CN111926461A - Double-electrode high-voltage electrostatic spinning melt-blowing device - Google Patents

Abstract

The invention discloses a melt-blown device for double-electrode high-voltage electrostatic spinning, which mainly includes a melt-blown die head support frame, a melt-blown upper die head, a melt-blown lower die head, a shuttle electrode plate, an electrode plate conductor sheet, and a support frame adjustment. Nut, bellows adjustment nut, suction bellows and porous electrode plate, meltblown die head support frame is used to support and fix the meltblown upper die head, meltblown lower die head and shuttle electrode plate; The high-voltage electrostatic field force is applied between the shuttle-type electrode plates, and the high-voltage electrostatic field force is applied between the shuttle-type electrode plate and the porous electrode plate. Diameter size and distribution of polymer fibers. Before the fiber is cured, the high-voltage electrostatic field of the two electrodes polarizes the fiber, and the electric charge can be retained in the fiber layer for a long time, and the fiber dipolarity has a long aging time. The application of dual electrodes simultaneously solves the problems of thick fiber diameter, wide diameter distribution, high energy consumption, and short dipolar aging.

Description

A melt-blown device for two-electrode high-voltage electrospinning

technical field

The invention relates to a melt-blown device for double-electrode high-voltage electrostatic spinning, belonging to the field of spinning equipment.

Background technique

Affected by the new coronavirus pneumonia, there is a large shortage of disposable masks and N95 masks for residents' daily protection. The price of N95 masks was as high as 80 yuan per piece, and the inner layer of meltblown cloth, which is the core of mask protection, is in short supply. 30,000 yuan / ton suddenly increased to 600,000-800,000 yuan / ton, a lot of money was injected into the meltblown cloth industry, but the prepared meltblown cloth has poor toughness, many crystal grains, and the filtration efficiency is lower than the national standard.

Spinning processing method is a manufacturing method of polymer micro-nanofibers, mainly including melt blowing method, electrospinning method, etc. Different preparation techniques have their own advantages and limitations. The advantages of the melt-blown method are high production efficiency and simple process flow, but the friction between the airflow and the polymer melt jet alone is not enough to thin the fibers to the nanometer level, so the diameter of the polymer fibers produced by the melt-blown method is in the Between 2-5 μm, the thicker fibers prepared by the melt-blown method are not conducive to the improvement of the filtration efficiency of 0.3 μm air-suspended particles from 95% to 100%. During the process of preparing fibers by the melt-blown method, when the fibers fall behind the collection plane , charge and polarize the cured fiber membrane. Since the fiber membrane produced by this method is charged and polarized after the fiber is cured, the charge retention time in the fiber membrane is short, so the dipolarity retention time of the fiber membrane is not long. The electrospinning method uses an electrostatic field to make the polymer melt overcome the surface tension to form a Taylor cone stimulated emission flow. However, the production efficiency is low, and it is difficult to meet the needs of batch preparation. Therefore, the fiber preparation process combining the melt blowing method and the electrospinning method can meet the dual requirements of batch preparation and high filtration efficiency at the same time.

Therefore, in view of the problems of thick diameter, uneven diameter distribution, large production energy consumption, and low dipolar aging efficiency of fiber membranes in the polymer fibers prepared by the existing melt-blown method above, the present invention proposes a dual-electrode high-voltage electrospinning method. The melt-blown device can effectively reduce the fiber diameter, reduce the diameter distribution range, reduce production energy consumption, increase the retention time of fiber dipolarity, and facilitate long-term storage.

SUMMARY OF THE INVENTION

Aiming at the problems that the polymer fibers prepared by the melt-blowing method have relatively thick diameters, uneven diameter distribution, high production energy consumption and low dipolar aging efficiency of the fiber film, a melt-blowing device for dual-electrode high-voltage electrospinning is proposed. The addition of dual-electrode high-voltage static electricity can greatly reduce the fiber diameter, and nanofibers with an average diameter of less than 1 μm can be prepared, and the uniformity and flatness of fiber laying are increased; Refinement, so the diameter distribution range of the produced fibers is also reduced; the addition of the double-electrode high-voltage electrostatic field force can greatly reduce the power consumption of the bellows and airflow auxiliary equipment; in the process of fiber falling, the double-electrode high-voltage electrostatic field force has The fiber undergoes two electric field polarizations, and the dipolar retention time of the produced fiber membrane is greatly increased.

The invention provides a melt-blown device for dual-electrode high-voltage electrostatic spinning, which mainly includes a melt-blown die head support frame, a melt-blown upper die head, a melt-blown lower die head, a shuttle electrode plate, an electrode plate conductor sheet, and a support frame adjusting nut , bellows adjustment nut, suction bellows and porous electrode plate, the meltblown upper die contains two gas runners and one melt runner; the meltblown lower die contains two gas runners; meltblown die head The support frame is used to support and fix the meltblown upper die head, the meltblown lower die head and the shuttle electrode plate; the support frame adjustment nut is used to adjust the height of the shuttle electrode plate; the electrode plate conductor piece is fixed on the two sides of the shuttle electrode plate. The porous electrode plate is placed on the top surface of the suction bellows; the bellows adjusting nut is used to adjust the height of the suction bellows from the ground.

The present invention is a melt-blown device for double-electrode high-voltage electrostatic spinning. The shuttle-shaped electrode plate is composed of two shuttle-shaped copper electrode plates, which are vertically placed on the support frame of the melt-blown die head. The conductor pieces of the two electrode plates are respectively fixed on both sides of the two shuttle-type copper electrode plates by screws, which are used to conduct the two shuttle-type copper electrode plates, so that the two shuttle-type copper electrode plates and the melt-blown die head are connected. maintain the same potential difference. The waist hole in the middle of the electrode plate conductor is used to move the set screw when adjusting the shuttle electrode plate. High-voltage static electricity is applied between the lower melt-blown die and the shuttle electrode plate for the first-stage electric field force to draw the thinned fibers, and the applied voltage range is 5-60 kV, and the preferred voltage range is 20-35 kV. The distance between the meltblown upper die and the shuttle electrode plate can be adjusted according to the voltage value. The adjustment method is to adjust the support frame adjustment nut on the support frame of the meltblown die head. The adjustment range is 10-60mm, and the preferred range is 20-35mm. The distance between the two shuttle electrode plates can be controlled by loosening the two set screws and sliding horizontally along the waist hole of the electrode plate conductor. The adjustment range is 20mm-60mm, and the preferred range is 30mm-50mm. Since the electrode plate conductor strips are fixed on both sides of the two shuttle electrode plates, it will not interfere with the distribution of the electric field strength between the lower die and the shuttle electrode plates. The uniform distribution of the electric field strength helps to improve the fiber fineness. . The upper and lower tips of the two shuttle-shaped electrode plates and the upper melt-blown die form a strong spatial electric field, which helps to refine the fiber drafting. The inner surface of the electrode plate is coated with PTFE. The excellent electrical insulation of PTFE weakens the adsorption capacity of the electrode plate, so that the fiber can quickly pass through the gap between the two shuttle electrode plates without sticking to the electrode. shuttle electrode plate.

The invention is a melt-blown device for double-electrode high-voltage electrospinning. The porous electrode plate is placed on the top surface of the suction bellows; high-voltage static electricity is applied between the shuttle electrode plate and the porous electrode plate for the second electric field force drafting For synthetic fibers, the applied voltage range is 80kV-160kV, and the preferred voltage range is 100kV-120kV. The distance between the shuttle electrode plate and the porous electrode plate is adjusted according to the voltage value. The adjustment method is to adjust the bellows adjusting nut of the suction bellows. The porous electrode plate has an array of mesh holes. The mesh holes on the porous electrode plate do not affect its supporting effect on the fiber layer. During the falling process, the fiber will absorb more charges due to the action of the electric field force, and when it falls to the porous electrode When it is on the plate, it will be quickly adsorbed on it, and the fiber layer accumulated on the porous electrode plate will be adsorbed on the electrode plate. This method will reduce the power loss of the suction bellows. The suction bellows is used to adsorb the fibers on the collection plane, and the collection plane of this device is the porous electrode plate.

The present invention is a melt-blown device for dual-electrode high-voltage electrostatic spinning, which applies a high-voltage electrostatic field force between a melt-blown upper die and a shuttle-type electrode plate, and applies a high-voltage electrostatic field force between the shuttle-type electrode plate and the porous electrode plate, The two high-voltage electrostatic field forces are used as the main force to refine the fiber drafting, which helps to greatly reduce the diameter and distribution of the polymer fibers. Before the fiber is cured, the high-voltage electrostatic field of the two electrodes polarizes the fiber, the charge can be retained in the fiber layer for a long time, and the fiber dipolarity has a long aging time. The application of dual electrodes simultaneously solves the problems of thick fiber diameter, wide diameter distribution, high energy consumption, and short dipolar aging.

The present invention is a melt-blown device for double-electrode high-voltage electrospinning. The first-stage electrode plate can also be of a "7" type structure, and the tip discharge effect is more obvious. In order to create a first-level electric field environment between the "7" type electrode plate and the lower melt-blown die, the bolts and supports are made of nylon and bakelite materials respectively. The bakelite bracket is adjusted in the vertical direction of melt blown and fixed to the upper die head of melt blown by nylon fastening bolts. The nylon bolts adjust the height through the vertical direction to adjust the bakelite bracket, and the nylon screws fix the "7" type electrode plate in the horizontal direction for adjustment. The bakelite bracket is matched with the inner threaded hole of the bakelite bracket adjusted in the horizontal direction. The bakelite bellows is placed about 150mm below the tip of the meltblown lower die, and the center opening is convenient for the placement of the array mesh electrode plate.

The present invention is a melt-blown device for double-electrode high-voltage electrospinning, and the first-stage electrode plate can also be a filamentary structure. The two bakelite strips with waist holes are fixed on the side of the bakelite bellows by M10 nylon fastening bolts, and the two electrets are connected with the bakelite strips with waist holes by winding the M10 nylon bolts with molybdenum wires and fixing them with nuts. The bakelite bellows holes It is a threaded hole and is matched with M10 nylon fastening bolts. The two electret molybdenum wires form a first-level electric field with the melt-blown lower die head. The array mesh electrode plate and the melt-blown lower die head form a second-level electric field. The electret molybdenum wire is located at About 10-60mm, preferably 20-30mm below the lower die head of melt blowing, the applied voltage is 5-60kv, preferably 20-35kV, and the bakelite bellows is placed about 150mm below the tip of the lower die head of melt blowing, and the center opening is convenient for The placement of the array mesh electrode plates, the applied voltage range is 80kV to 160kV, preferably the voltage range is 100kV to 120kV.

Description of drawings

Fig. 1 is the schematic diagram of the melt-blown device of a kind of two-electrode high-voltage electrospinning of the present invention;

Fig. 2 is the enlarged schematic diagram of the melt-blown die head shown in Fig. 1;

Fig. 3 is a three-dimensional schematic diagram of the shuttle electrode plate shown in Fig. 1;

Fig. 4 is the top view of the porous electrode plate shown in Fig. 1;

Figure 5 is a partial schematic view of the "7" type electrode plate device;

Fig. 6 is axonometric sectional view of "7" type electrode plate device;

Figure 7 is a schematic axonometric view of the wire electrode device.

In the figure: 1-meltblown die head support frame; 2-meltblown upper die head; 2-1-upper die gas flow channel; 2-2-melt flow channel; 3-meltblown lower die head; 3- 1- lower die gas flow channel; 4- shuttle electrode plate; 5- electrode plate conductor plate; 6- support frame adjusting nut; 7- air box adjusting nut; 8- suction air box; 9- porous electrode plate; 10 - height-adjusting nylon bolts; 11-nylon fastening bolts; 12-vertical adjustment of bakelite brackets; 13-width adjustment nylon bolts; 14-horizontal adjustment of bakelite brackets; 15-array mesh electrode plate; 16-electrical Wooden bellows; 17-nylon bolts; 18-support bakelite board; 19-"7" type electrode plate; 20-bakelite strips with waist holes; 21-M10 nylon fastening bolts; 22-molybdenum wire; 23-nut.

Detailed ways

The invention provides a melt-blown device for double-electrode high-voltage electrospinning. As shown in Figure 1, the meltblown device mainly includes a meltblown die head support frame 1, a meltblown upper die head 2, a meltblown lower die head 3, a shuttle electrode plate 4, an electrode plate conductor sheet 5, and a support frame adjustment nut 6. Bellows adjusting nut 7, suction bellows 8, porous electrode plate 9. The upper melt blowing die 2 includes an upper die gas flow channel 2-1 and a melt flow channel 2-2; the lower melt blowing die includes a lower die gas flow channel 3-1. The melt-blown die head support frame 1 is used to support and fix the melt-blown upper die head 2, the melt-blown lower die head 3, and the shuttle electrode plate 4; the support frame adjustment nut 6 is used to adjust the height of the shuttle electrode plate 4; the electrode plate The conductor sheet 5 is fixed on both sides of the shuttle electrode plate 4 with screws; the porous electrode plate 9 is placed on the top surface of the suction bellows 8; the bellows adjusting nut 7 is used to adjust the height of the suction bellows 8 from the ground.

In the production process of the melt-blown equipment, as shown in the enlarged schematic diagram of the melt-blown die head in Figure 2, the melt-blown upper die head 2 and the melt-blown lower die head 3 are connected by bolts, and the fit is tight and does not overflow. The upper die gas flow channel 2-1 and the lower die gas flow channel 3-1 together form the left gas flow channel and the right gas flow channel. The gas flow channels on both sides are used to draw the thinned fibers together. The melt flow channel 2-2 is used to flow out the melted and plasticized material.

Figure 3 shows a three-dimensional schematic diagram of the shuttle electrode plate. As shown in the figure, the shuttle electrode plate 4 is placed on the support frame 1 of the melt blowing die. The electrode plate conductor piece 5 is fixed in the waist hole below the two shuttle-shaped electrode plates 4 by means of a set screw, and is used to connect the two shuttle-shaped electrode plates 4 . The electrode plate conductor pieces 5 are placed on both sides of the shuttle electrode plate 4 and will not interfere with the electric field strength. High-voltage static electricity is applied between the lower melt-blown die 3 and the shuttle electrode plate 4 for the first-stage electric field force to draw the thinned fibers, and the applied voltage range is 5kV to 60kV, and the preferred voltage range is 20kV to 35kV. The distance between the meltblown upper die 2 and the shuttle electrode plate 4 can be adjusted according to the voltage value. The adjustment method is to adjust the support frame adjusting nut 6 on the meltblown die head support frame 1. The adjustment range is 10mm to 60mm. The preferred range is 20mm to 35mm. The slit spacing between the shuttle electrode plates 4 can be adjusted according to the voltage value. The adjustment method is to move horizontally and adjust the distance between the two shuttle electrode plates 4. After adjustment, use the set screws on the electrode plate conductors. For fixing, the set screw can move along the direction of the electrode plate conductor, and the adjustment range is 20mm to 60mm, and the preferred range is 30mm to 50mm. The porous electrode plate 9 is placed on the top surface of the suction bellows 8, as shown in Figure 4; high-voltage static electricity is applied between the shuttle electrode plate 4 and the porous electrode plate 9 for the second electric field force to draw the thinned fibers, which The applied voltage range is 80kV to 160kV, preferably the voltage range is 100kV to 120kV. The distance between the shuttle electrode plate 4 and the porous electrode plate 9 is adjusted according to the voltage value. The adjustment method is to adjust the bellows adjusting nut 7 of the suction bellows 8. The adjustment range is 150mm to 250mm, and the preferred range is 180mm to 220mm. .

The first-level electrode plate can also be changed to "7" type, as shown in Figure 5 and Figure 6, the effect of tip placement is more obvious. In order to create a first-level electric field environment between the "7" type electrode plate and the lower melt-blown die, the bolts and supports are made of nylon and bakelite materials respectively. The bakelite bracket 12 is adjusted in the vertical direction and fixed to the upper meltblown die head 2 by nylon fastening bolts 11. The height adjustment nylon bolt 10 and the width adjustment nylon bolt 13 adjust the bakelite bracket 12 in the vertical direction and the bakelite bracket in the horizontal direction. 14. The supporting bakelite boards 18 are connected together and can adjust the distance between the two "7" type electrode plates 19, the height difference between the "7" type electrode plate 19 and the lower meltblown template 3, and the distance between the two "7" type electrode plates 19 The adjustment range is 0-100mm, the preferred range is: 30-60mm, the adjustment range of the distance between the two "7" type electrode plates 19 and the tip of the lower melt blowing die 3 is 30mm-70mm, and the preferred range is 30-50mm. Nylon screws 17 fix the "7" type electrode plate 19 to the horizontally-adjusted bakelite bracket 14, and are matched with the inner threaded holes of the horizontally-adjusted bakelite bracket 14. The bakelite bellows 16 is placed about 150mm below the tip of the lower meltblown die 3, and the center opening is convenient for the placement of the array mesh electrode plate 15. The applied voltage range is 80kV to 160kV, and the preferred voltage range is 100kV to 120kV.

The primary electrode plate can also have a filamentary structure, as shown in FIG. 7 . Two bakelite strips 20 with waist holes are fixed on the side of bakelite bellows 16 by M10 nylon fastening bolts 21, and molybdenum wires 22 for two electrets are wound on M10 nylon tightening bolts 21 and fixed with the waist hole electricity by nut 23. The wooden strips 20 are connected, the 16 holes of the bakelite bellows are threaded holes, which are matched with the M10 nylon fastening bolts 21, the two electret molybdenum wires 22 and the melt-blown lower die 3 form a first-level electric field, and the array mesh electrode plate 15 is connected to the melting point. The lower die head 3 is sprayed to form a secondary electric field, the electret molybdenum wire 22 is located about 10-60mm, preferably 20-30mm below the lower die head 3 of melt-blown, the applied voltage is 5-60kv, preferably 20-35kV, bakelite bellows 16 is placed about 150mm below the tip of the lower melt blowing die 3, the center opening is convenient for the placement of the array mesh electrode plate 15, and the applied voltage range is 80kV to 160kV, and the preferred voltage range is 100kV to 120kV.

Implementation case

The filtration membrane test of sodium chloride aerosol was carried out using a particulate matter filtration efficiency tester. After adding high-voltage electrostatic auxiliary refinement, the filtration effect of the fiber filtration membrane on particulate matter of different diameters was significantly improved. The test results show that the average fiber diameter is reduced from 2-5μm to 1-2μm (the minimum detection diameter is 628nm) after the addition of dual-electrode high-voltage electrostatic; %, the filtration efficiency without electret treatment increased by about 4%; for example, the filtration efficiency of PM0.3 particulate matter increased from 97% to 99.97%. After calculation, the power loss of the suction bellows and airflow auxiliary equipment is reduced by about 1 kWh; the dipolar retention time of the fiber membrane is increased by about 90 days.

Experimental parameters: polypropylene material with a melt index of 1800g/10min; the heating temperature of the melt-blown die head is 240°C; the temperature of the hot air flow is 245°C; the air flow rate is 10m3/h; the suction air flow rate is 28m3/h; The net speed is 18m/min; the first-level electric field voltage is 30kV, and the second-level electric field voltage is 100kV; the distance between the first-level electrode plate and the melt-blown die head is 35mm, and the distance between the second-level electrode plate and the melt-blown die head is 150mm; The horizontal spacing between the electrode plates is 50mm.

Claims (10)

1. A double-electrode high-voltage electrostatic spinning melt-blowing device is characterized in that: the device mainly comprises a melt-blown die head support frame, a melt-blown upper die head, a melt-blown lower die head, a shuttle-shaped electrode plate, an electrode plate conductor sheet, a support frame adjusting nut, an air box adjusting nut, an air suction air box and a porous electrode plate, wherein the melt-blown upper die head comprises two gas flow channels and a melt flow channel; the lower melt-blown die head comprises two gas flow channels; the melt-blown die head support frame is used for supporting and fixing the melt-blown upper die head, the melt-blown lower die head and the shuttle-shaped electrode plate; the support frame adjusting nut is used for adjusting the height of the shuttle-shaped electrode plate; the electrode plate conductor sheets are fixed on two sides of the shuttle-shaped electrode plate; the porous electrode plate is arranged on the top end face of the air suction bellows; the air box adjusting nut is used for adjusting the height of the suction air box from the ground.

2. The melt-blowing device of the double-electrode high-voltage electrostatic spinning according to claim 1, characterized in that: the shuttle-shaped electrode plates are composed of two shuttle-shaped copper electrode plates, are vertically placed on the melt-blown die head support frame, and the two electrode plate conductor sheets are respectively fixed on the two sides of the two shuttle-shaped copper electrode plates by screws and are used for conducting the two shuttle-shaped copper electrode plates so that the two shuttle-shaped copper electrode plates keep the same voltage; the narrow gap between the electrode plate conductor sheets is used for moving the set screw when adjusting the shuttle-type electrode plate.

3. The melt-blowing device of the double-electrode high-voltage electrostatic spinning according to claim 1, characterized in that: the shuttle-shaped electrode plate is replaced by a 7-shaped electrode plate or a filiform electrode.

4. The melt-blowing device of the double-electrode high-voltage electrostatic spinning according to claim 1, characterized in that: applying high-voltage static electricity between the melt-blown lower die head and the shuttle-shaped electrode plate for drafting the refined fibers by primary electric field force, wherein the applied voltage range is 20-35 kV; high-voltage static electricity is applied between the shuttle-shaped electrode plate and the porous electrode plate for secondary electric field force to draw the refined fibers, and the applied voltage range is 80-160kV, and is preferable.

5. The melt-blowing device of the double-electrode high-voltage electrostatic spinning according to claim 1, characterized in that: the distance between the melt-blown upper die head and the shuttle-shaped electrode plate is adjusted according to the voltage value, the adjustment mode is that the adjustment is carried out through a support frame adjusting nut on a support frame of the melt-blown die head, and the adjustment range is 20-35 mm.

6. The melt-blowing device of the double-electrode high-voltage electrostatic spinning according to claim 1, characterized in that: the inner side planes of the electrode plates are coated with polytetrafluoroethylene.

7. The melt-blowing device of the double-electrode high-voltage electrostatic spinning according to claim 1, characterized in that: the porous electrode plate is provided with an array mesh.

8. The melt-blowing device of the double-electrode high-voltage electrostatic spinning according to claim 1, characterized in that: the distance between the shuttle-type electrode plate and the porous electrode plate is adjusted according to the voltage value by adjusting a bellows adjusting nut of a suction air bellows, and the adjusting range is 150-250mm, and the preferable range is 180-220 mm.

9. The melt-blowing device of the double-electrode high-voltage electrostatic spinning according to claim 1, characterized in that: the primary electrode plate is of a 7-shaped structure, and the bolt and the support piece are made of nylon and bakelite materials respectively; the bakelite support is adjusted to vertical direction is fixed in through nylon fastening bolt and melts and spouts the upper die head, height adjusting nylon bolt and width adjusting nylon bolt adjust the bakelite support with vertical direction, horizontal direction adjusts the bakelite support, support the bakelite plate and link together and can adjust two "7" type copper intervals, "7" type copper and melt and spout the difference in height between the die head down, the nylon screw will "7" type copper be fixed in horizontal direction and adjust the bakelite support, the bakelite bellows is arranged in and is melted about 150mm department below the die head most advanced, the central trompil is convenient for placing of array mesh plate electrode.

10. The melt-blowing device of the double-electrode high-voltage electrostatic spinning according to claim 1, characterized in that: the first-stage electrode plate is of a filamentous structure, two bakelite strips with waist holes are fixed on the side face of a bakelite air box through M10 nylon fastening bolts, molybdenum wires for two electret electrodes are wound on M10 nylon bolts and are fixedly connected with the bakelite strips with the waist holes through nuts, holes of the bakelite air box are threaded holes and are matched with the M10 nylon fastening bolts, the two electret molybdenum wires and a melt-blown lower die head form a first-stage electric field, the array mesh electrode plate and the melt-blown lower die head form a second-stage electric field, the electret molybdenum wires are located 20-30mm below the melt-blown lower die head, the applied voltage is 20-35kV, the bakelite air box is arranged 150mm below the tip end of the melt-blown lower die head, the center of the bakelite air box is provided with a hole for facilitating the arrangement of the array mesh electrode plate.

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