A stretching device for biodegradable films

Abstract

This invention discloses a stretching device for a biodegradable membrane, comprising a frame and a control device. The frame is equipped with a stretching unit for adjusting the membrane thickness, and an environmental control chamber is installed at the corresponding workstation of the stretching unit. The stretching unit consists of a pair of stretching rollers that can be synchronously or differentially displaced in the vertical direction. The inner cavity of the environmental control chamber is equipped with a spray humidification module for providing a controlled humidity atomizing medium to the membrane surface, and a heat preservation module for maintaining the inner cavity temperature within a set range. The environmental control chamber has an inlet and an outlet on its two sides, respectively. The stretching unit, the spray humidification module, and the heat preservation module are connected to the control device. The biodegradable membrane is input through the inlet and stretched by the stretching unit inside the environmental control chamber before being output from the outlet. This invention can adjust the membrane thickness according to the needs of the film product, and can comprehensively control the humidity, temperature, and electrostatics of the membrane during the stretching process, thereby improving product quality.

Description

Technical Field

[0001] This utility model relates to the technical field of plastic film production equipment, and in particular to a stretching device for a biodegradable film. Background Technology

[0002] Existing film stretching devices mostly use fixed stretching roller sets, which cannot fine-tune the film thickness online. At the same time, biodegradable films are extremely sensitive to environmental temperature and humidity. Insufficient humidity can easily cause cracks, while excessive humidity can cause adhesion. In addition, the film web is prone to accumulating static electricity during high-speed operation, which leads to dust adsorption and affects product quality.

[0003] Therefore, it is necessary to design a novel stretching device that can adjust the thickness online and comprehensively regulate the stretching environment of biodegradable membranes. Utility Model Content

[0004] The purpose of this invention is to provide a stretching device for biodegradable membranes, which can adjust the membrane thickness according to the needs of the membrane product, and can comprehensively control the humidity, temperature and static electricity of the membrane during the stretching process, thus effectively solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A stretching device for a biodegradable membrane includes a frame and a control device. The frame is equipped with a stretching unit for adjusting the membrane thickness and an environmental control chamber installed at the corresponding workstation of the stretching unit. The stretching unit consists of a pair of stretching rollers that can be synchronously or differentially displaced in the vertical direction. The inner cavity of the environmental control chamber is equipped with a spray humidification module for providing a controlled humidity atomizing medium to the membrane surface and a heat preservation module for maintaining the inner cavity temperature within a set range. The environmental control chamber has an inlet end and an outlet end on its two sides, respectively. The stretching unit, the spray humidification module, and the heat preservation module are respectively connected to the control device. The biodegradable membrane is input through the inlet end, stretched by the stretching unit inside the environmental control chamber, and output from the outlet end.

[0007] Furthermore, the stretching roller assembly includes an upper stretching roller located above and a lower stretching roller located below, and the bearing housings of the upper stretching roller and / or the lower stretching roller are mounted on the frame via servo electric cylinders.

[0008] Furthermore, the frame is provided with a preheating roller group located upstream of the stretching unit for preheating, a cooling roller group located downstream of the stretching unit for cooling and shaping, a first guide roller located between the preheating roller group and the upper stretching roller, and a second guide roller located between the lower stretching roller and the cooling roller group.

[0009] Furthermore, the upper stretching roller, the lower stretching roller, the first guide roller, and the second guide roller are all metal rollers with an anti-stick coating on their surfaces.

[0010] Furthermore, the spray humidification module includes an ultrasonic atomizer and a humidity sensor disposed in the inner cavity of the environmental control box, and the ultrasonic atomizer and the humidity sensor are respectively connected to the control device.

[0011] Furthermore, the heat preservation module includes an infrared radiation heating tube and a temperature sensor disposed in the inner cavity of the environmental control box, and the infrared radiation heating tube and the temperature sensor are respectively connected to the control device.

[0012] Furthermore, the insulation module also includes a hot air circulation duct equipped with an axial flow fan. One end of the hot air circulation duct is connected to the top of the environmental control box, and the other end of the hot air circulation duct is connected to the bottom of the environmental control box. The axial flow fan is connected to the control device.

[0013] Furthermore, the inlet end and the outlet end are respectively provided with flexible curtain-type seals.

[0014] Furthermore, the top wall of the environmental control box is provided with a transparent viewing window.

[0015] Furthermore, the inner cavity of the environmental control box is also equipped with an electrostatic elimination module for removing static electricity from the membrane surface, and the electrostatic elimination module is connected to the control device.

[0016] Compared with the prior art, the present invention provides a stretching device for a biodegradable membrane, which has the following beneficial effects:

[0017] This invention achieves online micro-adjustment of film thickness by installing a pair of vertically movable stretching rollers on the frame and using a servo electric cylinder for 0.01mm-level adjustment, reducing downtime for roller changes and improving continuous production yield. A multi-functional environmental control enclosure is installed outside the stretching station, integrating spray humidification, heat preservation, and static electricity elimination modules to ensure the film is stretched under optimal environmental conditions, improving product quality. Furthermore, the overall structure is compact, and the modular design of the enclosure facilitates the modification of existing production lines. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0020] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0021] Figure 3 This is a block diagram illustrating the control principle of this utility model.

[0022] Reference numerals: 1. Frame; 11. Preheating roller assembly; 12. Cooling roller assembly; 13. First guide roller; 14. Second guide roller; 2. Control device; 21. Humidity sensor; 22. Temperature sensor; 3. Tensioning unit; 31. Upper tensioning roller; 32. Lower tensioning roller; 33. Servo electric cylinder; 4. Environmental control box; 41. Inlet end; 42. Outlet end; 43. Transparent window; 5. Ultrasonic atomizer; 6. Infrared radiation heating tube; 7. Hot air circulation duct; 71. Axial flow fan; 8. Static electricity elimination module; 9. Biodegradable membrane. Detailed Implementation

[0023] The technical solution of this utility model will be clearly and completely described below through detailed embodiments and in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0024] Example 1

[0025] Please refer to Figure 1 and Figure 3 This embodiment provides a stretching device for a biodegradable membrane, including a frame 1 and a control device 2. The frame 1 is equipped with a stretching unit 3 for adjusting the membrane thickness and an environmental control box 4 installed at the corresponding workstation of the stretching unit. The stretching unit 3 consists of a pair of stretching rollers that can be synchronously or differentially displaced in the vertical direction. The inner cavity of the environmental control box 4 is equipped with a spray humidification module for providing a controlled humidity atomizing medium to the membrane surface and a heat preservation module for maintaining the inner cavity temperature within a set range. The environmental control box 4 has an inlet end 41 and an outlet end 42 on both sides. The stretching unit 3, the spray humidification module, and the heat preservation module are respectively connected to the control device 2. The biodegradable membrane 9 is input through the inlet end 41, stretched by the stretching unit 3 inside the environmental control box 4, and output from the outlet end 42.

[0026] In some specific implementations, the frame 1 is welded from rectangular steel tubes.

[0027] In some specific implementation methods, such as Figure 1As shown, the stretching roller assembly includes an upper stretching roller 31 located at the top and a lower stretching roller 32 located at the bottom. Specifically, the bearing seat of the upper stretching roller 31 is connected to the upper part of the frame via a servo electric cylinder 33, enabling vertical displacement of ±10mm stroke with a displacement accuracy of 0.01mm. The servo electric cylinder is an existing modular product that integrates a servo motor and a lead screw. Those skilled in the art can select appropriate specifications and models according to actual needs, so its specific structure will not be described in detail.

[0028] In some implementations, such as Figure 1 As shown, the frame 1 is equipped with a preheating roller group 11 located upstream of the stretching unit 3 for preheating, a cooling roller group 12 located downstream of the stretching unit 3 for cooling and shaping, a first guide roller 13 located between the preheating roller group 11 and the upper stretching roller 31, and a second guide roller 14 located between the lower stretching roller 32 and the cooling roller group 12. Specifically, the upper stretching roller 31, the lower stretching roller 32, the first guide roller 13, and the second guide roller 14 are all stainless steel rollers with hard chrome plating and a PTFE non-stick coating.

[0029] In some specific implementations, for example, the control device 2 is a PID controller, which can more precisely regulate temperature and humidity. PID controllers are a common type of controller in automation control, and those skilled in the art can select appropriate specifications and models according to actual needs; therefore, their specific structure will not be described in detail.

[0030] In some specific implementation methods, such as Figure 1 and Figure 3 As shown, the spray humidification module includes an ultrasonic atomizer 5 and a humidity sensor 21 disposed within the interior cavity of the environmental control box 4. The ultrasonic atomizer 5 and the humidity sensor 21 are respectively connected to the control device 2. Specifically, the ultrasonic atomizer is a general-purpose ultrasonic atomizing component (mainly including a container for providing water and a ceramic atomizing plate for atomization) that uses a ceramic atomizing plate to disperse liquid water molecules into micron-level water mist. This is an existing technology product, and those skilled in the art can select appropriate specifications and models according to actual needs; therefore, its specific structure will not be described in detail. Alternatively, those skilled in the art can use an atomizing nozzle as a replacement, using a water pump and hose to pump water to the atomizing nozzle to form water mist for humidification.

[0031] In some specific implementation methods, such as Figure 1 and Figure 3As shown, the insulation module includes an infrared radiation heating tube 6 and a temperature sensor 22 disposed inside the environmental control chamber 4. The infrared radiation heating tube 6 and the temperature sensor 22 are respectively connected to the control device 2. By using the infrared radiation heating tube, the temperature inside the environmental control chamber can be maintained effectively, avoiding large fluctuations.

[0032] In some specific implementation methods, such as Figure 1 and Figure 3 As shown, the insulation module also includes a hot air circulation duct 7 equipped with an axial flow fan 71. One end of the hot air circulation duct 7 is connected to the top of the environmental control box 4, and the other end is connected to the bottom of the environmental control box 4. The axial flow fan 71 is connected to the control device 2. The axial flow fan draws hot air from the top of the inner cavity of the environmental control box into the hot air circulation duct and blows it out from the bottom of the environmental control box, forming a laminar flow from bottom to top. This avoids the airflow directly impacting the membrane and causing vibration, ensuring that the temperature difference on the membrane surface is <0.5℃ and improving the flatness of the membrane roll end face after stretching.

[0033] In some specific implementation methods, such as Figure 1 As shown, the inlet end 41 and the outlet end 42 are respectively equipped with flexible curtain-type seals, thereby minimizing gas exchange between the inside and outside of the environmental control chamber without affecting the delivery of the biodegradable membrane. Specifically, as an example, the flexible curtain-type seal is a PVC flexible curtain.

[0034] In some specific implementation methods, such as Figure 1 As shown, the top wall of the environmental control box 4 is provided with a transparent viewing window 43, which facilitates observation of the internal membrane state.

[0035] In some specific implementation methods, such as Figure 1 and Figure 3 As shown, the inner cavity of the environmental control box 4 is also equipped with an electrostatic elimination module 8 for removing static electricity from the membrane surface. The electrostatic elimination module 8 is connected to the control device 2. Specifically, as an example, the electrostatic elimination module is an ion fan bar, which can generate positive and negative ions to neutralize the static electricity on the membrane surface and prevent dust accumulation.

[0036] In some specific embodiments, for example, the biodegradable membrane 9 can be made of materials such as polylactic acid, polybutylene adipate / terephthalate, or polyhydroxyalkanoate film.

[0037] Work process: Reference Figure 1 and Figure 3After being preheated (e.g., to 45°C) by the preheating roller assembly 11, the biodegradable membrane 9 enters the environmental control chamber 4. The humidity sensor 21 detects the humidity in real time and feeds the signal back to the ultrasonic atomizer 5 to maintain 55%RH. At the same time, the infrared radiation heating tube 6 is linked with the axial flow fan 71 to maintain the temperature at 45°C. The ion bar generates positive and negative ions to neutralize the static electricity on the membrane surface and prevent dust accumulation. In the environmental control chamber 4, the biodegradable membrane 9 is stretched to the target thickness by the upper stretching roller 31 and the lower stretching roller 32, and then cooled and shaped by the cooling roller assembly 12.

[0038] This embodiment achieves online fine-tuning of film thickness by installing a pair of vertically movable stretching rollers on the frame and using a servo electric cylinder to achieve adjustments in the 0.01mm range. This reduces downtime for roller changes and improves the continuous production yield. A multi-functional environmental control enclosure is installed outside the stretching station, integrating three major functional modules: spray humidity control, heat preservation, and static electricity elimination. This ensures that the film is stretched under optimal environmental conditions, improving product quality. Furthermore, the overall structure is compact, and the modular design of the enclosure facilitates the modification of existing production lines.

[0039] Example 2

[0040] refer to Figure 2 and Figure 3 The difference between this embodiment and Embodiment 1 is that the bearing seat of the upper stretching roller 31 is connected to the upper part of the frame through a servo electric cylinder, and the bearing seat of the lower stretching roller 32 is connected to the lower part of the frame through another servo electric cylinder. The two servo electric cylinders are driven independently and can achieve differential displacement, which can further reduce the film thickness tolerance to ±1μm, making it suitable for the production of high oxygen barrier biodegradable membranes. For example, when it is necessary to reduce the thickness, the upper stretching roller descends by 1mm while the lower stretching roller rises by 0.5mm, reducing the total gap by 1.5mm, and vice versa.

[0041] The above embodiments are merely illustrative of the concept and technical solution of this utility model, and are not intended to limit this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

[0042] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A stretching device for biodegradable films, comprising a frame and a control device, characterized in that, The frame is equipped with a stretching unit for adjusting the film thickness and an environmental control box installed at the corresponding stretching unit station. The stretching unit consists of a pair of stretching rollers that can be synchronously or differentially displaced in the vertical direction. The inner cavity of the environmental control box is equipped with a spray humidification module for providing a controlled humidity atomizing medium to the film surface and a heat preservation module for maintaining the inner cavity temperature within a set range. The environmental control box has an inlet end and an outlet end on both sides. The stretching unit, the spray humidification module, and the heat preservation module are respectively connected to the control device. The biodegradable film is input through the inlet end, stretched by the stretching unit inside the environmental control box, and output from the outlet end.

2. The stretching apparatus for biodegradable films according to claim 1, characterized in that, The stretching roller assembly includes an upper stretching roller located at the top and a lower stretching roller located at the bottom. The bearing housings of the upper stretching roller and / or the lower stretching roller are mounted on the frame via servo electric cylinders.

3. The stretching apparatus for biodegradable films according to claim 2, characterized in that, The frame is equipped with a preheating roller group located upstream of the stretching unit for preheating, a cooling roller group located downstream of the stretching unit for cooling and shaping, a first guide roller located between the preheating roller group and the upper stretching roller, and a second guide roller located between the lower stretching roller and the cooling roller group.

4. The stretching apparatus for biodegradable films according to claim 3, characterized in that, The upper stretching roller, the lower stretching roller, the first guide roller, and the second guide roller are all metal rollers with an anti-stick coating on their surfaces.

5. The stretching apparatus for biodegradable films according to claim 1, characterized in that, The spray humidification module includes an ultrasonic atomizer and a humidity sensor installed in the inner cavity of the environmental control box. The ultrasonic atomizer and the humidity sensor are respectively connected to the control device.

6. The stretching apparatus for biodegradable films according to claim 1, characterized in that, The insulation module includes an infrared radiation heating tube and a temperature sensor installed in the inner cavity of the environmental control box. The infrared radiation heating tube and the temperature sensor are respectively connected to the control device.

7. The stretching apparatus for biodegradable films according to claim 6, characterized in that, The insulation module also includes a hot air circulation duct equipped with an axial flow fan. One end of the hot air circulation duct is connected to the top of the environmental control box, and the other end of the hot air circulation duct is connected to the bottom of the environmental control box. The axial flow fan is connected to the control device.

8. The stretching apparatus for biodegradable films according to claim 1, characterized in that, The inlet end and the outlet end are respectively provided with flexible curtain-type seals.

9. The stretching apparatus for biodegradable films according to claim 1, characterized in that, The top wall of the environmental control box is equipped with a transparent viewing window.

10. The stretching apparatus for biodegradable films according to any one of claims 1 to 9, characterized in that, The inner cavity of the environmental control box is also equipped with an electrostatic elimination module for removing static electricity from the membrane surface, and the electrostatic elimination module is connected to the control device.

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