A screw-inlet self-decreasing viscosity melt electrospinning nozzle

Abstract

The application belongs to the technical field of melt electrospinning equipment, and provides a screw-embedded self-viscosity-reducing melt electrospinning nozzle, which comprises a first inner sleeve, a second inner sleeve arranged outside the first inner sleeve, a first flow gap arranged between the first inner sleeve and the second inner sleeve, an outer sleeve arranged outside the second inner sleeve, a stirring part for stirring the melt in the first sleeve, and a motor for driving the screw to rotate. The melt in the first inner sleeve is stirred by the screw, and the melt is sprayed onto the nozzle cone surface through the second flow outlet under the action of pressure. The melt is subjected to twice physical actions, so that the viscosity of the melt is greatly reduced, and the functions of refining the fiber and improving the product quality are achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of melt electrospinning equipment, and particularly relates to a screw-embedded self-viscosity reducing melt electrospinning nozzle. Background Technology

[0002] Electrospinning is an advanced manufacturing technology for polymer materials. It involves using a high-voltage electrostatic field to form a Taylor cone from a polymer solution or melt, generating a jet that cools and solidifies as it falls, forming fibers. Electrospinning, also known as polymer jet electrostatic stretching spinning, is vastly different from traditional methods and is one of the most commonly used industrial techniques for mass production of ultrafine fibers.

[0003] Many process parameters affect fiber diameter during fiber formation, such as voltage, melt flow rate, melt viscosity, take-up spindle speed, and fiber preparation environment. In high-end fields such as tissue engineering, biomedicine, and sensors, the requirements for fiber diameter are extremely stringent. Fibers produced by traditional nozzles cannot meet these requirements, making reducing fiber diameter a major research direction.

[0004] Melt viscosity is a characteristic that reflects the ease or difficulty of flow of a plastic melt. It is a measure of melt flow resistance; the higher the viscosity, the greater the flow resistance and the more difficult the flow. Electrospinning relies on electrostatic force to stretch the melt into fibers, and melt viscosity is one of the direct factors affecting the final fiber diameter.

[0005] The simplest and most convenient way to achieve fiber refinement is to adjust the rotation speed of the take-up drum. The higher the rotation speed, the smaller the fiber diameter. This is due to the mechanical stretching of the fiber when it is deposited on the take-up drum. However, it is difficult to match the rotation speed of the take-up drum with the spinning speed. If the take-up drum rotation speed is too slow, it will not only fail to achieve the purpose of fiber refinement, but also be difficult to collect. If the take-up drum rotation speed is too fast, excessive stretching will lead to necking and fiber breakage. The most common method at present is to use a spinning nozzle with airflow assistance. Although airflow assistance has a certain effect, it has a high cost in mass production in industrialization. When the auxiliary airflow is too large, it will also cause fiber breakage and affect the quality of the product. Summary of the Invention

[0006] This invention provides a screw-embedded self-viscosity-reducing melt electrospinning nozzle, which aims to solve the above-mentioned problems.

[0007] This invention is achieved by providing a screw-embedded self-viscosity-reducing melt electrospinning nozzle, comprising:

[0008] First inner sleeve;

[0009] A second inner sleeve is fitted outside the first inner sleeve. The first inner sleeve and the second inner sleeve are fixedly connected. The bottom end of the second inner sleeve is closed. A first flow gap is provided between the first inner sleeve and the second inner sleeve.

[0010] An outer sleeve is fitted over the second inner sleeve. The first inner sleeve is fixedly connected to the outer sleeve. The top and bottom ends of the outer sleeve are open. A second flow gap is provided between the outer sleeve and the second inner sleeve.

[0011] A stirring component for stirring the melt inside the first inner sleeve;

[0012] The outer sleeve has a first inlet at the top, the inner sleeve has an inflow channel at the top that communicates with the first inlet, the inner sleeve has a second inlet at the bottom, the two ends of the first flow slit are respectively connected to the inflow channel and the second inlet, the inner sleeve has a first outlet at the top that communicates with the second flow slit, and the bottom of the second flow slit is the second outlet.

[0013] As a further aspect of the present invention: the top of the second flow slit is 1 mm and the bottom of the second flow slit is 0.5 mm.

[0014] As a further aspect of the present invention: the stirring component includes:

[0015] A helical rod located inside the first inner sleeve;

[0016] A motor located above the screw is used to drive the screw to rotate.

[0017] As a further aspect of the present invention: the bottom end of the spiral rod is rotatably connected to the screw retainer provided at the bottom of the second inner sleeve.

[0018] As a further aspect of the present invention: the bottom end of the spiral rod is rotatably connected to the screw retainer provided at the bottom of the second inner sleeve.

[0019] As a further aspect of the present invention: the bottom end of the spiral rod is hollow and is sleeved on the outside of the screw fixer.

[0020] As a further aspect of the present invention: a sealing end cap is rotatably mounted on the upper part of the spiral rod, and the sealing end cap is fixedly connected to the outer sleeve.

[0021] As a further aspect of the present invention: a heating coil is spirally wound on the outer wall of the outer sleeve for heating the melt.

[0022] Compared with the prior art, the embodiments of this application have the following main advantages:

[0023] The screw-embedded self-viscosity-reducing electrospinning nozzle provided by this invention is configured with a first inner sleeve, a second inner sleeve, an outer sleeve, and a stirring component. The stirring component includes a screw rod and a motor. The screw rod stirs the melt entering the first inner sleeve and causes the melt to be sprayed onto the nozzle cone surface through a narrow slit in the second outlet under pressure. The melt undergoes two physical processes, which greatly reduces the melt viscosity, thereby refining the fibers and improving product quality. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a screw-embedded self-viscosity-reducing melt electrospinning nozzle provided by the present invention;

[0025] Figure 2 This is a cross-sectional view of the first inner sleeve and the second inner sleeve structure in a screw-embedded self-viscosity-reducing melt electrospinning nozzle provided by the present invention.

[0026] Figure 3 This is a schematic diagram of the structure of the first inner sleeve and the second inner sleeve in a screw-embedded self-viscosity-reducing melt electrospinning nozzle provided by the present invention.

[0027] Figure reference numerals: 1. Motor; 2. Coupling; 3. Screw rod; 4. Sealing end cap; 5. First flow outlet; 6. First flow inlet; 7. First inner sleeve; 8. Outer sleeve; 9. Second inner sleeve; 10. Heating coil; 11. Second flow inlet; 12. First flow slot; 13. Second flow outlet; 14. Screw retainer; 15. Bolt hole. Detailed Implementation

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0029] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] This invention provides a screw-embedded self-viscosity-reducing melt electrospinning nozzle, such as... Figures 1-3 As shown, it includes:

[0031] First inner sleeve 7;

[0032] A second inner sleeve 9 is fitted outside the first inner sleeve 7. The first inner sleeve 7 and the second inner sleeve 9 are fixed by bolts. The bottom end of the second inner sleeve 9 is closed. A first flow gap 12 is provided between the first inner sleeve 7 and the second inner sleeve 9.

[0033] An outer sleeve 8 is fitted outside the second inner sleeve 9. The top and bottom ends of the outer sleeve 8 are open. A second flow gap 121 is provided between the outer sleeve 8 and the second inner sleeve 9. The first inner sleeve 7 and the second inner sleeve 9 can be inserted into the outer sleeve 8 from the top of the outer sleeve 8. The first inner sleeve 7 and the outer sleeve 8 are fixed by bolts through bolt holes 15.

[0034] A stirring component for stirring the melt inside the first inner sleeve 7;

[0035] The outer sleeve 8 has a first inlet 6 at its top, the inner sleeve 7 has an inflow channel 61 at its top that communicates with the first inlet 6, and the inner sleeve 7 has a second inlet 11 at its bottom. In this embodiment, the bottom of the inner sleeve 7 is the opening, and the two ends of the first flow slit 12 are respectively connected to the inflow channel 61 and the second inlet 11.

[0036] The first inner sleeve 7 and the second inner sleeve 9 are inserted into the outer sleeve 8 from the top of the outer sleeve 8, and the first inlet 6 on the outer sleeve 8 corresponds to the inlet channel 61 on the first inner sleeve 7. The top of the first inner sleeve 7 is provided with a first outlet 5 that communicates with the second flow slot 121. In this embodiment, the first outlet 5 is preferably arc-shaped and its corresponding central angle is less than 180 degrees. Multiple first outlets 5 can be opened circumferentially at intervals on the top of the first inner sleeve 7, which helps the melt to enter from multiple circumferential first outlets 5 and be evenly distributed in the second flow slot 121. The bottom of the second flow slot 121 is the second outlet 13. In this embodiment, the bottom of the outer sleeve 8 is funnel-shaped, which helps the melt to diffuse outward from the second outlet 13 and be sprayed onto the nozzle cone surface.

[0037] After the raw material is melted and plasticized, the melt enters the inflow channel 61 on the first inner sleeve 7 through the first inlet 6 on the outer sleeve 8 via the extruder. Then, it enters the first flow slot 12 through the inflow channel 61 and then enters the first inner sleeve 7 through the first inlet 6. Subsequently, the stirring component stirs the melt in the first inner sleeve 7, and the melt with reduced viscosity enters the second flow slot 121 through the first outlet 5. Under pressure, the melt is sprayed from the second outlet 13 onto the nozzle cone surface, further reducing the melt viscosity. After the melt is evenly distributed, the high-voltage electrostatic generator is turned on to form a high-voltage electrostatic field. Under the action of the electrostatic field, a jet is formed, which cools and solidifies during the falling process to obtain ultrafine fibers.

[0038] Wherein, the top end of the second flow slit 121 is 1mm and the bottom end of the second flow slit 121 is 0.5mm, that is, the size of the second flow outlet 13 is 0.5mm;

[0039] In specific implementation, a 0.5mm thick flange can be provided at the bottom end of the second inner sleeve 9, and the bottom end of the second flow slit 121 is 1-0.5=0.5mm. The melt enters the second flow slit 121 from the first flow outlet 5, and then is sprayed onto the nozzle cone surface from the second flow outlet 13. Since the size of the second flow outlet 13 is narrower than that of the second flow slit 121, the melt is sprayed out faster.

[0040] Of course, the dimensions of the second flow slot 121 and the second flow outlet 13 can be designed according to requirements without too many restrictions;

[0041] In this embodiment, the stirring component includes:

[0042] The spiral rod 3 is located inside the first inner sleeve;

[0043] A motor 1 located above the screw rod 3 is used to drive the screw rod 3 to rotate. The output shaft of the motor 1 can be fixedly connected to the top of the screw rod 3 through a coupling 2.

[0044] The motor 1 drives the screw rod 3 to rotate, and the screw rod 3 stirs the melt, which greatly reduces the viscosity of the melt. At the same time, the rotation of the screw rod 3 drives the melt to rise, which not only makes the melt viscosity in the second flow slot 121 lower than the melt viscosity in the first inner sleeve 7, but also increases the melt pressure in the second flow slot 121, making the melt more evenly distributed in the second flow slot 121.

[0045] Specifically, the bottom end of the spiral rod 3 is rotatably connected to the screw retainer 14 provided at the bottom of the second inner sleeve 9. In this embodiment, the screw retainer 14 and the second inner sleeve 9 can be integrally set. The bottom end of the spiral rod 3 is hollow and is sleeved on the outside of the screw retainer 14 to improve the stability of the spiral rod 3 when rotating. When the spiral rod 3 rotates, the melt can act as a lubricant. The screw retainer 14 can be fixedly connected to the bottom of the second inner sleeve 9 by welding.

[0046] Preferably, a sealing end cover 4 is rotatably mounted on the upper part of the spiral rod 3, which can be rotatably mounted by bearings, and the sealing end cover 4 is fixedly connected to the outer sleeve 8 by bolts;

[0047] In a specific implementation, a heating coil 10 is spirally wound on the outer wall of the outer sleeve 8 for heating the melt.

[0048] In summary, this invention provides a screw-embedded self-viscosity-reducing melt electrospinning nozzle, the working principle of which is as follows:

[0049] After the raw material is melted and plasticized, the melt enters the inflow channel 61 on the first inner sleeve 7 through the first inlet 6 on the outer sleeve 8 via the extruder. Then, it enters the first flow slot 12 through the inflow channel 61 and then enters the first inner sleeve 7 through the first inlet 6. Subsequently, the motor 1 is started, and the screw rod 3 is driven by the coupling 2 to stir the melt. The melt with reduced viscosity enters the second flow slot 121 through the first outlet 5. Under pressure, the melt is sprayed from the second outlet 13 onto the nozzle cone surface to further reduce the melt viscosity. After the melt is evenly distributed, the high-voltage electrostatic generator is turned on to form a high-voltage electrostatic field. Under the action of the electrostatic field, a jet is formed, which cools and solidifies during the falling process to obtain ultrafine fibers.

[0050] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0051] It should be understood that the disclosed apparatus can be implemented in other ways, given the several embodiments provided in this application. For example, the apparatus embodiments described above are merely illustrative; the division of units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or communication connections shown or discussed may be through some interfaces; the indirect coupling or communication connections between devices or units may be telecommunications or other forms.

[0052] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0053] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. A screw-embedded self-viscosity-reducing melt electrospinning nozzle, characterized in that, include: First inner sleeve; A second inner sleeve is fitted outside the first inner sleeve. The first inner sleeve and the second inner sleeve are fixedly connected. The bottom end of the second inner sleeve is closed. A first flow gap is provided between the first inner sleeve and the second inner sleeve. An outer sleeve is fitted over the second inner sleeve. The first inner sleeve is fixedly connected to the outer sleeve. The top and bottom ends of the outer sleeve are open. A second flow gap is provided between the outer sleeve and the second inner sleeve. A stirring component for stirring the melt inside the first inner sleeve; The outer sleeve has a first inlet at the top, the inner sleeve has an inflow channel at the top that communicates with the first inlet, the inner sleeve has a second inlet at the bottom, the two ends of the first flow slit are respectively connected to the inflow channel and the second inlet, the inner sleeve has a first outlet at the top that communicates with the second flow slit, and the bottom of the second flow slit is the second outlet.

2. The screw-embedded self-viscosity-reducing melt electrospinning nozzle as described in claim 1, characterized in that, The top of the second flow slit is 1 mm, and the bottom of the second flow slit is 0.5 mm.

3. The screw-embedded self-viscosity-reducing melt electrospinning nozzle as described in claim 1, characterized in that, The stirring component includes: A helical rod located inside the first inner sleeve; A motor located above the screw is used to drive the screw to rotate.

4. The screw-embedded self-viscosity-reducing melt electrospinning nozzle as described in claim 3, characterized in that, The output shaft of the motor is fixedly connected to the top of the screw rod via a coupling.

5. The screw-embedded self-viscosity-reducing melt electrospinning nozzle as described in claim 3, characterized in that, The bottom end of the spiral rod is rotatably connected to the screw retainer provided at the bottom of the second inner sleeve.

6. The screw-embedded self-viscosity-reducing melt electrospinning nozzle as described in claim 5, characterized in that, The bottom end of the screw rod is hollow and is sleeved on the outside of the screw rod retainer.

7. The screw-embedded self-viscosity-reducing melt electrospinning nozzle as described in claim 3, characterized in that, A sealing end cap is rotatably mounted on the upper part of the screw rod, and the sealing end cap is fixedly connected to the outer sleeve.

8. The screw-embedded self-viscosity-reducing melt electrospinning nozzle as described in claim 1, characterized in that, A heating coil is spirally wound on the outer wall of the outer sleeve for heating the melt.

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