Multi-inter-tooth capillary enhanced electrostatic spinning device and spinning method thereof

Abstract

The invention provides a multi-inter-tooth capillary enhanced electrostatic spinning device and a spinning method thereof, and relates to the technical field of electrostatic spinning. Melt is heated and conveyed to a middle runner in a spray head; the melt firstly reaches the open slot of the second inner layer from the hollow runner in the spray head, enters the umbrella-shaped conical surface of the second inner layer, and quickly reaches the open slot of the first inner layer along with the increasing height of the melt in the hollow runner; the height difference between the annular groove and the opening groove between the first inner layer and the first outer layer is adjusted through the threads to control the flow speed of melt, the melt enters the umbrella-shaped conical surface of the first layer from the opening groove of the first layer, and when the melt reaches the position above the slits of the multi-tooth structure, the melt is sucked into each slit, and therefore the flow speed of the melt is controlled. And after the melt rapidly reaches the tip position of the nozzle in the slit, the melt is continuously conveyed to two adjacent teeth of the slit until the melt uniformly drips, and the high-voltage electrostatic generation device is turned on, so that the melt is induced to be electrified and forms jet flow under the action of electric field force.

Description

Technical field:

[0001] The invention provides a multi-teeth capillary enhanced electrostatic spinning device and a spinning method thereof, and relates to the technical field of electrostatic spinning. Background technology:

[0002] Electrospinning technology is an advanced manufacturing technology for polymer materials in which a polymer solution or melt forms a Taylor cone under the action of a high-voltage electrostatic field and then generates a jet, which evaporates or cools and solidifies during the falling process to form continuous long fibers.

[0003] In the past decade, with the vigorous development of electrospinning technology, electrospinning technology has become one of the most commonly used methods in industrial production. Electrospinning includes solution electrospinning and melt electrospinning. Due to the low efficiency of solution electrospinning, industrial mass production of fibers is limited, while melt electrospinning technology has attracted worldwide attention due to its advantages such as high output and abundant raw materials. Due to the existence of melt viscosity, one of the difficulties of melt electrospinning technology is the uneven dispersion of the melt at the tip of the nozzle. Whether it is linear electrospinning or disc electrospinning, there is an uneven number of fiber jets, and the number of fibers cannot be accurately controlled.

[0004] Therefore, in order to accurately control the number of fibers, some needle-free melt differential electrospinning devices have been proposed one after another. The number of fibers is regulated by controlling the voltage. However, the temperature of the melt is easily changed when exposed to the outside air, which causes the melt viscosity to change and affects the spinning stability. Summary of the invention:

[0005] In order to solve the above technical problems, the present invention proposes a multi-teeth intercapillary enhanced electrospinning device, comprising: a first outer layer of a nozzle, a first inner layer of a nozzle, a second outer layer of a nozzle and a second inner layer of a nozzle; the first outer layer of the nozzle and the second outer layer of the nozzle both have a multi-teeth structure;

[0006] A thread and an annular groove are arranged above the umbrella-shaped cone surface of the first inner layer of the nozzle, an open groove and a thread are arranged on the umbrella-shaped cone surface of the first inner layer of the nozzle, and the first outer layer of the nozzle and the first inner layer of the nozzle are connected by threads;

[0007] The outer part of the umbrella-shaped cone surface of the second inner layer of the nozzle is provided with threads and open grooves, the inner part of the umbrella-shaped cone surface of the second inner layer of the nozzle is provided with an annular groove, and the outer layer of the second inner layer of the nozzle is connected with the second outer layer of the nozzle by threads.

[0008] Furthermore, the diameter of the first outer layer of the nozzle is in the range of 100-300 mm, with 200-600 teeth and a tooth spacing of 0.5 mm; the diameter of the second outer layer of the nozzle is in the range of 100-200 mm, with 200-400 teeth and a tooth spacing of 0.5 mm.

[0009] Furthermore, the angles between the inner and outer umbrella-shaped cone surfaces of each layer of the nozzle and the horizontal plane are respectively in the range of 27°-29° and 30°-32°, and the gap is larger at the top and smaller at the bottom. The height difference between the inner and outer layers of each layer of the nozzle is adjusted by threads to adjust the height of the inner layer opening groove, thereby controlling the melt flow rate.

[0010] Furthermore, the number of open slots in each layer of the nozzle is 3-4, and the height of the open slots in the inner layer of the second layer is much greater than the height of the open slots in the inner layer of the first layer.

[0011] Furthermore, when the umbrella-shaped cone surface below the first inner layer fits with the umbrella-shaped cone surface above the second outer layer, it is the upper limit position of the second layer of the nozzle. At this time, the diameter of the spun fiber is large. When the bottom of the opening groove of the second outer layer and the top of the umbrella-shaped cone surface of the first inner layer are on the same horizontal plane, the second layer of the nozzle reaches the lower limit position. At this time, the fiber diameter is small. The fiber diameter can be adjusted by adjusting the position of the second layer of the nozzle between the two limit positions.

[0012] Furthermore, the top of the umbrella-shaped cone surface of the second inner layer of the nozzle is a one-way hollow structure, the upper part of the first inner layer of the nozzle is a hollow structure and is connected to the feed port, and the upper part of the umbrella-shaped cone surface of the first inner layer of the nozzle and the upper part of the umbrella-shaped cone surface of the second inner layer of the nozzle are provided with liquid circulation pipes.

[0013] Furthermore, the multi-teeth inter-capillary enhanced electrospinning device is covered with a heating device to control the nozzle temperature range to 250°C-260°C

[0014] The present invention also proposes a multi-teeth capillary enhanced electrospinning method, which is implemented by the multi-teeth capillary enhanced electrospinning device described above, and includes the following steps: heating the melt to a suitable temperature and conveying it to the middle flow channel inside the nozzle by an extruder; the melt first reaches the open groove of the second inner layer from the hollow flow channel inside the nozzle, and enters the umbrella-shaped cone surface of the second inner layer, and the height difference between the annular groove and the open groove between the inner and outer layers of the second layer is adjusted by a thread to control the melt flow rate;

[0015] As the height of the melt in the hollow flow channel increases, it quickly reaches the opening groove position of the first inner layer. The height difference between the annular groove and the opening groove between the inner and outer layers of the first layer is adjusted by the thread to control the melt flow rate, so that the melt enters the umbrella-shaped cone surface of the first layer from the opening groove position of the first layer.

[0016] When the melt reaches the top of the slit of the multi-tooth structure, the melt is sucked into each slit due to the capillary action of the slit. After the melt quickly reaches the tip of the nozzle in the slit, it is rapidly transported to the two teeth adjacent to the slit until the melt drips evenly. The high-voltage electrostatic generator is turned on to make the melt induced to be charged and form a jet under the action of the electric field force.

[0017] Furthermore, the tip of each tooth can form only one jet, and the nozzle can form up to 1,000 nanofibers at a time.

[0018] The purpose of the present invention is to provide a multi-tooth capillary enhanced electrospinning device. By optimizing the design of the nozzle structure and designing a unique tooth structure, the capillary action principle of the tiny slit can be used to accurately form a Taylor cone on each tooth, thereby achieving uniform distribution and stable spinning of the melt on the umbrella-shaped cone surface, and accurately controlling the number of fibers and the uniformity of the fibers by optimizing the number of teeth. In addition, in the specific implementation, since the device is internally provided with a thread, it can be connected to a DC motor through a rotating shaft to rotate it, so that the solution is continuously stretched to form continuous fibers under the strong tensile force of centrifugal force and electric field force. Under the joint action of centrifugal force and electrostatic force, the fibers can be further stretched to make the fiber diameter smaller, so that the spinning efficiency and precision of the device are further greatly improved when rotating. Description of the drawings:

[0019] Figure 1 It is an overall assembly diagram of the multi-teeth inter-capillary enhanced electrospinning device of the present invention;

[0020] Figure 2 is a cross-sectional view of a nozzle of the present invention;

[0021] Figure 3 It is the second layer assembly diagram of the nozzle of the present invention;

[0022] Figure 4 It is a first-layer assembly diagram of the nozzle of the present invention;

[0023] Figure 5 is a partial enlarged view of the tooth of the present invention;

[0024] Figure 6 This is a 3D display diagram of the nozzle of the present invention. Specific implementation method:

[0026] The specific implementation manner of the present invention is further illustrated below in conjunction with the accompanying drawings, and the technical solutions in the embodiments of the present invention are clearly and completely described.

[0027] like Figure 1 The figure shows an overall assembly diagram of a multi-tooth inter-capillary enhanced electrospinning device, including: a first outer layer 1 of the nozzle, a first inner layer 2 of the nozzle, a second outer layer 3 of the nozzle, a second inner layer 4 of the nozzle, liquid flow channels 12, 34, an annular groove 5, a first opening 6, a second opening 7, an annular groove 8, a third opening 9, a multi-tooth structure 10, a first outer layer multi-tooth structure 13, a first inner layer umbrella-shaped cone surface 11, a second inner layer umbrella-shaped cone surface 15, and a second outer layer multi-tooth structure 14.

[0028] Nozzle cross section Figure 2 It is indicated that the nozzle is divided into two layers, and each layer is further divided into an inner and outer layer. The first outer layer 1 of the nozzle has a diameter of 200 mm. The first outer layer multi-tooth structure 13 of the nozzle has a total of 600 teeth, and the tooth spacing is 0.5 mm. A thread and an annular groove 5 are provided above the umbrella-shaped cone surface of the first inner layer.

[0029] The first inner layer of the nozzle has an open groove and a thread on the top of the umbrella-shaped cone surface 11. The inner and outer layers are connected by threads, and the inner thread plays a role in fixing the nozzle. The upper part of the first inner layer is a hollow structure and is connected to the feed port. Figure 2 , Figure 3 The red part is the position of the liquid circulation pipeline, that is, the upper part of the first inner umbrella-shaped cone surface and the upper part of the second inner umbrella-shaped cone surface 15.

[0030] The included angles between the inner and outer umbrella-shaped cone surfaces and the horizontal plane are 27°-29° and 30°-32° respectively. The gap is larger at the top and smaller at the bottom, which is conducive to the flow of the melt. The height difference between the inner and outer layers can be adjusted by threads to adjust the height of the inner layer opening groove and thus control the melt flow.

[0031] The second outer layer 3 of the nozzle has a diameter of 128 mm. The second outer multi-tooth structure 14 of the nozzle has a total of 400 teeth, and the tooth spacing is 0.5 mm. A thread and an open groove 8 are provided outside above the umbrella-shaped cone surface of the second inner layer, and the height of the open groove of the second inner layer is much greater than the height of the open groove of the first inner layer, which is conducive to the melt flowing into the umbrella-shaped cone surface. The second inner layer 4 of the nozzle has a one-way hollow structure above the umbrella-shaped cone surface, and a thread and an open groove are provided outside, and the inner and outer layers are connected by threads.

[0032] The number of open slots is 3-4. Theoretically, the smaller the width of the open slots and the greater the number of open slots, the more evenly the melt is distributed on the umbrella-shaped cone surface.

[0033] When the lower conical surface of the first inner layer 2 is in contact with the upper conical surface of the second outer layer 3, it is the upper limit position of the second layer of the nozzle. At this time, the diameter of the spun fiber is relatively thick, and the diameter range is approximately between 400-600nm. When the lowermost part of the opening groove of the second outer layer 3 is at the same level as the uppermost part of the conical surface of the first inner layer, the second layer of the nozzle reaches the lower limit position. At this time, the minimum fiber diameter is approximately distributed between 300-400nm and the fiber distribution is more uniform than the upper limit position. The spinning effect is the best. The middle position is the adjustable position of the height of the second layer of the nozzle, thereby adjusting the fiber quality.

[0034] The method for realizing melt electrospinning using the above-mentioned multi-tooth capillary enhanced electrospinning device is as follows: first, the melt is heated to an appropriate temperature and transported by an extruder to the middle flow channel inside the nozzle. The entire device is covered with a heating device that can accurately control the nozzle temperature range within 250°C-260°C, thereby ensuring the melt temperature inside the nozzle and ensuring the stability of spinning.

[0035] The melt first reaches the position of the opening groove 9 of the second inner layer from the hollow flow channel inside the nozzle, and then enters the umbrella-shaped cone surface of the second inner layer from the opening groove 9. The height difference between the annular groove 8 and the opening groove 9 between the inner and outer layers of the second layer is adjusted by threads to control the melt flow rate so that the melt is evenly dispersed.

[0036] As the melt injection time increases, the height of the melt in the hollow flow channel becomes higher and higher, and quickly reaches the position of the opening groove 6 of the inner layer of the first layer. The melt flow rate is controlled by adjusting the height difference between the annular groove 5 and the opening groove 6 between the inner and outer layers through threads, so that the melt enters the umbrella-shaped cone surface of the first layer from the opening groove 6 position. The height difference between the second and first layer nozzles can be adjusted by threads, and since the height of the opening groove 9 of the outer layer of the second layer is much greater than the height of the opening groove 6 of the first layer, adjustment within a certain range will not affect the melt entering the umbrella-shaped cone surface of the first layer. Since the melt is continuously supplied, the melt will be evenly and continuously distributed on the edge of the nozzle.

[0037] The edge of the nozzle has a toothed structure. The first and second layers of the nozzle are respectively composed of 600 and 400 teeth evenly distributed in a circular array. The tooth spacing between every two teeth is a tiny slit of 0.5 mm. When the melt reaches the slit above the multi-tooth structure, the melt will not flow downward along the inner side of the cone, but due to the capillary action of the slit, the melt is sucked into each slit. After the melt quickly reaches the tip of the nozzle in the slit, it is quickly and continuously transported to the two teeth adjacent to the slit until the melt drips evenly. The high-voltage electrostatic generator is turned on to make the melt induced and charged, forming a jet under the action of the electric field force.

[0038] Since the width of each tooth is extremely small, only one jet can be formed at the tip of each tooth, that is, the nozzle can form 1,000 nanofibers at the same time and can accurately control the number of fibers.

[0039] In order to meet different production needs, in the specific implementation, since the device is provided with a thread inside, it can be connected to the DC motor through the rotating shaft to make it rotate, so that the solution is continuously stretched under the strong tensile force of the centrifugal force and the electric field force to form continuous fibers. Under the joint action of the centrifugal force and the electrostatic force, the fibers can be further stretched to make the fiber diameter smaller, so that the spinning efficiency and precision are further greatly improved when the device is rotating.

[0040] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A multi-teeth capillary enhanced electrospinning device, characterized in that: include: The first outer layer of the nozzle, the first inner layer of the nozzle, the second outer layer of the nozzle and the second inner layer of the nozzle; the first outer layer of the nozzle and the second outer layer of the nozzle both have a multi-tooth structure; A thread and an annular groove are arranged above the umbrella-shaped cone surface of the first inner layer of the nozzle, an open groove and a thread are arranged on the umbrella-shaped cone surface of the first inner layer of the nozzle, and the first outer layer of the nozzle and the first inner layer of the nozzle are connected by threads; The outer part of the umbrella-shaped cone surface of the second inner layer of the nozzle is provided with threads and open grooves, the inner part of the umbrella-shaped cone surface of the second inner layer of the nozzle is provided with an annular groove, and the outer layer of the second inner layer of the nozzle is connected with the second outer layer of the nozzle by threads.

2. The multi-teeth inter-capillary enhanced electrospinning device according to claim 1, characterized in that: The diameter of the first outer layer of the nozzle is in the range of 100-300 mm, with 200-600 teeth and a tooth spacing of 0.5 mm; the diameter of the second outer layer of the nozzle is in the range of 100-200 mm, with 200-400 teeth and a tooth spacing of 0.5 mm.

3. The multi-teeth inter-capillary enhanced electrospinning device according to claim 1, characterized in that: The angles between the inner and outer umbrella-shaped cone surfaces of each layer of the nozzle and the horizontal plane are 27°-29° and 30°-32° respectively. The gap is larger at the top and smaller at the bottom. The height difference between the inner and outer layers of each layer of the nozzle is adjusted by threads to adjust the height of the inner layer opening groove, thereby controlling the melt flow rate.

4. The multi-teeth inter-capillary enhanced electrospinning device according to claim 1, characterized in that: The number of opening slots in each layer of the nozzle is 3-4, and the height of the opening slots in the inner layer of the second layer is much greater than the height of the opening slots in the inner layer of the first layer.

5. The multi-teeth inter-capillary enhanced electrospinning device according to claim 1, characterized in that: When the umbrella-shaped cone surface below the first inner layer fits with the umbrella-shaped cone surface above the second outer layer, it is the upper limit position of the second layer of the nozzle. At this time, the diameter of the spun fiber is large. When the lowest level of the opening groove of the second outer layer and the highest level of the umbrella-shaped cone surface of the first inner layer are on the same horizontal plane, the second layer of the nozzle reaches the lower limit position. At this time, the fiber diameter is small. The fiber diameter can be adjusted by adjusting the position of the second layer of the nozzle between the two limit positions.

6. The multi-teeth inter-capillary enhanced electrospinning device according to claim 1, characterized in that: The top of the umbrella-shaped cone surface of the second inner layer of the nozzle is a one-way hollow structure, the upper part of the first inner layer of the nozzle is a hollow structure and is connected to the feed port, and the upper part of the umbrella-shaped cone surface of the first inner layer of the nozzle and the upper part of the umbrella-shaped cone surface of the second inner layer of the nozzle are provided with liquid flow pipes.

7. The multi-teeth inter-capillary enhanced electrospinning device according to claim 1, characterized in that: The multi-teeth inter-capillary enhanced electrospinning device is covered with a heating device to control the nozzle temperature range to be 250°C-260°C.

8. A multi-teeth capillary enhanced electrospinning method, characterized in that: The multi-teeth inter-capillary enhanced electrospinning device is implemented by any one of claims 1 to 7, comprising the following steps: the melt is heated to a suitable temperature and transported to the middle flow channel inside the nozzle by an extruder; the melt first reaches the open groove of the second inner layer from the hollow flow channel inside the nozzle, and enters the umbrella-shaped cone surface of the second inner layer, and the height difference between the annular groove and the open groove between the inner and outer layers of the second layer is adjusted by the thread to control the melt flow rate; As the height of the melt in the hollow flow channel increases, it quickly reaches the opening groove position of the first inner layer. The height difference between the annular groove and the opening groove between the inner and outer layers of the first layer is adjusted by the thread to control the melt flow rate, so that the melt enters the umbrella-shaped cone surface of the first layer from the opening groove position of the first layer. When the melt reaches the top of the slit of the multi-tooth structure, the melt is sucked into each slit due to the capillary action of the slit. After the melt quickly reaches the tip of the nozzle in the slit, it is rapidly transported to the two teeth adjacent to the slit until the melt drips evenly. The high-voltage electrostatic generator is turned on to make the melt induced to be charged and form a jet under the action of the electric field force.

9. The multi-teeth inter-capillary enhanced electrospinning device according to claim 8, characterized in that: The tip of each tooth can form only one jet, and the nozzle can form up to 1,000 nanofibers at the same time.

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