Preparation method and preparation device of spinning solution

Abstract

The invention relates to the technical field of spinning solution preparation, and discloses a spinning solution preparation method and a spinning solution preparation device, through shearing and extrusion of an extruder, polyethylene is converted into a melt with fluidity from a solid, then the melt is pressurized by a metering pump to form a high-temperature and high-pressure melt, and more importantly, through heating, a spinning solution is prepared. The feeding pipe is arranged, so that heat loss is reduced when the melt flows through the feeding pipe, melt solidification is prevented, meanwhile, magnetic force is applied to the magnetic material in the melt, the intermolecular acting force of the melt is further increased, the temperature and the dissolving temperature of the polyethylene melt are kept within a controllable range, and the polyethylene melt enters a reaction kettle; at the moment, the reaction kettle does not need to be slowly heated and pressurized, the dissolution reaction can be directly carried out, polymer degradation is avoided, continuous feeding and rapid dissolution at high temperature and high pressure can be realized, the preparation time is greatly shortened, and the preparation efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of spinning solution preparation, and in particular to a spinning solution preparation method and a preparation device thereof. Background Art

[0002] Flash spinning technology is a method for preparing nanofiber nonwoven fabrics. Its principle is to dissolve the fiber-forming polymer in an appropriate solvent under high temperature and high pressure conditions to form a uniform spinning solution, and then spray the solution from the spinneret. After spraying, the pressure suddenly drops to normal pressure, the solvent evaporates instantly due to overheating and generates a large amount of airflow. While the polymer is cooled, it is stretched to form nanofiber bundles. The direction of movement of the bundle can be changed by baffles and other equipment, and before reaching the receiving device, it passes through a high-voltage electrostatic field so that each fiber is charged and separated from each other, and then formed into a nonwoven fabric through processes such as laying and fixing the net.

[0003] In the existing spinning solution preparation process, the material is usually added to a reactor at room temperature and pressure. As the temperature of the reactor gradually rises, the polymer is easily degraded, which affects the preparation efficiency of the spinning solution. It is urgently necessary to keep the polymer under high temperature and high pressure before entering the reactor for reaction. Summary of the invention

[0004] The purpose of the present invention is to provide a safe and efficient method for preparing a spinning solution.

[0005] In order to achieve the above object, the present invention provides a method for preparing a spinning solution, which comprises the following steps:

[0006] The polyethylene, solvent, plasticizer and magnetic additive are mixed and added into the extruder;

[0007] The extruder is sheared and heated to form a melt, which is then output to a metering pump;

[0008] The metering pump is used to increase the pressure of the melt to 15-20 MPa;

[0009] When the melt is transported to the reactor through the feeding pipe, magnetic force and heating are simultaneously applied to the melt to make the melt temperature 200°C≤t≤220°C;

[0010] Shear dissolution is performed through the reactor.

[0011] In some embodiments of the present application, the magnetic auxiliary agent is made of one or more of nano ferrite, aluminum nickel cobalt alloy, and rare earth permanent magnetic materials, and its content is 0.05-1wt% of polyethylene.

[0012] In some embodiments of the present application, the plasticizer is made of one or more of white oil and decalin, and its content is 15-30wt% of the polyethylene.

[0013] In some embodiments of the present application, the feeding tube includes a tube body, an electromagnetic layer and a heating layer, the tube body is connected to the discharge port, the electromagnetic layer and the heating layer are arranged on the outer wall of the tube body in sequence from the inside to the outside, and the electromagnetic layer is used to apply magnetic force to the melt.

[0014] In some embodiments of the present application, the weight average molecular weight of the polyethylene is 100k to 4200k.

[0015] In some embodiments of the present application, the polyethylene in the melt has a diameter of 1 mm to 3.5 mm and a length of 3 mm to 5 mm when entering the reactor.

[0016] Another object of the present invention is to provide a spinning solution preparation device, which uses the above spinning solution preparation method, and the preparation device comprises:

[0017] An extruder, which is provided with a feeding port and a discharging port;

[0018] A feeding pipe, the feeding pipe comprises a pipe body, an electromagnetic layer and a heating layer, the pipe body is connected to the discharge port, the electromagnetic layer and the heating layer are sequentially arranged on the outer peripheral wall of the pipe body from the inside to the outside, and the electromagnetic layer is used to apply magnetic force to the melt;

[0019] A metering pump is arranged at the discharge port and connected to the pipe body;

[0020] The reaction kettle is connected with the extruder through the feeding pipe.

[0021] In some embodiments of the present application, the electromagnetic layer is an electromagnetic coil, the electromagnetic coil is wound outside the tube body, and the heating layer is attached to the outside of the electromagnetic coil.

[0022] In some embodiments of the present application, the extruder is a single-screw extruder, the aspect ratio of the screw of the extruder is 1:30-1:40, and the compression ratio of the screw is 2-4.

[0023] In some embodiments of the present application, a three-way valve is further included. The three-way valve is disposed between the extruder and the metering pump and connects the two. Another output port of the three-way valve is connected to a melt delivery pipeline.

[0024] The present invention provides a method for preparing a spinning solution, which has the following beneficial effects compared with the prior art:

[0025] The method for preparing the spinning solution provided by the present invention converts polyethylene from a solid into a melt with fluidity through shearing and extrusion of an extruder, and then pressurizes the polyethylene through a metering pump to form a high-temperature and high-pressure melt. More importantly, by heating, the heat loss of the melt is reduced when it flows through a feed pipe to prevent the melt from solidifying, and at the same time, by applying magnetic force to the magnetic material in the melt, the intermolecular force of the melt is further increased, so that the temperature of the polyethylene melt and its dissolution temperature are maintained within a controllable range before entering the reactor. At this time, the reactor does not need to be slowly heated and pressurized, and can directly carry out a dissolution reaction, thereby avoiding polymer degradation, and can achieve continuous feeding and rapid dissolution under high temperature and high pressure, greatly shortening the preparation time and improving the preparation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of a process for preparing a spinning solution according to an embodiment of the present invention;

[0027] Figure 2 It is a schematic structural diagram of a spinning solution preparation device according to an embodiment of the present invention.

[0028] In the figure: 1. extruder; 11. feeding port; 12. discharge port; 2. feeding pipe; 3. three-way valve; 4. reaction kettle; 5. melt conveying pipeline. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0030] It should be understood that, in the description of the present application, the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. The terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated, that is, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In addition, unless otherwise specified, "multiple" means two or more.

[0031] It should be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] like Figure 2 As shown, an embodiment of the present invention provides a spinning solution preparation device, which includes an extruder 1, a feeding pipe 2, a metering pump and a reaction kettle 4.

[0033] The extruder 1 is provided with a feed port 11 and a discharge port 12. The extruder 1 is a single screw extruder 1, the screw aspect ratio of the extruder 1 is 1:30 to 1:40, the compression ratio is 2 to 4, the screw is an equal-depth unequal-pitch screw, and the pitch of the metering section of the screw is the same as the screw diameter. Specifically, in this embodiment, corresponding to the reactor 4 with a capacity of 50 liters, the screw diameter can be specifically set to 65mm, the aspect ratio is 1:35, and the compression ratio is 4. Based on this, the extruder 1 with this screw setting can fully shear the polyethylene and the plasticizer. Under the high-temperature shearing action, the plasticizer enters the molecular chain of the polyethylene, increases the intermolecular force, and further dissolves to form a melt, so that the polyethylene in the melt enters the reactor 4 with a diameter of 1mm to 3.5mm and a length of 3mm to 5mm, which is convenient for the subsequent shearing and dissolution of the reactor 4.

[0034] The feeding tube 2 includes a tube body, an electromagnetic layer and a heating layer (not shown in the figure), the tube body is connected to the discharge port 12, and the electromagnetic layer and the heating layer are sequentially arranged on the outer peripheral wall of the tube body from the inside to the outside, and the electromagnetic layer is used to apply magnetic force to the melt. Preferably, the electromagnetic layer is an electromagnetic coil, which is wound outside the tube body, and the heating layer is arranged on the outside of the electromagnetic coil. Based on this, magnetic force and heating can be applied to the melt flowing through the tube body at the same time.

[0035] The metering pump is arranged at the discharge port 12 and connected to the pipe body, and is used for pressurizing the melt so as to keep the melt at 15-20 MPa.

[0036] The reactor 4 is connected to the extruder 1 through the feeding pipe 2. A cutting device or a crushing device is arranged in the reactor 4, so that the polyethylene strips are transformed into particles with certain specifications, which interact with the solvent to swell and finally complete the dissolution process.

[0037] Based on the above structure, the polyethylene and the plasticizer are fully sheared by a specially arranged extruder 1, and after the melt is formed, it is pressurized by a metering pump, and the melt is kept at high temperature and high pressure by a feeding pipe 2 provided with an electromagnetic layer and a heating layer to enter the reactor 4 for reaction and dissolution, thereby avoiding polymer degradation, and being able to achieve continuous feeding and rapid dissolution under high temperature and high pressure, greatly shortening the preparation time and improving the preparation efficiency.

[0038] Alternatively, if Figure 2 As shown, in this embodiment, the spinning solution preparation device further includes a three-way valve 3, which is disposed between the extruder 1 and the metering pump and connects the two, and another output port of the three-way valve 3 is connected to a melt conveying pipeline 5. Based on this, the melt can be diverted and conveyed through the three-way valve 3.

[0039] like Figure 1 As shown, the embodiment of the present invention also provides a method for preparing a spinning solution, which comprises the following steps:

[0040] S1, mixing polyethylene, solvent, plasticizer and magnetic additive and adding them into extruder 1;

[0041] S2, the melt is formed by shearing and heating through the extruder 1 and then output to the metering pump;

[0042] S3, pressurizing by a metering pump to make the melt pressure 15-20 MPa;

[0043] S4, when the melt is transported to the reactor 4 through the feeding pipe 2, magnetic force and heating are applied to the melt at the same time, so that the melt temperature is 200°C≤t≤220°C;

[0044] S5, performing shear dissolution through the reaction kettle 4.

[0045] Based on the above method, polyethylene is transformed from a solid into a fluid melt through shearing and extrusion by the extruder 1, and then pressurized by the metering pump to form a high-temperature and high-pressure melt. More importantly, by heating, the heat loss of the melt is reduced when it flows through the feeding pipe 2 to prevent the melt from solidifying. At the same time, by applying magnetic force to the magnetic material in the melt, the intermolecular force of the melt is further increased, so that the temperature of the polyethylene melt and its dissolution temperature are maintained within a controllable range before entering the reactor 4. At this time, the reactor 4 does not need to be slowly heated and pressurized, and can directly carry out a dissolution reaction, thereby avoiding polymer degradation, and can achieve continuous feeding and rapid dissolution under high temperature and high pressure, greatly shortening the preparation time and improving the preparation efficiency.

[0046] Optionally, in this embodiment, in step S1, the magnetic additive is made of one or more of nano ferrite, aluminum nickel cobalt alloy, and rare earth permanent magnetic material, and its content is 0.05-1wt% of polyethylene. The magnetic additive is mixed in the polyethylene and can attract the magnetic layer to increase the force of the molecules in the melt to prevent solidification. It should be understood that when magnetic force and heating are applied to the melt at the same time, the melt temperature is lower than the Curie temperature of the magnetic additive, that is, heating does not affect the magnetic properties of the magnetic additive.

[0047] Optionally, in this embodiment, the plasticizer is made of one or more of white oil and decalin, and the content thereof is 15-30 wt % of the polyethylene.

[0048] Optionally, in this embodiment, the weight average molecular weight of polyethylene is 100k-4200k. Among them, 100k-1000k, 1000k-2000k, 2000k-3000k, 3000k-4200k are preferred ranges of the average molecular weight. It should be understood that the molecular weight can be obtained by gel permeation chromatography.

[0049] Optionally, in this embodiment, the solvent is specifically 1,2-dichloroethane, and the final spinning solution concentration is 7% to 25wt%.

[0050] In summary, the embodiment of the present invention provides a method for preparing a spinning solution. Compared with the prior art, the preparation method has the advantages of high preparation efficiency and high safety.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a spinning solution, characterized in that: The steps include: Polyethylene, solvent, plasticizer and magnetic additive are mixed and added into an extruder (1); The extruder (1) is sheared and heated to form a melt, which is then output to a metering pump; The metering pump is used to increase the pressure of the melt to 15-20 MPa; When the melt is transported to the reaction kettle (4) through the feeding pipe (2), magnetic force and heating are simultaneously applied to the melt to make the melt temperature 200°C≤t≤220°C; The reaction kettle (4) is used for shear dissolution.

2. The method for preparing a spinning solution according to claim 1, wherein: The magnetic auxiliary agent is made of one or more of nano ferrite, aluminum nickel cobalt alloy, and rare earth permanent magnetic material, and its content is 0.05-1wt% of polyethylene.

3. The method for preparing a spinning solution according to claim 1, wherein: The plasticizer is made of one or more of white oil and decalin, and its content is 15-30wt% of the polyethylene.

4. The method for preparing a spinning solution according to claim 1, wherein: The feeding tube (2) comprises a tube body, an electromagnetic layer and a heating layer, the tube body is connected to the discharge port (12), the electromagnetic layer and the heating layer are arranged on the outer peripheral wall of the tube body in sequence from the inside to the outside, and the electromagnetic layer is used to apply magnetic force to the melt.

5. The method for preparing a spinning solution according to claim 4, characterized in that: The weight average molecular weight of the polyethylene is 100k to 4200k.

6. The method for preparing a spinning solution according to claim 1, wherein: The polyethylene in the melt has a diameter of 1 mm to 3.5 mm and a length of 3 mm to 5 mm when entering the reaction kettle (4).

7. A spinning solution preparation device, characterized in that: The method for preparing the spinning solution according to any one of claims 1 to 6 is applied, wherein the preparation device comprises: An extruder (1) is provided with a feeding port (11) and a discharging port (12); A feeding pipe (2), the feeding pipe (2) comprising a pipe body, an electromagnetic layer and a heating layer, the pipe body being connected to the discharge port (12), the electromagnetic layer and the heating layer being arranged on the outer peripheral wall of the pipe body in sequence from the inside to the outside, the electromagnetic layer being used to apply magnetic force to the melt; A metering pump, arranged at the discharge port (12) and connected to the pipe body; The reaction kettle (4) is connected to the extruder (1) via the feeding pipe (2).

8. The spinning solution preparation device according to claim 7, characterized in that: The electromagnetic layer is an electromagnetic coil, which is wound outside the tube body, and the heating layer is attached to the outside of the electromagnetic coil.

9. The spinning solution preparation device according to claim 7, characterized in that: The extruder (1) is a single-screw extruder (1), the length-to-diameter ratio of the screw of the extruder (1) is 1:30 to 1:40, and the compression ratio of the screw is 2 to 4.

10. The spinning solution preparation device according to claim 7, characterized in that: It also comprises a three-way valve (3), which is arranged between the extruder (1) and the metering pump and connects the two, and the other output port of the three-way valve (3) is connected to a melt conveying pipeline (5).

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