A method and apparatus for the continuous production of a polymer film

Abstract

The present application relates to the technical fields of high polymer preparation, in particular to a continuous preparation method and device of polymer film, the continuous preparation method of polymer film comprises the following steps: S1, continuously injecting polymer solution into the surface of coagulation bath to solidify into polymer film, the concentration difference of organic solvent in coagulation bath and polymer solution drives the rapid diffusion of organic solvent in polymer solution to coagulation bath, so that the polymer solution spontaneously spreads on the surface of coagulation bath, and the polymer solution on the surface of coagulation bath is made to form polymer-rich phase to rapidly solidify and form polymer film; S2, the polymer film is extracted by the first roller and the second roller, then dried by the drying box, and finally wound into polymer film product by the third roller, the continuous preparation method and device of polymer film can realize the rapid and continuous production of polymer film.

Description

Technical Field

[0001] This invention relates to the field of polymer preparation technology, and in particular to a continuous preparation method and apparatus for polymer films. Background Technology

[0002] Polymer membranes have extremely wide applications, with significant value in water treatment, electronic components, and medical and health fields. In the industrial preparation of polymer membranes, the most conventional methods are casting and melt extrusion. These methods are very mature for preparing micron-sized thick films; however, the technology currently available for industrial-scale preparation of nanoscale polymer membranes is quite limited. With the iterative updates in technology and market demands, polymer membranes are rapidly developing towards multifunctionality and ultrathinness.

[0003] With the rapid development of nanotechnology and the widespread application of high-performance nanodevices, increasing attention is being paid to ultrathin polymer films with nanometer-scale thickness. Ultrathin polymer films possess unique properties, such as high flexibility, transparency, large specific surface area, and finely controllable microstructure. Furthermore, from a materials development perspective, efforts are continuously being made to manufacture smaller, lighter, and more portable electronic devices while minimizing raw material and energy consumption to maintain high performance. Currently, there are many methods for preparing polymer nanofilms, among which the preparation of nanofilms on solid surfaces is relatively common, including spin coating, casting, dip-coating, and slot extrusion. Although these methods can achieve nanometer-scale control of polymer film thickness, they cannot be rapidly scaled up for continuous production. Moreover, most are based on solid substrates, making film peeling and collection difficult to integrate with the winding and collecting modules commonly used in current industrial production, thus failing to meet the needs of large-scale, continuous industrial production.

[0004] Currently, the most mature technology for the industrial preparation of ultrathin polymer films still involves casting a pre-dissolved polymer solution onto a heated mercury bath. After the solvent evaporates and the film is formed, it is retrieved from the mercury surface and rolled up. Due to the technical characteristics of this method, it is limited in the types of polymers that can be used, and it carries the risk of environmental toxicity from the large-scale volatilization of toxic mercury and organic solvents, making it environmentally unfriendly and energy-intensive.

[0005] In summary, existing industrial membrane fabrication technologies face significant limitations in the preparation of ultrathin polymer membranes. They suffer from inherent deficiencies in continuity and scalability, are difficult to integrate with existing processes, and are challenging to extend beyond existing equipment and processes. Industrial implementation is costly, and the reliability of the technology has not been extensively validated, posing significant risks. Therefore, developing a universal polymer membrane fabrication technology that can meet the production needs of polymer membranes with a wide range of thicknesses and can be quickly integrated into existing polymer membrane production processes and equipment lines is of paramount importance and urgency. Summary of the Invention

[0006] In order to overcome the above technical problems, the purpose of this invention is to provide a continuous preparation method and apparatus for polymer films, which can realize rapid and continuous production of polymer films.

[0007] To achieve the above objectives, the continuous preparation method of the polymer film designed in this invention includes the following steps:

[0008] S1: The polymer solution is injected onto the surface of the coagulation bath and solidified into a polymer film;

[0009] S2: The polymer film is extracted by the first and second rollers, then dried in a drying oven, and finally wound into the finished polymer film by the third roller;

[0010] The feature is that in step S1, the polymer solution is continuously injected from one end of the coagulation bath into the surface of the coagulation bath, causing the polymer solution to spread directionally towards the right side of the coagulation bath surface and solidify into a film on the surface of the coagulation bath.

[0011] As a preferred embodiment, in step S1, the mass concentration of the polymer solution is 0.1-60%, and the polymer includes polyvinylidene fluoride (PVDF), polyimide (PI), or aramid (ANF).

[0012] The coagulation bath is prepared by mixing organic solvent and water in a volume ratio of 0 / 100 to 90 / 10.

[0013] The organic solvent in the polymer solution is the same as the organic solvent in the coagulation bath, and the organic solvent includes N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), or dimethyl sulfoxide (DMSO).

[0014] As a preferred embodiment, in step S1, the polymer solution is continuously injected into the surface of the coagulation bath in the form of a thin liquid layer through a polymer solution expansion tank. The polymer solution expansion tank includes a polymer liquid inlet, a polymer liquid containment cavity, and a polymer liquid outlet connected sequentially from top to bottom.

[0015] The polymer liquid inlet is a circular hole with a diameter of 5-10 mm. The polymer liquid receiving cavity is a cuboid cavity structure with a thickness of 10-1000 μm and a width of 10-200 mm. The polymer liquid outlet is a rectangular notch opened at the bottom of the polymer liquid receiving cavity. The width of the polymer liquid outlet is 10-1000 μm and the length is 10-200 mm. The height of the polymer liquid outlet from the surface of the coagulation bath is 0.025-40 mm.

[0016] As a preferred embodiment, the polymer solution is injected into the polymer liquid inlet at a rate of 0.5 to 20 mm / s, and the polymer solution is stored in a thin liquid layer through the polymer liquid inlet cavity and transported to the polymer liquid outlet, and continuously injected into the liquid surface of the coagulation bath from the polymer liquid outlet.

[0017] As a preferred embodiment, in step S2, the first roller contacts the liquid surface of the coagulation bath, and the second roller is placed above the liquid surface of the coagulation bath. The first roller and the second roller separate the polymer film from the coagulation bath and drive the polymer film to be continuously conveyed forward.

[0018] As a preferred embodiment, the first roller rotates counterclockwise at a speed of 0.1 to 0.5 m / s, and the second roller rotates clockwise at a speed of 0.1 to 0.5 m / s.

[0019] As a preferred option, the thickness of the polymer film prepared is 0.1–100 μm.

[0020] A continuous polymer membrane preparation apparatus includes a first roller, a second roller, a drying oven, and a third roller; characterized in that it further includes a polymer solution expansion tank, a coagulation bath tank containing a coagulation bath, a coagulation bath component content detection device for stabilizing the volume concentration of organic solvent in the coagulation bath, and a pure water replenishment device.

[0021] A polymer solution expansion tank is provided above one end of the coagulation bath, a first roller and a second roller are provided in the middle of the coagulation bath, and a drying box and a third roller are placed in sequence at the other end of the coagulation bath; the coagulation bath component content detection device and the pure water replenishment device are respectively connected to the coagulation bath through pipes.

[0022] As a preferred embodiment, the polymer solution expansion tank includes a polymer liquid inlet, a polymer liquid containment cavity, and a polymer liquid outlet connected sequentially from top to bottom;

[0023] The polymer liquid inlet is a circular hole with a diameter of 5-10 mm. The polymer liquid receiving cavity is a cuboid cavity structure with a thickness of 10-1000 μm and a width of 10-200 mm. The polymer liquid outlet is a rectangular notch opened at the bottom of the polymer liquid receiving cavity. The width of the polymer liquid outlet is 10-1000 μm and the length is 10-200 mm. The height of the polymer liquid outlet from the surface of the coagulation bath is 0.025-40 mm.

[0024] As a preferred embodiment, the coagulation bath component content detection device includes a solution sampler and a high-performance liquid chromatograph. The solution sampler extracts the coagulation bath through a sampling pipeline and then transmits it to the high-performance liquid chromatograph. The pure water replenishment device includes a pure water storage tank, a micro-peristaltic pump, and pipelines. The pure water storage tank is connected to the coagulation bath through the micro-peristaltic pump and pipelines.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0026] (1) This invention employs a liquid surface spreading film-forming mechanism. When the polymer solution flows into the liquid surface of the coagulation bath, the organic solvent in the polymer solvent diffuses into the coagulation bath. This mass transfer process promotes the rapid and complete spreading of the polymer solution at the interface of the coagulation bath and the formation of a liquid film on the surface of the coagulation bath until the polymer liquid film forms a polymer-rich phase, which is then rapidly solidified on the liquid surface of the coagulation bath to form a polymer film. The liquid surface spreading film-forming mechanism of this invention enables the rapid forming of polymer films. Compared with traditional existing technologies such as casting and melt extrusion, firstly, the polymer film can be rapidly formed on the surface of the coagulation bath, significantly improving the forming speed; secondly, the film-forming process does not require heating to evaporate the organic solvent, which is environmentally friendly, and the coagulation bath can be repeatedly recycled, significantly reducing the treatment costs of waste gas and wastewater; in addition, the film-forming process does not require a membrane-carrier separation process, avoiding the polymer film structure damage problem caused by the separation process.

[0027] (2) The continuous preparation method of polymer membrane of the present invention. First, a polymer solution and a coagulation bath are prepared, then a membrane is spread on the liquid surface, and finally the polymer membrane is extracted, dried and collected. Compared with the existing technologies such as traditional casting and melt extrusion for preparing polymer membranes, which have problems such as long production cycle, complex process and difficulty in achieving nanoscale thickness, the continuous preparation method of polymer membrane of the present invention can realize rapid continuous production of polymer membranes and the thickness can reach the nanoscale.

[0028] (3) The continuous preparation method of polymer membrane of the present invention can adjust the thickness of polymer membrane by adjusting the mass concentration of polymer solution and the volume concentration of coagulation bath. The thickness of polymer membrane ranges from 0.1 to 100 μm. Compared with the traditional method, the thickness range of polymer membrane produced is larger, and the thinnest can reach the nanometer level, which can meet the production needs of polymer membrane with a large range of thickness.

[0029] (4) The continuous preparation apparatus for polymer membranes of the present invention injects polymer solution into the surface of the coagulation bath in a constant and thin liquid layer form through a polymer solution spreading tank. The constant and thin liquid layer form allows the polymer membrane to be oriented continuously and rapidly spread, which helps to form a stable and flat polymer membrane.

[0030] (5) The continuous preparation device for polymer membranes of the present invention is ingeniously designed to integrate a coagulation bath component content detection device and a pure water replenishment device into the device, which can realize real-time detection of coagulation bath components and pure water replenishment to maintain the constant coagulation bath components, thereby promoting the continuous preparation of polymer membranes. Attached Figure Description

[0031] Figure 1 The process flow diagrams are for the continuous preparation methods of polymer films in Examples 1-6.

[0032] Figure 2 The following is a front view of the continuous polymer membrane preparation apparatus of Examples 1-6; the components in the figure are labeled as follows: polymer solution expansion tank 1, polymer liquid inlet 1.1, polymer liquid inlet cavity 1.2, polymer liquid outlet 1.3, coagulation bath 2, first roller 3.1, second roller 3.2, drying oven 4, third roller 5, polymer membrane 6, coagulation bath 7, coagulation bath component content detection device 8, solution sampler 8.1, high performance liquid chromatograph 8.2, pure water replenishment device 9, pure water storage tank 9.1, micro-peristaltic pump 9.2, pipeline 9.3;

[0033] Figure 3 for Figure 2 Top view;

[0034] Figure 4 This is a plan view of the PVDF polymer film obtained in Example 1;

[0035] Figure 5 Here is a cross-sectional SEM image of the PVDF polymer film obtained in Example 1;

[0036] Figure 6 Here is a cross-sectional SEM image of the PI polymer film obtained in Example 2;

[0037] Figure 7 Here is a cross-sectional SEM image of the PVDF polymer film obtained in Example 3;

[0038] Figure 8 Here is a cross-sectional SEM image of the PVDF polymer film obtained in Example 4;

[0039] Figure 9 Here is a cross-sectional SEM image of the ANF polymer film obtained in Example 5;

[0040] Figure 10 Here is a cross-sectional SEM image of the ANF polymer film obtained in Example 6; Detailed Implementation

[0041] To better understand the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] The continuous preparation method of polymer films in Examples 1-6 below is achieved through a continuous polymer film preparation device, combined with... Figure 2 and Figure 3 As shown, the continuous polymer membrane preparation apparatus includes a first roller 3.1, a second roller 3.2, a drying oven 4, and a third roller 5; it also includes a polymer solution expansion tank 1, a coagulation bath tank 2 containing a coagulation bath 7, a coagulation bath component content detection device 8 for stabilizing the volume concentration of organic solvent in the coagulation bath 7, and a pure water replenishment device 9.

[0043] A polymer solution expansion tank 1 is provided above one end of the coagulation bath 2. A first roller 3.1 and a second roller 3.2 are provided in the middle of the coagulation bath 2. A drying oven 4 and a third roller 5 are placed in sequence at the other end of the coagulation bath 2. A coagulation bath component content detection device 8 and a pure water replenishment device 9 are respectively connected to the coagulation bath 2 through pipes.

[0044] The coagulation bath component content detection device 8 includes a solution sampler 8.1 and a high-performance liquid chromatograph 8.2. The solution sampler 8.1 extracts coagulation bath 7 through a sampling pipeline and transmits it to the high-performance liquid chromatograph 8.2. The high-performance liquid chromatograph 8.2 detects the volume percentage concentration of the organic solution in coagulation bath 7. When the volume percentage concentration of the organic solution exceeds the preset range, the pure water replenishment device 9 is activated through the control system. The pure water replenishment device 9 includes a pure water storage tank 9.1, a micro-peristaltic pump 9.2, and a pipeline 9.3. The pure water storage tank 9.1 is connected to the coagulation bath 2 through the micro-peristaltic pump 9.2 and the pipeline 9.3.

[0045] Example 1

[0046] Combination Figure 1 , Figure 2 and Figure 3 As shown, a continuous preparation method for PVDF polymer films includes the following steps:

[0047] (1) Preparation of polymer solution and coagulation bath:

[0048] Weigh out PVDF powder and place it in DMF to prepare a PVDF solution with a mass percentage of 18% (18 / 82 PVDF / DMF solution);

[0049] The coagulation bath was a 60% DMF solution (40 / 60 water / DMF mixture);

[0050] (2) The polymer solution is injected into the polymer solution expansion tank:

[0051] The PVDF solution is injected into the polymer solution expansion tank 1 at a rate of 0.5 mm / s through the polymer liquid injection port 1.1, forms a polymer liquid flow through the polymer liquid receiving cavity 1.2, and flows out through the polymer liquid outlet 1.3.

[0052] Among them, the combination Figure 2 and Figure 3 As shown, the polymer solution expansion tank 1 includes, from top to bottom, a polymer liquid inlet 1.1, a polymer liquid containment cavity 1.2, and a polymer liquid outlet 1.3. In this embodiment, the polymer liquid inlet 1.1 is a circular hole with a diameter of 5 mm. The polymer liquid containment cavity 1.2 is a regular cuboid cavity structure with a thickness of 10 μm and a width of 120 mm. The function of the polymer liquid containment cavity 1.2 is to store and transport the polymer solution in the form of a thin liquid layer. The polymer liquid outlet 1.3 is a rectangular notch opened at the bottom of the polymer liquid containment cavity 1.2 with a width of 10 μm and a length of 120 mm. The height of the polymer liquid outlet 1.3 from the coagulation bath surface is 0.025 mm.

[0053] (3) The polymer solution flows into the coagulation bath:

[0054] The polymer solution forms a thin liquid layer of polymer liquid flow on the upper left side of the coagulation bath through the polymer solution expansion tank 1, and flows into the liquid surface of the coagulation bath.

[0055] (4) The polymer solution spreads and forms a film on the surface of the coagulation bath:

[0056] The polymer solution spreads out on the surface of the coagulation bath to form a polymer liquid film. During the spreading process, the 18% PVDF polymer solution in the polymer liquid film reacts rapidly with the 60% DMF coagulation bath. The 60% DMF coagulation bath rapidly absorbs the DMF in the 18% PVDF polymer solution until the polymer liquid flow forms a PVDF-rich phase, which spreads rapidly on the surface of the coagulation bath and solidifies into a polymer film.

[0057] (5) Membrane extraction and transport:

[0058] When the first roller 3.1 contacts the surface of the coagulation bath liquid, the solidified polymer film quickly and automatically spreads to the position of the first roller 3.1. The first roller 3.1 rotates counterclockwise at a speed of 0.12 m / s, which can extract the polymer film from the surface of the coagulation bath liquid. The second roller 3.2 then rotates clockwise at a speed of 0.12 m / s, which can separate the polymer film from the coagulation bath surface, thereby achieving the purpose of film extraction.

[0059] (6) Drying and winding of the membrane:

[0060] After the extraction and transfer of the membrane in step (5), the wet membrane is transferred to a semi-enclosed drying oven 4. After infrared drying in the drying oven, the organic solvent and moisture remaining in the polymer membrane are completely removed to obtain the dried polymer membrane. The dried polymer membrane is received and wound by a third roller 5 that rotates clockwise at a speed of 0.12 m / s, thereby completing the continuous preparation of the PVDF polymer membrane.

[0061] Combination Figure 4 As shown, the PVDF polymer film obtained in this embodiment has a smooth surface (as shown in the figure). Figure 4 As shown), combined with Figure 5 As shown, its thickness is 13μm, and the internal micropores are uniform.

[0062] Example 2

[0063] Combination Figure 1 , Figure 2 and Figure 3 As shown, a continuous preparation method for PI polymer films includes the following steps:

[0064] (1) Preparation of polymer solution and coagulation bath:

[0065] Weigh out polyimide (PI) powder and place it in N-methylpyrrolidone (NMF) to prepare a 10% PI solution (10 / 90 PI / NMF solution by mass percentage);

[0066] The coagulation bath in the coagulation bath is a 70% NMF solution (30 / 70 water / DMF mixed solution) by volume.

[0067] (2) The polymer solution is injected into the polymer solution expansion tank:

[0068] The PI solution is injected into the polymer solution expansion tank 1 at a rate of 5 mm / s through the polymer liquid injection port 1.1, forms a polymer liquid flow through the polymer liquid flow containment cavity 1.2, and flows out through the polymer liquid flow outlet 1.3.

[0069] Among them, the combination Figure 2 and Figure 3As shown, the polymer solution expansion tank 1 includes, from top to bottom, a polymer liquid inlet 1.1, a polymer liquid containment cavity 1.2, and a polymer liquid outlet 1.3. In this embodiment, the polymer liquid inlet 1.1 is a circular hole with a diameter of 8 mm. The polymer liquid containment cavity 1.2 is a regular cuboid cavity structure with a thickness of 500 μm and a width of 200 mm. The function of the polymer liquid containment cavity 1.2 is to store and transport the polymer solution in the form of a thin liquid layer. The polymer liquid outlet 1.3 is a rectangular notch opened at the bottom of the polymer liquid containment cavity 1.2 with a width of 500 μm and a length of 200 mm. The height of the polymer liquid outlet 1.3 from the coagulation bath surface is 1.0 mm.

[0070] (3) The polymer solution flows into the coagulation bath;

[0071] The polymer solution forms a thin liquid layer of polymer liquid flow on the upper left side of the coagulation bath through the polymer solution expansion tank 1, and flows into the liquid surface of the coagulation bath.

[0072] (4) The polymer solution spreads and forms a film on the surface of the coagulation bath:

[0073] The polymer solution spreads on the surface of the coagulation bath to form a polymer liquid film. During the spreading process, the 10% PI solution in the polymer liquid film reacts rapidly with the 70% NMF coagulation bath. The 70% NMF coagulation bath rapidly absorbs the NMF in the 10% PI polymer solution until the polymer liquid flow forms a PI-rich phase, which spreads rapidly on the surface of the coagulation bath and solidifies into a polymer film.

[0074] (5) Membrane extraction and transport:

[0075] When the first roller 3.1 contacts the surface of the coagulation bath liquid, the solidified polymer film quickly and automatically spreads to the position of the first roller 3.1. The first roller 3.1 rotates counterclockwise at a speed of 0.26 m / s, which can extract the polymer film from the surface of the coagulation bath liquid. The second roller 3.2 then rotates clockwise at a speed of 0.26 m / s, which can separate the polymer film from the coagulation bath surface, thereby achieving the purpose of film extraction.

[0076] (6) Drying and winding of the membrane:

[0077] After the extraction process of the membrane in step (5), the wet membrane is transferred to a semi-closed drying oven 4. After infrared drying in the drying oven, the organic solvent and water remaining in the polymer membrane are completely removed to obtain the dried polymer membrane. The dried polymer membrane is received and wound by a third roller 5 that rotates clockwise at a speed of 0.26 m / s, thereby completing the continuous preparation of the PI polymer membrane.

[0078] Combination Figure 6 As shown, the PI polymer film obtained in this embodiment has a thickness of 10 μm and uniform micropores inside.

[0079] Example 3

[0080] Combination Figure 1 , Figure 2 and Figure 3 As shown, a continuous preparation method for PVDF polymer films includes the following steps:

[0081] (1) Preparation of polymer solution and coagulation bath:

[0082] Weigh out PVDF powder and place it in DMF to prepare a 7% PVDF solution (7 / 93 PVDF / DMF solution by mass percentage);

[0083] The coagulation bath in the coagulation bath is a 50% DMF solution (50 / 50 water / DMF mixed solution) by volume.

[0084] (2) The polymer solution is injected into the polymer solution expansion tank:

[0085] The PVDF solution is injected into the polymer solution expansion tank 1 at a rate of 10 mm / s through the polymer liquid injection port 1.1, forms a polymer liquid flow through the polymer liquid receiving cavity 1.2, and flows out through the polymer liquid outlet 1.3.

[0086] Among them, the combination Figure 2 and Figure 3 As shown, the polymer solution expansion tank 1 includes, from top to bottom, a polymer liquid inlet 1.1, a polymer liquid containment cavity 1.2, and a polymer liquid outlet 1.3. In this embodiment, the polymer liquid inlet 1.1 is a circular hole with a diameter of 10 mm. The polymer liquid containment cavity 1.2 is a regular cuboid cavity structure with a thickness of 1000 μm and a width of 100 mm. The function of the polymer liquid containment cavity 1.2 is to store and transport the polymer solution in the form of a thin liquid layer. The polymer liquid outlet 1.3 is a rectangular notch opened at the bottom of the polymer liquid containment cavity 1.2 with a length of 100 mm and a width of 1000 μm. The height of the polymer liquid outlet 1.3 from the coagulation bath surface is 0.45 mm.

[0087] (3) The polymer solution flows into the coagulation bath;

[0088] The polymer solution forms a thin liquid layer of polymer liquid flow on the upper left side of the coagulation bath through the polymer solution expansion tank 1, and flows into the liquid surface of the coagulation bath.

[0089] (4) The polymer solution spreads and forms a film on the surface of the coagulation bath:

[0090] The polymer solution spreads on the surface of the coagulation bath to form a polymer liquid film. During the spreading process, the 7% PVDF polymer solution in the polymer liquid film reacts rapidly with the 60% DMF coagulation bath. The 60% DMF coagulation bath rapidly absorbs the DMF in the 7% PVDF polymer solution until the polymer liquid flow forms a PVDF-rich phase, which spreads rapidly on the surface of the coagulation bath and solidifies into a polymer film.

[0091] (5) Membrane extraction and transport:

[0092] When the first roller 3.1 contacts the surface of the coagulation bath liquid, the solidified polymer film quickly and automatically spreads to the position of the first roller 3.1. The first roller 3.1 rotates counterclockwise at a speed of 10 m / s to extract the polymer film from the surface of the coagulation bath liquid. The second roller 3.2 then rotates clockwise at a speed of 10 m / s to separate the polymer film from the coagulation bath surface, thereby achieving the purpose of film extraction.

[0093] (6) Drying and winding of the membrane:

[0094] After the extraction process of the membrane in step (5), the wet membrane is transferred to a semi-closed drying oven 4. After infrared drying in the drying oven, the organic solvent and water remaining in the polymer membrane are completely removed to obtain the dried polymer membrane. The dried polymer membrane is received and wound by a third roller 5 that rotates clockwise at a speed of 10 m / s, thereby completing the continuous preparation of the PI polymer membrane.

[0095] Combination Figure 7 As shown, the PVDF polymer film obtained in this embodiment has a thickness of 1 μm and uniform internal micropores.

[0096] Example 4

[0097] Combination Figure 1 , Figure 2 and Figure 3 As shown, a continuous preparation method for PVDF polymer films includes the following steps:

[0098] (1) Preparation of polymer solution and coagulation bath:

[0099] Weigh out PVDF powder and place it in DMF to prepare a 60% PVDF solution (60 / 40 PVDF / DMF solution by mass percentage);

[0100] The coagulation bath in the coagulation bath is pure water.

[0101] (2) The polymer solution is injected into the polymer solution expansion tank:

[0102] The PVDF solution is injected into the polymer solution expansion tank 1 at a rate of 20 mm / s through the polymer liquid injection port 1.1, forms a polymer liquid flow through the polymer liquid receiving cavity 1.2, and flows out through the polymer liquid outlet 1.3.

[0103] Among them, the combination Figure 2 and Figure 3 As shown, the polymer solution expansion tank 1 includes, from top to bottom, a polymer liquid inlet 1.1, a polymer liquid containment cavity 1.2, and a polymer liquid outlet 1.3. In this embodiment, the polymer liquid inlet 1.1 is a circular hole with a diameter of 10 mm. The polymer liquid containment cavity 1.2 is a regular cuboid cavity structure with a thickness of 1000 μm and a width of 200 mm. The function of the polymer liquid containment cavity 1.2 is to store and transport the polymer solution in the form of a thin liquid layer. The polymer liquid outlet 1.3 is a rectangular notch opened at the bottom of the polymer liquid containment cavity 1.2 with a width of 200 mm and a thickness of 1000 μm. The height of the polymer liquid outlet 1.3 from the coagulation bath surface is 40 mm.

[0104] (3) The polymer solution flows into the coagulation bath;

[0105] The polymer solution forms a thin liquid layer of polymer liquid flow on the upper left side of the coagulation bath through the polymer solution expansion tank 1, and flows into the liquid surface of the coagulation bath.

[0106] (4) The polymer solution spreads and forms a film on the surface of the coagulation bath:

[0107] The polymer solution spreads on the surface of the coagulation bath to form a polymer liquid film. During the spreading process, the 60% PVDF polymer solution in the polymer liquid film reacts rapidly with the pure water coagulation bath. The pure water coagulation bath rapidly absorbs the DMF in the 60% PVDF polymer solution until the polymer liquid flow forms a PVDF-rich phase, which spreads rapidly on the surface of the coagulation bath and solidifies into a polymer film.

[0108] (5) Membrane extraction and transport:

[0109] When the first roller 3.1 contacts the surface of the coagulation bath, the solidified polymer film quickly and automatically spreads to the position of the first roller 3.1. The first roller 3.1 rotates counterclockwise at a speed of 0.31 m / s, which can extract the polymer film from the surface of the coagulation bath. The second roller 3.2 then rotates clockwise at a speed of 0.31 m / s, which can separate the polymer film from the surface of the coagulation bath, thereby achieving the purpose of film extraction.

[0110] (6) Drying and winding of the membrane:

[0111] After the extraction process of the membrane in step (5), the wet membrane is transferred to a semi-closed drying oven 4. After infrared drying in the drying oven, the organic solvent and water remaining in the polymer membrane are completely removed to obtain the dried polymer membrane. The dried polymer membrane is received and wound by a third roller 5 that rotates clockwise at a speed of 0.31 m / s, thereby completing the continuous preparation of the PI polymer membrane.

[0112] Combination Figure 8 As shown, the PVDF polymer film obtained in this embodiment has a thickness of 100 μm and uniform micropores inside.

[0113] Example 5

[0114] Combination Figure 1 , Figure 2 and Figure 3 As shown, a continuous preparation method for an ANF polymer film includes the following steps:

[0115] (1) Preparation of polymer solution and coagulation bath:

[0116] Weigh out ANF powder and place it in DMSO to prepare a 1% ANF solution (1 / 99 ANF / DMSO solution).

[0117] The coagulation bath in the coagulation bath is a 90% DMSO solution (10 / 90 water / DMSO mixed solution) by volume.

[0118] (2) The polymer solution is injected into the polymer solution expansion tank:

[0119] The ANF solution is injected into the polymer solution expansion tank 1 at a rate of 5 mm / s through the polymer liquid injection port 1.1, forms a polymer liquid flow through the polymer liquid receiving cavity 1.2, and flows out through the polymer liquid outlet 1.3.

[0120] Among them, the combination Figure 2 and Figure 3 As shown, the polymer solution expansion tank 1 includes, from top to bottom, a polymer liquid inlet 1.1, a polymer liquid containment cavity 1.2, and a polymer liquid outlet 1.3. In this embodiment, the polymer liquid inlet 1.1 is a circular hole with a diameter of 5 mm. The polymer liquid containment cavity 1.2 is a regular cuboid cavity structure with a thickness of 100 μm and a width of 120 mm. The function of the polymer liquid containment cavity 1.2 is to store and transport the polymer solution in the form of a thin liquid layer. The polymer liquid outlet 1.3 is a rectangular notch opened at the bottom of the polymer liquid containment cavity 1.2 with a length of 120 mm and a width of 100 μm. The height of the polymer liquid outlet 1.3 from the coagulation bath surface is 1 mm.

[0121] (3) The polymer solution flows into the coagulation bath;

[0122] The polymer solution forms a thin liquid layer of polymer liquid flow on the upper left side of the coagulation bath through the polymer solution expansion tank 1, and flows into the liquid surface of the coagulation bath.

[0123] (4) The polymer solution spreads and forms a film on the surface of the coagulation bath:

[0124] The polymer solution spreads on the surface of the coagulation bath to form a polymer liquid film. During the spreading process, the 1% ANF polymer solution in the polymer liquid film reacts rapidly with the 90% DMSO coagulation bath. The 90% DMSO coagulation bath rapidly absorbs the DMSO in the 1% ANF polymer solution until the polymer liquid flow forms an ANF-rich phase, which spreads rapidly on the surface of the coagulation bath and solidifies into a polymer film.

[0125] (5) Membrane extraction and transport:

[0126] When the first roller 3.1 contacts the surface of the coagulation bath liquid, the solidified polymer film quickly and automatically spreads to the position of the first roller 3.1. The first roller 3.1 rotates counterclockwise at a speed of 0.2 m / s, which can extract the polymer film from the surface of the coagulation bath liquid. The second roller 3.2 then rotates clockwise at a speed of 0.2 m / s, which can separate the polymer film from the coagulation bath surface, thereby achieving the purpose of film extraction.

[0127] (6) Drying and winding of the membrane:

[0128] After the extraction process of the membrane in step (5), the wet membrane is transferred to a semi-enclosed drying oven 4. After infrared drying in the drying oven, the organic solvent and water remaining in the polymer membrane are completely removed to obtain the dried polymer membrane. The dried polymer membrane is received and wound by a third roller 5 that rotates clockwise at a speed of 0.2 m / s, thereby completing the continuous preparation of the ANF polymer membrane.

[0129] Combination Figure 9 As shown, the ANF polymer film obtained in this embodiment has a thickness of 0.5 μm and uniform micropores inside.

[0130] Example 6

[0131] Combination Figure 1 , Figure 2 and Figure 3 As shown, a continuous preparation method for an ANF polymer film includes the following steps:

[0132] (1) Preparation of polymer solution and coagulation bath:

[0133] Weigh out ANF powder and place it in DMSO to prepare a 0.1% ANF solution (0.1 / 99.9 ANF / DMSO solution by mass percentage);

[0134] The coagulation bath in the coagulation bath is a DMSO solution with a volume ratio of 86% (a 14 / 86 water / DMSO mixed solution).

[0135] (2) Injection of polymer solution:

[0136] The ANF solution is injected into the polymer solution expansion tank 1 at a rate of 5 mm / s through the polymer liquid injection port 1.1, forms a polymer liquid flow through the polymer liquid receiving cavity 1.2, and flows out through the polymer liquid outlet 1.3.

[0137] Among them, the combination Figure 2 and Figure 3 As shown, the polymer solution expansion tank 1 includes, from top to bottom, a polymer liquid inlet 1.1, a polymer liquid containment cavity 1.2, and a polymer liquid outlet 1.3. In this embodiment, the polymer liquid inlet 1.1 is a circular hole with a diameter of 5 mm. The polymer liquid containment cavity 1.2 is a regular cuboid cavity structure with a thickness of 10 μm and a width of 90 mm. The polymer liquid containment cavity 1.2 serves to store and transport the polymer solution in the form of a thin liquid layer. The polymer liquid outlet 1.3 is a rectangular notch opened at the bottom of the polymer liquid containment cavity 1.2 with a width of 10 μm and a length of 90 mm. The height of the polymer liquid outlet 1.3 from the coagulation bath surface is 0.025 mm.

[0138] (3) The polymer solution flows into the coagulation bath;

[0139] The polymer solution forms a thin liquid layer of polymer liquid flow on the upper left side of the coagulation bath through the polymer solution expansion tank 1, and flows into the liquid surface of the coagulation bath.

[0140] (4) The polymer solution spreads and forms a film on the surface of the coagulation bath:

[0141] The polymer solution spreads on the surface of the coagulation bath to form a polymer liquid film. During the spreading process, the 0.1% ANF polymer solution in the polymer liquid film reacts rapidly with the 86% DMSO coagulation bath. The 86% DMSO coagulation bath rapidly absorbs the DMSO in the 0.1% ANF polymer solution until the polymer liquid flow forms an ANF-rich phase, which spreads rapidly on the surface of the coagulation bath and solidifies into a polymer film.

[0142] (5) Membrane extraction and transport:

[0143] When the first roller 3.1 contacts the surface of the coagulation bath liquid, the solidified polymer film quickly and automatically spreads to the position of the first roller 3.1. The first roller 3.1 rotates counterclockwise at a speed of 0.5 m / s to extract the polymer film from the surface of the coagulation bath liquid. The second roller 3.2 then rotates clockwise at a speed of 0.5 m / s to separate the polymer film from the coagulation bath surface, thereby achieving the purpose of film extraction.

[0144] (6) Drying and winding of the membrane:

[0145] After the extraction process of the membrane in step (5), the wet membrane is transferred to a semi-enclosed drying oven 4. After infrared drying in the drying oven, the organic solvent and water remaining in the polymer membrane are completely removed to obtain the dried polymer membrane. The dried polymer membrane is received and wound by a third roller 5 that rotates clockwise at a speed of 0.5 m / s, thereby completing the continuous preparation of the ANF polymer membrane.

[0146] Combination Figure 10 The ANF polymer film shown has a thickness of 0.1 μm and uniform micropores inside.

[0147] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A continuous preparation method for a polymer film, comprising the following steps: S1: The polymer solution is injected onto the surface of the coagulation bath and solidified into a polymer film; S2: The polymer film is extracted by the first roller (3.1) and the second roller (3.2), then dried in the drying oven (4), and finally wound into the finished polymer film by the third roller (5); Its features are: In step S1, the polymer solution is continuously injected from one end of the coagulation bath into the surface of the coagulation bath, causing the polymer solution to spread directionally towards the right side of the coagulation bath surface and solidify into a film on the surface of the coagulation bath. In step S1, the mass concentration of the polymer solution is 0.1-60%, and the polymer includes polyvinylidene fluoride, polyimide, or aramid. The coagulation bath is prepared by mixing organic solvent and water in a volume ratio of 0 / 100 to 90 / 10. The organic solvent in the polymer solution is the same as the organic solvent in the coagulation bath, and the organic solvent includes N,N-dimethylformamide, N-methylpyrrolidone, dimethylacetamide, or dimethyl sulfoxide; In step S1, the polymer solution is continuously injected into the surface of the coagulation bath in the form of a thin liquid flow through the polymer solution expansion tank (1). The polymer solution expansion tank (1) includes a polymer liquid flow inlet (1.1), a polymer liquid flow containment cavity (1.2), and a polymer liquid flow outlet (1.3) connected sequentially from top to bottom. The polymer liquid inlet (1.1) is a circular hole with a diameter of 5 to 10 mm. The left side wall of the polymer liquid receiving cavity (1.2) extends downward and connects to the top of the left side wall of the coagulation bath (2). The polymer liquid receiving cavity (1.2) is a cuboid cavity structure with a thickness of 10 to 1000 μm and a width of 10 to 200 mm. The polymer liquid outlet (1.3) is a rectangular notch set at the bottom of the polymer liquid receiving cavity (1.2). The width of the polymer liquid outlet (1.3) is 10 to 1000 μm and the length is 10 to 200 mm. The height of the polymer liquid outlet (1.3) from the surface of the coagulation bath is 0.025 to 40 mm. The polymer solution is injected into the polymer liquid inlet (1.1) at a rate of 0.5 ~ 20 mm / s, and is transported to the polymer liquid outlet (1.3) in the form of a thin liquid layer through the polymer liquid containment cavity (1.2). It is then continuously injected onto the surface of the coagulation bath liquid through the polymer liquid outlet (1.3). In step S2, the first roller (3.1) is positioned above the surface of the coagulation bath and in contact with the surface of the coagulation bath; the second roller (3.2) is positioned above the surface of the coagulation bath at a higher position than the first roller (3.1); the first roller (3.1) and the second roller (3.2) separate the polymer film from the coagulation bath and drive the polymer film to be continuously conveyed forward; The first roller (3.1) rotates counterclockwise at a speed of 0.1 ~ 0.5 m / s, and the second roller (3.2) rotates clockwise at a speed of 0.1 ~ 0.5 m / s; The first roller (3.1) and the second roller (3.2) rotate at the same speed; The thickness of the polymer film prepared is 0.1~100μm.

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