Drawing machine anti-dripping and anti-dissolving mechanism for polyimide film production
By installing electric heating tubes and pre-condensation devices at the outlet and inlet of the stretching machine, the problem of solvent condensation caused by temperature difference in the stretching machine was solved, improving film quality and production safety, and reducing pollution and waste.
Patent Information
- Application Number
- CN202423317539.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-11-25
- Estimated Expiration
- 2034-12-31
AI Technical Summary
During the production of polyimide film, the temperature difference between the inside and outside of the stretching machine causes solvent gas to condense, forming small droplets that fall onto the film, resulting in quality contamination and waste.
Electric heating tubes are installed at the outlet and inlet of the stretching machine, combined with a pre-condensation device, including a cooling water circulation pipe and a solvent diversion pipe, to reduce the concentration of solvent vapor and water vapor and prevent condensation. The electric heating tubes heat the cold air, and the pre-condensation device treats the area not covered by the exhaust pipe.
It effectively prevents solvent dripping, improves film quality, reduces pollution, enhances production safety, and reduces environmental impact.
Smart Images
Figure CN223590089U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of polyimide film production, in particular to a stretching machine anti-dripping mechanism for polyimide film production. BACKGROUND
[0002] At present, the general process of preparing polyimide film by using a thermal imine method is as follows: after defoaming, the polyamide acid solution is pressed into the die head storage tank of the front box body from the stainless steel solution storage tank through the pipeline, the steel belt is installed on the large drum of the front and rear box bodies and is operated in a certain direction, the solution in the storage tank is uniformly covered on the surface of the steel belt under the action of the die head scraper, a liquid film with uniform thickness is formed, and then the liquid film is dried in the drying channel; after one rotation, the liquid film becomes a solid film which is peeled off from the large drum of the front box body as the solvent evaporates; the peeled film enters the stretching machine for transverse stretching and imidization stage again through the guide roller. After high-temperature imidization, the film needs to be cut off by the cutting mechanism to remove the waste edges with pinholes on both sides of the film, and then the cut film needs to undergo a series of process procedures such as thickness detection, dust sticking treatment, annealing treatment and flaw detection, and finally the winding machine is used to complete the winding work.
[0003] Among them, due to the temperature difference between the inside and outside of the stretching machine box, the solvent gas volatilized by the film heating is extremely easy to form small droplets at the inlet and outlet parts of the stretching machine box when meeting cold, and when the weight of the small droplets gathered is greater than the adhesion, the small droplets will drop on the film running below, causing the quality pollution of the whole roll of film. This not only leads to the decline and waste of the film quality, but also increases the workload for selecting high-quality film. In order to produce high-quality film and further increase the profits of enterprises, it is urgent to solve the problem of dripping solution of the stretching machine. SUMMARY
[0004] To solve the above problems, the technical scheme adopted by the application is a stretching machine anti-dripping mechanism for polyimide film production, which comprises a stretching machine provided with an exhaust pipe, an exhaust port is arranged in the stretching machine, and the stretching machine comprises an electric heating pipe arranged at the outlet position of the stretching machine, an electric heating pipe arranged at the inlet position of the stretching machine and a pre-condensation device arranged inside the outlet position of the stretching machine. The pre-condensation device comprises a cooling water circulation pipe, a solvent drainage pipe and a solvent tank. The cooling water circulation pipe is arranged above the solvent tank, the solvent drainage pipe is arranged above the solvent tank, and the solvent drainage pipe is arranged above the solvent tank.
[0005] Optionally, the electric heating pipe is wrapped with a protective plate, and the protective plate is made of austenitic stainless steel.
[0006] Optionally, the cooling water circulation pipe comprises an inner cooling water circulation pipe arranged inside the stretching machine and an outer cooling water circulation pipe arranged outside the stretching machine, and the water inlet pipe of the outer cooling water circulation pipe is arranged in close contact with the air exhaust pipe of the stretching machine.
[0007] Optionally, the electric heating pipe is provided with electrically conductive plates at both ends, and the electrically conductive plates are connected to the electric heating pipe in groups through mechanical fasteners.
[0008] Optionally, the electrically conductive plates are internally provided with temperature sensors connected to a temperature monitoring system.
[0009] Optionally, the pre-condensation device is arranged at a position 1 / 3-2 / 3 of the distance between the last air outlet in the forward direction of the stretching machine and the outlet position of the stretching machine.
[0010] Optionally, the length of the electric heating pipe is consistent with the maximum production width of the film.
[0011] Optionally, the electric heating pipe covers the bottom surface and the inner side wall of the upper wall of the outlet of the stretching machine, and covers the bottom surface and the inner side wall of the upper wall of the inlet of the stretching machine.
[0012] The polyimide film production stretching machine anti-dripping mechanism provided in the present application has the following beneficial effects:
[0013] 1. The electric heating pipe arranged at the outlet and inlet positions of the stretching machine heats the cold air entering the interior of the stretching machine, avoiding the condensation of solvents at the outlet and inlet positions of the stretching machine, and eliminating the problem of film pollution caused by solvent dripping;
[0014] 2. The pre-condensation device reduces the concentration of solvent vapor and water vapor at the outlet of the stretching machine, on the one hand further preventing the condensation of solvents or water vapor, and on the other hand reducing the escape of solvent vapor outside the stretching machine, improving the safety of the operators in the production environment. BRIEF DESCRIPTION OF DRAWINGS
[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments or prior art description will be briefly introduced as follows.
[0016] Figure 1 The stretching machine top view schematic diagram (the film traction device and heating device have been hidden) provided in the embodiments of the present application;
[0017] Figure 2 The C-C sectional view (the film traction device and heating device have been hidden) of Figure 1 ;
[0018] Figure 3 The enlarged view of Figure 1 place A;
[0019] Figure 4 is an enlarged view of A in FIG. 1; Figure 1 is an enlarged view of A in FIG. 1;
[0020] Figure 5 is a front view of an electric heating tube provided by an embodiment of the present application;
[0021] Figure 6 is a left view of an electric heating tube provided by an embodiment of the present application;
[0022] Figure 7 is a right view of an electric heating tube provided by an embodiment of the present application;
[0023] Figure 8 is a perspective view of a pre-condensing device provided by an embodiment of the present application;
[0024] Figure 9 is a side view of a pre-condensing device provided by an embodiment of the present application;
[0025] Figure 10 is an A-A sectional view of FIG. 1. Figure 9
[0026] Reference signs: 1 - stretching machine box body; 2 - air inlet mechanism; 3 - air outlet mechanism; 4 - electric heating tube; 5 - stretching machine inlet; 6 - stretching machine outlet; 7 - air outlet pipe; 8 - stretching machine outlet upper wall; 9 - stretching machine inlet upper wall; 10 - solvent flow guide pipe; 11 - solvent flow guide pipe opening; 12 - cooling water circulation pipe; 13 - pre-condensing device; 14 - solvent tank; 15 - conductive plate; 16 - protection plate. DETAILED DESCRIPTION
[0027] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.
[0028] As Figures 1 to 4 and Figures 8 to 10 As shown, a kind of anti-dripping mechanism of polyimide film production stretching machine, including the stretching machine being provided with exhaust pipe 7, by air supply mechanism 2 to the inside of stretching machine box 1, usually air supply position is at the bottom of stretching machine box, by exhaust mechanism 3 from the stretching machine box 1, exhaust pipe 7 is provided with exhaust port in the inside of stretching machine, the position of stretching machine outlet 6 is provided with electric heating tube 4, the position of stretching machine inlet 5 is provided with electric heating tube 4.Pre-cooling device 13 is set to the inside of the position of stretching machine outlet 6, pre-cooling device 13 includes cooling water circulation pipe 12, solvent drainage pipe 10 and solvent tank 14, cooling water circulation pipe 12 is set to the above of solvent tank 14, solvent drainage pipe 10 is located in the pipe body of the inside of stretching machine and is all above solvent tank 14, and solvent drainage pipe orifice 11 is opened in the bottom of solvent tank 14.
[0029] When using, cooling water is circulated in cooling water circulation pipe 12, and solvent vapor and water vapor near the position are condensed on cooling water circulation pipe, and then drop into solvent tank 14, and are extracted by solvent drainage pipe 10 through solvent drainage pipe orifice 11.After extraction, solvent can be collected and separated, and can be used secondly.
[0030] The heat treatment process of polyimide film thermal imidization production procedure includes three stages: solvent evaporation stage, imidization stage and annealing stage, the temperature in the inside of stretching machine gradually rises from the beginning of film precursor entering the stretching machine to annealing zone, thus, the distribution of possible condensed liquid drops in the inside of stretching machine also has obvious stage characteristics.In the area where film completes annealing and leaves the stretching machine, the temperature difference between stretching machine and outside is large, at this time, solvent vapor that is not treated completely by exhaust pipe 7 still exists in the inside of stretching machine, and water vapor generated in imidization and annealing stage also exists, solvent composition is complex, and the temperature difference between the inside and outside of stretching machine is large, a large amount of solvent condensation phenomenon exists, and if the number of exhaust pipe arranged in this place is increased, the high-temperature treatment procedure in the inside of stretching machine is easily affected, and more external cold air is introduced.Therefore, not only anti-dripping electric heating plate is arranged in this place, but also pre-cooling device 13 is arranged;When just entering the stretching machine, the solvent content in film precursor is high, but the temperature gradient in this place is stable, the temperature difference is small, the number of exhaust pipe 7 arranged is large, the influence of cold air introduced from outside on this place is low, and solvent condensation phenomenon is less, so only anti-dripping electric heating tube 4 is arranged.
[0031] As shown in the figure, Figure 3 And Figure 4As shown, in another embodiment of this application, the electric heating tube 4 is externally wrapped with a protective plate 16, which is made of austenitic stainless steel. In this embodiment, the protective plate 16 is made of austenitic stainless steel grade 316, which has good corrosion resistance and high thermal conductivity due to its high chromium content. Its thermal conductivity increases at high temperatures, enabling rapid transfer of heat generated by the electric heating tube 4. Through its excellent resistance to chemical corrosion, it resists corrosion that may be caused by solvent vapors, preventing the electric heating tube 4 from being directly exposed to solvent vapors and thus mitigating potential safety risks. It also ensures uniform heat distribution around the protective plate 16.
[0032] like Figure 2 , Figure 8 , Figure 9 and Figure 10 As shown, in another embodiment of this application, the cooling water circulation pipe 12 includes an inner cooling water circulation pipe 12 disposed inside the stretching machine and an outer cooling water circulation pipe disposed outside the stretching machine. The inlet pipe of the outer cooling water circulation pipe is fitted to the exhaust pipe 7 of the stretching machine. The solvents evaporated during the polyimide film production process mainly include N,N-dimethylacetamide, dimethylformamide, tetrahydrofuran, methanol, and N-methylpyrrolidone. Among them, the boiling point of methanol is 64.7°C, the boiling point of tetrahydrofuran is 66°C, and the boiling points of the other solvents are all above 150°C. Preheating the cooling water in advance can reduce the impact of the cooling water circulation pipe 12 on the internal thermal order of the stretching machine. The temperature of the cooling water entering the stretching machine should be 20-50°C, and the specific temperature is affected by the season, but should not exceed 50°C.
[0033] like Figures 5-7 As shown, in another embodiment of this application, conductive plates 15 are provided at both ends of the electric heating tube 4, and the conductive plates 15 are connected to the electric heating tube 4 in groups by mechanical fasteners. The conductive plates 15 reduce the local overheating phenomenon caused by current concentration at both ends of the electric heating tube 4, extend the service life of the electric heating tube 4, fix the electric heating tube 4, and enhance the mechanical strength at both ends of the electric heating tube 4.
[0034] The conductive plates 15 are used to fix the electric heating tubes 4 in groups, enabling them to be rotated for maintenance.
[0035] like Figure 6 and Figure 7 As shown, in another embodiment of this application, a temperature sensor is provided inside the conductive plate 15, and the temperature sensor is connected to a temperature monitoring system. The temperature of the electric heating tube 4 and the conductive plate 15 is monitored in real time. When the temperature monitoring system receives an overheating signal, it immediately cuts off the power supply or reduces the heating power to prevent the electric heating tube 4 from heating up further.
[0036] like Figure 2 and Figure 3As shown, in another embodiment of this application, the pre-condensation device 13 is located at a distance of 1 / 3 to 2 / 3 from the last exhaust port of the stretching machine in the direction of the polyimide film's advance. The pre-condensation device 13 is mainly used to handle areas that cannot be covered by the exhaust port, and is therefore located between the last exhaust port and the stretching machine outlet 6.
[0037] like Figure 2 and Figure 3 As shown, in another embodiment of this application, the length of the electric heating tube 4 is consistent with the maximum production width of the film. In order to ensure that the cold air entering the stretching machine is fully heated, the length of the electric heating tube 4 should be consistent with the maximum production width of the film. The stretching machine is usually provided with air vents on both sides of the film production width to reduce the amount of cold air intrusion.
[0038] In another embodiment of this application, the electric heating tube 4 covers the bottom surface and inner side wall of the upper wall 8 at the outlet of the stretching machine, and the electric heating tube 4 covers the bottom surface and inner side wall of the upper wall 9 at the inlet of the stretching machine.
[0039] The upper wall 8 at the outlet of the stretching machine and the upper wall 9 at the inlet of the stretching machine are in direct contact with the outside air and have a low temperature. This area is prone to become a heterogeneous interface for solvent vapor condensation. Placing the electric heating tube 4 at this location can not only heat the cold air entering the stretching machine, but also heat the upper wall 8 at the outlet of the stretching machine and the upper wall 9 at the inlet of the stretching machine.
[0040] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.
Claims
1. A drip solution preventing mechanism for a stretching machine for polyimide film production, comprising a stretching machine provided with an exhaust pipe, the exhaust pipe being provided with an exhaust port inside the stretching machine, characterized in that: The device comprises an electric heating pipe arranged at the outlet position of the drawing machine, an electric heating pipe arranged at the inlet position of the drawing machine, and a pre-condensing device arranged inside the outlet position of the drawing machine, wherein the pre-condensing device comprises a cooling water circulation pipe, a solvent drainage pipe, and a solvent tank, the cooling water circulation pipe is arranged above the solvent tank, the solvent drainage pipe is arranged above the solvent tank, and the solvent drainage pipe is arranged at the bottom of the solvent tank.
2. The stretching machine anti-dripping mechanism for polyimide film production according to claim 1, characterized in that: The electric heating pipe is wrapped with a protective plate made of austenitic stainless steel.
3. The stretching machine anti-dripping mechanism for polyimide film production according to claim 1, characterized in that: The cooling water circulation pipe comprises an inner cooling water circulation pipe arranged inside the drawing machine and an outer cooling water circulation pipe arranged outside the drawing machine, and the water inlet pipe of the outer cooling water circulation pipe is arranged in close contact with the exhaust pipe of the drawing machine.
4. The stretching machine anti-dripping mechanism for polyimide film production according to claim 2, characterized in that: The electric heating pipe is provided with conductive plates at both ends, and the conductive plates are connected to the electric heating pipe in groups through mechanical fasteners.
5. The stretching machine anti-dripping mechanism for polyimide film production according to claim 4, characterized in that: The conductive plates are provided with temperature sensors inside, and the temperature sensors are connected to a temperature monitoring system.
6. The stretching machine anti-dripping mechanism for polyimide film production according to claim 1, characterized in that: The pre-condensing device is arranged at a position 1 / 3-2 / 3 away from the last exhaust port of the drawing machine in the direction of the movement of the polyimide film and the outlet position of the drawing machine.
7. The stretching machine anti-dripping mechanism for polyimide film production according to claim 6, characterized by: The length of the electric heating pipe is consistent with the maximum production width of the film.
8. The stretching machine anti-dripping mechanism for polyimide film production according to claim 7, characterized by: The electric heating pipe covers the bottom surface and the inner side wall of the upper wall of the outlet of the drawing machine, and the electric heating pipe covers the bottom surface and the inner side wall of the upper wall of the inlet of the drawing machine.