Spinneret-orifice-free melt-blown spinning device based on rotary screen

Abstract

The invention relates to the technical field of fiber spinning equipment, in particular to a non-spinneret orifice type melt-blowing spinning device based on a rotary screen, which comprises a rack, the melt processing mechanism is arranged on the rack and is used for outputting a polymer melt with flowability and dragging the polymer melt; a driving mechanism; the rotary positioning mechanism is arranged on the rack and connected with the driving mechanism, and the driving mechanism drives the rotary positioning mechanism to rotate; and the screen mesh is arranged opposite to the outlet end of the melt processing mechanism and connected with the rotary positioning mechanism, and the screen mesh is positioned through the rotary positioning mechanism and driven to rotate. The driving mechanism is used for positioning the screen through the rotary positioning mechanism and driving the screen to rotate, so that the rotating stability of the screen is improved, the problem that the screen and surrounding parts are prone to friction damage due to the deviation phenomenon is solved, the service life of the screen is prolonged, melt is stably output, prepared fibers are uniform, and production continuity is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber spinning equipment, and in particular to a spinneret-free melt-blown spinning device based on a rotary screen. Background Art

[0002] Meltblown spinning is an industrialized process that uses high-temperature airflow to draw a polymer melt jet extruded from a spinneret at high speed. Current meltblown technology primarily relies on a spinneret to extrude the melt jet, and the spinneret's aperture directly determines the fiber diameter. However, spinneret processing is difficult, making it difficult to produce fibers with diameters below 1μm using traditional meltblown technology. Furthermore, spinnerets are highly imported, and reducing their aperture not only increases melt extrusion pressure and production costs but also can lead to problems such as melt blockage and cleaning difficulties. High melt extrusion pressures can also cause burrs in the spinneret orifices, compromising fiber quality. Therefore, overcoming the limitations of spinneret apertures and developing spinneret-free meltblown spinning technology, while simultaneously reducing fiber size and increasing nanofiber yield, holds significant research and development value and application significance for the development of high-throughput nanofiber technology.

[0003] In related technologies, screens are often used to achieve spinneret-free meltblown spinning. However, the device still has some limitations in terms of melt output and operational stability. For example, the screen is prone to deviation during rotation, and it is prone to friction damage with surrounding components, resulting in a short service life of the screen, poor stability of the prepared fiber, and difficulty in continuous production. Summary of the Invention

[0004] The present invention provides a spinneret-free melt-blown spinning device based on a rotary screen, which is used to solve the problem in the related art that the screen may deviate or be damaged during rotation, resulting in a short service life of the screen, poor stability of the prepared fiber, and difficulty in continuous production.

[0005] The present invention provides a spinneret-free melt-blown spinning device based on a rotary screen, comprising: frame; A melt processing mechanism is provided on the frame and is used to output a polymer melt having fluidity and to pull the polymer melt; Drive mechanism; A rotation positioning mechanism is provided on the frame and connected to the driving mechanism, and is driven by the driving mechanism to rotate the rotation positioning mechanism; The screen is arranged opposite to the outlet end of the melt processing mechanism and is connected to the rotation positioning mechanism. The screen is positioned and driven to rotate by the rotation positioning mechanism. The screen is evenly distributed with a plurality of micropores, and the plurality of micropores are used to disperse the polymer melt on the screen. The micropores extending axially also form a guide channel, and the melt processing mechanism draws the polymer melt through the guide channel.

[0006] The spinneret-free melt-blown spinning device based on a rotary screen provided by the present invention further includes: a heating mechanism, which is arranged on the frame and upstream of the melt processing mechanism along the rotation direction of the screen, for heating the screen.

[0007] According to the spinneret-free melt-blown spinning device based on a rotary screen provided by the present invention, the rotation positioning mechanism includes: a slewing support bearing, the slewing support bearing includes a bearing inner ring and a bearing outer ring rotatably connected to each other, the bearing outer ring is fixed on the frame, the driving mechanism is connected to the outer side of the bearing inner ring, and the screen is fixed to the inner side of the bearing inner ring and rotates synchronously with the bearing inner ring.

[0008] The spinneret-free melt-blown spinning device based on a rotary screen provided by the present invention also includes: a plurality of connectors; an annular gap is formed between the screen and the inner ring of the bearing, the connectors are evenly spaced in the annular gap along the circumferential direction, and one end of the connector is connected to the screen, and the other end of the connector is connected to the inner ring of the bearing.

[0009] According to the spinneret-free melt-blown spinning device based on a rotary screen provided by the present invention, the driving mechanism includes: A motor, arranged on the frame; A transmission belt, wherein the output end of the motor is connected to the outer side of the bearing inner ring through the transmission belt.

[0010] The spinneret-free melt-blown spinning device based on a rotary screen provided by the present invention further includes: a surrounding plate, which is arranged on the outside of the screen, and the connector is fixedly connected to the surrounding plate.

[0011] According to the spinneret-free melt-blown spinning device based on a rotary screen provided by the present invention, the melt processing mechanism includes: Melt feeding and heating module, used for feeding melt-blown grade resin material and heating and melting the melt-blown grade resin material; a melt transfer module, one end of which is connected to the melt feeding and heating module, and the other end of which is disposed toward the screen, for spraying the melt-blown grade resin material in a molten state onto the screen; The jet drawing module is directed toward the screen and is located downstream of the melt transfer module, and is used for blowing air onto the screen to draw the melt-blown grade resin material through the guide channel to form a jet.

[0012] According to the spinneret-free melt-blown spinning device based on a rotary screen provided by the present invention, the melt feeding and heating module comprises: a screw extruder; The screw extruder has at least four heating zones, the temperature range of the first heating zone is 25-100°C, and the temperature range of the second heating zone to the fourth heating zone is 25-300°C; The rotation speed of the screw extruder ranges from 0 to 30 rpm.

[0013] According to the spinneret-free melt-blown spinning device based on a rotary screen provided by the present invention, the melt transfer module comprises: an L-shaped melt channel, wherein a strip-shaped spray slot is formed at one end of the L-shaped melt channel toward the screen; A first heating unit is provided in the L-shaped melt channel, and the temperature range of the first heating unit is 250-350°C; The vertical distance between the outlet end surface of the strip spray slot and the screen is in the range of 0.5-2 cm; The width of the strip spray seam ranges from 1 to 7 mm.

[0014] According to the spinneret-free melt-blown spinning device based on a rotary screen provided by the present invention, the jet drafting module includes: Air compressor, the output air pressure range is 0.2-0.5Mpa; An air knife is connected to the air compressor, and a second heating unit is provided between the air compressor and the air knife, wherein the temperature of the second heating unit ranges from 260° C. to 350° C.; The vertical distance between the blade edge of the air knife and the screen is in the range of 1-3 cm, and the horizontal distance between the air knife and the melt transfer module is in the range of 1-2 cm.

[0015] The spinneret-free melt-blown spinning device based on a rotary screen provided by the present invention further includes: a fiber collecting module, located on a side of the screen away from the melt processing mechanism, for collecting polymer fibers.

[0016] According to the spinneret-free melt-blown spinning device based on a rotary screen provided by the present invention, the mesh size of the micropores on the screen is in the range of 40-100 mesh; the length of the guide channel formed by the micropores extending axially is in the range of 0.1-0.4 mm; driven by the rotation and positioning mechanism, the rotation speed of the screen is less than 10 rpm.

[0017] The present invention provides a spinneret-free meltblown spinning device based on a rotary screen, comprising: a frame, a melt processing mechanism, a drive mechanism, a rotation positioning mechanism, and a screen. The melt processing mechanism is disposed on the frame and is used to output a fluid polymer melt and to pull the polymer melt; the rotation positioning mechanism is disposed on the frame and is connected to the drive mechanism, and is driven to rotate by the drive mechanism; the screen is disposed opposite to the outlet end of the melt processing mechanism and is connected to the rotation positioning mechanism, and is positioned and driven to rotate by the rotation positioning mechanism. The screen is evenly distributed with a plurality of micropores, which are used to disperse the polymer melt on the screen, and the micropores extending axially also form a guide channel, and the melt processing mechanism draws the polymer melt through the guide channel. The present invention provides a spinneret-free melt-blown spinning device based on a rotary screen, which uses a driving mechanism to position the screen through a rotating positioning mechanism and drive the screen to rotate, thereby improving the rotation stability of the screen and avoiding the problem of friction damage between the screen and surrounding components caused by deviation, thereby increasing the service life of the screen, and the prepared fiber has high stability, ensuring production continuity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 It is a schematic diagram of the three-dimensional structure of a spinneret-free melt-blown spinning device based on a rotary screen provided in one embodiment of the present invention.

[0020] Figure 2 It is a front view of a spinneret-free melt-blown spinning device based on a rotary screen provided in one embodiment of the present invention.

[0021] Figure 3 It is a top view of a spinneret-free melt-blown spinning device based on a rotary screen provided in one embodiment of the present invention.

[0022] Figure 4 It is a left view of a spinneret-free melt-blown spinning device based on a rotary screen provided in one embodiment of the present invention.

[0023] Figure 5 It is a schematic structural diagram of a melt transfer module and a jet drawing module provided in one embodiment of the present invention.

[0024] Figure 6It is a bottom view of a melt transfer module and a jet drawing module provided in one embodiment of the present invention.

[0025] Figure 7 It is a schematic structural diagram of the screen and the enclosure provided in one embodiment of the present invention.

[0026] Figure 8 is a SEM image of the PLA fiber prepared in Example 1 of the present invention.

[0027] Figure 9 3 is a diameter distribution diagram of the PLA fiber prepared in Example 1 of the present invention.

[0028] Figure 10 This is a physical picture of the PLA fiber prepared in Example 1 of the present invention.

[0029] Figure 11 is a SEM image of the PP fiber prepared in Example 2 of the present invention.

[0030] Figure 12 This is a physical picture of the melt residue on the screen surface in Comparative Example 1 of the present invention.

[0031] Reference numerals: 1: Frame; 2: Driving mechanism; 21: Motor; 22: Active turntable; 23: Transmission belt; 3: Rotation positioning mechanism; 31: Slewing support bearing; 4: Screen; 41: Enclosure; 42: Micropore; 5: Melt feeding and heating module; 51: Screw extruder; 6: Melt transfer module; 61: Strip spray slot; 7: Jet drawing module; 71: Air knife; 8: Heating mechanism; 9: Connector. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0033] In the description of this embodiment, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this embodiment.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this embodiment, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0035] In this embodiment, unless otherwise specified or limited, the terms "disposed," "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed or detachable connections, or integration; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this embodiment based on specific circumstances.

[0036] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0037] The following combination Figures 1-12 The present invention describes a spinneret-free melt-blown spinning device based on a rotary screen. The spinneret-free melt-blown spinning device based on a rotary screen comprises: a frame 1, a melt processing mechanism, a driving mechanism 2, a rotation and positioning mechanism 3, and a screen 4.

[0038] Among them, the melt processing mechanism is arranged on the frame 1, which is used to output the fluid polymer melt and pull the polymer melt; the rotation positioning mechanism 3 is arranged on the frame 1 and is connected to the driving mechanism 2, and the rotation positioning mechanism 3 is driven to rotate by the driving mechanism 2; the screen 4 is arranged opposite to the outlet end of the melt processing mechanism and is connected to the rotation positioning mechanism 3, and the screen 4 is positioned and driven to rotate by the rotation positioning mechanism 3. A plurality of micropores 42 are evenly distributed on the screen 4, and the plurality of micropores 42 are used to disperse the polymer melt on the screen 4, and the micropores 42 extending axially also form a diversion channel, and the melt processing mechanism draws the polymer melt through the diversion channel.

[0039] Specifically, the frame 1 serves as the support and mounting structure for the device, upon which the melt processing mechanism, drive mechanism 2, rotation and positioning mechanism 3, and screen 4 are mounted. Meltblown-grade resin is added to the melt processing mechanism and then melted, extruded, and pulled through the heating, melting, extrusion, and pulling processes. Specifically, the meltblown-grade resin is first heated until a molten polymer melt is formed, which is then extruded onto screen 4, where it is pulled through by the ejected airflow. Finally, the drawn fibers are collected beneath screen 4.

[0040] The driving mechanism 2 serves as the power source for the rotation of the screen 4, and can drive the screen 4 to rotate clockwise or counterclockwise. During the rotation of the screen 4, the melt is stretched through the screen 4, and the rotation speed should not be too fast or too slow; if the rotation speed is too fast, the melt will not have enough time to stretch, and if the rotation speed is too slow, the melt will increase in viscosity due to cooling and solidify.

[0041] The rotation positioning mechanism 3 is installed on the frame 1 and has the following two functions: 1. Rotational transmission function: The driving mechanism 2 drives the rotation positioning mechanism 3 to rotate, thereby transmitting the rotational motion to the screen 4, thereby driving the screen 4 to rotate; 2. Positioning function: The screen 4 is installed in the rotating positioning mechanism 3. The rotating positioning mechanism 3 positions the screen 4 to avoid the problem of the screen 4 going off during the rotation process.

[0042] The positioning and rotation of the screen 4 are driven by the rotating positioning mechanism 3, thereby improving the rotation stability of the screen 4 and avoiding the problem of friction damage between the screen and surrounding components caused by deviation, thereby increasing the service life of the screen 4, and the prepared fiber has high stability, ensuring production continuity.

[0043] The screen 4 is evenly distributed with a plurality of micropores 42, which have the following two functions: 1. The multiple micropores 42 on the screen 4 are used to evenly disperse the polymer melt on the screen 4, forming multiple melt jets through the micropores 42; 2. The micropores 42 extending in the axial direction form a flow channel through which the melt processing mechanism stretches the polymer melt. In the following embodiment, the flow channel is an airflow channel, and the jet stretching module sprays air onto the screen 4, and the airflow passes through the airflow channel to stretch the polymer melt.

[0044] The present invention provides a spinneret-free meltblown spinning device based on a rotary screen, comprising: a frame 1, a melt processing mechanism, a drive mechanism 2, a rotation and positioning mechanism 3, and a screen 4. The melt processing mechanism is disposed on the frame 1 and is used to output a fluid polymer melt and to pull the polymer melt; the rotation and positioning mechanism 3 is disposed on the frame 1 and connected to the drive mechanism 2, and is driven by the drive mechanism 2 to rotate the rotation and positioning mechanism 3; the screen 4 is disposed opposite the outlet end of the melt processing mechanism and is connected to the rotation and positioning mechanism 3. The rotation and positioning mechanism 3 positions the screen 4 and drives the screen 4 to rotate. The screen 4 is uniformly distributed with a plurality of micropores 42, which are used to disperse the polymer melt on the screen 4. The micropores 42 extending axially also form a diversion channel, through which the melt processing mechanism draws the polymer melt. The present invention provides a spinneret-free melt-blown spinning device based on a rotary screen, which uses a driving mechanism 2 to position the screen 4 through a rotating positioning mechanism 3 and drive the screen 4 to rotate, thereby improving the rotation stability of the screen 4, avoiding the problem of deviation causing friction damage between it and surrounding components, thereby increasing the service life of the screen 4, and the prepared fiber has high stability, ensuring production continuity.

[0045] In one embodiment of the present invention, the spinneret-free melt-blown spinning device based on a rotary screen further includes: a heating mechanism 8, which is provided on the frame 1 and is arranged upstream of the melt processing mechanism along the rotation direction of the screen 4, for heating the screen 4. Specifically, in this embodiment, by arranging the heating mechanism 8 above the screen 4, the screen 4 is preheated. Before the melt falls into the screen 4, the screen 4 is preheated by the heating mechanism 8 to ensure that the melt does not increase in viscosity or solidify due to the low temperature of the screen 4 at the moment of contact with the screen 4, thereby improving the fiber quality. The heating temperature of the heating mechanism 8 is in the range of 250-350°C.

[0046] In one embodiment of the present invention, the rotation positioning mechanism 3 includes a slewing support bearing 31, which comprises an inner ring and an outer ring rotatably connected to each other. The outer ring is fixed to the frame 1, and the drive mechanism 2 is connected to the outer side of the inner ring. The screen 4 is fixed to the inner side of the inner ring and rotates synchronously with the inner ring. In this embodiment, the rotation positioning mechanism 3 utilizes a slewing support bearing 31, which has the ability to support the screen 4 and position the screen 4 inside its inner ring, driving the screen 4 to rotate synchronously. Specifically, the outer ring is fixed to the frame 1, and the inner ring rotates relative to the outer ring via rolling elements (such as balls) arranged between the outer and inner rings.

[0047] In one embodiment of the present invention, the spinneret-free melt-blown spinning device based on a rotary screen further includes: a plurality of connectors 9; an annular gap is formed between the screen 4 and the inner ring of the bearing, and the connectors 9 are evenly spaced in the annular gap along the circumferential direction, with one end of the connector 9 connected to the screen 4 and the other end of the connector 9 connected to the inner ring of the bearing. Preferably, the connectors 9 are triangular connectors 9 fixed to the inner side of the bearing inner ring, and are distributed at a predetermined distance along the circumference of the bearing inner ring. Through holes are formed in the connectors 9, and fasteners are used to secure the connectors 9 to the screen 4 to ensure the positioning and synchronous rotation of the screen 4.

[0048] In one embodiment of the present invention, the drive mechanism 2 includes a motor 21 and a transmission belt 23. The motor 21 is mounted on the frame 1; the output end of the motor 21 is connected to the outer side of the bearing inner ring via the transmission belt 23. In this embodiment, the motor 21 is fixed to the frame 1, and the output shaft of the motor 21 is connected to the driving turntable 22. The driving turntable 22 is connected to the outer side of the bearing inner ring via the transmission belt 23, thereby driving the bearing inner ring to rotate. Specifically, both the bearing inner ring and the driving turntable 22 are provided with grooves for mounting the transmission belt 23, and the transmission belt 23 is tensioned and assembled within the grooves, ensuring synchronous transmission between the driving turntable 22 and the bearing inner ring.

[0049] In one embodiment of the present invention, the spinneret-free melt-blown spinning device based on the rotary screen further includes a panel 41. The panel 41 is arranged on the outside of the screen 4, and the connector 9 is fixedly connected to the panel 41. Figure 7 In the structure shown, the screen 4 is a circular screen 4, and the enclosure 41 is an annular enclosure 41, which is fixed on the outer edge of the screen 4 and forms an integral structure with the screen 4. The enclosure 41 has the following three functions: 1. Easy positioning of the screen 4: the screen 4 is connected to each connector 9 through the enclosure 41, which is easy to assemble; 2. Protection of the screen 4: Since the enclosure 41 is located outside the screen 4, the screen 4 is prevented from contacting the bearing, thereby reducing the wear of the screen 4; 3. Preventing the melt from being thrown out: the enclosure 41 protrudes from the screen 4 in the height direction, thereby preventing the melt from being thrown out of the screen 4 due to centrifugal force.

[0050] In one embodiment of the present invention, the melt processing mechanism includes: a melt feeding and heating module 5, a melt transfer module 6, and a jet drawing module 7. The melt feeding and heating module 5 is used to feed and heat the meltblown-grade resin material; the melt transfer module 6 is connected to the melt feeding and heating module 5 at one end and disposed toward the screen 4 at the other end, and is used to spray the molten meltblown-grade resin material onto the screen 4; the jet drawing module 7 is disposed toward the screen 4 and downstream of the melt transfer module 6, and is used to blow air toward the screen 4, drawing the molten meltblown-grade resin material through the guide channel to form a jet. Specifically, the melt feeding and heating module 5, the melt transfer module 6, and the jet drawing module 7 are all disposed on the frame 1.

[0051] In one embodiment of the present invention, the melt feeding and heating module 5 includes a screw extruder 51. The screw extruder 51 has at least four heating zones, with the first heating zone having a temperature range of 25-100°C, and the second through fourth heating zones having a temperature range of 25-300°C. The screw extruder 51 also has a rotational speed range of 0-30 rpm. Specifically, a meltblown-grade resin is added to the melt feeding and heating module 5 and heated until it melts, forming a polymer melt with a certain fluidity and viscosity. The heating module includes at least four heating zones to ensure sufficient heating of the resin. The first heating zone has a temperature range of 25-100°C, and the second through fourth heating zones have a temperature range of 25-300°C. The heating module conveys the melt via a rotating screw, with a rotational speed range of 0-30 rpm.

[0052] In one embodiment of the present invention, the melt transfer module 6 includes an L-shaped melt channel with a strip-shaped spray slot 61 formed at one end of the L-shaped melt channel facing the screen 4. A first heating unit is provided within the L-shaped melt channel, and the temperature of the first heating unit ranges from 250°C to 350°C. The vertical distance between the outlet end face of the strip-shaped spray slot 61 and the screen 4 ranges from 0.5 to 2 cm. The width of the strip-shaped spray slot 61 ranges from 1 to 7 mm. Specifically, the melt transfer module 6 is an integrated block with an L-shaped melt channel formed inside. One end is a hole connected to the end of the screw extruder 51, and the other end is a strip-shaped spray slot 61. The L-shaped melt channel conveys the melt horizontally, and the melt spray direction is changed at the strip-shaped spray slot 61, spraying the melt downward and toward the screen 4. The melt is first conveyed through the hole to the strip-shaped spray slot 61. At the same time, the module can be heated internally to insulate the melt and maintain its fluidity. The heating temperature of the first heating unit should be equal to or higher than the temperature of the melt heating module, preferably in the range of 250-350°C. The strip-shaped spray slot 61 has a length of 5 cm and a width of 0.5 cm.

[0053] In one embodiment of the present invention, the jet drawing module 7 includes: an air compressor and an air knife 71. The air pressure output by the air compressor is in the range of 0.2-0.5 MPa; the air knife 71 is connected to the air compressor, and a second heating unit is provided between the air compressor and the air knife 71, and the temperature of the second heating unit is in the range of 260-350°C. The vertical distance between the blade of the air knife 71 and the screen 4 is in the range of 1-3 cm, and the horizontal distance between the air knife 71 and the melt transfer module 6 is in the range of 1-2 cm. Preferably, the second heating unit can be an air heating pack, and a freeze dryer is also provided between the air compressor and the air knife 71. The air knife 71 is located behind the strip spray slit 61, and the air knife 71 and the strip spray slit 61 are arranged in parallel. The gap between the air knife 71 is in the range of 0.08-0.32 mm, and the length of the air knife 71 is greater than or equal to the length of the strip spray slit 61.

[0054] In one embodiment of the present invention, the rotary screen-based spinneret-free meltblown spinning apparatus further includes a fiber collection module, located on the side of the screen 4 facing away from the melt processing mechanism, for collecting polymer fibers. Preferably, the fiber collection module is located directly below the air knife 71 and can be a mesh filter basket or a drum for collecting the drawn fibers. The vertical distance between the fiber collection module and the air knife 71 ranges from 20 to 80 cm. The resulting fibers can be in the form of a film, felt, or fluffy cotton.

[0055] In one embodiment of the present invention, the mesh size of the micropores 42 on the screen 4 ranges from 40 to 100 meshes; the length of the guide channel formed by the micropores 42 extending axially ranges from 0.1 to 0.4 mm; and driven by the rotation and positioning mechanism 3, the rotation speed of the screen 4 is less than 10 rpm.

[0056] The following two parameter examples are provided.

[0057] Example 1: First, turn on the temperature switches for the melt feeding and heating module 5 and the melt transfer module 6, setting the temperatures to 50°C, 195°C, 225°C, 255°C (the temperature parameters for the four heating zones of the screw extruder 51, respectively), and 270°C (the temperature parameter for the first heating unit in the L-shaped melt channel). Then, start the air compressor, set the air pressure and temperature to 0.3 MPa and 310°C, respectively, and activate the heating mechanism 8. After the temperature stabilizes, the heating mechanism 8 temperature in the local area of the screen 4 is set to 300°C. Meltblown-grade PLA resin is added to the feed port of the screw extruder 51, and the screw is started, with the screw speed set to 3 rpm. Next, the motor 21 for controlling the rotation of the screen 4 is started. The rotation speed of the screen 4 is 5 rpm, the mesh size of the screen 4 is 80 meshes, the length of the guide channel is 0.18 mm, the vertical distance between the screen 4 and the air knife 71 is 1 cm, the vertical distance between the screen 4 and the strip slit 61 at the outlet end of the L-shaped melt channel is 1 cm, the width of the strip spray slit 61 is 6 mm, the horizontal distance between the air knife 71 and the outlet end of the L-shaped melt channel is 1 cm, the gap between the air knife 71 is 0.16 mm, and the vertical distance between the screen 4 and the fiber collection module is 80 cm. The morphology of the PLA fiber prepared by the parameters of this embodiment is as follows: Figure 8 As shown, the PLA fibers have uniform diameter and smooth surface, with an average diameter of 640 nm (as shown in Figure 9 ), most of the fibers are nanometer-sized. The fibers prepared by the parameters of this embodiment are fluffy and soft, such as Figure 10 shown.

[0058] Example 2: The equipment used in this example is the same as that in Example 1, and the equipment parameters are basically the same as those in Example 1, except that the temperatures of the various zones of the screw extruder 51 used are set to 50°C, 190°C, 220°C, and 240°C, respectively; the temperature of the first heating unit is 260°C; the temperature of the localized heating mechanism 8 of the screen 4 is 270°C; and the raw material used is polypropylene (MFI 1500). The temperature and pressure of the air compressor are set to 0.2 MPa and 280°C, respectively. The obtained fibers are finer, with a fiber diameter of 505 nm (e.g., Figure 11 shown).

[0059] Comparative Example 1: The equipment used is the same as that in Example 1, and its equipment parameters are basically the same as those in Example 1. The difference is that the screen 4 is not heated, and the surface of the screen 4 is at room temperature, which cools the melt, resulting in a large amount of solidified melt remaining on the fiber collection module. The mesh of the screen 4 is blocked by the solidified melt, resulting in the inability to continue spinning (such as Figure 12 shown).

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A spinneret-free melt-blown spinning device based on a rotary screen, characterized in that: include: Rack (1); A melt processing mechanism, provided on the frame (1), for outputting a polymer melt having fluidity and pulling the polymer melt; Driving mechanism (2); A rotation positioning mechanism (3) is provided on the frame (1) and is connected to the driving mechanism (2), and drives the rotation positioning mechanism (3) to rotate via the driving mechanism (2); The screen (4) is arranged opposite to the outlet end of the melt processing mechanism and is connected to the rotation positioning mechanism (3). The screen (4) is positioned and driven to rotate by the rotation positioning mechanism (3). The screen is evenly distributed with a plurality of micropores (42). The plurality of micropores (42) are used to disperse the polymer melt on the screen, and the micropores (42) extending in the axial direction also form a guide channel. The melt processing mechanism stretches the polymer melt through the guide channel.

2. The spinneret-free melt-blown spinning device based on a rotary screen according to claim 1, characterized in that: Also includes: A heating mechanism (8) is provided on the frame (1) and is arranged upstream of the melt processing mechanism along the rotation direction of the screen (4) for heating the screen (4).

3. The spinneret-free melt-blown spinning device based on a rotary screen according to claim 1, characterized in that: The rotation positioning mechanism (3) comprises: a slewing support bearing (31), the slewing support bearing (31) comprises a bearing inner ring and a bearing outer ring rotatably connected to each other, the bearing outer ring is fixed on the frame (1), the driving mechanism (2) is connected to the outer side of the bearing inner ring, and the screen (4) is fixed to the inner side of the bearing inner ring and rotates synchronously with the bearing inner ring.

4. The spinneret-free melt-blown spinning device based on a rotary screen according to claim 3, characterized in that: Also includes: A plurality of connectors (9); an annular gap is formed between the screen (4) and the inner ring of the bearing, the connectors (9) are evenly spaced in the annular gap along the circumferential direction, and one end of the connector (9) is connected to the screen (4), and the other end of the connector (9) is connected to the inner ring of the bearing.

5. The spinneret-free melt-blown spinning device based on a rotary screen according to claim 3, characterized in that: The driving mechanism (2) comprises: A motor (21) is provided on the frame (1); A transmission belt (23), wherein the output end of the motor (21) is connected to the outer side of the bearing inner ring via the transmission belt (23).

6. The spinneret-free melt-blown spinning device based on a rotary screen according to claim 4, characterized in that: Also includes: A panel (41) is provided on the outside of the screen (4), and the connector (9) is fixedly connected to the panel (41).

7. The spinneret-free melt-blown spinning device based on a rotary screen according to any one of claims 1 to 6, characterized in that: The melt processing mechanism comprises: A melt feeding and heating module (5) is used to feed the melt-blown grade resin material and heat and melt the melt-blown grade resin material; a melt transfer module (6), one end of which is connected to the melt feeding and heating module (5) and the other end of which is disposed toward the screen (4) and is used to spray the melt-blown grade resin material in a molten state onto the screen (4); The jet drawing module (7) is directed toward the screen (4) and is located downstream of the melt transfer module (6), and is used to blow air onto the screen (4) to draw the melt-blown grade resin material in a molten state through the guide channel to form a jet.

8. The spinneret-free melt-blown spinning device based on a rotary screen according to claim 7, characterized in that: The melt feeding and heating module (5) comprises: a screw extruder (51); The screw extruder (51) has at least four heating zones, the temperature range of the first heating zone is 25-100°C, and the temperature range of the second heating zone to the fourth heating zone is 25-300°C; The rotation speed of the screw extruder (51) ranges from 0 to 30 rpm.

9. The spinneret-free melt-blown spinning device based on a rotary screen according to claim 7, characterized in that: The melt transfer module (6) comprises: an L-shaped melt channel, wherein a strip-shaped spray slot (61) is formed at one end of the L-shaped melt channel facing the screen (4); A first heating unit is provided in the L-shaped melt channel, and the temperature range of the first heating unit is 250-350°C; The vertical distance between the outlet end surface of the strip-shaped spray slot (61) and the screen (4) is in the range of 0.5-2 cm; The width of the strip-shaped spray seam (61) ranges from 1 to 7 mm.

10. The spinneret-free melt-blown spinning device based on a rotary screen according to claim 7, characterized in that: The jet drafting module (7) comprises: Air compressor, the output air pressure range is 0.2-0.5Mpa; An air knife (71) is connected to the air compressor, and a second heating unit is provided between the air compressor and the air knife (71), wherein the temperature of the second heating unit ranges from 260° C. to 350° C.; The vertical distance between the blade edge of the air knife (71) and the screen (4) is in the range of 1-3 cm, and the horizontal distance between the air knife (71) and the melt transfer module (6) is in the range of 1-2 cm.

11. The spinneret-free melt-blown spinning device based on a rotary screen according to any one of claims 1 to 6, characterized in that: Also includes: A fiber collecting module is located on the side of the screen (4) facing away from the melt processing mechanism and is used to collect polymer fibers.

12. The spinneret-free melt-blown spinning device based on a rotary screen according to any one of claims 1 to 6, characterized in that: The mesh size of the micropores (42) on the screen (4) ranges from 40 to 100 meshes; the length of the guide channel formed by the micropores (42) extending in the axial direction ranges from 0.1 to 0.4 mm; Driven by the rotation positioning mechanism (3), the rotation speed of the screen (4) is less than 10 rpm.

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