A film stretching and shaping mechanism for BOPA film production

Abstract

The present invention relates to a film stretching and shaping mechanism for BOPA film production, which includes a frame, a film clamping and feeding device, a film traction device, a drying device, a film path extension device, a temperature compensation control device, a film thickness measuring device and a control device. The film path extension device includes at least one front film path extension module and at least one rear film path extension module. The film clamping and feeding device, the drying device, the front film path extension module, the temperature compensation control device, the rear film path extension module, the film thickness measuring device and the film traction device are arranged in sequence along the conveying direction of the film. The temperature compensation control device can perform temperature compensation by cooling or heating the film surface. The film thickness measuring device is electrically connected to the corresponding input end of the control device, and the temperature compensation control device is electrically connected to the corresponding output end of the control device. The present invention can improve the stretching and shaping effect of the film, prevent the film from having uneven expansion, uneven thickness at the edges and other situations, and improve the performance and quality of the BOPA film finished product.

Description

Technical Field

[0001] The present invention relates to film production equipment, and particularly to a film stretching and shaping mechanism for BOPA film production. Background Art

[0002] BOPA film (biaxially oriented nylon film) is a functional polymer material. With its excellent mechanical strength, gas barrier property, chemical stability, and high-temperature resistance characteristics, it is widely used in the fields of food, drug packaging, and industry. Especially in the fields of food packaging and drug packaging, BOPA film can block oxygen and water vapor, effectively extend the shelf life of products, and meet the high-end packaging requirements with its transparency and wear resistance.

[0003] At present, the production process of BOPA film mainly includes three major steps: raw material pre-drying, polymerization reaction, and biaxial stretching. First, the raw materials (nylon 6 (PA6) or nylon 66 (PA66) particles) are pre-dried to remove moisture to avoid bubbles or other defects in the subsequent processing; then, the monomers (such as cyclic caprolactam) are polymerized into long-chain polymers through ring-opening polymerization technology under high temperature and pressure to ensure the completeness of the polymerization reaction and the high performance of the product; finally, the polymerized polyamide resin forms BOPA film through the biaxial stretching process. The biaxial stretching process is to stretch the polyamide resin longitudinally and transversely at the same time to improve its strength and stiffness. This process usually includes two stages: hot stretching and cold stretching, and a film stretching and shaping mechanism is required to perform stretching and shaping treatment on the film semi-finished product to meet the product quality requirements.

[0004] However, the existing film stretching and shaping mechanisms have the following disadvantages during the stretching and shaping process of the film semi-finished product: (1) It mainly relies on methods such as cold water, cold rollers, and rapid freezing by a blower (cold stretching) to solve the problem of the film surface temperature. This way of rapidly reducing the film temperature will cause uneven film expansion, and the film will undergo secondary deformation under winding compression, resulting in warping and uneven thickness of the finished film; (2) Its stretching and shaping effect on the film semi-finished product is not good, affecting the performance and product quality of the film finished product; (3) Its process adaptability is insufficient. It is difficult to flexibly adjust the cooling rate according to the specification requirements of the film and cannot adapt to the performance requirements of different specifications of films, restricting the diversified production of products. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a film stretching and shaping mechanism for BOPA film production, which can improve the stretching and shaping effect on the film and prevent the film from being unevenly expanded, warping, and uneven in thickness, thereby improving the performance and product quality of the BOPA film finished product. The technical solutions adopted are as follows:

[0006] A film stretching and shaping mechanism for BOPA film production, comprising a frame, a film clamping and conveying device, and a film traction device, characterized in that: it further includes a drying device, a film path extension device, a temperature compensation control device, a film thickness measuring device, and a control device. The film clamping and conveying device, the film traction device, the drying device, the film path extension device, the temperature compensation control device, and the film thickness measuring device are all installed on the frame. The film path extension device includes at least one front film path extension module and at least one rear film path extension module. The film clamping and conveying device, the drying device, each front film path extension module, the temperature compensation control device, each rear film path extension module, the film thickness measuring device, and the film traction device are arranged in sequence along the conveying direction of the film; the temperature compensation control device can cool or heat the film surface to achieve temperature compensation; the film thickness measuring device is electrically connected to the corresponding input end of the control device, and the temperature compensation control device is electrically connected to the corresponding output end of the control device.

[0007] Generally, the above-mentioned film stretching and shaping mechanism is arranged between the film production device and the film winding device. During operation, the film production device is used to produce and continuously send out the film; the film sent out by the film production device undergoes stretching and shaping through the film stretching and shaping mechanism, and finally is wound at the film winding device.

[0008] When the above-mentioned film stretching and shaping mechanism is working, the film is driven by the film clamping and conveying device and the film traction device, and sequentially passes through the film clamping and conveying device, the drying device, the front film path extension module, the temperature compensation control device, the rear film path extension module, and the film thickness measuring device; when the film passes through the drying device, the drying device dries the film surface to remove a large amount of moisture on the film surface; when the film passes through the film path extension device, the front film path extension module and the rear film path extension module of the film path extension device can effectively extend the walking path and walking time of the film, so that the film can achieve natural cooling within this time, evaporate the residual moisture, so as to adjust the film surface wrinkles, film pulling force, etc., and ensure that the finished film will not appear warping and other situations. The film thickness measuring device can real-time detect the actual thickness value of the passing film and send it to the control device, and then the control device controls the temperature compensation control device to cool or heat the corresponding part of the film surface to achieve temperature compensation, so that the film surface temperature and stretching degree reach the ideal state, improving the stretching and shaping effect of the film: when it is detected that the thickness of the passing film is less than the preset value, the control device controls the temperature compensation control device to cool the corresponding part of the film surface, so that the film surface temperature decreases, and when it is detected that the thickness of the passing film is greater than the preset value, the control device controls the temperature compensation control device to heat the corresponding part of the film surface, so that the film surface temperature increases. This film stretching and shaping mechanism can improve the stretching and shaping effect of the film, and can prevent the film from appearing uneven expansion, uneven warping and thickness, etc., thereby improving the performance and product quality of the BOPA film finished product.

[0009] As a preferred embodiment of the present invention, the film feeding device includes two feeding rollers that are pressed against each other and rotate relative to each other. When the film passes through the film feeding device, the film passes between the two feeding rollers and moves from front to back under the drive of the two feeding rollers.

[0010] As a preferred embodiment of the present invention, the film traction device includes two traction rollers that are pressed against each other and rotate relative to each other. When the film passes through the film traction device, the film passes between the two traction rollers and moves from front to back under the drive of the two traction rollers.

[0011] The number of the above-mentioned front film path extension modules and rear film path extension modules can be determined according to the actual production situation. As a preferred embodiment of the present invention, the film path extension device includes two front film path extension modules and two rear film path extension modules, and the two front film path extension modules, the temperature compensation control device, and the two rear film path extension modules are arranged in sequence along the conveying direction of the film. Thereby, the walking path and walking time of the film can be further effectively extended, and the natural cooling effect on the film can be improved.

[0012] As a preferred embodiment of the present invention, both the front film path extension module and the rear film path extension module include a first guide roller group and a second guide roller group. The second guide roller group is arranged on one side of the first guide roller group. The first guide roller group includes a plurality of first guide rollers arranged in sequence along a first direction, and the second guide roller group includes a plurality of second guide rollers arranged in sequence along the first direction. Moreover, each first guide roller and each second guide roller are arranged alternately in sequence along the first direction. When the film passes through the front film path extension module or the rear film path extension module, the film successively wraps around the surfaces of each first guide roller and each second guide roller (that is, first wraps around the surface of a first guide roller, then wraps around the surface of a second guide roller, and then wraps around the surface of another first guide roller, and so on). Thereby, the walking path and walking time of the film can be effectively extended.

[0013] As a preferred embodiment of the present invention, the temperature compensation control device includes two first temperature compensation rollers, two movable adjustment rollers, and two position adjustment mechanisms. The two first temperature compensation rollers are rotatably mounted on the frame and arranged side by side left and right. The two movable adjustment rollers are respectively arranged below the corresponding first temperature compensation rollers. The two position adjustment mechanisms correspond to the two movable adjustment rollers one by one. The movable adjustment rollers are mounted on the frame through the corresponding position adjustment mechanisms. The roller surfaces of the two first temperature compensation rollers are in contact with the surface of the film. The two position adjustment mechanisms are electrically connected to the corresponding output terminals of the control device. When the film passes through the temperature compensation control device, the film sequentially wraps around the surfaces of the two first temperature compensation rollers, and the corresponding parts of the film surface are cooled or heated by the two first temperature compensation rollers to achieve temperature compensation. Moreover, the control device can control the position adjustment mechanism to adjust the position of the corresponding movable adjustment roller, so that the movable adjustment roller moves towards or away from the film surface, to adjust the wrap angle formed between the temperature compensation roller and the film surface, so as to increase or decrease the fitting tightness with the film, and increase or decrease the temperature of the film surface.

[0014] As a further preferred embodiment of the present invention, the position adjustment mechanism includes a connecting pin shaft, a swing arm, and an electric push rod. The first end of the swing arm is hinged to the frame through the connecting pin shaft. The movable adjustment roller is rotatably mounted on the middle section of the swing arm. The cylinder body of the electric push rod is hinged to the frame, and the push rod of the electric push rod is hinged to the second end of the swing arm. The electric push rod is electrically connected to the corresponding output terminal of the control device. During operation, the control device can drive the swing arm to swing around the connecting pin shaft by the telescopic movement of the push rod of the electric push rod, driving the movable adjustment roller to move towards or away from the film surface.

[0015] As a further preferred embodiment of the present invention, the temperature compensation control device further includes two second temperature compensation rollers. The two second temperature compensation rollers are rotatably mounted on the frame. The two second temperature compensation rollers are arranged side by side left and right above the two first temperature compensation rollers and are in contact with the surface of the film. One first temperature compensation roller, one second temperature compensation roller, the other second temperature compensation roller, and the other first temperature compensation roller are arranged in sequence along the conveying direction of the film. When the film passes through the temperature compensation control device, the film sequentially wraps around the surfaces of one first temperature compensation roller, one second temperature compensation roller, the other second temperature compensation roller, and the other first temperature compensation roller, and the corresponding parts of the film surface are cooled or heated by the two first temperature compensation rollers and the two second temperature compensation rollers to achieve temperature compensation. Thus, the temperature compensation control device can control the temperature compensation of the film surface more accurately.

[0016] As a further preferred embodiment of the present invention, a heat-conducting medium flow channel is provided inside the first temperature compensation roller and the second temperature compensation roller. Specifically, the heat-conducting medium flow channel has a heat-conducting medium inlet and a heat-conducting medium outlet, and the heat-conducting medium inlet and the heat-conducting medium outlet are respectively communicated with the heat-conducting medium outlet and the heat-conducting medium return port of the heat-conducting medium supply device. According to production needs, by introducing a heat-conducting medium (such as heat-conducting oil or water) into the heat-conducting medium flow channel, the temperature compensation roller can be formed into a heating roller or a cooling roller to adapt to the performance requirements of different specifications of films.

[0017] As a preferred embodiment of the present invention, the film stretching and shaping mechanism for BOPA film production further includes a film deviation rectifying device, which is arranged between the temperature compensation control device and the film thickness measuring device. The film deviation rectifying device can perform deviation rectifying operations on the film to ensure accurate thickness measurement of the film by the film thickness measuring device.

[0018] The above-mentioned film deviation rectifying device adopts the prior art, and its structure can refer to the Chinese utility model patent specification with the publication number CN211310316U and the patent name "A Film Deviation Rectifying Device".

[0019] As a preferred embodiment of the present invention, the drying device adopts an oven.

[0020] As a preferred embodiment of the present invention, the film thickness measuring device adopts a film thickness gauge.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) This kind of film stretching and shaping mechanism can convey and apply biaxial stretching to the film through the film pinch conveying device and the film traction device, and dry the surface of the film through the drying device to remove a large amount of moisture on the film surface. Then, through the film path extension device, the walking path and walking time of the film can be effectively extended, so that the film can reach natural cooling during this time, evaporate the residual moisture, and adjust the film surface wrinkles, film pulling force, etc., which can prevent the film from having uneven expansion, uneven thickness at the edges, etc.

[0023] (2) This kind of film stretching and shaping mechanism can detect the actual thickness value of the passing film in real time through the film thickness measuring device and send it to the control device, and then the control device controls the temperature compensation control device to cool or heat the corresponding part of the film surface to achieve temperature compensation, so that the surface temperature and stretching degree of the film reach an ideal state, improving the stretching and shaping effect of the film, and thus improving the performance and product quality of the BOPA film finished product. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic structural diagram of a preferred embodiment of the present invention.

[0025] Figure 2 It is a schematic structural diagram of the rear film path extension module in the preferred embodiment of the present invention.

[0026] Figure 3 It is a schematic structural diagram of the temperature compensation control device in the preferred embodiment of the present invention. Specific embodiments

[0027] As Figures 1 - 3 shown, this film stretching and shaping mechanism for BOPA film production includes a frame 1, a film clamping and feeding device 2, a film traction device 3, a drying device 4, a film path extension device 5, a temperature compensation control device 6, a film thickness measuring device 7, and a control device (not shown in the figure). The film clamping and feeding device 2, the film traction device 3, the drying device 4, the film path extension device 5, the temperature compensation control device 6, and the film thickness measuring device 7 are all installed on the frame 1. The film clamping and feeding device 2, the drying device 4, the film path extension device 5, the film thickness measuring device 7, and the film traction device 3 are arranged in sequence along the conveying direction of the film 20. The temperature compensation control device 6 is located between the drying device 4 and the film thickness measuring device 7, and the temperature compensation control device 6 can cool or heat the surface of the film 20 to achieve temperature compensation. The film thickness measuring device 7 is electrically connected to the corresponding input end of the control device, and the temperature compensation control device 6 is electrically connected to the corresponding output end of the control device.

[0028] In this embodiment, the film clamping and feeding device 2 includes two clamping and feeding rollers 21 that are pressed against each other and rotate relative to each other. When the film 20 passes through the film clamping and feeding device 2, the film 20 passes between the two clamping and feeding rollers 21 and moves forward to backward under the drive of the two clamping and feeding rollers 21.

[0029] In this embodiment, the film traction device 3 includes two traction rollers 31 that are pressed against each other and rotate relative to each other. When the film 20 passes through the film traction device 3, the film 20 passes between the two traction rollers 31 and moves forward to backward under the drive of the two traction rollers 31.

[0030] In this embodiment, the drying device 4 uses an oven.

[0031] Refer to Figure 1 、 Figure 2, the film path extension device 5 includes two front film path extension modules 51 and two rear film path extension modules 52. The two front film path extension modules 51, the temperature compensation control device 6, and the two rear film path extension modules 52 are arranged in sequence along the conveying direction of the film 20. Both the front film path extension module 51 and the rear film path extension module 52 include a first guiding roller group 501 and a second guiding roller group 502. The second guiding roller group 502 is arranged on one side of the first guiding roller group 501. The first guiding roller group 501 includes a plurality of first guiding rollers 5011 arranged successively from top to bottom. The second guiding roller group 502 includes a plurality of second guiding rollers 5021 arranged successively from top to bottom. And each of the first guiding rollers 5011 and each of the second guiding rollers 5021 are arranged alternately successively from top to bottom. When the film 20 passes through the front film path extension module 51 or the rear film path extension module 52, the film 20 successively wraps around the surfaces of each of the first guiding rollers 5011 and each of the second guiding rollers 5021 (that is, first wraps around the surface of a first guiding roller 5011, then wraps around the surface of a second guiding roller 5021, then wraps around the surface of another first guiding roller 5011, and so on). Thus, the walking path and walking time of the film 20 can be effectively extended, and the natural cooling effect on the film 20 can be improved.

[0032] In this embodiment, the film thickness measuring device 7 uses a film thickness gauge; the control device uses a PLC controller.

[0033] Reference Figure 3, the temperature compensation control device 6 includes two first temperature compensation rollers 61, two second temperature compensation rollers 62, two movable adjusting rollers 63 and two position adjusting mechanisms 64. The two first temperature compensation rollers 61 and the two second temperature compensation rollers 62 are rotatably mounted on the frame 1. The two first temperature compensation rollers 61 are arranged side by side left and right. The two second temperature compensation rollers 62 are arranged side by side left and right above the two first temperature compensation rollers 61. The two movable adjusting rollers 63 are respectively arranged below the corresponding first temperature compensation rollers 61. The two position adjusting mechanisms 64 correspond to the two movable adjusting rollers 63 one by one. The movable adjusting rollers 63 are mounted on the frame 1 through the corresponding position adjusting mechanisms 64. One first temperature compensation roller 61, one second temperature compensation roller 62, the other second temperature compensation roller 62, and the other first temperature compensation roller 61 are arranged in sequence along the conveying direction of the film 20. The roller surfaces of the two first temperature compensation rollers 61 and the two second temperature compensation rollers 62 are all in contact with the surface of the film 20. The two position adjusting mechanisms 64 are electrically connected to the corresponding output terminals of the control device. When the film 20 passes through the temperature compensation control device 6, the film 20 successively wraps around the surfaces of one first temperature compensation roller 61, one second temperature compensation roller 62, the other second temperature compensation roller 62, and the other first temperature compensation roller 61. The corresponding parts of the surface of the film 20 are cooled or heated by the two first temperature compensation rollers 61 and the two second temperature compensation rollers 62 to achieve temperature compensation. And the control device can control the position adjusting mechanism 64 to adjust the position of the corresponding movable adjusting roller 63, so that the movable adjusting roller 63 moves towards or away from the surface of the film 20, so as to adjust the wrap angle formed between the first temperature compensation roller 61 and the surface of the film 20, so as to increase or decrease the fitting tightness between it and the film 20, and increase or decrease the temperature of the surface of the film 20.

[0034] In this embodiment, the position adjusting mechanism 64 includes a connecting pin shaft 641, a swing arm 642 and an electric push rod 643. The first end of the swing arm 642 is hinged on the frame 1 through the connecting pin shaft 641. The movable adjusting roller 63 is rotatably mounted on the middle section of the swing arm 642. The cylinder body of the electric push rod 643 is hinged on the frame 1. The push rod of the electric push rod 643 is hinged to the second end of the swing arm 642. The electric push rod 643 is electrically connected to the corresponding output terminal of the control device. During operation, the control device can drive the swing arm 642 to swing around the connecting pin shaft 641 by the telescopic movement of the push rod of the electric push rod 643, driving the movable adjusting roller 63 to move towards or away from the surface of the film 20.

[0035] In this embodiment, this film stretching and shaping mechanism further includes a film deviation rectifying device 9. The film deviation rectifying device 9 is arranged between the temperature compensation control device 6 and the film thickness measuring device 7. The film deviation rectifying device 9 can perform deviation rectifying operation on the film 20 to ensure the accuracy of the thickness measurement of the film 20 by the film thickness measuring device 7.

[0036] The working principle of this film stretching and shaping mechanism is briefly described as follows:

[0037] The film stretching and shaping mechanism is arranged between the film production device 200 and the film winding device (not shown in the figure).

[0038] During operation, the film production device 200 is used to produce and continuously send out the film 20. The film 20 sent out by the film production device 200 undergoes stretching and shaping through the film stretching and shaping mechanism, and finally is wound at the film winding device. Driven by the film pinch device 2 and the film traction device 3, the film 20 sequentially passes through the film pinch device 2, the drying device 4, the film path extension device 5, the temperature compensation control device 6, and the film thickness measuring device 7. When the film 20 passes through the drying device 4, the drying device 4 dries the surface of the film 20 to remove a large amount of moisture on the surface of the film 20. When the film 20 passes through the film path extension device 5, the film path extension device 5 can effectively extend the walking path and walking time of the film 20, enabling the film 20 to achieve natural cooling and evaporate the residual moisture during this time, so as to adjust the film surface wrinkles, film pulling force, etc., and ensure that the finished film does not have problems such as warping edges. The film thickness measuring device 7 can real-time detect the actual thickness value of the passing film 20 and send it to the control device, and then the control device controls the temperature compensation control device 6 to cool or heat the corresponding part of the surface of the film 20 to achieve temperature compensation, so that the surface temperature and stretching degree of the film 20 reach an ideal state, improving the stretching and shaping effect of the film 20: when it is detected that the thickness of the passing film 20 is less than the preset value, the control device controls the temperature compensation control device 6 to cool the corresponding part of the surface of the film 20, reducing the surface temperature of the film 20; when it is detected that the thickness of the passing film 20 is greater than the preset value, the control device controls the temperature compensation control device 6 to heat the corresponding part of the surface of the film 20, increasing the surface temperature of the film 20.

[0039] In addition, it should be noted that for the specific embodiments described in this specification, the names of their various parts, etc. can be different. Any equivalent or simple changes made according to the structure, features, and principles of the inventive concept of this invention patent are included in the protection scope of this invention patent. Those skilled in the technical field to which this invention belongs can make various modifications, supplements, or use similar methods to replace the specific embodiments described, as long as they do not deviate from the structure of this invention or exceed the scope defined by this claim book, they should all belong to the protection scope of this invention.

Claims

1. A film stretching and shaping mechanism for BOPA film production, comprising a frame, a film clamping and feeding device, and a film traction device, characterized in that: It also includes a drying device, a film path extension device, a temperature compensation control device, a film thickness measuring device and a control device. The film clamping and feeding device, the film traction device, the drying device, the film path extension device, the temperature compensation control device and the film thickness measuring device are all installed on the frame. The film path extension device includes two front film path extension modules and two rear film path extension modules. Both the front film path extension module and the rear film path extension module include a first guiding roller group and a second guiding roller group. The second guiding roller group is arranged on one side of the first guiding roller group. The first guiding roller group includes a plurality of first guiding rollers arranged in sequence along a first direction, and the second guiding roller group includes a plurality of second guiding rollers arranged in sequence along the first direction. And each first guiding roller and each second guiding roller are arranged alternately in sequence along the first direction. The film clamping and feeding device, the drying device, the two front film path extension modules, the temperature compensation control device, the two rear film path extension modules, the film thickness measuring device and the film traction device are arranged in sequence along the conveying direction of the film. The temperature compensation control device can cool or heat the surface of the film to achieve temperature compensation. The film thickness measuring device is electrically connected to the corresponding input end of the control device, and the temperature compensation control device is electrically connected to the corresponding output end of the control device.

2. The film stretching and shaping mechanism for BOPA film production according to claim 1, characterized in that: The film clamping and feeding device includes two clamping and feeding rollers that are pressed against each other and rotate relatively; the film traction device includes two traction rollers that are pressed against each other and rotate relatively.

3. The film stretching and shaping mechanism for BOPA film production according to claim 1, characterized in that: The temperature compensation control device includes two first temperature compensation rollers, two movable adjustment rollers and two position adjustment mechanisms. The two first temperature compensation rollers are rotatably installed on the frame and arranged side by side left and right. The two movable adjustment rollers are respectively arranged below the corresponding first temperature compensation rollers. The two position adjustment mechanisms correspond to the two movable adjustment rollers one by one. The movable adjustment rollers are installed on the frame through the corresponding position adjustment mechanisms. The roller surfaces of the two first temperature compensation rollers are both in contact with the surface of the film; the two position adjustment mechanisms are electrically connected to the corresponding output end of the control device.

4. The film stretching and shaping mechanism for BOPA film production according to claim 3, characterized in that: The position adjustment mechanism includes a connecting pin shaft, a swing arm and an electric push rod. The first end of the swing arm is hinged to the frame through the connecting pin shaft. The movable adjustment roller is rotatably installed on the middle section of the swing arm. The cylinder body of the electric push rod is hinged to the frame, and the push rod of the electric push rod is hinged to the second end of the swing arm; the electric push rod is electrically connected to the corresponding output end of the control device.

5. The film stretching and shaping mechanism for BOPA film production according to claim 3, characterized in that: The temperature compensation control device also includes two second temperature compensation rollers. The two second temperature compensation rollers are rotatably installed on the frame. The two second temperature compensation rollers are arranged side by side left and right above the two first temperature compensation rollers and are in contact with the surface of the film. One first temperature compensation roller, one second temperature compensation roller, the other second temperature compensation roller and the other first temperature compensation roller are arranged in sequence along the conveying direction of the film.

6. The film stretching and shaping mechanism for BOPA film production according to claim 5, characterized in that: A heat conduction medium flow channel is arranged inside the first temperature compensation roller and the second temperature compensation roller.

7. A film stretching and shaping mechanism for BOPA film production according to any one of claims 1-6, characterized in that: The film stretching and shaping mechanism for BOPA film production also includes a film deviation rectifying device, and the film deviation rectifying device is arranged between the temperature compensation control device and the film thickness measuring device.

8. A film stretching and shaping mechanism for BOPA film production according to any one of claims 1-6, characterized in that: The drying device uses an oven; the film thickness measuring device uses a film thickness gauge.

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