WO2022007181A1

WO2022007181A1 - Melt-blown nonwoven fabric electret adding device and adding method

Info

Publication number: WO2022007181A1
Application number: PCT/CN2020/114599
Authority: WO
Inventors: 王猛; 马新宇; 王文涛
Original assignee: 浙江宸唯环保科技股份有限公司
Priority date: 2020-07-06
Filing date: 2020-09-10
Publication date: 2022-01-13
Also published as: CN111876902A

Abstract

A melt-blown nonwoven fabric electret adding device and an adding method. The device comprises a spinneret and a receiving device; a melt channel is formed in the spinneret; a triangular block is provided on the spinneret; the bottom edge of the triangular block is fixedly connected to the spinneret; a spinneret hole is formed in the triangular block and is communicated with the melt channel; air knives are provided at the left and right sides of the triangular block and are bilaterally symmetrically distributed by using the spinneret hole as a center; a stretching airflow channel is formed between the top of each air knife and the spinneret; an air outlet is formed at the side of the air knife close to the triangular block, and the other side of the air knife is distant from the triangular block; an air gap is formed between the side of the air knife close to the triangular block and the side edge of the triangular block; one end of the stretching airflow channel is communicated with the spinneret hole by means of the air gap, and the other end of the stretching airflow channel is provided with an aerosol generator and a hot airflow device; the receiving device is located directly below the spinneret hole and the air knives; and the spinneret is located directly above the air knives. The beneficial effect of the present invention is that the spinneret hole is not blocked.

Description

A kind of melt-blown non-woven electret adding device and adding method thereof

technical field

The invention relates to the related technical field of melt-blown non-woven fabrics, in particular to a melt-blown non-woven fabric electret adding device and an adding method thereof.

Background technique

Melt-blown non-woven fabric is a polymer chip with high melt index MFI, which is heated and melted by an extruder to become a fluid high-temperature polymer melt, and the melt is sprayed from the spinneret hole to form a spinning stream. There are high-speed hot air streams on both sides to clamp the high-temperature melt thin stream, and the ultra-fine fiber shape is formed after pulling and stretching. On the receiving device, it is gathered into a network structure, and the fibers are bonded to each other into a non-woven form by using the residual heat of the melt that has not been completely cooled.

Ordinary meltblown non-woven fabrics have high air resistance. In order to reduce air resistance, electret modification is adopted in the industry. This kind of melt-blown fiber non-woven fabric with electret has much lower air resistance than ordinary melt-blown non-woven fabric, which greatly improves the filtration performance of melt-blown material, so the addition of electret is very important.

The existing method for adding electrets to melt-blown nonwovens is that the electrets are first mixed and co-extruded with a matrix polymer (such as polypropylene) to form an electret masterbatch. The melt-blown fiber resin and electret masterbatch are added to the extruder at the same time for blending and melting, and are sprayed into filaments in the form of a blend through the spinneret hole. Under the action of high-voltage static electricity, the carriers generated by the partial discharge of the electric field are captured by the charge trap of the electret in the electret masterbatch, so that the fibers obtain static electricity, and the melt-blown electret filter non-woven material is obtained. . Common electret materials include: tourmaline, silicon dioxide, etc.

The existing electret blending addition methods have many disadvantages. The first is that the amount of addition is difficult to adjust in a wide range. Electrets are generally inorganic materials such as tourmaline. Excessive addition of tourmaline will reduce the toughness of meltblown fibers, resulting in broken wires and other phenomena, but will weaken the filtration efficiency, so the addition amount should not be too much; the addition of tourmaline is too small. The electret effect is not good, and the improvement of filtration efficiency is limited. Secondly, the large-sized particles in the inorganic electret material are easy to block the spinneret holes, causing downtime for maintenance, resulting in a decrease in the production efficiency of the meltblown fiber and an increase in the cost.

technical problem

The present invention provides a melt-blown non-woven electret adding device that is not easy to block the spinneret holes in order to overcome the disadvantage that the large-diameter particles in the inorganic electret material easily block the spinneret holes in the prior art, and how to add it.

technical solutions

In order to achieve the above purpose, the present invention adopts the following technical solutions: a melt-blown non-woven electret adding device, which comprises a spinneret and a receiving device, wherein the spinneret is provided with a melt channel, and the spinneret is provided with a melt channel. There is a triangular block on the plate, the bottom edge of the triangular block is fixedly connected with the spinneret, the triangular block is provided with a spinneret hole, and the spinneret hole is communicated with the melt channel. There are air knives on both sides. The two air knives are symmetrically distributed on the left and right with the spinneret hole as the center. A drafting airflow channel is formed between the top of the air knife and the spinneret, and one side of the air knife is close to the triangle. The other side of the air knife is far away from the triangular block, an air gap is formed between the side of the air knife close to the triangular block and the side of the triangular block, and the air outlet is located at the bottom of the air knife and is located below the spinneret hole, one end of the drafting airflow channel is communicated with the spinneret hole through an air gap, the other end of the drafting airflow channel is provided with an aerosol generator and a hot air flow device, and the receiving device Directly below the spinneret hole and air knife, the spinneret is located just above the air knife.

A melt channel is arranged in the spinneret, a triangular block is arranged on the spinneret, the bottom edge of the triangular block is fixedly connected with the spinneret, a spinneret hole is arranged in the triangular block, and the spinneret hole is communicated with the melt channel. There are air knives on the left and right sides of the triangular block. The two air knives are symmetrically distributed with the spinneret hole as the center. A drafting airflow channel is formed between the top of the air knife and the spinneret, and one side of the air knife is close to the triangle. The other side of the air knife is far away from the triangular block, and an air gap is formed between the side of the air knife close to the triangular block and the side of the triangular block. Below, one end of the drafting airflow channel is communicated with the spinneret hole through an air gap, the other end of the drafting airflow channel is provided with an aerosol generator and a hot air flow device, and the receiving device is located directly below the spinneret hole and the air knife. The spinneret is located directly above the air knife. The melt-blown fiber resin is added to the extruder for melting, and is ejected into filaments through the spinneret hole. At the same time, the electret is dispersed by the aerosol generator into an aerosol with a certain concentration and a certain particle diameter, which is added to the drafting air flow pipeline, and clamps the high-temperature melt stream together with the high-speed hot air flow generated by the hot air flow device. After pulling and stretching, an ultra-fine fiber form is formed, and the electret can be attached to the outer surface of the high-temperature melt. The cooling air flows out from the air outlet of the air knife to cool the high-temperature melt trickle, so that it is received by the receiving device and condensed into a network. Under the action of a high-voltage electrostatic field, the carriers generated by the partial discharge of the electric field are absorbed by the electret masterbatch. The electret in the electret is trapped in the charge trap, so that the fibers obtain static electricity, and the melt-blown electret filter non-woven fabric is obtained. By the method provided by the present invention, the electret material is dispersed on the outer surface of the melt-blown fiber, and a distribution structure of "coconut bread" is obtained. In the previous method, a "grape pie" distribution structure was obtained by blending and adding electret/fiber resin. The electret is added through the air gap, does not pass through the melt channel, and will not block the spinneret hole, so the production efficiency is improved, the cost is reduced, and the purpose of not easily blocking the spinneret hole is achieved.

Preferably, the included angle formed by the drafting airflow channel and the air gap is an obtuse angle. This design facilitates the mixing of the high-speed hot air flow generated by the aerosol and the hot air flow device to flow to the end of the spinneret hole through the drafting air flow channel and the air gap in turn, to clamp the high temperature melt stream, and to form ultra-fine fibers after pulling and stretching. form, the electret can be attached to the outer surface of the high temperature melt.

Preferably, one end of the melt channel is located at the top of the spinneret, the other end of the melt channel is located at the bottom of the spinneret and communicated with the spinneret hole, and the diameter of one end of the melt channel located at the top of the spinneret is larger than the diameter of the other end. diameter. This design is convenient for the melt-blown fiber resin to be added through the large-diameter end of the melt channel after being melted by the extruder, and flow through the spinneret hole through the small-diameter end, and the filaments are ejected through the spinneret hole. The design is reasonable and the melting point is improved. The utilization rate of spray fiber resin.

Preferably, the hot air device is provided with a mixing box, the aerosol generator is provided with a jet port, the aerosol generator is communicated with the interior of the mixing box through the jet port, and one end of the mixing box is respectively connected to the aerosol generator and the hot air flow. The device is communicated, the other end of the mixing box is communicated with the drafting airflow channel, and a flow guiding device is arranged in the mixing box. The electret is dispersed by the aerosol generator into an aerosol with a certain concentration and a certain particle diameter, which is mixed with the high-speed hot air flow generated by the hot air flow device first in the mixing box, and is guided through the diversion device to make it evenly dispersed to In the drafting airflow channel and air gap, the high-temperature melt stream is clamped, thereby improving the uniformity of mixing and dispersion of aerosol and high-speed hot airflow.

Preferably, the hot air flow device includes an air compressor and an air heater, one end of the air heater is connected to the air compressor, the other end of the air heater is connected to the mixing box, and the air compressor is connected to the interior of the mixing box through the air heater Pass. The air compressor generates high-speed airflow, and the air heater heats the high-speed airflow to form a high-speed hot airflow mixed with aerosol to clamp the high-temperature melt trickle while heating it to prevent the high-temperature melt trickle from cooling and solidifying.

Preferably, one end of the mixing box that communicates with the drafting airflow channel is provided with a transfer port, one end of the transfer port is matched with the mixing box, and the other end of the transfer port is matched with the drafting airflow channel. The airflow channels are connected, and the guide device includes a guide impeller and several guide plates. The aerosol generator and the air heater are located on one side of the guide impeller, and the interface is located on the other side corresponding to the guide impeller. The flow plate is located in the transfer port and is fixedly connected with the inner side wall of the transfer port. The inside of the transfer port is divided into several guide chambers of the same volume by several guide plates, and the interior of the mixing box is connected to the drafting chamber through several guide chambers. The airflow passages are connected, the shape of the mixing box is curved, and the curved part of the mixing box is located between the transfer port and the guide impeller. The electret is dispersed by the aerosol generator into an aerosol with a certain concentration and a certain particle diameter, and is initially mixed with the high-speed hot air flow generated by the air compressor through the air heater in the mixing box, and then mixed and guided by the guide impeller. , to improve the flow and mixing speed of aerosol and high-speed hot air; the mixed air enters the curved part of the mixing box. After the collision with the side wall of the mixing box, the molecules in the mixed air change the direction of movement, thereby accelerating Mixing between the molecules of the mixed air flow, and make it fully mixed to improve the mixing efficiency; finally, the mixed air flow is guided into the guide cavity through the guide plate, so that it is evenly dispersed into the drafting air flow channel and air gap, and the high temperature melt The thin stream is clamped to improve the uniformity of mixing and dispersion of aerosols and high-velocity hot air.

The present invention also provides a method for adding a melt-blown non-woven electret, comprising the following steps: step 1, the melt-blown fiber resin is added to an extruder for melting, and a high-temperature melt spinning thin stream is sprayed through a spinneret hole; At the same time, the electret is dispersed by the aerosol generator into an aerosol with a certain concentration and a certain particle diameter, which is added to the drafting airflow channel and mixed with the high-speed hot airflow.

Step 2: After mixing the aerosol with the high-speed hot air flow, it enters the air gap through the drafting airflow channel, and is blown out by the compressed air to clamp the two sides of the high-temperature melt spinning thin stream. fiber state.

Step 3: The electret particles are attached to the high temperature melt surface of the melt-blown fiber, and after cooling, a melt-blown fiber covered by the electret particles is formed.

The original method of adding electrets in the industry is blending, that is, physical blending of electrets such as tourmaline and meltblown resin. The addition amount of tourmaline is limited, and the addition amount is too high (generally no more than 3%), which will cause the fiber toughness to decrease, the phenomenon of wire breakage will occur, and the filtration performance will decrease instead. In this method, the electret is added through the drafting airflow channel after the melt-blown resin is formed into a fiber, and the electret is sprayed and coated on the outside of the fiber, which can greatly increase the amount of tourmaline added (up to 8% or more). ), significantly enhance the electret effect, and at the same time achieve the purpose of not easily blocking the spinneret hole, so the production efficiency is improved and the cost is reduced; Compared with the in vivo blending modification, the static voltage is higher, the static electricity is maintained for a longer time, and the filtration performance stability is also better.

Preferably, the electret aerosol concentration is 1-10 g/m ³ , preferably 3 g/m ³ .

Preferably, the average diameter of the electret particles is 0.03-3 μm; preferably 0.05-0.5 μm.

Preferably, the material used for the electret is tourmaline or fumed silica.

beneficial effect

The beneficial effects of the invention are: the adjustable range of the addition amount of electret material in the fiber becomes larger; the spinneret hole will not be blocked, so the production efficiency is improved and the cost is reduced; the electret is coated on the outside of the melt-blown fiber, The electret effect on the fiber surface is better than that of the blending modification in the fiber matrix, the static voltage is higher, the static electricity is maintained for a longer time, and the filtration performance stability is also better.

Description of drawings

Figure 1 is a schematic structural diagram of the present invention.

FIG. 2 is a top view of the hot air device and mixing box of FIG. 1 .

3 is a graph showing the relationship between the amount of electret added and the QF value of the fibers in Example 1 and Example 3.

4 is a graph showing the relationship between the amount of electret added and the QF value of the fibers in Example 2 and Example 4.

FIG. 5 is a performance diagram of the meltblown fibers obtained by the method of blending and adding the tourmaline electret described in Example 1. FIG.

FIG. 6 is a graph showing the properties of meltblown fibers obtained by the method of blending and adding _{the SiO 2 electret described in Example 2. FIG.}

FIG. 7 is a performance diagram of the meltblown fibers obtained by the addition method of the present invention using the tourmaline electret described in Example 3. FIG.

FIG. 8 is a performance diagram of the meltblown fibers obtained by the addition method of the present invention _{using the SiO 2 electret described in Example 4. FIG.}

In the figure: 1. Spinneret, 2. Receiver, 3. Melt channel, 4. Triangular block, 5. Spinneret hole, 6. Air knife, 7. Drafting airflow channel, 8. Air outlet, 9. Air Gap, 10. Aerosol Generator, 11. Hot Air Device, 12. Mixing Box, 13. Jet Port, 14. Air Compressor, 15. Air Heater, 16. Adapter, 17. Guide Impeller, 18 . deflector, 19. deflector cavity.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

In the embodiment shown in FIG. 1, a melt-blown non-woven electret adding device includes a spinneret 1 and a receiving device 2. The spinneret 1 is provided with a melt channel 3, and the spinneret 1 There is a triangular block 4 on it, the bottom edge of the triangular block 4 is fixedly connected with the spinneret 1, the triangular block 4 is provided with a spinneret hole 5, and the spinneret hole 5 is communicated with the melt channel 3. There are air knives 6 on both sides, and the two air knives 6 are symmetrically distributed around the spinneret hole 5. The top of the air knives 6 and the spinneret 1 form a drafting airflow channel 7. Close to the triangular block 4 and have an air outlet 8, the other side of the air knife 6 is far away from the triangular block 4, and an air gap 9 is formed between the side of the air knife 6 close to the triangular block 4 and the side of the triangular block 4, and the air outlet 8 Located at the bottom of the air knife 6 and below the spinneret hole 5, one end of the drafting airflow channel 7 is communicated with the spinneret hole 5 through the air gap 9, and the other end of the drafting airflow channel 7 is provided with an aerosol generator 10 and The hot air flow device 11 and the receiving device 2 are located directly below the spinneret hole 5 and the air knife 6 , and the spinneret 1 is located directly above the air knife 6 . The included angle formed by the drafting airflow channel 7 and the air gap 9 is an obtuse angle. One end of the melt channel 3 is located at the top of the spinneret 1, the other end of the melt channel 3 is located at the bottom of the spinneret 1 and communicated with the spinneret hole 5, and the melt channel 3 is located at the top of the spinneret 1. One end diameter larger than the diameter of the other end.

As shown in FIG. 1 , the hot air device 11 is provided with a mixing box 12 , and the aerosol generator 10 is provided with a spray port 13 , and the aerosol generator 10 is communicated with the interior of the mixing box 12 through the spray port 13 , and the mixing box 12 One end of the mixing box 12 is communicated with the aerosol generator 10 and the hot air flow device 11 respectively, and the other end of the mixing box 12 is communicated with the drafting air flow channel 7. The mixing box 12 is provided with a flow guiding device. The hot air flow device 11 includes an air compressor 14 and an air heater 15. One end of the air heater 15 is connected to the air compressor 14, and the other end of the air heater 15 is connected to the mixing box 12. The air compressor 14 passes through the air heater 15. It communicates with the inside of the mixing box 12 .

As shown in Figures 1 and 2, the end of the mixing box 12 that communicates with the drafting airflow channel 7 is provided with a transfer port 16, one end of the transfer port 16 is matched with the mixing box 12, and the other end of the transfer port 16 is connected to the drafting airflow. The channels 7 are matched, the mixing box 12 is communicated with the drafting airflow channel 7 through the transfer port 16, the guide device includes a guide impeller 17 and several guide plates 18, and the aerosol generator 10 and the air heater 15 are located in the guide. One side of the flow impeller 17, the transfer port 16 is located on the other side corresponding to the guide impeller 17, the deflector 18 is located in the transfer port 16 and is fixedly connected with the inner wall of the transfer port 16, and the interior of the transfer port 16 passes through several blocks The guide plate 18 is divided into several guide cavities 19 of the same volume. The interior of the mixing box 12 is communicated with the drafting airflow channel 7 through several guide cavities 19. The shape of the mixing box 12 is partially curved. The mixing box 12 The curve-shaped part of is located between the transfer port 16 and the guide impeller 17 .

The present invention also provides a method for adding a melt-blown non-woven electret, which is characterized by comprising the following steps: Step 1, the melt-blown fiber resin is added to an extruder for melting, and a high-temperature melt is sprayed through the spinneret hole 5 At the same time, the electret is dispersed by the aerosol generator 10 into an aerosol with a certain concentration and a certain particle diameter, which is added to the drafting airflow channel 7 and mixed with the high-speed hot air flow.

Step 2: After the aerosol is mixed with the high-speed hot air flow, it enters the air gap 9 through the drafting airflow channel 7, and is blown out by the compressed air to clamp both sides of the high-temperature melt spinning thin stream, and form after drawing and stretching. Ultrafine fiber state.

The concentration of electret aerosol is 1-10 g/m ³ , preferably 3 g/m ³ .

The average diameter of the electret particles is 0.03-3 μm; preferably 0.05-0.5 μm.

The material used for the electret is tourmaline or fumed silica.

The comprehensive performance of electret-modified meltblown fibers is evaluated by index QF. QF is calculated by the following formula: QF=-ln(1-efficiency%)/resistance. The larger the QF, the better the comprehensive performance of the filter material.

Example 1: Electret material Tourmaline was mixed and co-extruded with polypropylene with a melt index of MFI=1500 to form an electret masterbatch. Polypropylene particles with a melt index MFI=1800 are used, and the melt-blown fiber resin and electret masterbatch (the mass percentage of tourmaline added is 0.5wt%-6.2wt%) are simultaneously added to the extruder for melt blending, and the extrusion temperature is 250 ℃ , the melt temperature is 255 °C, and the blend is sprayed out through the spinneret hole to form a spinning stream. The pulling air temperature is 265 ℃, and the ultra-fine fiber shape is formed after pulling and stretching. On the receiving device, it gathers into a net-like structure at a certain speed, and the gram weight is about 30g/m ² . The fiber web was subjected to high-voltage electrostatic action (10kV) to obtain a melt-blown electret filter non-woven material. Under the condition of surface wind speed of 5.3cm/s, its efficiency (the particle size of the test particle is 0.3μm, and the surface wind speed of the test material is 5.3cm/s) and air resistance are tested. Calculate the QF value. Using the tourmaline electret described in Example 1, the properties of the meltblown fibers obtained by the blending addition method are shown in Figure 5.

Example 2: Electret material Vapor-phase SiO ₂ and polypropylene with a melt index of MFI=1500 were mixed and co-extruded to form an electret masterbatch. Polypropylene particles with melt index MFI=1800 were used, melt-blown fiber resin and electret masterbatch (SiO ₂ added mass percentage of 0.5wt%-4.3wt%) were added to the extruder for melt blending at the same time, and the extrusion temperature was 250 ℃ , the melt temperature is 255 °C, and the blend is sprayed out through the spinneret hole to form a spinning stream. The pulling air temperature is 265 ℃, and the ultra-fine fiber shape is formed after pulling and stretching. On the receiving device, it gathers into a net-like structure at a certain speed, and the gram weight is about 30g/m ² . The fiber web was subjected to high-voltage electrostatic action (10kV) to obtain a melt-blown electret filter non-woven material. Under the condition of surface wind speed of 5.3cm/s, its efficiency (the particle size of the test particle is 0.3μm, and the surface wind speed of the test material is 5.3cm/s) and air resistance are tested. Calculate the QF value. The added amount of tourmaline is calculated by the actual mass percentage _{of SiO 2 in the final fiber product.} Example 2 using the SiO ₂ electret, the resulting blend is added the meltblown fiber properties shown in Fig.

Example 3: Polypropylene pellets with a melt index MFI=1800 were added to an extruder for melt extrusion, the extrusion temperature was 250°C, the melt temperature was 255°C, and the filaments were ejected through the spinneret to form a spinning stream. The silk box temperature is 255°C. The tourmaline powder is dispersed by the aerosol generator into an aerosol with a concentration of 1-10g/m ³ and an average particle diameter of 0.1μm, which is added to the drafting airflow duct, and the tourmaline entering the air gap of the melt-blown component at a temperature of 265°C. It is blown out with the high-speed hot air flow on both sides of the spinning stream. The electret is able to adhere to the high temperature melt. The spinning thin stream forms ultra-fine fiber shape after being drawn and stretched by high-speed air flow. On the receiving device, it gathers into a net-like structure at a certain speed, and the gram weight is about 30g/m ² . Under the action of high-voltage static electricity (10kV), the fiber web can obtain a melt-blown electret filter non-woven material. Under the condition of surface wind speed of 5.3cm/s, its efficiency (the particle size of the test particle is 0.3μm, and the surface wind speed of the test material is 5.3cm/s) and air resistance are tested. Calculate the QF value. The added amount of tourmaline is calculated by the mass percentage of the actual tourmaline in the final fiber product. Using the tourmaline electret described in Example 3, the properties of the meltblown fibers obtained by the addition method involved in the present invention are shown in FIG. 7 .

Example 4: Polypropylene pellets with a melt index MFI=1800 were added to an extruder for melt extrusion, the extrusion temperature was 250°C, the melt temperature was 255°C, and the filaments were ejected through the spinneret to form a spinning stream, and the filaments were spun. The silk box temperature is 255°C. The gas phase method SiO ₂ powder is dispersed by the aerosol generator into an aerosol with a concentration of 2-10g/m ³ and an average particle diameter of 0.08μm, which is added to the drafting airflow duct, and the temperature of the drafting air is 265°C. The stone is blown out with the high-speed hot air flow on both sides of the spinning stream. The electret is able to adhere to the high temperature melt. The spinning thin stream forms ultra-fine fiber shape after being drawn and stretched by high-speed air flow. On the receiving device, it gathers into a net-like structure at a certain speed, and the gram weight is about 30g/m ² . The fiber web was subjected to high-voltage electrostatic action (10kV) to obtain a melt-blown electret filter non-woven material. Under the condition of surface wind speed of 5.3cm/s, its efficiency (the particle size of the test particle is 0.3μm, and the surface wind speed of the test material is 5.3cm/s) and air resistance are tested. Calculate the QF value. The added amount of fumed SiO ₂ is calculated as the actual mass percentage _{of SiO 2} in the final fiber product. _{Using the SiO 2} electret described in Example 4, the properties of the meltblown fibers obtained by the addition method involved in the present invention are shown in FIG. 8 .

As shown in FIG. 3 , comparing Example 1 and Example 3, the electret material is tourmaline, and the blending method and the method involved in the present invention are respectively adopted. In the case of different electret addition amounts, the present invention is adopted. The QF values of the fibers obtained by the addition methods involved are all larger than those obtained by the blending method. At the same time, the blending method is adopted, the addition amount of tourmaline is limited, and the addition amount is too high (generally no more than 3%), which will cause the fiber toughness to decrease, the phenomenon of wire breakage occurs, and the filtration performance decreases. In contrast, by using this method, the amount of tourmaline added (up to 8% or more) can be greatly increased, and the electret effect can be significantly enhanced.

As shown in FIG. 4 , comparing Example 2 and Example 4, the electret material is SiO ₂ , and the blending method and the method involved in the present invention are respectively adopted. In the case of different electret addition amounts, the present invention is adopted. The QF values of the fibers obtained by the addition methods involved are all larger than those obtained by the blending method. At the same time, by using the blending method, _{the addition amount of SiO 2} is limited. If the addition amount is too high, the fiber tenacity will decrease, the wire breakage will occur, and the filtration performance will decrease. Enhance electret effect.

To sum up, the comprehensive performance of the filter material using the adding method involved in the present invention is better than that of the filter material using the blending method. In this method, the electret is added through the drafting airflow channel after the melt-blown resin is formed into a fiber, and the electret is sprayed and coated on the outside of the fiber, which can greatly increase the amount of tourmaline added and significantly enhance the electret effect. At the same time, the purpose of not easily blocking the spinneret hole is achieved, so the production efficiency is improved and the cost is reduced; the electret is coated on the outside of the melt-blown fiber, and the electret effect on the fiber surface is better than that of the blending modification in the fiber matrix. Well, the static voltage is higher, the static electricity lasts longer, and the filtration performance is more stable.

Claims

A melt-blown non-woven electret adding device, characterized in that it comprises a spinneret (1) and a receiving device (2), wherein the spinneret (1) is provided with a melt channel (3), so that the The spinneret (1) is provided with a triangular block (4), the bottom edge of the triangular block (4) is fixedly connected with the spinneret (1), and a spinneret hole ( 5), the spinneret hole (5) is communicated with the melt channel (3), the left and right sides of the triangular block (4) are provided with air knives (6), and two air knives (6) are used to spray The wire holes (5) are symmetrically distributed on the left and right as the center, a drafting airflow channel (7) is formed between the top of the air knife (6) and the spinneret (1), and one side of the air knife (6) is close to The triangular block (4) is provided with an air outlet (8), the other side of the air knife (6) is far away from the triangular block (4), and the air knife (6) is close to the triangular block (4) on one side and the triangular block (4). An air gap (9) is formed between the sides of the block (4), the air outlet (8) is located at the bottom of the air knife (6) and below the spinneret hole (5), and the drafting airflow channel (7) ) is communicated with the spinneret hole (5) through an air gap (9), and the other end of the drafting airflow channel (7) is provided with an aerosol generator (10) and a hot air flow device (11), the The receiving device (2) is located directly below the spinneret hole (5) and the air knife (6), and the spinneret (1) is located directly above the air knife (6).
The device for adding a melt-blown non-woven electret according to claim 1, wherein the angle formed by the drafting airflow channel (7) and the air gap (9) is an obtuse angle.
A melt-blown non-woven electret adding device according to claim 1 or 2, wherein one end of the melt channel (3) is located at the top of the spinneret (1), and the melt The other end of the channel (3) is located at the bottom of the spinneret (1) and communicated with the spinneret hole (5). diameter.
A melt-blown non-woven electret adding device according to claim 1, characterized in that, a mixing box (12) is provided on the hot air flow device (11), and the aerosol generator (10) A jet port (13) is provided on the top, the aerosol generator (10) is communicated with the interior of the mixing box (12) through the jet port (13), and one end of the mixing box (12) is respectively connected to the aerosol generator (10) is communicated with the hot air flow device (11), the other end of the mixing box (12) is communicated with the drafting air flow channel (7), and a flow guiding device is arranged in the mixing box (12).
A melt-blown non-woven electret adding device according to claim 4, characterized in that the hot air flow device (11) comprises an air compressor (14) and an air heater (15), the air One end of the heater (15) is connected to the air compressor (14), the other end of the air heater (15) is connected to the mixing box (12), and the air compressor (14) passes through the air heater (15) It communicates with the interior of the mixing box (12).
The device for adding melt-blown non-woven electrets according to claim 5, characterized in that a transfer port (16) is provided at one end of the mixing box (12) that communicates with the drafting airflow channel (7). , one end of the transfer port (16) is matched with the mixing box (12), the other end of the transfer port (16) is matched with the drafting airflow channel (7), and the mixing box (12) is passed through the transfer port. (16) is communicated with the drafting airflow channel (7), the guide device includes a guide impeller (17) and several guide plates (18), the aerosol generator (10) and the air heater ( 15) Both are located on one side of the guide impeller (17), the transfer port (16) is located on the other side corresponding to the guide impeller (17), and the guide plate (18) is located in the transfer port (16) and is fixedly connected to the inner side wall of the transfer port (16), the interior of the transfer port (16) is divided into several guide cavities (19) of the same volume by several guide plates (18), and the mixing box ( The interior of 12) is communicated with the drafting airflow channel (7) through several guide cavities (19), the shape of part of the mixing box (12) is curvilinear, and the shape of the mixing box (12) is curvilinear The part is located between the transfer port (16) and the guide impeller (17).
A method for adding a melt-blown non-woven electret, which is characterized by comprising the following steps: step 1, melt-blown fiber resin is added to an extruder for melting, and a high-temperature melt spinning fine is sprayed out through a spinneret hole (5). At the same time, the electret is dispersed by the aerosol generator (10) into an aerosol with a certain concentration and a certain particle diameter, which is added to the drafting airflow channel (7) and mixed with the high-speed hot air flow; step 2, the aerosol and After the high-speed hot air flow is mixed, it enters the air gap (9) through the drafting air flow channel (7), and is blown out by the compressed air to clamp the two sides of the high-temperature melt spinning thin stream, and then pull and stretch to form an ultra-fine In step 3, electret particles are attached to the high temperature melt surface of the melt-blown fibers, and after cooling, electret particles-coated melt-blown fibers are formed.
The method for adding a melt-blown nonwoven electret according to claim 7, wherein the electret aerosol concentration is 1-10 g/m 3 , preferably 3 g/m 3 .
The method for adding a melt-blown nonwoven electret according to claim 7, wherein the average diameter of the electret particles is 0.03-3 μm; preferably 0.05-0.5 μm.
The method for adding a melt-blown nonwoven electret according to claim 7, wherein the material used for the electret is tourmaline or fumed silica.