Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0061—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
  • D01D13/00—Complete machines for producing artificial threads
  • D01D13/02—Elements of machines in combination
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0015—Electro-spinning characterised by the initial state of the material
  • D01D5/003—Electro-spinning characterised by the initial state of the material the material being a polymer solution or dispersion
  • D01D5/0046—Electro-spinning characterised by the initial state of the material the material being a polymer solution or dispersion the fibre formed by coagulation, i.e. wet electro-spinning
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
  • D01D5/0076—Electro-spinning characterised by the electro-spinning apparatus characterised by the collecting device, e.g. drum, wheel, endless belt, plate or grid
• • 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
• • 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
  • D01D5/12—Stretch-spinning methods

Definitions

• the invention relates to a method of producing a linear nanofibrous structure in an AC electric field from a polymer solution or melt, in which a spinning area with a supercritical AC electric field intensity is formed on a spinning electrode. In the spinning area, nanofibers are formed, which are carried away from the spinning electrode by the action of an electric wind in the direction of the maximum values of the gradient of the generated electric fields.
• the invention also relates to a device for producing a linear nanofibrous structure in an AC electric field from a polymer solution or melt, wherein a spinning area with a supercritical value of AC electric field intensity is created on a spinning electrode mounted in a spinning chamber and connected to a source of high alternating voltage and coupled to a means for applying the polymer solution or melt to the surface of the spinning electrode,
• oriented nanofibers are the basis for the construction of nanofibrous yarns.
• numerous methods have been developed in the field of DC electrospinning to obtain longitudinally oriented fiber bundles which can be attributed to two main aspects, that is, obtaining highly ordered nanofibers by improving a collecting device or by influencing the electric field by means of auxiliary electrodes.
• CN111118677 discloses production of nanofibrous yarn by DC electrostatic spinning.
• the device comprises a cylindrical collector which consists of a cavity and a throat which is rotatable about its axis, wherein the diameter of the upper opening of the throat is smaller than the diameter of the lower opening of the cavity.
• a DC electrostatic rotating spinning electrode mounted inside the lower opening of the cavity is a DC electrostatic rotating spinning electrode connected to a high voltage DC source into which a solution to be subjected to electrospinning is fed.
• pressurized air inlets open into the inner space of the collector and above them is arranged a counter electrode which can be grounded or connected to a voltage source of opposite polarity to the rotating spinning electrode.
• the nanofibers are twisted immediately after their formation due to the rotation of the spinning electrode and the subsequent action of the vortex, so that there is no parallelization of the nanofibers before twisting, the twisting takes place unevenly and, as a result, their strength and appearance is variable.
• CN111286792 describes a horizontal arrangement of a DC electrostatic spinning device comprising a rotating jet spinning electrode and a collecting electrode formed by a hollow cylinder which is arranged coaxially against the jet spinning electrode, wherein a DC electric field is formed between the spinning electrode and the collecting electrode. At least two air jets directed towards the axis of the collecting electrode are arranged around the rotating jet spinning electrode. Due to an electric wind, the nanofibers formed by the rotating jet spinning electrode are carried to the hollow cylinder forming the collecting electrode, wherein due to the rotation of the jet spinning electrode and the air currents from the jets, they are twisted into yam which, after passing through the cavity of the collecting electrode, is drawn off and wound on a bobbin.
• the aim is to twist the nanofibers as soon as possible after they are formed without achieving their parallelization.
• the disadvantages of DC electrostatic production of nanofibrous yarn include low yarn cohesion, irregular twist and poor orientation of the nanofibers.
• nanofibers are formed from a polymer solution in a jet head from which the nanofibers are drawn off by the action of high-speed air flow generated in a Venturi tube and, through a funnel- shaped collection tube, enter a Venturi collection system, where they are straightened and oriented into oriented bundles of nanofibers by sucking the bundle of nanofibers using the Venturi effect.
• the oriented bundles of nanofibers are subsequently twisted and agglomerate by the action of the twisting device into a nanofibrous yarn, which is in the next step wound on a bobbin.
• the twisting device comprises air jets for supplying the air flow in the tangential direction towards the yarn to be twisted.
• nanofibrous yarns From the point of view of the subsequent processing and use of nanofibrous yarns, it is not enough to only obtain oriented fibers in order to meet the current requirements for their preparation, but it is necessary to be able to obtain oriented fibers or fiber bundles continuously and to impart evenly a certain degree of twist to them in order to ensure their length and degree of orientation.
• the nanofibers in the nanofiber bundle are already oriented longitudinally due to the method of their formation, i.e., they are oriented in agreement with the axis of the bundle.
• Existing DC electrospinning technologies for the continuous production of nanofibrous yarns have a low yield and poor quality of the produced nanofibrous yarn. Therefore, core yams are currently produced by DC electrospinning.
• CZ PV 2007-179 discloses a linear fibrous structure comprising polymeric nanofibers which form a coating on the surface of a core formed by a supporting linear fibrous structure, at least some of the nanofibers being trapped between the fibers of the surface portion of the core.
• Nanofibers are produced by DC electrostatic spinning (i.e., using high voltage DC sources), wherein the supporting linear structure is guided through a spinning space between a spinning electrode and a collecting electrode and outside the spinning space it is imparted with a false twist. Therefore, the supporting linear structure in the spinning space rotates about its axis and individual nanofibers carried through the spinning space to the collecting electrode are deposited on its surface.
• the nanofibers are trapped on the supporting linear structure, but some of them fly past and are trapped only on the collecting electrode. This problem has not been eliminated even by an embodiment in which the collecting electrode is formed by a conductive supporting linear structure. In this embodiment, too, a large part of the nanofibers fly past the linear supporting structure and are trapped on the walls of the spinning space.
• the actual fibrous structure is produced by the passage of the supporting linear structure through the spinning space several times, wherein the supporting linear structure outside the spinning space is returned through part of the circumference of at least one cylinder, onto which it approaches obliquely, so that after returning, the supporting linear structure faces the spinning electrode with its opposite side.
• the supporting linear structure does not rotate about its axis, and so the nanofibers are deposited during each passage on the side of the supporting linear structure that faces the spinning electrode. Due to the multiple passage of the supporting linear structure through the spinning space, a larger amount of nanofibers is deposited on it than in the previous solution, yet some of the nanofibers fly over as far as to the collecting electrode.
• the nanofibers are deposited on the surface of the supporting linear structure in a disorderly manner as individual nanofibers in layers, and their cohesion with the core surface is low. Fixation of the nanofibers to the surface of the supporting linear structure is achieved by subsequent wrapping with at least one cover thread.
• EP2931951 B1 discloses a method of producing polymeric nanofibers, in which polymeric nanofibers are formed by applying an electric field to a polymer solution or melt placed on the surface of a spinning electrode, wherein the electric field for spinning is alternately formed between the spinning electrode to which an AC voltage is applied and air and/or gas ions generated and/or supplied to the vicinity of the spinning electrode, without a collecting electrode, whereby, depending on the phase of the AC voltage on the spinning electrode, polymeric nanofibers with opposite electric charge and/or with sections with opposite electric charge are formed, which, after their formation due to the action of electrostatic forces, aggregate into a linear structure in the form of a cable or belt which moves freely in space away from the spinning electrode in the direction of the gradient of the electric fields.
• the object of the invention is to provide a device for performing this method.
• the object of the invention is achieved by a method of producing a linear nanofibrous structure in an alternating electric field by spinning a polymer solution or melt, wherein the principle of the invention consists in that at least one spinning area is created on a spinning electrode with a supercritical AC electric field intensity and a finite length, from which the emerging nanofibers are carried by the effect of the electric wind in the direction of the maximum values of the electric field gradient away from the spinning area towards a moving electrically neutral collector on whose circumferential surface which is located opposite the spinning area and which forms the collection area of the moving electrically neutral collector, are deposited in the form of a fluffy band of nanofibers, which is moved by the movement of the electrically neutral collector into a withdrawal area, in which it is withdrawn from the surface of the electrically neutral collector by a tensile force and subsequently wound onto the bobbin of the winding device, the nanofibers being at least partially parallelized by the tensile force.
• the fluffy band of nanofibers is rounded during transfer to the withdrawal area on the surface of the electrically neutral collector, thereby tapering it so that it can be wound directly or is more easily formed into a twist triangle during the taper when imparting a twist without the risk of damage to the edges of the fluffy band of nanofibers.
• the fluffy band of nanofibers Prior to winding or drawing-off, the fluffy band of nanofibers is acted upon by a twisting device which tapers the fluffy band of nanofibers into a twist triangle and then imparts a twist to it, thereby forming a nanofibrous yarn.
• a significant feature of the method is that the twist is imparted to the fluffy band of nanofibers between two clamping points, that is between the withdrawal area of the electrically neutral collector and the point of the winding or drawing- off of the nanofibrous yarn on the bobbin, wherein residual amount of twists imparted to the fluffy band of nanofibers by the twisting device is retained in the nanofibrous yarn being wound after leaving the twisting device.
• An important feature of the method according to the invention is also the fact that the spinning area of the spinning electrode is formed on the circumference of a disk spinning electrode, or at a bending point of the belt spinning electrode, where the spinning area is arranged transversely to the direction of movement of a spinning belt, or on a linear flexible structure of a linear spinning electrode.
• a device for producing a nanofibrous yarn by AC electrospinning of a polymer solution or melt the principle of which consists in that an electrically neutral collector coupled to a drive is arranged above a spinning electrode in the path of the nanofibers, wherein the area of the surface of the electrically neutral collector against the spinning electrode forms a collection area of nanofibers for continuous deposition of nanofibers in the form of a fluffy band of nanofibers, wherein a withdrawal area of the fluffy band of nanofibers is formed on the surface of the electrically neutral collector in the direction of movement of the collector downstream of the collection area, downstream of which a winding device is arranged in the direction of the withdrawal of the fluffy band of nanofibers.
• the winding device serves to generate a tensile force for withdrawing the fluffy band of nanofibers from the surface of the electrically neutral collector.
• the tensile force can also be generated by a drawing-off device located between the withdrawal area and the winding device. In this manner, it is possible to separate the technological tensile force, i.e., the tension associated with ballooning the yarn and the withdrawal strength, and the winding tensile force, i.e., the winding tension. Appropriate winding tensile force can be then selected with respect to the construction of the bobbin.
• a twisting device is arranged in the direction of the withdrawal of the fluffy band of nanofibers upstream of the winding device or the drawing-off device, so that nanofibrous yam is fed into the winding device.
• 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 a spinning electrode.
• the electrically neutral collector may consist of an electrically neutral drum collector or an electrically neutral belt collector.
• the electrically neutral collector is formed by an electrically neutral drum collector, a collection area of nanofibers is formed on it against the spinning electrode in a preferred embodiment, and in the area of the surface of the drum collector facing away from the spinning electrode, a withdrawal area of the drum collector is formed for withdrawing the fluffy band of nanofibers.
• rounding means are assigned to the fluffy band of nanofibers between the collection area and the withdrawal area of the electrically neutral drum collector.
• the rounding means reduce the width/thickness of the fluffy band of nanofibers and thus simplify its twisting and/or winding.
• this collector is an endless conveyor belt encircling two upper cylinders 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 thereon in a fluffy band of nanofibers.
• the fluffy band of nanofibers is fed by the movement of the endless conveyor belt into the upper branch of the endless conveyor belt the end of which in the direction of movement of the endless conveyor belt forms a withdrawal area for withdrawing the fluffy band of nanofibers from the electrically neutral belt collector.
• This embodiment allows rounding means to be assigned to the fluffy band of nanofibers on the upper branch of the endless conveyor belt, which tapers the fluffy band of nanofibers and improves its properties for withdrawing and subsequent twisting.
• the amount of the polymer solution 21 is normally adjusted by a known unillustrated wiping device.
• a spinning space 31 In the vicinity of the upper part of the circumference of the disk spinning electrode 11 and above it, in the spinning chamber 3, there is a spinning space 31.
• an electrically neutral collector 4 coupled to an unillustrated known drive is rotatably mounted.
• the upper part of the disk spinning electrode 11 forms a spinning area 110, in which nanofibers 5_are formed, the nanofibers 5 being carried through the spinning space 31 to the surface of the electrically neutral collector 4, which is covered with a suitable coating, for example by a flat textile made of a material which allows easy withdrawing of the nanofibers from the surface of the electrically neutral collector 4.
• a further increase in the strength of the nanofibrous yam 54 produced can be achieved, for example, by twisting the nanofibrous yam 54 with a permanent twist on a suitable device (not shown).
• the endless conveyor belt 421 moves counter-clockwise, wherein its lower branch 4211 situated between the lower cylinders 423 is arranged against the spinning area 110 of the rotating disk spinning electrode 11 and the nanofibers 5 formed in the spinning area 110 of the rotating disk spinning electrode 11 ae deposited on the lower branch of the endless conveyor belt 421 into a fluffy band 51 of nanofibers.
• the lower branch 4211 of the endless conveyor belt 421 thus forms the collection area 420 of the electrically neutral belt collector 42.
• the fluffy band 51 of nanofibers transported to the upper branch 4212 of the endless conveyor belt 421 whose end forms the withdrawal area 4201 of the electrically neutral belt collector 42, from which the fluffy band 51 of nanofibers is withdrawn and guided to the twisting device 6, by which a twist is imparted to it.
• the fluffy band 51 of nanofibers tapers into a twist triangle 52 due to the action of the twist and subsequently and is subsequently formed into a nanofiber yam 54, as described in the previous variant of the device with the electrically neutral drum collector 41.
• This arrangement allows a larger amount of nanofibers 5 to be deposited on the electrically neutral belt collector 42, thereby forming a fluffy band 51 of nanofibers of greater thickness and weight.
• this arrangement provides sufficient space on the upper branch 4212 of the endless conveyor belt 421 for rounding the fluffy band 51 of nanofibers by known unillustrated rounding means. If the endless conveyor belt 421 moves in the opposite direction, the withdrawal area 4201 will be formed again at the end of the upper branch 4212 of the endless conveyor belt 421 , but according to the figures it will be on the right-hand side.
• the rotating disk spinning electrode 11 can be replaced with a spinning electrode with a direct spinning area, which may consist of a belt spinning electrode 12 or a linear spinning electrode 13 formed by a linear flexible structure, which will be described hereinafter.
• the device with a belt spinning electrode 12 is shown in Figs. 8a to 8d.
• the device comprises a reservoir 2 of a polymer solution 21 , into which a rewinding shaft 8 coupled to the drive 81 extends with part of its circumference.
• a blade is 121 is fixedly mounted in the spinning chamber 3 on the device frame, for example, by means of struts 82.
• the electrically neutral belt collector 42 is configured in the same manner as in the embodiment according to Figs. 5-7.
• the belt collector 42 comprises an endless conveyor belt 421 engirdling two upper cylinders 422 and two lower cylinders 423, of which at least one cylinder 422, 423 is a drive cylinder.
• the axes of rotation of all cylinders 422, 423 of the belt collector 42 are perpendicular to the axis of rotation of the rewinding shaft 8.
• the lower branch 4211 of the endless conveyor belt 421 represents the collection area 420 of the electrically neutral belt collector 42.
• the fluffy band 51 of nanofibers is transported to the upper branch 4212 of the endless conveyor belt 421 , whose end forms the withdrawal area 4201 of the electrically neutral belt collector 42, from which the fluffy band 51 of nanofibers is withdrawn and guided in the direction of the arrow to the twisting device 6, by which it is imparted a twist.
• the fluffy band 51 of nanofibers is tapered into a twist triangle 52 due to the twist action and subsequently a nanofibrous yarn 54 is formed from it, as described in the previous variant of the device with the electrically neutral drum collector 41.
• the direction of the movement of the endless conveyor belt can be reversed and the above- mentioned arrangement is only side reversed.
• the withdrawal area 4201 of the electrically neutral belt collector 42, in which the fluffy band 51 of nanofibers is withdrawn from the endless conveyor belt 421 is therefore at the end of the lower branch 4211 of the endless conveyor belt 421. From the withdrawal area 4201, the fluffy band 51 of nanofibers is fed in the direction of the arrow to the twisting device, where it is twisted into a nanofibrous yam 54, as described above. As already described above, the direction of the movement of the endless conveyor belt can be reversed and the above-mentioned arrangement is only side reversed.
• the linear spinning electrode 13 consists of an endless linear flexible structure which is in the embodiment shown in Figs. 9a to 9d mounted on two rotatably mounted pulleys 131 coupled to an unillustrated drive. At least one of the pulleys 131 extends with part of its circumference to the reservoir 2 of the polymer solution 21. In the embodiment shown, each pulley 131 has its reservoir_2 of the polymer solution 21
• the linear flexible structure consisting of the linear spinning electrode 13 may be formed by, for example, a string, a belt, a strap, or a structure with a more fragmented surface composed of several mutually intertwined parts, such as a cable, a cord, a multi-core formation, etc. Similar to the previous embodiments, 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 electric voltage source by one of known methods.
• an electrically neutral belt collector 42 Above the spinning area 130 of the linear spinning electrode 13 is arranged an electrically neutral belt collector 42, whose lower branch 4211 is arranged at least above the entire length of the spinning area 130 of the linear spinning electrode 13, as shown in Figs. 9b and 9d.
• the electrically neutral belt collector 42 is configured similarly as in the previous embodiments and comprises an endless conveyor belt 421 engirdling two upper cylinders 422 and two lower cylinders 423, of which at least one cylinder 422, 423 is a drive cylinder.
• the axes of rotation of all cylinders 422, 423 of the belt collector 42 are parallel with the axes of the pulleys 131.
• the endless conveyor belt 421 moves counter-clockwise, wherein its lower branch 4211 situated between the lower cylinders 423 is arranged against the spinning area 130 of the linear spinning electrode and 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 51 of nanofibers.
• the lower branch 4211 of the endless conveyor belt 421 thus represents the collection area 420 of the electrically neutral belt collector 42.
• the fluffy band 51 of nanofibers is transported to the upper branch 4212 of the endless conveyor belt 421 , whose end forms the withdrawal area 4201 of the electrically neutral belt collector 42, from which the fluffy band 51 of nanofibers is withdrawn and guided in the direction of the arrow into the twisting device 6 and by twisting it, a nanofibrous yam is formed.
• the direction of the movement of the endless conveyor belt can be reversed and the above-mentioned arrangement is only side reversed.
• FIG. 9c and 9d An alternative embodiment of this arrangement of the device for producing nanofibrous yam is shown in Figs. 9c and 9d.
• the direction of the movement of the endless conveyor belt 421 is changed, and so it moves clockwise, as shown in Fig. 9d.
• the other parts of the device and their functions remain the same as in the embodiment according to Figs. 9a and 9b.
• the withdrawal area 4201 of the electrically neutral belt collector 42 is thus at the end of the lower branch 4211 of the endless conveyor belt 421.
• the fluffy band 51 of nanofibers is fed in the direction of the arrow to the twisting device and a nanofibrous yam is formed by twisting it.
• the direction of movement of the endless conveyor belt can be reversed and the above-mentioned arrangement is only side reversed.
• the endless linear flexible structure can be replaced with a linear flexible structure of finite length, which is wound on pulleys 131.
• Both pulleys 131 extend in this embodiment with their lower parts of its circumference to the polymer solution 21.
• the pulleys 131 are coupled to a known unillustrated reciprocating drive and rotate alternately in both directions, wherein the linear flexible structure is held in tension between them.
• Yarns and threads made of fibers are the most commonly used construction elements in the textile industry for the production of various types of textiles, e.g., fabrics and knitwear.
• the use of 100% nanofibrous yarns in the conventional way of textile production means significant potential for the production of so-called nanotextiles, which exhibit excellent optical, electrical, mechanical and biological properties due to the effects associated with their extremely large specific surface area and low flexibility (bending modulus).
• Nanofibrous yams will find application as structural units of surgical threads, tissue carriers for the repair of nerves, tendons, bones and blood vessels. They have the potential to become structural elements for harvesting and storage of energy, for actuators of mechatronic devices, for sensors and filters. List of references

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

Applications Claiming Priority (2)

Publications (1)

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ID=88416859

Family Applications (1)

Country Status (5)

Family Cites Families (2)

• 2022
  • 2022-09-02 CZ CZ2022-370A patent/CZ2022370A3/cs unknown
• 2023
  • 2023-08-24 WO PCT/CZ2023/050054 patent/WO2024046515A2/en not_active Ceased
  • 2023-08-24 CN CN202380063107.8A patent/CN119816632A/zh active Pending
  • 2023-08-24 EP EP23790226.7A patent/EP4581199A2/en active Pending
  • 2023-08-24 JP JP2025507761A patent/JP2025530575A/ja active Pending

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