A device for preparing a short porous fiber and a method for preparing the same

Abstract

This invention discloses a porous short hybrid fiber preparation apparatus and method, comprising an outer pipe and a collection device; the tail end of the outer pipe is provided with an end cap, a connecting pipe, and a nozzle, the nozzle having a first Venturi hollow flow channel structure, through which the spinning solution encounters and forms a spinning solution containing air bubbles; the head and tail connecting sections of the outer pipe are provided with a second Venturi hollow flow channel structure, through which the spinning solution forms spinning droplets containing air bubbles; an electrode needle is provided in the head of the outer pipe, through which the spinning droplets become charged, and the high-voltage electrostatically charged spinning droplets are ablated by the repulsion of like charges to form charged spinning droplets, which are then stretched by the electric field force of a high-voltage electric field to form fiber filaments. By using gas mixing and electrostatic stretching technology, smaller diameter fiber filaments can be prepared to deposit porous short hybrid fibers, improving fiber preparation efficiency and quality.

Description

Technical Field

[0001] This invention belongs to the field of porous short fiber preparation technology, and particularly relates to a porous short hybrid fiber preparation device and preparation method. Background Technology

[0002] Porous fibers refer to individual fibers with a loose and porous structure. This loose and porous structure gives the fibers higher specific surface area, porosity, roughness, and better adsorption and surface activity; therefore, porous fibers are widely used in chemical, medical, and testing fields. Traditional methods for preparing porous fibers mainly involve initiating phase separation, including solvent evaporation-induced phase separation, non-solvent-induced phase separation, and electrospinning polymer blending phase separation. This method requires adding another substance for separation to the spinning solution, increasing production costs. After preparation, subsequent testing and post-processing are also required, making the manufacturing process cumbersome and resulting in relatively large fiber diameters.

[0003] Short hybrid fibers refer to fiber structures with a length of 35-150 mm and are a common raw material for fiber production. Current technologies for preparing short fibers generally involve first preparing long fibers, followed by post-processing such as shearing and rinsing (as described in patent CN105926161B). This method increases the complexity of manufacturing and production costs. Conventional methods only involve one stretching process for the fiber filaments, resulting in larger fiber diameters. Furthermore, not only are the fiber sizes larger when preparing short hybrid fibers, but the process also requires numerous cumbersome steps, including shearing and rinsing, as well as the addition of separation materials, post-processing testing, and recovery of separated materials, all of which increase costs when preparing porous fibers. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a porous short hybrid fiber preparation device and preparation method, which can prepare fiber filaments with smaller diameter through gas mixing and electrostatic stretching technology, so as to deposit porous short hybrid fibers, thereby improving the fiber preparation efficiency and quality.

[0005] Technical Solution: To achieve the above objectives, the present invention provides a porous short hybrid fiber preparation device, comprising an outer pipe and a collecting device arranged in an upward and downward orientation, with a drawing gap formed between the outer pipe and the collecting device; the tail of the outer pipe is a cylindrical hollow structure, inside which an end cap, a connecting pipe, and a nozzle are coaxially connected in sequence; the end cap is provided with a liquid inlet interface communicating with the connecting pipe; the nozzle has a first Venturi hollow flow channel structure inside; the nozzle is provided with a nozzle inlet flow channel that guides the first Venturi hollow flow channel structure; when the spinning solution flows through the first Venturi hollow flow channel structure, it encounters the gas introduced through the nozzle inlet flow channel to form a spinning solution containing bubbles; the head and tail connecting sections of the outer pipe are provided with a second Venturi hollow flow channel structure. The hollow channel structure allows the spinning solution containing air bubbles to diffuse through its expansion section, forming air-bubble-containing spinning droplets. The head of the outer channel is a conical hollow structure with several electrode needles connected to a high-voltage power supply inside. The air-bubble-containing spinning droplets become charged through the electrode needles. The air-bubble-containing and electrostatically charged spinning droplets are reduced in size due to the mutual repulsion of like charges, forming charged spinning droplets containing air bubbles. A high-voltage electric field is formed between the charged spinning droplets and the grounded collection device, within the range of the drawing distance. The charged spinning droplets containing air bubbles are stretched by the electric field force of the high-voltage electric field to form fiber filaments, thereby depositing a loose and porous short mixed fiber body on the collection device.

[0006] Furthermore, the nozzle inlet air passage is located on the side of the nozzle, and includes an upper nozzle inlet air passage and a lower nozzle inlet air passage in the nozzle height direction. The upper nozzle inlet air passage corresponds to the contraction section of the first Venturi hollow flow channel structure inside the nozzle, and the lower nozzle inlet air passage corresponds to the expansion section of the first Venturi hollow flow channel structure inside the nozzle.

[0007] Furthermore, the nozzle air intake channel is divided into several groups, and the several groups of nozzle air intake channels are distributed in a circular array along the circumferential direction of the nozzle.

[0008] Furthermore, the air intake direction of the nozzle inlet passage corresponding to the contraction section of the first Venturi hollow flow channel structure is inclined upward; the air intake direction of the nozzle lower inlet passage corresponding to the expansion section of the first Venturi hollow flow channel structure is inclined downward.

[0009] Furthermore, the outer pipe is provided with a lower air inlet port that connects to the air inlet channel of the nozzle head. The lower air inlet port is connected to a lower air storage cylinder and a lower air pump through an air guide pipe. The outer pipe is provided with a nozzle bracket for installation with the nozzle head. The outer wall of the integral structure formed by the connection pipe and the nozzle head and the inner wall of the outer pipe form an annular air inlet channel. The end cap is closed on the tail end of the outer pipe. The end cap is provided with an upper air inlet port. The upper air inlet port is connected to the lower air inlet channel of the nozzle head through the annular air inlet channel, and the upper air inlet port is connected to an upper air storage cylinder and an upper air pump through an air guide pipe.

[0010] Furthermore, the air inlet channel on the nozzle head is at the same height as the lower air inlet interface and is connected by a pipe.

[0011] Furthermore, the liquid inlet is connected to the connecting pipe and located at the center of the end cap. The liquid inlet is connected to a storage tank and a solution pump through a liquid guide pipe.

[0012] Furthermore, the height of the collecting device is adjustable. By changing the height of the collecting device, the electric field force of the high-voltage electric field is changed, thereby adjusting the tensile force acting on the charged spinning droplets containing air bubbles.

[0013] A method for preparing a porous short hybrid fiber preparation device, the specific steps of which are as follows:

[0014] Step S1: Assemble the porous short hybrid fiber preparation device, start the solution pump, and set the flow rate to 20 ml / min;

[0015] Step S2: Start the air pump and set the flow rate to 0.8 m³ / h. 3 / min; Start the lower air pump and set the flow rate to 0.3m³ / min. 3 / min;

[0016] Step S3: When the spinning solution flows through the first Venturi hollow channel structure, air bubbles are introduced for the first time, forming a spinning solution containing air bubbles.

[0017] Step S4: When the spinning solution containing air bubbles flows through the second Venturi hollow channel structure, air bubbles are mixed in for the second time, and the diffusion effect of the expansion section of the second Venturi hollow channel structure forms spinning droplets containing air bubbles.

[0018] Step S5: Start the high-voltage power supply and set the voltage to 30kV. The spinning droplets containing air bubbles are charged with high-voltage static electricity under the action of the electrode needle. The charged spinning droplets containing air bubbles are further dispersed into smaller droplets due to the repulsion between them due to the same static electricity. At the same time, a high-voltage electric field is formed between the droplets and the grounded collection device. Under the action of the electric field force of the high-voltage electric field, the charged spinning droplets containing air bubbles move towards the collection device and are stretched into fibers. Finally, a short, loose, porous, mixed fiber body is deposited on the collection device.

[0019] Beneficial effects: This invention can prepare small-diameter fibers through gas mixing and electrostatic stretching technology, so as to deposit porous short hybrid fibers. During gas mixing, two gas mixing operations are performed through the Venturi hollow channel structure to form smaller charged spinning droplets containing air bubbles. During electrostatic stretching, small-diameter fibers can be produced with only one stretching operation. Then, porous short hybrid fibers can be deposited on the collection device, which effectively improves the efficiency and quality of fiber preparation. Attached Figure Description

[0020] Figure 1 A schematic diagram of the apparatus for preparing porous short heterogeneous fibers;

[0021] Figure 2 This is a structural diagram of the external pipe, end cap, connecting pipe, and nozzle;

[0022] Figure 3 This is a schematic diagram of the external pipeline structure;

[0023] Figure 4 This is a schematic diagram of the nozzle structure;

[0024] Figure 5 This is a schematic diagram of the connecting pipe structure;

[0025] Figure 6 This is a schematic diagram of the end cap structure. Detailed Implementation

[0026] The invention will now be further described with reference to the accompanying drawings.

[0027] like Figure 1 , Figure 2 as well as Figure 3As shown, a porous short hybrid fiber preparation device includes an outer pipe 4 and a collecting device 1 arranged in an upward and downward orientation, with a drawing gap 20 between the outer pipe 4 and the collecting device 1. The tail of the outer pipe 4 is a cylindrical hollow structure, inside which an end cap 14, a connecting pipe 12, and a nozzle 11 are coaxially connected in sequence. The end cap 14 is provided with a liquid inlet 142 communicating with the connecting pipe 12. The nozzle 11 has a first Venturi hollow flow channel structure inside, and a nozzle inlet flow channel is provided on the nozzle 11 to conduct the first Venturi hollow flow channel structure. When the spinning solution flows through the first Venturi hollow flow channel structure, it encounters the gas introduced through the nozzle inlet flow channel to form a spinning solution containing bubbles. The head and tail connecting sections of the outer pipe 4 are provided with a second Venturi hollow flow channel structure. The hollow channel structure allows the spinning solution containing air bubbles to diffuse through its expansion section, forming spinning droplets containing air bubbles. The head of the outer pipe 4 is a conical hollow structure, with several electrode needles 41 connected to a high-voltage power supply 3 inside. The spinning droplets containing air bubbles become charged through the electrode needles 41. The spinning droplets containing air bubbles and carrying high-voltage static electricity are reduced in size by the mutual repulsion of like charges, forming charged spinning droplets containing air bubbles. A high-voltage electric field is formed between the charged spinning droplets containing air bubbles and the grounded collection device 1 within the range of the drawing distance 20. The charged spinning droplets containing air bubbles are stretched by the electric field force of the high-voltage electric field to form fiber filaments 2, so as to deposit a loose and porous short mixed fiber body on the collection device 1. This invention utilizes gas mixing and electrostatic stretching techniques to prepare small-diameter fiber filaments, which are then deposited as porous short hybrid fibers. During gas mixing, two gas mixing operations are performed through a Venturi hollow channel structure to form smaller charged spinning droplets containing air bubbles. During electrostatic stretching, the small-diameter fiber filaments 2 can be stretched in a single operation, and then porous short hybrid fibers can be deposited on a collecting device 1, effectively improving the efficiency and quality of fiber preparation.

[0028] like Figure 4 As shown, the nozzle inlet channel is located on the side of the nozzle 11, and includes an upper nozzle inlet channel 111 and a lower nozzle inlet channel 112 in the height direction of the nozzle 11. The upper nozzle inlet channel 111 corresponds to the contraction section of the first Venturi hollow channel structure within the nozzle 11, and the lower nozzle inlet channel 112 corresponds to the expansion section of the first Venturi hollow channel structure within the nozzle 11. The gas entering the contraction section of the first Venturi hollow channel structure from the upper nozzle inlet channel 111 achieves the first mixing of the spinning solution, and the gas entering the expansion section of the first Venturi hollow channel structure from the lower nozzle inlet channel 112 achieves the second mixing of the spinning solution. This results in a large number of air bubbles remaining in the spinning solution, ultimately forming spinning droplets containing air bubbles, preparing for subsequent electrostatic refining and stretching.

[0029] To ensure uniform gas mixing, the nozzle inlet channel of the present invention is composed of several groups, and the several groups of nozzle inlet channels are distributed in a circular array along the circumferential direction of the nozzle 11.

[0030] The Venturi structure can be roughly divided into three sections: a contraction section, a minimum cross-section section, and an expansion section. The liquid velocity in the contraction section is high. To increase the amount of gas mixed into the spinning solution as it passes through the contraction section of the first Venturi hollow channel structure, the air inlet channel 111 on the nozzle corresponding to the contraction section of the first Venturi hollow channel structure is tilted upwards. This creates an impact effect on the downward-flowing spinning solution, making it easier for the gas to mix into the spinning solution. Conversely, the liquid velocity in the contraction section is low, and a large gas impact would affect the normal flow of the liquid. Therefore, a co-current flow method for gas mixing is better. Thus, the air inlet channel 112 on the lower part of the nozzle corresponding to the expansion section of the first Venturi hollow channel structure is tilted downwards. The gas in the lower part of the nozzle's air inlet channel 112 enters the downward-flowing spinning solution at an angle, creating a co-current flow effect that does not obstruct flow and allows for gas mixing.

[0031] like Figure 1 , Figure 2 , Figure 3 , Figure 5 as well as Figure 6 As shown, the outer pipe 4 is provided with a lower air inlet 43 that connects to the air inlet channel 111 of the nozzle head. The lower air inlet 43 is connected to the lower gas cylinder 9 and the lower air pump 10 through an air guide pipe. Inside the outer pipe 4, a nozzle bracket 42 is provided for installation with the nozzle 11. The outer wall of the integral structure formed by the connecting pipe 12 and the nozzle 11 and the inner wall of the outer pipe 4 form an annular air inlet channel 15. The end cap 14 covers the tail end of the outer pipe 4. The end cap 14 is provided with an upper air inlet 141, which connects to the lower air inlet channel 112 of the nozzle head through the annular air inlet channel 15. The upper air inlet 141 is also connected to the upper gas cylinder 5 and the upper air pump 6 through an air guide pipe. More specifically, the upper air inlet channel 111 of the nozzle head and the lower air inlet 43 are at the same height and connected by a pipe to improve air intake smoothness. The liquid inlet 142 is connected to the connecting pipe 12 and is located at the center of the end cap 14. The liquid inlet 142 is connected to the liquid storage tank 7 and the solution pump 8 through the liquid guide pipe.

[0032] It should be noted that the tail end of the structure described in this invention is the upper part, and the head end is the lower part. The solution pump is a Reif TYD01-02 syringe pump with a flow rate range of 10 μl / hr to 100 ml / hr. Both the lower air pump 10 and the upper air pump 6 are YBM-7.5A / 7.5KW models with a flow rate range of 0-1.2 m³ / h. 3 / min. The output voltage range of high-voltage power supply 3 is -30kV to 60kV.

[0033] The height of the collecting device 1 is adjustable. By changing the height of the collecting device 1, the electric field force of the high-voltage electric field is changed, thereby adjusting the tensile force acting on the charged spinning droplets containing air bubbles. When the height of the collecting device 1 is changed, the electric field force of the high-voltage electric field also changes accordingly, thereby achieving the purpose of adjusting the tensile force on the droplets and meeting more spinning production needs, such as drawing length, radial dimension, etc.

[0034] A method for preparing a porous short hybrid fiber preparation device, the specific steps of which are as follows:

[0035] Step S1: Assemble the porous short hybrid fiber preparation device, start the solution pump 8, and set the flow rate to 20 ml / min;

[0036] Step S2: Start the upper air pump 6 and set the flow rate to 0.8m³ / h. 3 / min; Start the lower air pump 10 and set the flow rate to 0.3m³ / min. 3 / min;

[0037] Step S3: When the spinning solution flows through the first Venturi hollow channel structure, air bubbles are introduced for the first time, forming a spinning solution containing air bubbles.

[0038] Step S4: When the spinning solution containing air bubbles flows through the second Venturi hollow channel structure, air bubbles are mixed in for the second time, and the diffusion effect of the expansion section of the second Venturi hollow channel structure forms spinning droplets containing air bubbles.

[0039] Step S5: Start the high-voltage power supply 3 and set the voltage to 30kV. The spinning droplets containing air bubbles are charged with high-voltage static electricity under the action of the electrode needle 41. The spinning droplets containing air bubbles and charged are further dispersed into smaller droplets due to the repulsion between them due to the same static electricity. At the same time, a high-voltage electric field is formed between the droplets and the grounded collection device 1. Under the action of the electric field force of the high-voltage electric field, the spinning droplets containing air bubbles and charged move towards the collection device 1 and are stretched into fiber filaments 2. Finally, a short mixed fiber body with loose and porous structure is deposited on the collection device 1.

[0040] The more detailed spinning preparation principle of this invention is as follows: Solution pump 8 delivers the spinning solution from storage tank 7 to inlet port 142, and the spinning solution flows along connecting pipe 12 to the tail of nozzle 11. Simultaneously, lower air pump 10 delivers gas to nozzle head inlet channel 111 through lower air inlet port 43. At the tail of nozzle 11, the spinning solution mixes with the gas flowing into nozzle head inlet channel 111, causing the gas to carry bubbles. The spinning solution continues to flow along nozzle 11, which has a first Venturi hollow channel structure. In the expansion section of the first Venturi hollow channel structure, based on the Venturi effect, nozzle 11 draws gas from upper air pump 6 from upper air inlet port 141 to annular inlet channel 15 along lower inlet channel 112 into the head of nozzle 11 and further diffuses it, causing the spinning solution to contain more bubbles. After the spinning solution containing air bubbles flows out from the nozzle head, it enters the outer pipe 4. Since the outer pipe 4 has a second Venturi hollow flow channel structure, when the spinning solution containing a large number of air bubbles flows out to the expansion section of the first Venturi hollow flow channel structure of the outer pipe 4, the spinning solution diffuses into spinning droplets containing air bubbles. Since the head of the outer pipe 4 is equipped with an electrode needle 41 and connected to a high-voltage power supply 3, the spinning droplets containing air bubbles are charged with high-voltage static electricity. Due to the mutual repulsion between the like electrical charges, smaller charged spinning droplets containing air bubbles are formed. A high-voltage electrostatic field is formed between the charged spinning droplets containing air bubbles and the grounded collection device 1. The droplets move towards the collection device 1 and are stretched by the electric field force to form fiber filaments 2, which are deposited on the collection device 1. Since the spinning droplets contain a large number of air bubbles, a short mixed fiber body with loose and porous structure is finally deposited.

[0041] The present invention also has the following advantages:

[0042] 1) It utilizes gas to generate bubbles to form a porous structure, eliminating the need for adding separation substances and thus reducing costs;

[0043] 2) By using gas to generate bubbles to form a porous structure, the process of recycling and separating materials is eliminated, simplifying production;

[0044] 3) The venturi tube is used twice to ensure that the spinning solution and gas are fully mixed, thereby increasing the fiber porosity;

[0045] 4) By utilizing the Venturi tube structure and electrode needle structure to form spinning droplets, short hybrid fibers are directly deposited on the collecting device, eliminating the need for post-processing such as shearing of long fibers.

[0046] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A device for preparing porous short hybrid fibers, characterized in that: The device includes an outer pipe (4) arranged in an upward and downward orientation and a collection device (1), with a drawing gap (20) between the outer pipe (4) and the collection device (1); the tail of the outer pipe (4) is a cylindrical hollow structure, with an end cap (14), a connecting pipe (12) and a nozzle (11) coaxially connected inside. The end cap (14) is provided with a liquid inlet (142) that connects to the connecting pipe (12). The nozzle (11) has a first Venturi hollow flow channel structure inside, and a nozzle inlet flow channel that connects to the first Venturi hollow flow channel structure is provided on the nozzle (11). When the spinning solution flows through the first Venturi hollow flow channel structure, it meets the gas introduced through the nozzle inlet flow channel to form a spinning solution containing bubbles; the head and tail connecting sections of the outer pipe (4) are provided with a second Venturi hollow flow channel. The flow channel structure, when the spinning solution containing bubbles flows through the second Venturi hollow flow channel structure, forms spinning droplets containing bubbles through diffusion in its expansion section; the head of the outer pipe (4) is a conical hollow structure, and a number of electrode needles (41) connected to the high voltage power supply (3) are provided inside. The spinning droplets containing bubbles are charged through the electrode needles (41). The spinning droplets containing bubbles and charged with high voltage static electricity are reduced to small size by the mutual repulsion of the same electrical properties to form charged spinning droplets containing bubbles. A high voltage electric field is formed between the grounded collection device (1) and the high voltage electric field within the range of the drawing distance (20). The charged spinning droplets containing bubbles are stretched by the electric field force of the high voltage electric field to form fiber filaments (2) so as to deposit short mixed fiber bodies with loose and porous structure on the collection device (1); The nozzle inlet air passage is located on the side of the nozzle (11), and includes an upper nozzle inlet air passage (111) and a lower nozzle inlet air passage (112) in the height direction of the nozzle (11). The upper nozzle inlet air passage (111) corresponds to the contraction section of the first Venturi hollow flow channel structure in the nozzle (11), and the lower nozzle inlet air passage (112) corresponds to the expansion section of the first Venturi hollow flow channel structure in the nozzle (11).

2. The apparatus for preparing porous short hybrid fibers according to claim 1, characterized in that: The nozzle inlet air passage is composed of several groups, and the several groups of nozzle inlet air passage are distributed in a circular array along the circumferential direction of the nozzle (11).

3. The apparatus for preparing porous short hybrid fibers according to claim 1, characterized in that: The air intake direction of the nozzle head air intake channel (111) corresponding to the contraction section of the first Venturi hollow flow channel structure is inclined upward; the air intake direction of the nozzle head lower air intake channel (112) corresponding to the expansion section of the first Venturi hollow flow channel structure is inclined downward.

4. The apparatus for preparing porous short hybrid fibers according to claim 1, characterized in that: The outer pipe (4) is provided with a lower air inlet (43) that connects to the air inlet channel (111) of the nozzle head. The lower air inlet (43) is connected to the lower air storage cylinder (9) and the lower air pump (10) through the air guide pipe. The outer pipe (4) is provided with a nozzle bracket (42) for installation with the nozzle (11). The outer wall of the integral structure formed by the connection pipe (12) and the nozzle (11) and the inner wall of the outer pipe (4) form an annular air inlet channel (15). The end cap (14) is closed on the tail end of the outer pipe (4). The end cap (14) is provided with an upper air inlet (141). The upper air inlet (141) is connected to the lower air inlet channel (112) of the nozzle head through the annular air inlet channel (15). The upper air inlet (141) is connected to the upper air storage cylinder (5) and the upper air pump (6) through the air guide pipe.

5. The apparatus for preparing porous short hybrid fibers according to claim 4, characterized in that: The air intake channel (111) on the nozzle head is at the same height as the lower air intake port (43) and is connected by a pipe.

6. The apparatus for preparing porous short hybrid fibers according to claim 4, characterized in that: The liquid inlet (142) is connected to the connecting pipe (12) and located at the center of the end cap (14). The liquid inlet (142) is connected to the storage tank (7) and the solution pump (8) through the liquid guide pipe.

7. The apparatus for preparing porous short hybrid fibers according to claim 6, characterized in that: The height of the collecting device (1) is adjustable. By changing the height of the collecting device (1), the electric field force of the high voltage electric field is changed, so as to adjust the tensile force acting on the charged spinning droplets containing bubbles.

8. The method for preparing a porous short hybrid fiber preparation device according to claim 7, characterized in that: The specific steps are as follows: Step S1: Assemble the porous short hybrid fiber preparation device, start the solution pump (8), and set the flow rate to 20 ml / min; Step S2: Start the air pump (6) and set the flow rate to 0.8 m³ / s. 3 / min; start the lower air pump (10) and set the flow rate to 0.3m. 3 / min; Step S3: When the spinning solution flows through the first Venturi hollow channel structure, air bubbles are introduced for the first time, forming a spinning solution containing air bubbles. Step S4: When the spinning solution containing air bubbles flows through the second Venturi hollow channel structure, air bubbles are mixed in for the second time, and the diffusion effect of the expansion section of the second Venturi hollow channel structure forms spinning droplets containing air bubbles. Step S5: Start the high voltage power supply (3) and set the voltage to 30kV. The spinning droplets containing bubbles are charged with high voltage static electricity under the action of the electrode needle (41). The spinning droplets containing bubbles and charged are further dispersed into smaller droplets due to the repulsion between them by the same static electricity. At the same time, a high voltage electric field is formed between the droplets and the grounded collection device (1). Under the action of the electric field force of the high voltage electric field, the spinning droplets containing bubbles and charged move toward the collection device (1) and are stretched into fiber filaments (2). Finally, a short mixed fiber body with loose and porous structure is deposited on the collection device (1).

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