PVB (polyvinyl butyral) adhesive film drying equipment

Abstract

The utility model relates to the technical field of PVB (Polyvinyl Butyral) adhesive film production, and discloses PVB adhesive film drying equipment which comprises a rack, the drying bin is connected with the rack, and the drying bin is provided with a feeding port and a discharging port; the conveying device is connected with the rack and is suitable for conveying the PVB adhesive film in the drying bin and conveying the PVB adhesive film from the feeding hole to the discharging hole; the heating device is connected with the rack, is arranged corresponding to the drying bin and is suitable for heating the PVB adhesive film in the drying bin; the negative pressure device is communicated with the drying bin and is used for pumping away water vapor in the drying bin. According to the PVB adhesive film drying device, the problems that the time consumption is long and the cost is high when PVB adhesive films with the water content reaching the standard are obtained are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of PVB film production, and particularly relates to a PVB film drying device. Background Art

[0002] PVB film is a polyvinyl butyral film and is an important component of laminated glass and photovoltaic module products, which can improve the safety and sound insulation performance of glass. The PVB film itself contains hydrophilic groups and can form hydrogen bonds with water molecules, thereby adsorbing water molecules on the surface. Therefore, when the PVB film is exposed to a humid environment, both its surface and interior will absorb moisture. The moisture content of the PVB film will directly affect the quality of products such as laminated glass. When the moisture content of the PVB film exceeds the standard, the bonding force decreases, which easily leads to glass delamination. In addition, when the moisture content exceeds the standard, the impact resistance of the laminated glass may also decrease.

[0003] In related technologies, generally there are two ways to control the moisture content of the PVB film. One is to blow hot air on the PVB film to force the moisture in the PVB film to be discharged. The other is to set up a dry storage space such as a lamination workshop, control the overall humidity of the storage space through a dehumidification device, and store the PVB film in the storage space for a long time to allow the moisture to naturally discharge.

[0004] However, among the above methods for reducing the moisture content of the PVB film, the method of blowing hot air can generally only remove the moisture on the surface of the PVB film and it is difficult to control the moisture inside the PVB film. And the method of storing the PVB film in a dry storage space for a long time takes a long time, and the cost of controlling the humidity through a dehumidification device for a long time is relatively high. Summary of the Utility Model

[0005] In view of this, the utility model provides a PVB film drying device to solve the problems of long time consumption and high cost in obtaining a PVB film with a qualified moisture content.

[0006] The utility model provides a PVB film drying device, including: a frame; a drying chamber connected to the frame, the drying chamber having a feed inlet and a discharge outlet; a conveying device connected to the frame, adapted to convey the PVB film in the drying chamber and convey the PVB film from the feed inlet to the discharge outlet; a heating device connected to the frame, corresponding to the drying chamber and distributed along the conveying track of the conveying device, adapted to heat the PVB film in the drying chamber; a negative pressure device communicating with the drying chamber and used to evacuate the water vapor in the drying chamber.

[0007] Beneficial effects: The frame provides an installation basis for other components and devices of the equipment. The PVB film is transported by the transport device, passing through the drying chamber. Then, the PVB film is processed by the heating device and the negative pressure device in the drying chamber. The negative pressure device evacuates the negative pressure or vacuum in the drying chamber, greatly reducing the boiling point of water. Then, the PVB film is heat-treated by the heating device, forcing the moisture on the surface and inside of the PVB to be discharged together and separated from the PVB film. At the same time, the negative pressure device evacuates the discharged moisture from the drying chamber, thus achieving efficient and rapid reduction of the moisture content on the surface and inside of the PVB film, with less time consumption and controllable cost.

[0008] In an alternative embodiment, the transport device includes a plurality of horizontal transport parts, which are spaced apart in the height direction. Longitudinal transport parts are respectively arranged between adjacent horizontal transport parts, and two adjacent longitudinal transport parts are respectively arranged at different ends of the corresponding horizontal transport part. The horizontal transport part is adapted to transport the PVB film horizontally, and the longitudinal transport part is adapted to transport the PVB film longitudinally. The plurality of longitudinal transport parts and the plurality of horizontal transport parts cooperate to form an "S"-shaped transport track arranged in the height direction.

[0009] Beneficial effects: Through the cooperation of a plurality of horizontal transport parts and longitudinal transport parts, the PVB film is transported in an "S"-shaped track in the height direction, thereby extending the treatment distance for water treatment of the PVB film within a limited floor area of the equipment and extending the treatment time without changing the output speed of the PVB film, thus effectively improving the reliability of the water removal effect on the PVB film and enhancing the space utilization rate.

[0010] In an alternative embodiment, the horizontal transport part includes a plurality of first transport rollers, which are spaced apart horizontally. The longitudinal transport part includes a plurality of second transport rollers, which are spaced apart in an arc shape in the height direction.

[0011] Beneficial effects: By using the first transport rollers and the second transport rollers to transport the PVB film in the drying chamber, the contact area between the transport device and the PVB film is reduced, enabling more surfaces of the PVB film to be exposed to the drying environment in the drying chamber, further improving the water removal efficiency of the PVB film.

[0012] In an alternative embodiment, the longitudinal transport part further includes a plurality of third transport rollers, which are spaced apart in an arc shape in the height direction. When the second transport rollers transport the PVB film, the third transport rollers are located on the side of the PVB film away from the second transport rollers and are in contact with the PVB film.

[0013] Beneficial effects: By arranging a plurality of third conveying rollers at the position of the longitudinal conveying part, and making the third conveying rollers cooperate with the second conveying rollers from opposite sides of the PVB film to jointly convey the PVB film, the guiding and limiting of the PVB film are improved at the bending part of the movement track, and then the softened PVB film after heating is stably conveyed, preventing the PVB film from deviating from the conveying track and causing equipment blockage and jamming, and improving the functional reliability of the conveying device. In addition, the stretching effects on the inner bending side and the outer bending side of the PVB film at the bending part are different. By contacting the film with the conveying rollers with heat conduction on both sides, the moisture in the PVB film can be more easily and fully precipitated.

[0014] In an optional embodiment, a plurality of groups of negative pressure devices are provided, and the plurality of groups of negative pressure devices are respectively communicated with the positions where different lateral conveying parts of the drying chamber are located.

[0015] Beneficial effects: By arranging a plurality of groups of negative pressure devices and respectively communicating with the positions where the lateral conveying parts are located, the uniformity of the pressure in the drying chamber can be improved, and the moisture discharged from the PVB film can be timely evacuated from the drying chamber, avoiding the situation that moisture re-enters during the cooling process of the PVB film, resulting in the unqualified moisture content of the PVB film.

[0016] In an optional embodiment, there is an interval between the heating device and the discharge port, the conveying track of the conveying device passes through the interval and extends to the discharge port, and the area where the interval is located forms a cooling section, and the cooling section is suitable for cooling and hardening the PVB film.

[0017] Beneficial effects: By arranging an interval between the heating device and the discharge port, the PVB film conveyed by the conveying device is cooled and hardened again in a dry environment after being heated and dewatered in the drying chamber.

[0018] In an optional embodiment, an elastic sealing component is arranged at the discharge port, and the elastic sealing component elastically expands and contracts relative to the film surface of the PVB film. In the state where the PVB film is output from the discharge port, the elastic end of the elastic sealing component abuts at least on one film surface of the PVB film, and the elastic sealing component is used for elastically sealing the discharge port.

[0019] Beneficial effects: By arranging an elastic sealing component at the discharge port, since the elastic sealing component elastically expands and contracts relative to the film surface of the PVB film, when the PVB film is output from the discharge port, the elastic sealing component abuts on the surface of the PVB film, thereby reducing the situation that external air enters the drying chamber from the discharge port and affecting the overall humidity in the drying chamber, and at the same time improving the negative pressure degree in the drying chamber and enhancing the water removal effect on the PVB film.

[0020] In an alternative embodiment, a cutting device is further included. The cutting device is connected to the frame, is located behind the discharge port in the conveying direction, and is used for cutting the processed PVB film.

[0021] Beneficial effects: Since the device can not only perform water treatment on sheet-shaped PVB films, but also continuously perform water treatment on the unwound PVB film strip. In the case of treating the PVB film strip, the PVB film can be immediately cut into a predetermined size after it exits the drying chamber, enabling the water-treated PVB film to quickly enter a ready-to-use state. It can also quickly package the water-treated PVB film, eliminating the need for re-unwinding and water treatment when in use, greatly enhancing convenience and practicality.

[0022] In an alternative embodiment, a closed unwinding chamber is further included. The unwinding device is disposed in the unwinding chamber, and the unwinding chamber has a material outlet, which is hermetically connected to the feed inlet.

[0023] Beneficial effects: By providing an unwinding chamber to accommodate the unwinding device and connecting the material outlet of the unwinding chamber to the feed inlet, on the one hand, the unwinding chamber is connected to the drying chamber. With the aid of the negative pressure device and heating device communicated with the drying chamber, a dry environment is provided for the unwinding chamber, and the unwound PVB film roll is isolated from the external environment, preventing the PVB film from absorbing moisture during unwinding. At the same time, by enclosing the drying chamber to form a sealed space and cooperating with vacuum pumping, it is more conducive to the precipitation of water vapor in the PVB film, further controlling the water removal effect on the PVB film.

[0024] In an alternative embodiment, an unwinding device is further included, which is disposed opposite to the feed inlet and is adapted to unwind and unfold the roll of the PVB film.

[0025] Beneficial effects: By providing an unwinding device, it is convenient to unwind the PVB film roll and then input the unwound PVB film into the drying chamber, increasing the contact area between the PVB film and the dry negative pressure environment in the drying chamber and improving the water removal efficiency. Description of the Drawings

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0027] Figure 1It is a schematic diagram of the overall structure of a PVB film drying device according to an embodiment of the present invention;

[0028] Figure 2 It is a schematic diagram of the overall structure of another PVB film drying device according to an embodiment of the present invention;

[0029] Figure 3 It is a schematic diagram of the overall structure of yet another PVB film drying device according to an embodiment of the present invention.

[0030] Explanation of reference numerals:

[0031] 100, frame; 200, drying chamber; 201, elastic sealing assembly; 300, conveying device; 301, horizontal conveying part; 3011, first conveying roller; 302, vertical conveying part; 3021, second conveying roller; 3022, third conveying roller; 400, heating device; 500, negative pressure device; 600, cutting device; 700, unwinding bin. Detailed implementation manners

[0032] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] The following combines Figures 1 to 3 , and describes the embodiments of the present invention.

[0034] According to an embodiment of the present invention, on the one hand, a PVB film drying device is provided. Please refer to Figure 1 , including: a frame 100; a drying chamber 200, connected to the frame 100, the drying chamber 200 having a feed inlet and a discharge outlet; a conveying device 300, connected to the frame 100, adapted to convey the PVB film in the drying chamber 200 and convey the PVB film from the feed inlet to the discharge outlet; a heating device 400, connected to the frame 100, arranged corresponding to the drying chamber 200 and distributed along the conveying track of the conveying device 300, adapted to heat the PVB film in the drying chamber 200; a negative pressure device 500, communicating with the drying chamber 200 and used to evacuate the water vapor in the drying chamber.

[0035] In this embodiment, the frame 100 provides an installation basis for other components and devices of the equipment. The PVB film is transported by the transport device 300 so that the PVB film passes through the drying chamber 200, and then the PVB film is processed by the heating device 400 and the negative pressure device 500 in the drying chamber 200. The negative pressure device 500 evacuates negative pressure or vacuum in the drying chamber 200, greatly reducing the boiling point of water. Then, the PVB film is heated by the heating device 400, forcing the moisture on the surface and inside of the PVB to be discharged together and separated from the PVB film. At the same time, the negative pressure device 500 evacuates the discharged moisture from the drying chamber 200, thus achieving efficient and rapid reduction of the moisture content on the surface and inside of the PVB film, with less time consumption and controllable cost.

[0036] Specifically, the specific form of the transport device 300 is not limited in this embodiment. The transport device 300 transports the PVB film through transport rollers. In some embodiments not shown, the transport device 300 can also transport the PVB film through structures such as a conveyor belt 601 and a conveyor chain plate.

[0037] In addition, specifically, the specific form of the heating device 400 is not limited in this embodiment. The heating device 400 can be a hot air blower using hot air spray heating, a heating resistance wire, or other forms of devices, as long as it has the function of heating and can increase the temperature of the PVB film.

[0038] It should be noted that the negative pressure device 500 can be a vacuum pump or a negative pressure fan. The negative pressure device 500 can be directly installed on the drying chamber 200 or installed at other positions and connected to a specified position on the drying chamber 200 through a pipeline. This embodiment does not limit the specific form and specific installation position of the negative pressure device 500.

[0039] In one embodiment, please refer to Figure 2 , the transport device 300 includes a plurality of horizontal transport parts 301, and the plurality of horizontal transport parts 301 are spaced apart in the height direction. Longitudinal transport parts 302 are respectively arranged between adjacent horizontal transport parts 301, and two adjacent longitudinal transport parts 302 are respectively arranged at different ends of the corresponding horizontal transport part 301. The horizontal transport part 301 is adapted to transport the PVB film horizontally, and the longitudinal transport part 302 is adapted to transport the PVB film longitudinally. The plurality of longitudinal transport parts 302 and the plurality of horizontal transport parts 301 cooperate to form an "S"-shaped transport trajectory arranged in the height direction.

[0040] In this embodiment, through the cooperation of multiple horizontal conveying parts 301 and vertical conveying parts 302, the PVB film is transported in an "S" - shaped trajectory in the height direction, so that the equipment extends the treatment distance for water removal of the PVB film within a limited floor area, and extends the treatment time without changing the output speed of the PVB film, thereby effectively improving the reliability of the water removal effect of the PVB film and improving the space utilization rate.

[0041] Specifically, the height direction is the direction away from the ground when the equipment is installed on a horizontal ground.

[0042] In one embodiment, please refer to Figure 2 , the horizontal conveying part 301 includes a plurality of first conveying rollers 3011, and the plurality of first conveying rollers 3011 are spaced apart horizontally. The vertical conveying part 302 includes a plurality of second conveying rollers 3021, and the plurality of second conveying rollers 3021 are spaced apart in an arc shape in the height direction.

[0043] Specifically, the second conveying rollers 3021 are arranged in a circular arc shape to avoid sharp corners in the conveying trajectory of the PVB film, which may cause the PVD film to rupture and be scratched.

[0044] In this embodiment, by using the first conveying rollers 3011 and the second conveying rollers 3021 to convey the PVB film in the drying chamber 200, the contact area between the conveying device and the PVB film is reduced, so that more surfaces of the PVB film are exposed to the drying environment in the drying chamber 200, further improving the water removal efficiency of the PVB film.

[0045] In one embodiment, please refer to Figure 2 , the vertical conveying part 302 further includes a plurality of third conveying rollers 3022, and the plurality of third conveying rollers 3022 are spaced apart in an arc shape in the height direction. When the second conveying rollers 3021 convey the PVB film, the third conveying rollers 3022 are located on the side of the PVB film away from the second conveying rollers 3021 and are in contact with the PVB film.

[0046] In this embodiment, a plurality of third conveying rollers 3022 are arranged at the longitudinal conveying portion 302, and the third conveying rollers 3022 cooperate with the second conveying rollers 3021 from opposite sides of the PVB film to jointly convey the PVB film, thereby improving the guidance and position limiting of the PVB film at the bend of the motion trajectory, and then stably conveying the PVB film softened by heating, preventing the PVB film from escaping from the conveying trajectory and causing equipment blockage and jamming, thereby improving the functional reliability of the conveying device 300. In addition, at the bend, the inner and outer curved sides of the PVB film receive different stretching effects, and the conveying rollers with heat conduction on both sides contact the film, so that the water vapor in the PVB film can be more easily and fully precipitated.

[0047] In one embodiment, see Figure 2 There are multiple groups of negative pressure devices 500, and the multiple groups of negative pressure devices 500 are respectively connected to the positions where different horizontal conveying parts 301 of the drying chamber 200 are located.

[0048] In this embodiment, by providing a plurality of negative pressure devices 500 and respectively connecting them with the positions of the transverse conveying parts 301, the uniformity of the pressure in the drying chamber 200 can be improved, and the moisture discharged from the PVB film can be promptly extracted from the drying chamber 200 to avoid the re-entry of moisture during the cooling process of the PVB film, resulting in the moisture content of the PVB film not meeting the standard.

[0049] In one embodiment, see Figure 2 A gap is provided between the heating device 400 and the discharge port, and the conveying track of the conveying device 300 passes through the gap and extends to the discharge port. The area where the gap is located constitutes a cooling section, and the cooling section is suitable for cooling and hardening the PVB film.

[0050] In this embodiment, by setting a gap between the heating device 400 and the discharge port, the PVB film transported by the transport device 300 is heated and dehydrated in the drying chamber 200, and then cooled in a dry environment to harden again.

[0051] In one embodiment, refer to 3, an elastic sealing component 201 is provided at the discharge port, and the elastic sealing component elastically expands and contracts relative to the film surface of the PVB film. When the PVB film is output from the discharge port, the elastic end of the elastic sealing component at least presses against one film surface of the PVB film, and the elastic sealing component is used to elastically seal the discharge port.

[0052] Specifically, the specific form of the elastic sealing component 201 is not limited in this embodiment. Specifically, the elastic sealing component 201 may include two elastic clamping blocks. When the PVB film is output from the discharge port, the two elastic clamping blocks are respectively arranged on both sides of the PVB film and are respectively in contact with the PVB film.

[0053] In this embodiment, by arranging the elastic sealing component 201 at the discharge port, since the elastic sealing component elastically expands and contracts relative to the film surface of the PVB film, when the PVB film is output from the discharge port, the elastic sealing component abuts against the surface of the PVB film, thereby reducing the situation that external air enters the drying chamber 200 from the discharge port and affecting the overall humidity in the drying chamber 200. At the same time, the negative pressure degree in the drying chamber 200 is also increased, improving the water removal effect on the PVB film.

[0054] In one embodiment, please refer to Figure 2 , and further includes a cutting device 600. The cutting device 600 is connected to the frame 100. The cutting device 600 is located behind the discharge port in the conveying direction, and the cutting device 600 is used to cut the processed PVB film.

[0055] Specifically, a conveyor belt is provided on the frame 100 at the discharge port. The cutting device 600 is arranged above the conveyor belt and cooperates with the conveyor belt to cut the PVB film and transport the cut PVB film.

[0056] It should be noted that the specific form of the cutting device 600 is not limited in this embodiment, as long as it can complete the cutting action of the PVB film. Exemplarily, the cutting device 600 includes a cylinder and a cutter. The cutter is arranged on the piston rod of the cylinder, and the cylinder is arranged on the frame 100. The cutter is driven by the cylinder to press down to cut the PVB film.

[0057] In this embodiment, since the device can not only perform water treatment on the sheet-shaped PVB film, but also perform continuous water treatment on the unwound PVB film strip. In the case of treating the PVB film strip, after the PVB film is output from the drying chamber 200, it is immediately cut into a predetermined size, which can make the PVB film after water treatment quickly enter the ready-to-use state, and can also quickly package the PVB film after water treatment. When waiting to be used, there is no need to unwind and perform water treatment again, greatly improving the convenience and practicality.

[0058] In one embodiment, please refer to Figure 2 , and further includes a closed unwinding bin 700. The unwinding device is arranged in the unwinding bin 700. The unwinding bin 700 has a material outlet, and the material outlet is hermetically connected to the feed inlet.

[0059] In this embodiment, by providing a unwind bin 700 for accommodating the unwind device and connecting the material outlet of the unwind bin 700 to the feed inlet, on the one hand, the unwind bin 700 is connected to the drying bin 200. With the negative pressure device 500 and the heating device 400 communicated with the drying bin 200, a drying environment is provided for the unwind bin 700, and the unwound PVB film coil is isolated from the external environment, preventing the PVB film from absorbing moisture during the unwinding process, and further controlling the water removal effect on the PVB film.

[0060] In one embodiment, it further includes an unwind device, which is disposed opposite to the feed inlet, and the unwind device is adapted to unwind and expand the coil of the PVB film.

[0061] In this embodiment, by providing an unwind device (not shown in the figure), it is convenient to unwind the PVB film coil, and then the unwound PVB film is input into the drying bin 200, increasing the contact area between the PVB film and the dry negative pressure environment in the drying bin 200 and improving the water removal efficiency.

[0062] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A PVB film drying device, characterized in that: include: Rack(100); A drying bin (200) connected to the frame (100), wherein the drying bin (200) has a feed inlet and a discharge outlet; A conveying device (300) connected to the frame (100) and adapted to convey the PVB film in the drying chamber (200) and to convey the PVB film from the feed port to the discharge port; A heating device (400) connected to the frame (100), arranged corresponding to the drying bin (200), and distributed along a conveying track of the conveying device (300), suitable for heating the PVB film in the drying bin (200); A negative pressure device (500) is connected to the drying chamber (200) and is used to extract water vapor from the drying chamber (200).

2. The PVB film drying equipment according to claim 1, characterized in that: The transport device (300) comprises a plurality of transverse conveying parts (301), the plurality of transverse conveying parts (301) are spaced apart in the height direction, a longitudinal conveying part (302) is respectively arranged between adjacent transverse conveying parts (301), and two adjacent longitudinal conveying parts (302) are arranged at different ends of the corresponding transverse conveying parts (301), the transverse conveying part (301) is suitable for conveying the PVB adhesive film in the transverse direction, and the longitudinal conveying part (302) is suitable for conveying the PVB adhesive film in the longitudinal direction, and the plurality of longitudinal conveying parts (302) and the plurality of transverse conveying parts (301) cooperate to form an "S"-shaped conveying track arranged in the height direction.

3. The PVB film drying equipment according to claim 2, characterized in that: The transverse conveying portion (301) comprises a plurality of first conveying rollers (3011), and the plurality of first conveying rollers (3011) are distributed at intervals in the transverse direction; the longitudinal conveying portion (302) comprises a plurality of second conveying rollers (3021), and the plurality of second conveying rollers (3021) are distributed at intervals in an arc shape in the height direction.

4. The PVB film drying equipment according to claim 3, characterized in that: The longitudinal conveying portion (302) further comprises a plurality of third conveying rollers (3022), wherein the plurality of third conveying rollers (3022) are distributed in an arc shape at intervals along the height direction, and when the second conveying roller (3021) conveys the PVB film, the third conveying roller (3022) is located on a side of the PVB film away from the second conveying roller (3021), and the third conveying roller (3022) is in contact with the PVB film.

5. The PVB film drying equipment according to claim 2, characterized in that: The negative pressure device (500) is provided in multiple groups, and the multiple groups of the negative pressure device (500) are respectively connected to the positions where different transverse conveying parts (301) of the drying chamber (200) are located.

6. The PVB film drying equipment according to claim 1, characterized in that: A gap is provided between the heating device (400) and the discharge port, the conveying track of the conveying device (300) passes through the gap and extends to the discharge port, and the area where the gap is located constitutes a cooling section, which is suitable for cooling and hardening the PVB adhesive film.

7. The PVB film drying equipment according to claim 1, characterized in that: An elastic sealing component (201) is provided at the discharge port, and the elastic sealing component is elastically expandable and contractible relative to the film surface of the PVB film. When the PVB film is discharged from the discharge port, the elastic end of the elastic sealing component at least presses against one film surface of the PVB film, and the elastic sealing component is used to elastically seal the discharge port.

8. The PVB film drying equipment according to any one of claims 1 to 7, characterized in that: It also comprises a cutting device (600), the cutting device (600) being connected to the frame (100), the cutting device (600) being located behind the discharge port in the conveying direction, and the cutting device (600) being used to cut the processed PVB film.

9. The PVB film drying equipment according to claim 7, characterized in that: It also includes a closed unwinding bin (700), wherein the unwinding bin (700) has a material outlet, and the material outlet is sealed and connected to the material feed port.

10. The PVB film drying equipment according to claim 1, characterized in that: It also includes an unwinding device, which is arranged opposite to the feed port, and the unwinding device is suitable for unwinding and unfolding the roll of the PVB film.

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