Spinning nozzle, spinning device and spinning method

Abstract

The invention provides a spinning nozzle, a spinning device and a spinning method, and relates to the technical field of spinning, the spinning nozzle comprises a nozzle body, the nozzle body is internally provided with a cavity, one end of the nozzle body is provided with a feed inlet, the other end of the nozzle body is provided with a plurality of suspension needles in the circumferential direction, and the suspension needles are in sliding fit with the other end of the nozzle body; the air inlet pipe is inserted into the cavity, a material channel is formed between the air inlet pipe and the spray head body, and the air inlet pipe is used for transmitting heating airflow; the problem that in the prior art, fiber fineness is not uniform in melt electrostatic spinning is solved.

Description

Technical Field

[0001] This invention belongs to the field of spinning technology, and more specifically, relates to a spinning nozzle, a spinning device, and a spinning method. Background Technology

[0002] Electrospinning technology, also known as electrospinning, is a technology that introduces electrostatic force to stretch polymer fluids, enabling polymer fibers to reach micro- and nano-scale diameters.

[0003] Electrospinning technology is classified into solution electrospinning and melt electrospinning based on the characteristics of the processed materials. Melt electrospinning is a method for preparing fibers using high-temperature molten polymers. The earliest mention of melt electrospinning dates back to 1936, but truly significant articles on it didn't appear in academic journals until 1981. The authors published a series of three articles; the first detailed the spinning process of PP and PE and the basic characterization of fiber diameter, while the other two described spinning models and the deformation analysis of droplets in an electric field, demonstrating that even polymer melts with poor conductivity could be electrospinned. This provided a research basis for the development of melt electrospinning. A second related article appeared 20 years later, studying the single-needle spinning process of several major thermoplastic polymers under vacuum. This article, to some extent, sparked a resurgence in research on melt electrospinning. Since then, research on melt electrospinning has increased significantly.

[0004] The basic principle of melt electrospinning is to prepare fibers using high-temperature molten polymers. Compared to solution electrospinning, melt electrospinning does not require the use of solvents during the process, avoiding the steps of solvent treatment and removal. This improves the simplicity and efficiency of the process and avoids energy waste. The solvent preparation and treatment process of solution electrospinning usually requires high costs and needs to consider issues such as solvent recovery and environmental pollution. Melt electrospinning eliminates these steps and related costs, making fiber preparation costs more controllable and affordable, and is also environmentally friendly.

[0005] Currently, key challenges in melt electrospinning include uneven fiber fineness and the difficulty of refining fibers to the hundreds of nanometer scale. Existing technologies include a slit-type spinning device, but this device does not effectively address the uniform distribution of the melt at the slit, resulting in uneven fiber fineness. Other existing technologies involve appropriately introducing an external magnetic field near the collecting plate. Experimental results show that electrospun nanofibers with an introduced magnetic field exhibit an ordered microstructure, and fibers produced using magnetic field-assisted electrospinning (MFAES) are more uniform compared to those produced without an introduced magnetic field. However, this method is only suitable for solution electrospinning and has limitations for melt electrospinning. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a spinning nozzle, spinning device, and spinning method to solve the problem of uneven fiber fineness in melt electrospinning.

[0007] To achieve the above objectives, the present invention provides a spinning nozzle, comprising:

[0008] The nozzle body has a cavity inside, a feed port is provided at one end of the nozzle body, and multiple suspension needles are provided circumferentially at the other end of the nozzle body, with the suspension needles slidingly engaged with the other end of the nozzle body.

[0009] An air inlet pipe is inserted into the cavity, and a material channel is formed between the air inlet pipe and the nozzle body. The air inlet pipe is used to transmit heated airflow.

[0010] Optionally, a lateral flow channel is provided at one end of the nozzle body. The lateral flow channel is located on the outer periphery of the cavity, and one end of the lateral flow channel is connected to the material channel, while the other end of the lateral flow channel forms the feed inlet.

[0011] Optionally, it also includes a heating element disposed on the outer periphery of the nozzle body, the heating element being used to heat the molten material in the material channel.

[0012] Optionally, the heating component includes a heating sleeve fitted around the outer periphery of the nozzle body and a heating wire wound around the outer periphery of the heating sleeve.

[0013] Optionally, the heating jacket is connected to a temperature sensor.

[0014] Optionally, one end of the air inlet pipe is sealed to one end of the nozzle body, and an outwardly protruding limiting part is provided on the outer periphery of the air inlet pipe. The limiting part contacts the nozzle body but does not completely block the material channel.

[0015] Optionally, the sidewall of the cavity near the other end of the nozzle body is an outwardly expanding conical surface.

[0016] Optionally, the suspension needle is V-shaped, and the open end of the suspension needle is provided with a pair of locking parts, which extend in a direction that approaches each other. The other end of the nozzle body is provided with a first annular groove and a second annular groove on its outer and inner circumferences, respectively. The suspension needle engages with the first annular groove and the second annular groove through the pair of locking parts.

[0017] Optionally, the conical surface is tilted at an angle of 30° to 75° relative to the axis of the nozzle body.

[0018] The present invention also provides a spinning apparatus, comprising:

[0019] The aforementioned spinning nozzle;

[0020] An electrostatic generating component is used to form an electrostatic field on the outside of the other end of the nozzle body of the spinning nozzle, so as to guide the generation of a Taylor cone through a suspended needle.

[0021] Optionally, the negative electrode of the electrostatic generating component is connected to the nozzle body of the spinning nozzle.

[0022] The present invention also provides a spinning method, utilizing the above-described spinning apparatus, comprising:

[0023] The molten material is fed into the material channel through the feed inlet;

[0024] Introduce heated airflow into the air inlet duct;

[0025] An electrostatic field is formed on the outer side of the other end of the nozzle body of the spinning nozzle by an electrostatic generating component, so as to guide the generation of Taylor cone through the suspension needle.

[0026] Optionally, the melt material is a polymer.

[0027] This invention provides a spinning nozzle, a spinning device, and a spinning method. Its advantages are as follows: the spinning nozzle forms an annular slit-shaped material channel between the nozzle body and the air inlet pipe, allowing molten material to pass through. Heated airflow is transmitted through the center of the air inlet pipe to assist in the spinning process, providing axial stretching of the fibers and maintaining the spinning temperature. This prolongs the stretching force application time and reduces fiber fineness. Multiple suspended needles, circumferentially slidable at the other end of the nozzle body, can separate from each other under the influence of an electrostatic field and are evenly distributed along the circumference. These needles guide the production of the Taylor cone, avoiding uneven fiber thickness caused by Taylor cone fusion during the spinning process, resulting in more uniform fiber fineness.

[0028] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0029] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0030] Figure 1 A schematic diagram of the overall structure of a spinning nozzle according to Embodiment 1 of the present invention is shown.

[0031] Figure 2A schematic diagram of the suspended needle of a spinning nozzle according to Embodiment 1 of the present invention is shown.

[0032] Figure 3 It shows Figure 1 A magnified view of part I.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Air inlet pipe; 2. Nozzle body; 3. Heating wire; 4. Top wire; 5. Heating sleeve; 6. Temperature sensor; 7. Suspension needle; 8. Snap-fit ​​part; 9. First annular groove; 10. Second annular groove; 11. Material channel; 12. Lateral flow channel. Detailed Implementation

[0035] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0036] Example 1

[0037] like Figure 1 As shown, the present invention provides a spinning nozzle, comprising:

[0038] The nozzle body 2 has a cavity inside. One end of the nozzle body 2 has a feed port, and the other end of the nozzle body 2 has a plurality of suspension needles 7 arranged circumferentially. The suspension needles 7 slide and engage with the other end of the nozzle body 2.

[0039] Air inlet pipe 1 is inserted into the cavity, and a material channel 11 is formed between air inlet pipe 1 and nozzle body 2. Air inlet pipe 1 is used to transmit heated airflow.

[0040] Specifically, to address the problem of uneven fiber fineness in existing melt electrospinning technologies, the spinning nozzle provided by this invention forms an annular slit-shaped material channel 11 between the nozzle body 2 and the air inlet pipe 1. The melt material can pass through the material channel 11. The center of the air inlet pipe 1 transmits a heating airflow for assistance. The heating airflow is the airflow used for heating, which can be hot air. It can axially stretch the fibers during the spinning process, maintain the spinning temperature, prolong the stretching force application time, and reduce fiber fineness. Multiple suspension needles 7, which are circumferentially slidable at the other end of the nozzle body 2, can separate from each other under the action of an electrostatic field and are evenly distributed along the circumference. The multiple suspension needles 7 guide the production of the Taylor cone, avoiding the problem of uneven fiber fineness caused by the fusion of Taylor cones during the spinning process, thus making the fiber fineness more uniform.

[0041] Furthermore, the spinning nozzle is used for electrospinning of molten materials, such as polymers like polyethylene; and because the spinning nozzle has multiple suspended needles 7, a single spinning nozzle can spin dozens of filaments, resulting in high spinning efficiency and reducing heat loss during the spinning process.

[0042] Optionally, a lateral flow channel 12 is provided at one end of the nozzle body 2. The lateral flow channel 12 is located on the outer periphery of the cavity, and one end of the lateral flow channel 12 is connected to the material channel 11, while the other end of the lateral flow channel 12 forms a feed inlet.

[0043] Specifically, the feeding direction of the lateral flow channel 12 forms an angle with the axial direction of the material channel 11, and the lateral flow channel 12 is used for feeding.

[0044] In this embodiment, as Figure 1 As shown, the lateral flow channel 12 can be opened at the upper end of the nozzle body 2, while the material channel 11 can be set vertically.

[0045] Optionally, it also includes a heating element disposed on the outer periphery of the nozzle body 2, which is used to heat the molten material in the material channel 11.

[0046] Specifically, the heating element is used to heat the molten material in the material channel 11 and keep it in a molten state.

[0047] Optionally, the heating component includes a heating sleeve 5 fitted around the outer periphery of the nozzle body 2 and a heating wire 3 wound around the outer periphery of the heating sleeve 5.

[0048] Specifically, heating wire 3 is an electric heating wire 3, which generates heat after being powered on, and its heating power is easy to adjust so that the heat can be controlled.

[0049] Optionally, the heating jacket 5 is connected to a temperature sensor 6.

[0050] Specifically, temperature sensor 6 can monitor the heating temperature in real time in order to regulate the heating temperature of the molten material.

[0051] In this embodiment, a slot is provided on the outer side of the heating sleeve 5 for winding and fixing the heating wire 3 and the temperature sensor 6 onto the heating sleeve 5, and the heating sleeve 5 is fixed to the outer side of the nozzle body 2 using the top screw 4.

[0052] Optionally, one end of the air inlet pipe 1 is sealed to one end of the nozzle body 2, and an outwardly protruding limiting part is provided on the outer periphery of the air inlet pipe 1. The limiting part contacts the nozzle body 2 but does not completely block the material channel 11.

[0053] Specifically, the upper end of the material channel 11 is closed and the lower end is open. The limiting part is used to contact the cavity wall of the cavity to form a radial limit on the air inlet pipe 1.

[0054] In this embodiment, as Figure 1 As shown, the upper end of the cavity is provided with a first limiting step, the upper end of the air inlet pipe 1 is provided with a second limiting step that cooperates with the first limiting step, and a sealing part is provided near the second limiting step of the air inlet pipe 1. The sealing part is sealed to the nozzle body 2 to block the upper end of the material channel 11.

[0055] In this embodiment, three keys arranged radially at 120° intervals are provided on the outer periphery of the middle part of the air inlet pipe 1. The keys serve as limiting parts, and the outer periphery of the keys contacts the cavity wall.

[0056] Optionally, the sidewall of the cavity near the other end of the nozzle body 2 is an outwardly expanding conical surface.

[0057] Specifically, the molten material flowing out from the material channel 11 can flow along the conical surface and form a Taylor cone under the guidance of the suspension needle 7.

[0058] In this embodiment, as Figure 1 As shown, the cone-shaped surface makes the wall thickness of the lower end of the nozzle body 2 gradually thin from the inside to the outside, and then the suspension needle 7 is installed at the lowest position.

[0059] Optionally, the suspension needle 7 is V-shaped, and the open end of the suspension needle 7 is provided with a pair of locking parts 8. The pair of locking parts 8 extend in a direction that approaches each other. The other end of the nozzle body 2 is provided with a first annular groove 9 and a second annular groove 10 on its outer and inner circumferences, respectively. The suspension needle 7 is engaged with the first annular groove 9 and the second annular groove 10 through the pair of locking parts 8.

[0060] Specifically, such as Figure 2 As shown, the suspended needle 7 includes two arms. The lower ends of the two arms are integrally connected to form a needle-like structure. The first arm is set in a vertical direction, and the second arm is set in an inclined direction. The extension direction of the second arm is matched as closely as possible to the inclination angle of the conical surface to facilitate melt flow.

[0061] In this embodiment, the snap-fit ​​part 8 is formed in a tadpole shape at the connection position with the support arm. The arc-shaped snap-fit ​​part 8 can make the suspension needle 7 slide more smoothly when it is snapped into the first annular groove 9 and the second annular groove 10. This is beneficial because the adjacent suspension needles 7 repel each other due to the charge carried by the adjacent suspension needles 7 under the action of electrostatics, and the repulsion force is uniform, so that the multiple suspension needles 7 are evenly distributed along the circumference.

[0062] Optionally, the angle of inclination of the conical surface relative to the axis of the nozzle body 2 is 30°-75°.

[0063] In this embodiment, the suspended needle 7 is elastic and can be inserted into the first annular groove 9 and the second annular groove 10. The suspended needle 7 and the nozzle body 2 are in line contact, which can reduce friction.

[0064] In this embodiment, the suspension needle 7 is made of conductive material, which allows the suspension needles 7 to repel each other under the action of electrostatic force and slide apart along the first annular groove 9 and the second annular groove 10, avoiding the problem of uneven fiber thickness caused by the fusion of Taylor cones during the spinning process, and making the fiber fineness more uniform.

[0065] Example 2

[0066] The present invention also provides a spinning apparatus, comprising:

[0067] The aforementioned spinning nozzle;

[0068] An electrostatic generating component is used to form an electrostatic field on the outside of the other end of the nozzle body 2 of the spinning nozzle, so as to guide the generation of the Taylor cone through the suspension needle 7.

[0069] Specifically, the electrostatic generating component can form an electrostatic field below the spinning nozzle. Under the action of the electrostatic field, the suspended needles 7 are evenly distributed along the circumference and guide the molten material in the molten state, thereby guiding the generation of Taylor cones and avoiding the problem of uneven filament thickness caused by the fusion of Taylor cones during the spinning process.

[0070] In this embodiment, a feeding component is also included. The feeding component can be a screw extruder, a plunger feeder, or feed using the gravity of the melt itself.

[0071] Optionally, the negative electrode of the electrostatic generating component is connected to the nozzle body 2 of the spinning nozzle.

[0072] Specifically, the nozzle body 2 is connected to the grounding electrode of the static electricity generating component, which improves safety performance.

[0073] In this embodiment, the air inlet duct 1 can be directly supplied with hot air using an air heater, or it can be supplied with hot air using an air compressor in conjunction with a heating device.

[0074] Example 3

[0075] The present invention also provides a spinning method, utilizing the above-described spinning apparatus, comprising:

[0076] Melt material is fed into material channel 11 through the feed inlet;

[0077] Inject heated airflow into air inlet duct 1;

[0078] An electrostatic field is formed on the outside of the other end of the nozzle body 2 of the spinning nozzle by an electrostatic generating component, so as to guide the generation of Taylor cone through the suspension needle 7.

[0079] Furthermore, it also includes heating the material being incorporated within the material channel 11 to bring it to a molten state.

[0080] In this embodiment, the method further includes receiving the fibers output from the spinning device using a receiver to form a nonwoven fabric.

[0081] Optionally, the melt material is a polymer.

[0082] Specifically, the melt material can be one of the following: polypropylene, polylactic acid, polyhydroxyalkanoate, polybutylene succinate, polycaprolactone, polyurethane, polyadipic acid, butylene terephthalate, or a mixture of multiple polymers.

[0083] In summary, the spinning method provided by this invention utilizes the aforementioned spinning apparatus with the above-mentioned spinning nozzle. Taking the spinning of polypropylene as the melt raw material as an example: the material is fed through an extruder and fed through a side channel 12, with the melt material flowing out uniformly along the circumferential slit-shaped material channel 11; a nozzle body 2 with a conical surface is used, and multiple suspension needles 7 are provided at the lower end of the nozzle body 2. A single nozzle can spin dozens of filaments, resulting in high spinning efficiency and reducing heat loss during the spinning process; by introducing heated airflow into the air inlet pipe 1, a central hot airflow is formed to assist the axial stretching of the fibers during the spinning process, maintain the ambient temperature, prolong the stretching force action time, and reduce fiber fineness; the suspension needles 7 guide the generation of Taylor cones, and electrostatic force is used to control the separation of the suspension needles 7 and their uniform distribution along the circumference, avoiding the problem of uneven filament thickness caused by the fusion of Taylor cones during the spinning process, thus making the fiber fineness more uniform; the output fibers can be received by a movable receiving plate to obtain nonwoven fabric.

[0084] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A spin jet, characterized in that include: The nozzle body has a cavity inside, a feed port is provided at one end of the nozzle body, and multiple suspension needles are provided circumferentially at the other end of the nozzle body, with the suspension needles slidingly engaged with the other end of the nozzle body. An air inlet pipe is inserted into the cavity, and a material channel is formed between the air inlet pipe and the nozzle body. The air inlet pipe is used to transmit heated airflow.

2. The spinhead of claim 1 wherein, One end of the nozzle body is provided with a lateral flow channel, which is located on the outer periphery of the cavity. One end of the lateral flow channel is connected to the material channel, and the other end of the lateral flow channel forms the feed inlet.

3. The spinhead of claim 1 wherein, It also includes a heating element disposed on the outer periphery of the nozzle body, the heating element being used to heat the molten material in the material channel.

4. The spinhead of claim 3, wherein The heating component includes a heating sleeve fitted around the outer periphery of the nozzle body and a heating wire wound around the outer periphery of the heating sleeve.

5. The spinhead of claim 4 wherein, The heating jacket is connected to a temperature sensor.

6. The spinhead of claim 1 wherein, One end of the air inlet pipe is sealed to one end of the nozzle body. The outer periphery of the air inlet pipe is provided with an outwardly protruding limiting part. The limiting part contacts the nozzle body but does not completely block the material channel.

7. The spinhead of claim 1 wherein, The sidewall of the cavity near the other end of the nozzle body is a tapered surface that gradually expands outward.

8. The spinhead of claim 7, wherein The suspension needle is V-shaped, and the open end of the suspension needle is provided with a pair of locking parts. The pair of locking parts extend in a direction that approaches each other. The other end of the nozzle body is provided with a first annular groove and a second annular groove on its outer and inner circumferences, respectively. The suspension needle engages with the first annular groove and the second annular groove through the pair of locking parts.

9. The spinhead of claim 7 wherein, The conical surface is tilted at an angle of 30°-75° relative to the axis of the nozzle body.

10. A spinning device, characterized by include: The spinning nozzle according to any one of claims 1-9; An electrostatic generating component is used to form an electrostatic field on the outside of the other end of the nozzle body of the spinning nozzle, so as to guide the generation of a Taylor cone through a suspended needle.

11. The spinning device of claim 10, wherein The negative electrode of the electrostatic generating component is connected to the nozzle body of the spinning nozzle.

12. A spinning method using the spinning device according to claim 10 or 11, characterized by, include: The molten material is fed into the material channel through the feed inlet; Introduce heated airflow into the air inlet duct; An electrostatic field is formed on the outer side of the other end of the nozzle body of the spinning nozzle by an electrostatic generating component, so as to guide the generation of Taylor cone through the suspension needle.

13. The method of claim 11, wherein the method further comprises: The melt material is a polymer.

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