this reel to the spiral groove of the other reel. Spinning takes place along the entire circumference of the spinning electrode and, preferably, also along the entire length of its active part, whereby the nanofibres formed by the action of Coulomb forces aggregate into a voluminous structure which moves away from the spinning electrode due to the action of an electric wind driven by ions generated by corona discharges of the electric field in the vicinity of the spinning electrode. The part of the spinning electrode which is currently situated in the space between the reels and constitutes the active part of the spinning electrode, on whose surface the spinning process takes place, performs, in conjunction with the movement in the direction of its longitudinal axis, additional reciprocating sliding movement in the direction perpendicular to the longitudinal axis of the active part of the spinning electrode due to the winding and unwinding of the spinning electrode into/from the spiral grooves of the reels. This process makes it possible to form uniform planar layers of nanofibres with high spinning output. These planar layers can be used, among other things, for the formation of linear structures - e.g., yarns, etc. Depending on the guiding of the spinning electrode between the reels and the orientation of their spiral grooves, the entire active part of the spinning electrode, when performing the additional reciprocating movement, moves in the same direction or the opposite ends of the active part of the spinning electrode move in mutually opposite directions.
In a variant where the spinning electrode is not closed in an endless loop, the reels perform reciprocating rotary movement during spinning, changing the sense of their rotation as well as the sense of movement of the active part of the spinning electrode in the direction of its longitudinal axis.
In a variant where the spinning electrode is closed in an endless loop, the reels perform rotary movement during spinning, whereby the sense of rotation and the sense of movement of the active part of the spinning electrode in the direction of its longitudinal axis preferably remain the same during spinning; however, they may also change in this variant during spinning, if necessary.
In all the variants, it is advantageous if the drive of one of the reels slows down the movement of the spinning electrode when it is wound, thereby keeping it tensioned. The drive that slows down the movement of the spinning electrode is the drive of the reel from which the spinning electrode is currently being unwound. The reel drives are interconnected in a master-slave manner, changing their roles depending on which reel currently serves as winding and unwinding.
In order to direct the voluminous structure formed by the nanofibres, an air flow is created in the space in which the voluminous structure moves after its formation, which supports the movement of the structure away from the spinning electrode. In a preferred variant, this air flow is generated by an electric wind driven by ions generated by corona electric field discharges in the vicinity of an auxiliary electrode mounted in the vicinity of the spinning electrode to which AC voltage is supplied during spinning.
The formed voluminous structure formed by nanofibres is mechanically deposited on the collector or guided away, e.g., sucked into a suction nozzle.
During spinning, it is advantageous if the excess polymer solution or melt is removed from the sides and circumference of the reel which wades in the polymer solution or melt during its rotation by at least one wiping means. This helps to ensure that the optimum amount of polymer solution or melt remains on the surface of the spinning electrode for spinning and to prevent unwanted spinning, e.g., from the surface of the reels, etc.
In addition, the objective of the invention is achieved by a device for spinning a polymer solution or melt using AC voltage, which comprises at least one spinning electrode, whose principle consists in that the spinning electrode is formed by a linear flexible structure mounted on two rotatably mounted reels which are coupled to a drive, wherein the section of the spinning electrode which is situated between the reels constitutes the active part of the spinning electrode, which is intended for spinning the polymer solution or melt. Both reels are on their circumference provided with a spiral groove where the spinning electrode is temporarily wound, whereby the length of the groove of each reel corresponds at least to the length of the active part of the spinning electrode, the depth of the groove is equal to or greater than the diameter or height of the spinning electrode and a part of the spinning electrode with a length corresponding to at least the active part of the spinning electrode is placed altogether in the grooves of both reels, wherein at least one of the reels intervene with part of its circumference into the reservoir of the polymer solution or melt.
In a preferred variant of the embodiment, an auxiliary electrode is arranged in the space of the active part of the spinning electrode along at least part of its length, to which AC voltage is supplied, preferably the same as to the spinning electrode.
Preferably, at least one wiping means for wiping excess polymer solution or melt from the sides and circumference of the reel is assigned to the reel that intervenes into the reservoir of polymer solution or melt. In a more preferred variant, two wiping means are assigned to each reel, each of which being assigned to the opposite side of the reel.
At least one collector for collecting the formed nanofibres is arranged in the space above or next to the spinning electrode. Such a collector is, e.g., a rotatably mounted cylindrical body, a planar textile material, a thread or fibre cable, a suction nozzle, etc. In a preferred variant of embodiment, both reels intervene with part of their circumference into the reservoir of polymer solution or melt. In this case, they may intervene into a common reservoir solution of polymer solution or melt, or a separate reservoir can be assigned to each of them.
The spinning electrode can be closed in an endless loop.
To increase performance of the spinning process, the device according to the invention may comprise two or more spinning electrodes arranged next to each other. In this case, it is advantageous if the active parts of at least some of the spinning electrodes lie in one active plane.
The reel drives are preferably interconnected in a master-slave manner with the possibility of interchanging their functions, which allows one of the motors to slow down the movement of the spinning electrode during spinning, thereby keeping it tensioned.
Description of the drawings
In the enclosed drawing, Fig. 1 schematically shows a cross-section of a first variant of the device for spinning a polymer solution or melt using AC voltage according to the invention, Fig. 2 shows a cross-section through a second variant of the device for spinning a polymer solution or melt using AC voltage according to the invention and Fig. 3 shows a cross-sectional view of a third variant of the device for spinning a polymer solution or melt using AC voltage according to the invention. Fig. 4 schematically shows a view of the circumference of a reel carrying the spinning electrode of the device. Fig. 5 schematically represents one variant of guiding the spinning electrode in the spinning space and of its additional movement, Fig. 6 shows a second variant of guiding the spinning electrode in the spinning space and of its additional movement.
Examples of embodiment
The method of spinning a polymer solution or melt using alternating current (AC) voltage according to the invention will be explained with reference to exemplary embodiments of the device for performing this method which are shown schematically in Figs. 1 to 3 and their function.
The device 1 for spinning a polymer solution or melt using AC voltage according to the invention comprises in its spinning space at least one spinning electrode 2 consisting of a linear flexible structure (e.g. a string, a strip, a strap, a chain, etc.), preferably in particular a structure with a rugged surface composed of several interlaced and intertwined parts, such as e.g. a cable, a cord, a multi-core structure, etc.) of electrically conductive or non-conductive material which is mounted on two reels 3. The reels 3 are arranged in/on an unillustrated frame of the device 1 rotatably around their horizontally oriented axis and each of them is coupled to an unillustrated drive, e.g., a servomotor. Preferably, the drives of the two reels 3 are interconnected via unillustrated bus in a master-slave manner and at the same time constitute the tensioning means of the spinning electrode 2. During the spinning process, the functions of the individual drives alternate, with each drive acting alternately as master and subsequently as slave. This arrangement makes it possible that at each moment the drive of one of the reels 3 slows down the movement of the spinning electrode 2, thus keeping it tensioned.
Each reel 3 (see Fig. 4) is provided with a spiral groove 30 on its circumference to accommodate temporarily part of the length of the spinning electrode 2. The dimensions and shape of the cross section of the groove 30 correspond to the dimensions and shape of the spinning electrode 2, wherein the depth of the groove 30 is equal to or greater than the diameter or thickness of the spinning electrode 2 so that the part of the spinning electrode 2 placed in the groove 30 of the reel 3 does not extend above the surface of the reel 3 and no spinning takes place thereon. The reels 3 are preferably made of an electrically non-conductive material, especially plastics, and the transitions between their surfaces or their edges are preferably rounded. The radii of the rounding are determined mainly by the spinning conditions and are chosen to prevent reaching the critical intensity of the electric field at which the spinning of the polymer solution or melt 4 deposited on the surface of the reels 3 would take place.
The section of the spinning electrode 2 that is situated between the reels 3 constitutes the active part 20 of the spinning electrode 2, i.e., the part of the spinning electrode 2 on which the polymer solution or melt 4 deposited on its surface is spun. In the grooves 30 of the two reels 3 together, is preferably placed a part of the spinning electrode 2 with a length which corresponds at least to the length of the active part 20 of the spinning electrode 2, whereby during spinning, the spinning electrode 2 is wound from one reel 3 to another and a new part of the spinning electrode 2 with fresh polymer solution or melt 4 is constantly entering the space between the reels 3. The length of the groove 30 of each reel 3 corresponds to at least the length of the active part 20 of the spinning electrode 2 and the spinning electrode 2 is preferably placed into these grooves 3 in one layer.
Both reels 3 intervene with their lower part into the polymer solution or melt 4 stored in the reservoir 5. In it, the polymer solution or melt 4 deposited on the surface of the spinning electrode 2 (whereby the more rugged the surface of the spinning electrode 2, the more solution or melt 4 is deposited thereon) on which it is carried out during the subsequent winding into space between the reels 3, where it is spun (see below). To remove the excess polymer solution or melt 4, each reel 3 is provided with at least one wiping means 6 - e.g., an obliquely arranged bar with a U-shaped recess to receive the body of the reel 3, wherein the bar wipes during its rotation the excess polymer solution or melt 4 both from the sides and from the circumference of the reel 3, thereby ensuring the desired, predetermined amount of the polymer solution or melt 4 on the surface of the spinning electrode 2. In a preferred variant of embodiment, each reel 3 is provided with two wiping means 6 - an outer wiping means 61 and an inner wiping means 62 (see Fig. 2 and Fig. 3), each of which is arranged on the opposite side of the reel 3. The outer wiping means 61 is intended primarily to wipe off the excess polymer solution or melt 4 from the surface of the spinning electrode 2 and the reel 3 as the reel 3 exits the reservoir 5 and at the same time to remove the excess residual unspun polymer solution or melt 4 from the surface of the spinning electrode 2 and the reel 3 before the reel 3 enters the polymer solution or melt 4 in the reservoir 5. The inner wiping means 62 then prevents carrying out the polymer solution or melt on the surface of the reel 3 to the vicinity of the active part 20 of the spinning electrode 2, especially during the winding of the spinning electrode 2 on the respective reel 3.
The reservoir_5 of polymer solution or melt 4 may be common to both reels 3 (see Fig. 1), or a separate reservoir 5 may be assigned to each of the reels 3. The advantage of the second variant is that it requires a smaller amount of the polymer solution or melt 4 currently present in the reservoir 5 and at the same time it allows to combine two different polymer solutions or melts 4 (e.g., in terms of the type of polymer and/or concentration) - each stored in one of the reservoirs 5. The reservoir/reservoirs 5 of the polymer solution or melt 4 is/are preferably provided with an unillustrated cover/covers which prevents/prevent the solution from drying out, or cooling the polymer melt, and optionally is/are provided with also one or more heating means for heating the melt and/or maintaining it at the desired temperature.
In an unillustrated variant of embodiment, the spinning electrode 2 can be closed in an endless loop, whereby in this case only one reel 3 can intervene to the reservoir 5 of polymer solution or melt 4; more preferably, both reels intervene into the reservoir 5. In another variant of embodiment, a separate reservoir 5 is assigned to each of the reels 3, whereby the spinning electrode 2 is guided out of these reservoirs 5, or guided into them, e.g., by means of unillustrated guiding elements which change its direction, such as pulleys etc., or it can, with a suitable seal, pass through holes in their walls.
In any of the variants, at least one unillustrated tensioning means, e.g., a tensioning pulley, may be assigned to the spinning electrode 2, or one of the reels 3 is slidably mounted and coupled to a resilient element, e.g., a spring, which acts in the direction of the active part 20 of the spinning electrode 2.
For spinning, the spinning electrode 2 and/or the polymer solution or melt 4 is connected to an unillustrated source of AC voltage, either directly or via, e.g., the reservoir 5 of polymer solution or melt 4 and/or the wiping means 6, 61_, 62.
At least one suitable collector 7 is arranged or guided in the space above the spinning electrode 2 for collecting and depositing the formed polymer nanofibres. Due to the principle of electrostatic spinning based on AC voltage, this collector 7 does not have to be (but can be) made of an electrically conductive material, since the formed voluminous nanofibre structure moves towards the collector 7 by the action of the so-called electric wind, i.e., a flow of gas (air) driven by ions generated by corona discharges of the electric field in the vicinity of the spinning electrode 2, and is captured thereon mechanically, by the effect of frictional forces. This spontaneously generated electric wind prevents, among others, the newly formed nanofibres from being attracted back towards the spinning electrode 2 during the next alternating half-wave, when its polarity changes. Instead, the nanofibres are attracted to one another and, due to Coulomb forces form groups within the plume. The speed and intensity of the electric wind depends on the geometry of the action member (i.e., the spinning electrode 2), the strength of the electric field, as well as on the frequency of the alternating current supplied to the spinning electrode 2. A suitable collector is, e.g., a cylindrical body 8 (Fig. 1 , Fig. 2), which during spinning rotates around its horizontally oriented longitudinal axis which is preferably arranged parallel with the active part 20 of the spinning electrode/electrodes 2, while the formed nanofibre structure is wound on this collector; non-woven fabric 9 (Fig. 3), which during spinning preferably moves perpendicularly or obliquely to the active part 20 of the spinning electrode/electrodes 2, less preferably parallel with the active part 20 of the spinning electrode/electrodes 2 on which the formed nanofibre structure is deposited in a planar layer; or a textile linear structure, such as a thread or a fibrous cable which is preferably guided parallel with the active part 20 of the spinning electrode/electrodes 2 onto which the nanofibre structure can be wound. In general, however, the collector 7 may be of any construction; optionally, instead of a collector, at least one unillustrated suction nozzle may be arranged in the space above or next to the spinning electrode/electrodes 2, the suction nozzle being connected to an unillustrated vacuum system, whereby the formed nanofibre structure is sucked into the suction nozzle and, led by a conduit connected to it out of the spinning space for further processing or treatment. If necessary, more mutually independent collectors 7 may be used to capture the formed nanofibre structure. Optionally, a collector 7 which consists of several separate elements/bodies may be used for this purpose.
In order to support and/or control the movement of the formed nanofibre structure away from the spinning electrode 2, a suitable element/suitable elements is/are arranged in the space in which the voluminous structure moves after its formation for inducing a flow of air or gas oriented away from the spinning electrode 2, for example, towards the collector 7. Such an element is, e.g., a suction nozzle 10 arranged in the vicinity of the collector 7, or, if the collector 7 is permeable, behind the collector 7 (in the direction of movement of the nanofibre structure) and/or at least one unillustrated exhaust nozzle arranged in the vicinity of the spinning electrode 2 and oriented towards the collector 7. When using such an element/elements the collector 7 may be arranged substantially in any position relative to the spinning electrode/electrodes 2, e.g., next to it/them, wherein the nanofibre material formed is directed towards it by a flow of air or other suitable gas. Another suitable rectifying element is at least one auxiliary electrode 1J_ mounted in the vicinity of the spinning electrode 2, e.g., in the space below its active part 20 (Figs. 2 and 3), to which AC voltage is supplied, preferably the same as to the spinning electrode 2, or to the polymer solution or melt 4 arranged on the spinning electrode 2. Thus, during spinning, an electric wind is generated in the vicinity of the auxiliary electrode 11 which assists in the orientation and movement of the formed nanofibre structure in the direction of the connecting line between the auxiliary electrode 1J_ and the active part 20 of the spinning electrode 2, e.g. towards the collector 7. The auxiliary electrode 1J_ is preferably made of an electrically conductive material and is parallel with at least a part of the active part 20 of the spinning electrode 2.
In order to achieve the required spinning performance, it is possible to arrange a plurality of spinning electrodes 2 next to one another, preferably in parallel. Each of the spinning electrodes 2 is preferably mounted on separate reels 3 connected to separate drives. In another variant of embodiment, at least some of the reels 3 can be mounted on a common shaft or connected to one common drive by means of a transmission device (e.g., gears, belt, chain, etc.). The reservoirs 5 of the polymer solution or melt 4 may be separate for each spinning electrode 2, or may be common to two or more spinning electrodes 2 arranged next to one another, or their reels 3. The active parts 20 of the two or more spinning electrodes 2 preferably lie in a common active plane.
During the spinning process, by the action of the drives of the reels 3, the spinning electrode 2 is alternately wound from one reel 3 to another, whereby a new part of the spinning electrode 2 which constitutes the active part of the spinning electrode 2 continuously enters the space between the reels 3 with fresh polymer solution or melt 4. The reels 3 perform a reciprocating rotary movement during the spinning process, changing the sense of rotation of the reels 3 and the sense of movement of the active part 20 of the spinning electrode 2 in the direction of its longitudinal axis. The drives of the reels 3 function alternately as master and then as slave, when the drive which currently serves as winding acts as master and the drive which serves as unwinding acts as slave, whereby during winding this drive slows down the spinning electrode 2, thereby keeping it tensioned. If the spinning electrode 2 is closed in an endless loop, it can be wound during spinning from one reel 3 to another preferably continuously in one direction. The reels 3 perform a rotary movement during spinning, the sense of their rotation and the sense of movement of the active part 20 of the spinning electrode 2 in the direction of its longitudinal axis preferably remain the same during spinning; however, if necessary, they may change during spinning.
The spinning electrode 2 is during spinning unwound from the spiral groove 30 of one reel 3 and at the same time is wound into the spiral groove 30 of the other reel 3, wherein the part of the spinning electrode wound in the spiral groove 30 of any of the reels 3 does not extend beyond its circumference.
As part of the length of the spinning electrode 2 arranged in the groove 30 of the reel 3 passes through the polymer solution or melt 4 in the reservoir 5, the polymer solution or melt 4 is deposited on its surface (and possibly also in its structure) and subsequently is carried out into the space between the reels 3, where it is spun from the active part 20 of the spinning electrode 2. Spinning takes place along the entire circumference of the spinning electrode 2 and, preferably, also alongthe entire length of its active part 20. The created nanofibres move away from the surface of the spinning electrode 2 under the influence of the electric wind generated by the spinning electrode and aggregate into voluminous structure - a plume. This structure is after its formation carried towards the collector/collectors 7 by the electric wind generated by the auxiliary electrode 1J_ and/or by a flow/flows of air or other gas generated by the nozzle/nozzles opening into the space in which this volumetric structure moves.
Due to the wiping means 6, 61_, 62, only a predetermined amount of polymer solution or melt 4 required to make the spinning process as efficient as possible is applied to the spinning electrode 2 - so that the spinning process takes place along the entire length of the active part 20 of the spinning electrode 2, but at the same time to prevent formation of droplets of solution 4 or polymer melt formed on the surface of the spinning electrode 2 and their dripping. When being wound between the reels 3 with spiral grooves 30, the spinning electrode 2 performs a movement in the direction of its longitudinal axis and its active part 20 also performs an additional reciprocating sliding movement in a direction perpendicular to the longitudinal axis of the spinning electrode 2. According to the method of mounting the spinning electrode 2 on the individual reels 3 and/or guiding their grooves 30, the entire active part 20 of the spinning electrode 2 moves in the same direction when performing this additional movement (see arrows A and B in Fig. 5) or the opposite ends of the active part 20 of the spinning electrode 2 move in opposite directions (see arrows A and B in Fig. 6), in which case the centre of the active zone 20 may be at some moment without an additional movement. The advantage of this additional movement is that during the depositing of the formed nanofibres on the collector 7 into a planar layer, it increases its homogeneity.
The high voltage source can preferably operate at different frequencies and with different time courses of waveform shapes: sine, rectangle, triangular sawtooth, jumps, etc. During experiments, it has been found that it can be advantageous if an electrical voltage with an asymmetrical course is applied to the polymer solution or melt 4 and/or to the spinning electrode 2, i.e., the voltage at which the absolute values of the maxima of both polarities differ, and/or for which the average value is set as non-zero - it has a positive or negative value. In such a case, it is the electric charge of the polarity whose absolute value is higher that prevails in the structure of the formed nanofibre volume structure, which results in the formation of repulsive forces between this structure and the spinning electrode 2 which promote the movement of this structure away from this electrode 2, increasing the spinning performance.

Claims

PATENT CLAIMS
1. A method of spinning a polymer solution or melt (4) from the surface of a spinning electrode (2) formed by a linear flexible structure, in which alternating current (AC) voltage is supplied to the spinning electrode (2) and/or to the polymer solution or melt (4) on the surface of the spinning electrode (2), characterized in that during spinning, the spinning electrode (2) is wound between two driven reels (3) which are provided with a spiral groove (30) on their circumference, whereby the spinning electrode (2) unwinds from the spiral groove (30) of one reel (3) and at the same time winds into the spiral groove (30) of the other reel (3), without extending beyond the circumference of any of the reels (3), whereby at least one of these reels (3) with the part of the spinning electrode (2) arranged in the spiral groove (30) wades in the polymer solution or melt (4) stored in a reservoir (5), where the polymer solution or melt (4) is deposited on the surface of the spinning electrode (2), as a result of the winding of this electrode (2) it is carried out into the space between the reels (3), where it is spun from the surface of the spinning electrode (2), whereby spinning takes place around the entire circumference of the spinning electrode (2), and the part of the spinning electrode (2) that is currently situated in the space between the reels (3) performs an additional reciprocating movement due to winding the spinning electrode (2) into the spiral groove of one reel (3) and unwinding it from the spiral groove of the other reel (3), the additional movement being performed in a direction perpendicular to the longitudinal axis of the active part (20) of the spinning electrode (2).
2. The method according to claim 1 , characterized in that the entire part of the spinning electrode (2) that is currently situated in the space between the reels (3) moves in the same direction when performing the additional reciprocating sliding movement.
3. The method according to claim 1 , characterized in that the opposite ends of the part of the spinning electrode (2) that is currently situated in the space between the reels (3) move in mutually opposite direction when performing the additional reciprocating sliding movement.
4. The method according to claim 1 , characterized in that the drive of one of the reels (3) during the winding of the spinning electrode (2) slows down the movement of this reel (3) and thus keeps the spinning electrode (2) tensioned.
5. The method according to claim 1 or 4, characterized in that the drives of the reels (3) function alternately as master and slave, wherein the drive which currently serves as winding, acts as master, and the drive which serves as unwinding acts as slave, slowing down the movement of this reel (3).
6. The method according to claim 1 , characterized in that excess polymer solution or melt (4) is removed from the sides and circumference of the reel (3) which is submerged in the polymer solution or melt (4) during its rotation by at least one wiping means (6).
7. The method according to claim 1 , characterized in that electric voltage with an asymmetrical voltage profile in which the maximum absolute values of the two polarities differ is supplied to the spinning electrode (2) and/or to the polymer solution or melt (4) on its surface.
8. A device for spinning a polymer solution or melt (4) by the method according to claim 1 using AC voltage, which comprises at least one spinning electrode (2) formed by a linear flexible structure arranged on two rotatably mounted reels (3) which are coupled to a drive, characterized in that both reels (3) are provided on their circumference with a spiral groove (30) for placing temporarily the spinning electrode (2), wherein the length of this groove (30) of each of the reels (3) corresponds to at least the length of the part of the spinning electrode (2) between the reels (3), the depth of the groove (30) of each of the reels (3) is equal to or greater than the diameter or height of the linear flexible structure constituting the spinning electrode (2), and in the grooves (30) of both reels (3) is placed the part of the spinning electrode (2) with a length that corresponds altogether at least to the length of the spinning electrode (2) between the reels (3), whereby at least one of the reels (3) intervenes with part of its circumference into a reservoir (5) of the polymer solution or melt (4).
9. The device according to claim 8, characterized in that an auxiliary electrode (11) is arranged in the space between the reels (3), along at least a part of length of the spinning electrode (2).
10. The device according to claim 8, characterized in that at least one wiping means (6) for wiping excess polymer solution or melt (4) from the sides and circumference of the reel (3) is assigned to the reel (3) which intervenes into the reservoir (5) of the polymer solution or melt (4).
11. The device according to claim 8 or 10, characterized in that two wiping means (61, 62) are assigned to the reel (3) which intervenes into the reservoir (5) of the polymer solution or melt (4), each of the wiping means being assigned to the opposite side of the reel (3).
12. The device according to claim 8, characterized in that both reels (3) intervene with parts of their circumferences into the reservoir (5) of the polymer solution or melt (4).
13. The device according to claim 8 or 12, characterized in that both reels (3) intervene with parts of their circumferences into a common reservoir (5) of the polymer solution or melt (4).
14. The device according to claim 8, characterized in that it comprises two or more spinning electrodes (2) arranged next to each other.
15. The device according to claim 14, characterized in that parts of two or more spinning electrodes (2) arranged next to each other between the reels (3) lie in one active plane.
EP22712796.6A 2021-02-16 2022-02-14 Method of spinning a polymer solution or melt using alternating electric voltage and a device for performing the method Pending EP4225982A1 (en)

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PCT/CZ2022/050016 WO2022174846A1 (en) 2021-02-16 2022-02-14 Method of spinning a polymer solution or melt using alternating electric voltage and a device for performing the method

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