A spinning nozzle based on electrostatic jetting and its spinning process

Abstract

This invention relates to the field of spinning nozzle technology, specifically to a spinning nozzle based on electrostatic air jetting. The nozzle is a long, hollow, conductive metal tube with a pointed tip. The conductive metal can be connected to electrodes to complete electrostatic spinning. The conductive metal is hollow inside, and the nozzle is open on both sides. Gaps are formed on both sides of the pointed tip at the top of the nozzle to allow gas to pass through for spinning. The aperture of the gaps gradually narrows. A guide vane is provided inside the gap. The inner and outer walls of the gap are divided into an outer slit and an inner slit, with the outer and inner slits facing opposite directions to the guide vane. This invention designs the nozzle shape so that the electric field strength is maximized at the triangular tip, which can overcome the surface tension of the spinning solution under the same voltage to form multiple jets, increasing the yield of electrostatic spinning.

Description

Technical Field

[0001] The present invention relates to the technical field of spinning nozzles, and specifically to a spinning nozzle based on electrostatic air jet and its spinning process. Background Art

[0002] In traditional processes, we often carry out dyeing and finishing after producing yarns or fabrics. However, this dyeing and finishing method has complex processes, consumes a large amount of energy, and causes significant pollution. If the chemicals used in the dyeing and finishing process are directly discharged without treatment, it will lead to water pollution, soil pollution, air pollution, and even affect the health of workers. A large amount of heat energy will also be consumed during the dyeing and finishing process to heat water and dry textiles, resulting in persistent pollution. On this basis, a new dyeing and finishing method is introduced. By reconstructing the textile process, the means of dyeing and finishing are changed, and the existing technology of mosaic spinning and its implementation path in the new method are introduced. This method replaces the most polluting link in traditional dyeing and finishing. With the advantages of streamlined processes and no wastewater discharge, it conforms to the direction of environmental protection and low-carbon development in China and is expected to create a new method for coloring textiles that can be widely applied in factories.

[0003] Chinese patent document CN201910567381.4 proposed "An anti-cotton web curling device for a submicron fiber / cotton blended yarn production line". This device is used as the carrier of the receiving device proposed in claim 6 to prevent the curling of the cotton web on the receiving device in claim 6.

[0004] After retrieval, Chinese patent document CN200710036447.4 proposed "A jet electrostatic spinning device for producing nanofibers". A vertical nozzle is installed below the liquid storage tank, bubbles appear on the liquid surface, and fibers are pulled out under the action of high pressure.

[0005] However, this technology still has deficiencies. Its principle mainly utilizes bubbles to form "tips", and then fibers are pulled out under the action of an electrostatic field. The role of air jet spinning is insufficient, and the spinning efficiency only increases slightly based on needleless electrostatic spinning.

[0006] After retrieval, Chinese patent document CN202321032166.2 proposed "A multi-nozzle combined jet electrostatic spinning machine". By combining air jet and static electricity on the same nozzle and then arranging them in an array, multiple nozzles are added to electrostatic air jet spinning to solve the problem of low production efficiency.

[0007] However, this technology still has deficiencies. During operation, to solve the problem of frequently replacing the receiving device, this technology uses a trigger post to adjust the orientation of the receiving device to achieve double-sided receiving of spinning. During the flipping process of the receiving device, the liquid supply and gas supply processes are paused, and the whole process is not continuous. When the humidity is high, the solution will coagulate, clogging the needle. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a spinning nozzle based on electrostatic jetting and its spinning process. This solves the problem that traditional nozzles have low electrostatic spinning efficiency, which can only reduce the speed of the cotton web and has a significant impact on factory capacity. The new nozzle greatly improves production efficiency, increases the content of micro and nanofibers in the product, and expands the product's functionality and application range.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a spinning nozzle based on electrostatic jetting, comprising an outer slit, an inner slit, a nozzle, a jet, and a receiving device. The nozzle is a long, hollow conductive metal with a pointed tip. The conductive metal can be connected to electrodes to complete electrostatic spinning. The conductive metal is hollow inside, and the nozzle is open on both sides. Gaps are formed on both sides of the pointed tip at the top of the nozzle to allow gas to pass through and complete the jet spinning. The aperture of the gaps gradually narrows, and guide vanes are provided inside the gaps. The inner and outer walls of the gaps are divided into an outer slit and an inner slit, with the outer and inner slits facing opposite directions to the guide vanes.

[0010] Preferably, the cross-section of the nozzle is composed of an upper triangle and a lower hollow cuboid. The base angle ∠1 of the upper triangle of the nozzle is in the range of 30°-75°. For low-viscosity solutions, 30°-50° is selected to increase the electric field strength and reduce droplet splashing. For high-viscosity solutions, 60°-75° is selected to prolong the solution residence time and improve spinning stability. The width of the outer side b of the lower hollow cuboid of the nozzle is 2-8cm, the height of the outer side a is 1-5cm, the width of the inner side d is 1-6cm, and the height of the inner side c is 1-4cm. The length ratio of the gap h to the non-g portion of the electrode nozzle is (2-10):1. Increasing the proportion of the gap portion can improve the air-jet spinning effect.

[0011] Preferably, the guide vane at the gap is tilted to the left to guide the airflow to the left, and the guide vane on the opposite side is tilted to the right to guide the airflow to the opposite side; the tilt angle of the guide vane is 15°-30°, and the surface of the guide vane is polished or coated to reduce airflow friction loss and prevent turbulence.

[0012] Preferably, the width of the guide plate is 0.1mm-5mm, the thickness is 0.1mm-6mm, the spacing between the guide plates is 1.2-2 times their own width, and the length of the guide plate is adapted to the gap length of the spinning nozzle based on electrostatic jetting and the tilt angle of the guide plate itself.

[0013] Preferably, the air pressure of the air pump is adjusted to 0-20 kPa, and the air pressure needs to be increased by 20%-30% in wide-area scenarios to maintain uniformity.

[0014] Preferably, the fiber receiving device includes a motor-driven metal roller, which is grounded or connected to the negative terminal of a high-voltage generator. The fiber receiving device is a flat conveyor belt with a cotton web adsorbed on its outer ring, and the cotton web runs at a speed of 40-200 m / min.

[0015] More preferably, the voltage regulation range of the high-voltage generator is 0-100kV.

[0016] Working principle: Electrospinning uses a high-voltage electrostatic field to charge the polymer solution, overcoming surface tension to form Taylor cones, which are eventually stretched into nanofibers; Air-jet spinning uses a high-speed airflow (compressed air or nitrogen) to mechanically stretch the solution, forming micron-sized fibers. Based on airflow stretching, the solution enters the electric field more quickly, and the mutual repulsion of charges makes the resulting submicron-sized fibers more uniform.

[0017] This invention provides a spinning nozzle based on electrostatic air jetting and its spinning process. It has the following beneficial effects:

[0018] This invention designs the nozzle shape so that the electric field strength is maximized at the apex of the triangle. This allows multiple jets to be formed under the same voltage, overcoming the surface tension of the spinning solution and increasing the yield of electrospinning.

[0019] This invention uses high-speed airflow to further stretch the fibers and accelerate the spinning speed. At the same time, the guide plate adjusts the airflow direction and disperses the fibers to prevent agglomeration, enabling continuous and large-scale production of nanofibers.

[0020] This invention greatly improves production efficiency by combining electrostatic air-jet spinning with spinning, maintaining the speed of the cotton web and increasing production capacity. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the spinning process provided by the present invention;

[0022] Figure 2 This is a partially enlarged schematic diagram of the nozzle portion of the present invention;

[0023] Figure 3 This is a schematic diagram of the guide vanes inside the nozzle gap; the left and right diagrams respectively indicate the direction.

[0024] Figure 4 This is a schematic diagram of the nozzle cross-section of the present invention;

[0025] Figure 5 This is a partial schematic diagram of the nozzle of the present invention.

[0026] Among them, 1. outside the slit; 2. inside the slit; 3. nozzle; 4. jet; 5. receiving device. Additionally, a. outer height of the lower hollow cuboid; b. outer width of the lower hollow cuboid; c. inner height of the lower hollow cuboid; d. inner width of the lower hollow cuboid; e. upper end of the gap; f. lower end of the gap; g. electrode non-gap; h. electrode gap. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0028] like Figure 1-5 As shown, this embodiment of the invention provides a spinning nozzle based on electrostatic jetting, including a nozzle 3. The nozzle 3 is a long, hollow conductive metal with a pointed tip. The conductive metal can be connected to an electrode to complete electrostatic spinning. The conductive metal is hollow inside, and the nozzle 3 is open on both the front and rear sides. The tip at the top of the nozzle 3 has gaps on both sides to allow gas to pass through and complete jet spinning. The aperture of the gap gradually becomes thinner. A guide plate is provided inside the gap. The inner and outer walls of the gap are divided into an outer slit 1 and an inner slit 2, and the outer slit 1 and the inner slit 2 are opposite in direction to the guide plate.

[0029] The nozzle is made of conductive metal. The cross-section of nozzle 3 consists of an upper triangle and a lower hollow cuboid. The base angle ∠1 of the upper triangle of nozzle 3 is 35°. The width of the outer side b of the lower hollow cuboid is 8.3cm, the height of the outer side a is 2.8cm, the width of the inner side d is 1.6cm, and the height of the inner side c is 5.7cm. The length ratio of the electrode gap h to the non-gap part is 3:1.

[0030] The guide vanes at the gaps are tilted to the left to guide the airflow to the left, while the guide vanes on the opposite side are tilted to the right to guide the airflow to the opposite side. The tilt angle of the guide vanes is 18°, and the surface of the guide vanes is polished or coated to reduce airflow friction loss and prevent turbulence.

[0031] The guide vane has a width of 0.2 mm, a thickness of 0.2 mm, a spacing of 0.3 mm, and a length that is compatible with the gap length of a spinning nozzle based on electrostatic jetting and the tilt angle of the guide vane itself. Example

[0032] A spinning process based on electrostatic jet spinning:

[0033] The spinning solution is a polymer solution prepared from polyacrylonitrile (PAN) and N,N-dimethylformamide (DMF). The mass fraction of the PAN polymer solution is 10%.

[0034] Step 1): Adjust the distance between the fiber receiving device 5 and the spinning nozzle 3, and then turn on the fiber receiving device 5. The fiber receiving device 5 includes a metal roller driven by a motor. The metal roller is grounded or connected to the negative terminal of the high voltage generator. The fiber receiving device is a flat conveyor belt with a cotton web adsorbed on the outer ring. The running speed of the cotton web is set to 120m / min.

[0035] Step 2): Turn on the liquid supply device and set the liquid supply flow rate;

[0036] Step 3): Turn on the air pump and slowly increase the voltage to the required spinning air pressure. The air pressure of the air pump is adjusted to 12 kPa.

[0037] Step 4): Turn on the high voltage generator and slowly increase the voltage to the required spinning voltage. Adjust the voltage of the high voltage generator to 45kV.

[0038] Step 5): Turn on the spinning brush head and make it reciprocate on the spinning nozzle. The spinning liquid in the spinning brush head drips evenly onto the surface of nozzle 3.

[0039] Step 6): The spinning solution surface on the spinning nozzle 3 forms a jet 4 under the action of the high voltage electrostatic field of the high voltage generator and flies towards the fiber receiving device 5;

[0040] Step 7): After the solvent in the jet evaporates, it is stretched, solidified, and deposited on the receiving device 5 with a cotton web to form nanofibers and mix with the cotton web.

[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A spinning nozzle based on electrostatic jetting, comprising a nozzle (3) and a fiber receiving device (5), characterized in that: The nozzle (3) is a long, hollow conductive metal with a pointed tip. The conductive metal can be connected to an electrode to complete electrospinning. The conductive metal is hollow inside and the nozzle (3) is open on both sides. The nozzle (3) has gaps on both sides of the pointed tip at the top to complete air jet spinning. The aperture of the gap gradually becomes smaller. A guide plate is provided inside the gap. The inner and outer walls of the gap are divided into the outer surface of the slit (1) and the inner surface of the slit (2). The outer surface of the slit (1) and the inner surface of the slit (2) are opposite to the direction of the guide plate.

2. The spinning nozzle based on electrostatic air jetting according to claim 1, characterized in that: The cross-section of the nozzle (3) is composed of an upper triangle and a lower hollow cuboid. The base angle ∠1 of the upper triangle of the nozzle (3) is in the range of 30°-75°. For low viscosity solutions, 30°-50° is selected to increase the electric field strength and reduce droplet splashing. For high viscosity solutions, 60°-75° is selected to prolong the solution residence time and improve the spinning stability. The width of the outer b side of the lower hollow cuboid of the nozzle (3) is 2-8cm, the height of the outer a side is 1-5cm, the width of the inner d side is 1-6cm, and the height of the inner c side is 1-4cm. The length ratio of the gap h to the non-g part of the electrode nozzle (3) is (2-10):

1. Increasing the proportion of the gap part can improve the air-jet spinning effect.

3. A spinning nozzle based on electrostatic air jetting according to claim 1, characterized in that: The guide vane at the gap (1) is tilted to the left to guide the airflow to blow out to the left, and the guide vane at the opposite side (2) is tilted to the right to guide the airflow to blow out to the opposite side; the tilt angle of the guide vane is 15°-30°, and the surface of the guide vane is polished or coated to reduce airflow friction loss and prevent turbulence.

4. A spinning nozzle based on electrostatic air jetting according to claim 1, characterized in that: The width of the guide plate is 0.1mm-5mm, the thickness is 0.1mm-6mm, the spacing between the guide plates is 1.2-2 times their own width, and the length of the guide plate is adapted to the gap length of the electrostatic jet spinning nozzle (3) and the tilt angle of the guide plate itself.

5. A spinning nozzle based on electrostatic air jetting according to claim 1, characterized in that: The fiber receiving device (5) includes a metal roller driven by a motor. The metal roller is grounded or connected to the negative terminal of a high-voltage generator. The fiber receiving device (5) is a flat conveyor belt with a cotton web adsorbed on the outer ring. The running speed of the cotton web is 40-200m / min.

6. A spinning nozzle based on electrostatic air jetting according to claim 5, characterized in that: The voltage regulation range of the high-voltage generator is 0-100kV.

7. A spinning process based on an electrostatic air jet spinning nozzle according to any one of claims 1-6, comprising the following steps: Step 1): Adjust the distance between the fiber receiving device (5) and the spinning nozzle (3), and then turn on the fiber receiving device (5). Step 2): Turn on the liquid supply device and set the liquid supply flow rate; Step 3): Turn on the air pump and slowly increase the voltage to the required spinning air pressure; Step 4): Turn on the high voltage generator and slowly increase the voltage to the required spinning voltage; Step 5): Turn on the spinning brush head and make it reciprocate on the spinning nozzle. The spinning liquid in the spinning brush head drips evenly onto the surface of the nozzle (3). Step 6): The spinning solution surface on the spinning nozzle (3) forms a jet (4) under the action of the high voltage electrostatic field of the high voltage generator and flies towards the fiber receiving device (5). Step 7): After the solvent in the jet evaporates, it is stretched, solidified, and deposited on the receiving device (5) with cotton web to form nanofibers and mix with the cotton web.

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