Precision forming system and method for producing high-performance PEEK film

Abstract

The invention belongs to the field of high-performance special engineering plastic processing, and discloses a precision forming system and method for producing a high-performance PEEK film, the system comprises an extrusion system and a shaping and winding system, the extrusion system is sequentially connected with an extruder main body, a melt pump, a rapid screen changer and a clothes hanger type extrusion mold; and the shaping and rolling system covers casting guide point precision regulation and control, gradient crystallization and dynamic heat shaping, multi-parameter closed-loop detection control, constant tension rolling and an auxiliary unit. The production method comprises the steps of setting initial forming conditions through precise regulation and control of a casting guide point, completing different crystallization processes through gradient crystallization and dynamic thermal management, quantitatively controlling cooling time through dynamic thermal management, controlling thickness tolerance in a multi-parameter closed-loop mode, and avoiding film deformation through constant-tension rolling. According to the invention, the PEEK film with the thickness of 0.005-0.5 mm can be produced, the thickness tolerance can be dynamically and precisely controlled, and the stable quality of the film is ensured.

Description

Technical Field

[0001] This invention relates to the field of high-performance special engineering plastics processing, and specifically to a precision molding system and method for polyether ether ketone (PEEK) films, specifically a precision molding system and method for producing high-performance PEEK films. Background Technology

[0002] In the current film production technology field, during the film production process, plastic granules are heated, melted, and extruded through an extruder to be shaped into sheet-like film products. Most of the current film products are made of plastic materials such as PC and PA. With the increase in application fields and the expansion of the market, the requirements for films are getting higher and higher, especially for properties such as high temperature resistance and high strength. Films made of PEEK have begun to appear.

[0003] Polyetheretherketone (PEEK), a semi-crystalline, high-performance thermoplastic engineering plastic, can be used continuously at 250°C. It maintains high flexural and compressive strength at high temperatures, exhibits high rigidity, good dimensional stability, and a low coefficient of linear expansion. Except for concentrated sulfuric acid, it is resistant to almost any chemical; moreover, it maintains good chemical stability even at high temperatures and is inherently flame-retardant. PEEK films possess high heat resistance, good electrical and mechanical properties, and can be used continuously at temperatures up to 240°C. In particular, its resistance to chemicals, hydrolysis, and radiation is outstanding among high-performance films.

[0004] However, the inherent characteristics of PEEK material, such as its extremely high melting point of 343℃, high melt viscosity, and narrow crystallization window, present challenges that traditional equipment cannot overcome in its thin film production. Surface quality defects: Traditional single-roller or double-roller cooling and shaping methods cannot match the complex crystallization kinetics of PEEK. The cooling rate is either too fast, causing the internal stress to be "frozen" and forming "flow lines", or too slow or uneven, causing excessive growth of spherulites and forming "crystal points".

[0005] Uncontrolled Mechanical Properties and Crystallinity: Crystallinity and crystal morphology are key factors determining the tensile strength, heat resistance, and transparency of PEEK films. Existing equipment lacks precise segmented control over the crystallization process, resulting in uneven crystallinity or deviations from ideal values. This causes the tensile strength of the film (typically only 90 MPa) to fall far short of the theoretical potential of PEEK materials, and makes it impossible to customize product structures according to application requirements.

[0006] Poor thickness control accuracy: PEEK melt has high viscosity and is extremely sensitive to fluctuations in pressure and flow rate. Traditional extruders are directly driven, and even small fluctuations in motor speed can directly lead to uneven output, resulting in large film thickness tolerances (typically ≥ ±0.04 mm), which cannot meet the requirements of high-end electronics, medical and other fields.

[0007] Therefore, there is an urgent need in this field for a dedicated production line control system and method that can actively intervene in the PEEK "stress-crystallization" process and achieve multi-parameter coordinated precision control. Summary of the Invention

[0008] The primary objective of this invention is to provide a control system for a precision extrusion production line of PEEK film, so as to systematically solve the problems of surface flow lines, numerous crystal points, low tensile strength, and uneven thickness of PEEK films produced by existing technologies.

[0009] Another objective of this invention is to provide a method for producing PEEK films using the aforementioned control system, thereby achieving stable and continuous production of high-performance PEEK films by precisely controlling the crystallization and stress relief processes of PEEK.

[0010] The technical solution adopted by this invention to solve its technical problem is as follows: A control system for a precision extrusion production line of PEEK film includes, in sequence, an extrusion system and a shaping and winding system. The extrusion system includes an extruder body, the outlet of which is sequentially connected to a melt pump, a quick screen changer, and a coat hanger-type extrusion die. The shaping and winding system includes a precision casting point control unit, a gradient crystallization and dynamic heat setting unit, a multi-parameter closed-loop detection and control unit, a constant tension winding unit, and an auxiliary unit. The precision casting point control unit consists of a lifting driver and a horizontal driver, used to coordinate the control of the air gap L and the traction angle α. The multi-parameter closed-loop detection and control unit includes a thickness measuring device.

[0011] Furthermore, the lifting drive adjusts the vertical distance, i.e., the air gap L, between the hanger-type extrusion die and the first shaping roller via a V-shaped slide; the horizontal drive adjusts the angle, i.e., the traction angle α, between the exit plane of the hanger-type extrusion die and the cross-section of the first shaping roller via a shaping and winding system slide.

[0012] Furthermore, the gradient crystallization and dynamic heat setting unit includes three setting rollers: a first setting roller, a second setting roller, and a third setting roller, whose temperature is independently controlled by an oil temperature controller to form a gradient temperature field.

[0013] Furthermore, the multi-parameter closed-loop detection and control unit includes an optical thickness gauge, which is connected to the central controller to form a thickness closed-loop control system.

[0014] Furthermore, the constant tension winding unit includes a dual-station winding roller driven by a torque motor, which can automatically adjust the torque according to the winding diameter.

[0015] Furthermore, the auxiliary unit includes an antistatic device, an edge-cutting device, and an edge-cutting take-up roller.

[0016] A method for producing PEEK film using a production line control system first sets the initial forming conditions of the melt film by coordinating the air gap L and the traction angle α to control the initial molecular orientation and internal stress; then, the melt film is sequentially passed through a three-roll gradient temperature field of high temperature, medium temperature and low temperature in a gradient crystallization and dynamic heat setting unit; the film covering angle is changed by adjusting the spacing of the setting rollers; then the thickness is controlled based on real-time data from a thickness measuring device; finally, a torque motor is used for winding to maintain a constant winding tension to avoid film deformation.

[0017] Furthermore, the air gap L can be adjusted to a range of 5-100mm, and the traction angle α can be adjusted to a range of 10-90°.

[0018] Furthermore, the spacing of the shaping rollers can be adjusted from 50 to 150 mm, and different functions can be performed according to different ranges. The temperature of the first shaping roller is 230 to 255°C, the temperature of the second shaping roller is 180 to 205°C, and the temperature of the third shaping roller is 50 to 185°C.

[0019] Furthermore, based on the real-time data from the thickness measuring device, the central controller synchronously controls the rotation speed of the main unit and melt pump, the die lip opening of the coat hanger extrusion die, and the rotation speed of the servo motor of the shaping roller according to the film thickness, so as to dynamically control the thickness tolerance within ±0.01mm.

[0020] Compared with the prior art, the beneficial effects of the present invention include: The "gradient crystallization and dynamic stress relief" process fundamentally solves the flow lines and crystal point problems of PEEK films. At the same time, by inducing ordered crystallization, the tensile strength of the film is increased to over 96 MPa, which is superior to products on the market.

[0021] By independently adjusting the temperature and spacing of the three shaping rollers, the crystallization process of PEEK can be precisely controlled, thereby producing films with different crystallization states (from highly crystalline to lowly crystalline) to meet diverse application requirements.

[0022] Through a multi-parameter collaborative control system of "melt pump flow stabilization + optical thickness measurement closed-loop feedback", the film thickness tolerance is stably controlled within ±0.02mm, and the optimal tolerance can reach ±0.01mm.

[0023] The constant tension winding system and dual-station winding design prevent the film from being accidentally stretched and thinned during the winding process, ensuring stability and efficiency throughout the entire process from extrusion to finished product.

[0024] This production line can not only produce standard PEEK films, but also proactively customize the production of a series of products with different microstructures, from high transparency (low crystallinity) to high heat resistance (high crystallinity), through preset spacing-temperature-speed process combinations, to meet the needs of different fields such as aerospace, flexible circuits, and medical packaging. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the PEEK film precision extrusion production line control system of the present invention; Figure 2 This is a schematic diagram of the structure of an optical thickness measuring instrument for thin films; Figure 3 This is a schematic diagram of roller spacing adjustment. (a) is the default reference state, which is suitable for producing high transparency and high toughness films; (b) is the increased spacing state, which is suitable for producing general high performance films; (c) is the decreased spacing state, which is suitable for producing fast crystallization grades or products that pursue high surface gloss. Figure 4 This is an enlarged view of the distance (air gap L) and included angle (traction angle α) positions in the precision control unit of the casting point; Figure 5 This is a process flow diagram of a thin film thickness control method provided in an embodiment of the present invention.

[0026] The attached figures are labeled as follows: 1. Extruder body; 2. Sliding track; 3. Reducer; 4. Drying cylinder; 5. Heated extrusion cylinder; 6. Melt pump; 7. Quick screen changer; 8. Coat hanger type extrusion die; 9. First shaping roller; 10. Second shaping roller; 11. Third shaping roller; 12. Adjusting motor; 13. First shaping roller slide; 14. Third shaping roller adjusting motor; 15. Third shaping roller slide; 16. Oil temperature controller; 17. Shaping and winding system slide; 18. Horizontal drive; 19. Lifting drive; 20. V-shaped slide; 21. Fixed roller; 22. Optical thickness gauge; 221. Upper probe; 222. Lower probe; 223. Display device; 23. Static electricity remover; 24. Edge trimming device; 25. First winding roller; 26. Second winding roller; 27. Edge trimming winding roller. Detailed Implementation

[0027] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] This invention uses a single system applicable to the production of crystalline, amorphous, and semi-crystalline thin films.

[0030] (1) Control system for PEEK film precision extrusion production line The control system for a precision extrusion production line of PEEK film includes, in sequence, an extrusion system and a shaping and winding system. The extrusion system includes: an extruder body 1, the outlet of which is sequentially connected to a melt pump 6, a quick screen changer 7, and a coat hanger-type extrusion die 8. The melt pump 6 is used to provide a stable, fluctuation-free melt output; the quick screen changer 7 is used to filter gel and impurities in the melt. The coat hanger-type extrusion die 8 is used to extrude a thin film melt with a uniform initial thickness.

[0031] The shaping and winding system includes a precision control unit for the casting point, a gradient crystallization and dynamic heat shaping unit, a multi-parameter closed-loop detection and control unit, a constant tension winding unit, and auxiliary units.

[0032] The precision control unit for the casting point consists of a lifting driver 19 and a horizontal driver 18. The lifting driver 19 adjusts the vertical distance (air gap L) between the coat hanger-type extrusion die 8 and the first shaping roller 9 via a V-shaped slide 20. The horizontal driver 18 adjusts the angle (traction angle α) between the exit plane of the coat hanger-type extrusion die 8 and the tangential surface of the first shaping roller 9 via a shaping and winding system slide 17. The air gap L and the traction angle α work together to achieve precise control of the initial forming conditions (casting point) of the melt.

[0033] Specifically, the lifting driver 19 horizontally raises the distance L between the first shaping roller 9, the second shaping roller 10, the third shaping roller 11 and the coat hanger-type extrusion die 8 via the V-shaped slide 20, and the horizontal driver 18 longitudinally adjusts the angle α formed between the melt film and the first shaping roller 9 via the shaping and winding system slide 17.

[0034] The gradient crystallization and dynamic heat setting unit includes a first setting roller 9, a second setting roller 10, and a third setting roller 11. The three setting rollers have the same outer diameter to ensure consistent linear velocity during rotation. They rotate synchronously via servo motors. The temperatures of the three setting rollers are independently controlled by an oil temperature controller 16, creating a gradient temperature field: high temperature (230–255°C for stress relief) for the first setting roller 9, medium temperature (180–205°C for inducing ordered crystallization) for the second setting roller 10, and low temperature (150–185°C for structural setting) for the third setting roller 11. By adjusting motor 12, the third setting roller adjustment motor 14, the first setting roller slide 13, and the third setting roller slide 15, the distance between the first setting roller 9, the third setting roller 11, and the second setting roller 10 is dynamically adjusted, thereby changing the film's coating angle (θ) and residence time (t), and precisely controlling the crystallization and stress relaxation processes at each stage. The distance between the adjusting motor 12 and the third shaping roller adjusting motor 14 is adjusted. The distance between the rollers is 50-150mm. Changing the distance changes the angle.

[0035] Multi-parameter closed-loop detection and control unit: includes an optical thickness gauge 22 installed after the three shaping rollers, which is connected to the central controller. The central controller synchronously controls the rotation speed (coarse flow adjustment) of the main unit and melt pump 6, the die lip opening (local fine adjustment) of the coat hanger type extrusion die 8, and the rotation speed (fine speed adjustment) of the shaping roller servo motor according to the film thickness, thus forming a thickness closed-loop control system.

[0036] The collaborative control logic is as follows: When the optical thickness gauge 22 detects that the thickness is continuously too high, the central controller first slightly increases the speed of the shaping roller to quickly reduce the thickness; then, it synchronously increases the speed of the main machine and the melt pump to match the new output demand and maintain stable system pressure; at the same time, according to the thickness distribution curve, it finely adjusts the mold opening in the corresponding area of ​​the mold to correct the lateral uniformity. This strategy of speed traction, flow rate follow-up, and mold lip correction avoids systemic oscillations caused by the adjustment of a single component and achieves dynamic and precise control of thickness tolerance (up to ±0.01mm).

[0037] The constant tension winding unit includes a dual-station first winding roller 25 and a second winding roller 26 driven by a torque motor. These rollers automatically adjust the torque according to the winding diameter to maintain a constant winding tension, ensuring consistent tensile force on the film during winding and preventing the film from becoming thinner due to increased torque as the winding diameter increases. During the forming process, the first winding roller 25 and the second winding roller 26 alternately wind the film, ensuring continuous production. The winding rollers drive the paper tube to rotate, winding the PEEK film onto the paper tube.

[0038] Auxiliary units include an antistatic device, a cutting device 24, and a cutting and winding roller 27, to improve film cleanliness and width consistency.

[0039] (2) PEEK film production method based on the above production line control system S1. Precision control of casting point: By coordinating the adjustment of air gap (L) and traction angle (α), the initial forming conditions of melt film are actively set, the initial molecular orientation and internal stress of melt film are controlled, and the range of air gap L is 5-100mm, and the range of traction angle α is 10-90°. S2. Gradient Crystallization and Dynamic Thermal Management: The melt film is sequentially passed through a three-roll gradient temperature field of high temperature (235-255℃), medium temperature (185-205℃), and low temperature (165-185℃). During this process, the spacing between the first shaping roller 9, the third shaping roller 11, and the second shaping roller 10 is dynamically adjusted simultaneously to change the film's wrapping angle (θ). For shaping rollers with a diameter of D, when the spacing is adjusted to S, the corresponding wrapping angle θ can be determined by the formula θ = 2 * arccos[(S / 2) / (D / 2)], respectively completing stress relief, ordered crystallization, and structural shaping. The spacing adjustment range is 50-150 mm; 50-80 mm provides a large contact area for structural shaping; 80-120 mm is suitable for ordered crystallization; and 120-150 mm is suitable for stress relief. S3. Dynamic thermal management: In step S2, the roller spacing is dynamically adjusted to change the wrapping angle, the contact area between the extruded film and the shaping roller is adjusted, and the cooling time of the film on each roller is quantitatively controlled t = (θ / 360°) * (πD / v), thereby precisely controlling the PEEK crystallization. S4. Multi-parameter closed-loop control: Based on the real-time data of the optical thickness gauge 22, the central controller coordinates and controls the speed of the melt pump 6, the opening of the die lip of the coat hanger extrusion die 8, and the speed of the servo motor of the shaping roller to dynamically control the thickness tolerance within ±0.01mm. S5. Constant tension winding: A torque motor is used for winding to maintain a constant winding tension and avoid film deformation.

[0040] The control method of this invention is based on the coordinated relationship between the spacing settings of the first shaping roller 9 and the third shaping roller 11, the temperature settings of the three shaping rollers, and the production line speed, all of which are stored together in the equipment's process formula library. For a given PEEK raw material grade and target film thickness, the system calls upon a composite process parameter set that integrates "temperature-speed-spacing".

[0041] The extruder body 1 is equipped with a sliding rail 2, which can push the extruder back and forth for adjustment, facilitating equipment maintenance and adjustment. The extruder body 1 is equipped with a motor, which is connected to a reducer 3 to drive the screw inside the heated extrusion cylinder 5 to rotate; the heated extrusion cylinder 5 has 5 heating zones.

[0042] PEEK granules enter the heated extrusion cylinder 5 through the drying cylinder 4. The heated extrusion cylinder 5 extrudes the molten PEEK material. A melt pump 6 is provided in front of the heated extrusion cylinder 5 to provide a stable melt speed, which can avoid the melt flow rate variation caused by motor fluctuations, thus avoiding uneven film thickness. A quick screen changer 7 is connected in front of the melt pump 6. The quick screen changer 7 filters the molten PEEK to remove gel and other particulate matter formed by heating the PEEK granules. A coat hanger-type extrusion die 8 is connected in front of the quick screen changer 7 to extrude PEEK molten material of uniform thickness.

[0043] The shaping and winding system also includes a fixed roller 21 and an optical thickness gauge 22. The optical thickness gauge 22 includes a display device 223 and a detection probe. The detection probe is divided into an upper probe 221 and a lower probe 222. The upper probe 221 and the lower probe 222 scan left and right synchronously. The optical thickness gauge 22 is connected to the central controller.

[0044] (3) The specific implementation process is as follows: PEEK granules enter the heated extrusion cylinder 5 through the drying cylinder 4. The heated extrusion cylinder 5 is equipped with 5 heating zones with a temperature of 345-395℃. The molten PEEK material is stably transported by the melt pump 6, which has a temperature of 370-390℃ and a speed of 25-45 rpm / min. After passing through the filter screen in the quick screen changer 7, which also has a temperature of 370-390℃, the molten material enters the coat hanger-type extrusion die 8, which has a temperature of 330-375℃. The thickness of the molten material film is controlled by adjusting the gap of the die lips of the coat hanger-type extrusion die 8. The temperatures of the first shaping roller 9, 10, and 11 are set at 235-255℃, 10, and 11 respectively, and the rotation speeds of the three shaping rollers are set at 0.5-8 rpm. The film tension is adjusted by changing the distance between the three shaping rollers. The film passes through the fixed roller 21 and enters the optical thickness gauge 22 for detection. After being pulled by the static eliminator 23, the static electricity on the surface is removed. The edges of both ends of the film are cut off by the edge trimming device 24. The first winding roller 25 and the second winding roller 26 are wound up. The winding tension is 3.5-5.5 NM, and a roll-type PEEK film can be obtained. Films with a thickness of 0.005-0.5 mm can be produced.

[0045] Examples 1-3 The process parameters for Examples 1-3 were adjusted according to Table 1, product performance was tested, and commercially available products were selected as comparative examples. The specific results are as follows: Table 1. Process parameters and product performance of the examples Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A PEEK film precision extrusion production line control system, characterized by, The system includes an extrusion system and a shaping and winding system. The extrusion system includes an extruder body (1), whose outlet is connected in sequence to a melt pump (6), a quick screen changer (7), and a coat hanger-type extrusion die (8). The shaping and winding system includes a casting point precision control unit, a gradient crystallization and dynamic heat shaping unit, a multi-parameter closed-loop detection and control unit, a constant tension winding unit, and an auxiliary unit. The casting point precision control unit is composed of a lifting driver and a horizontal driver, which are used to coordinate the control of the air gap L and the traction angle α. The multi-parameter closed-loop detection and control unit includes a thickness measuring device.

2. The PEEK film precision extrusion line control system of claim 1, wherein, The gradient crystallization and dynamic heat setting unit includes three setting rollers: the first setting roller (9), the second setting roller (10) and the third setting roller (11), whose temperature is independently controlled by the oil temperature controller (16) to form a gradient temperature field.

3. The PEEK film precision extrusion line control system of claim 1, wherein, The multi-parameter closed-loop detection and control unit includes an optical thickness gauge (22), which is connected to the central controller to form a thickness closed-loop control system.

4. The control system for a precision PEEK film extrusion production line according to claim 1, characterized in that, The lifting driver (19) adjusts the vertical distance, i.e. the air gap L, between the hanger-type extrusion die (8) and the first shaping roller (9) through the V-shaped slide 20; the horizontal driver 18 adjusts the angle between the exit plane of the hanger-type extrusion die (8) and the cross-section of the first shaping roller (9), i.e. the traction angle α, through the shaping and winding system slide 17.

5. The control system for a precision PEEK film extrusion production line according to claim 1, characterized in that, The constant tension winding unit includes a dual-station winding roller driven by a torque motor, which can automatically adjust the torque according to the winding diameter.

6. The control system for a precision PEEK film extrusion production line according to claim 1, characterized in that, The auxiliary unit includes an antistatic device (23), an edge trimming device (24), and an edge trimming take-up roller (27).

7. A method for producing PEEK film based on the production line control system according to any one of claims 1-6, characterized in that, First, the initial forming conditions of the melt film are set by coordinating the air gap L and the traction angle α to control the initial molecular orientation and internal stress. Then, the melt film is passed through the three-roll gradient temperature field of high temperature, medium temperature and low temperature in the gradient crystallization and dynamic heat setting unit. The film covering angle is changed by adjusting the spacing of the setting rollers. Then, the thickness is controlled based on the real-time data of the thickness measuring device. Finally, a torque motor is used for winding to keep the winding tension constant to avoid film deformation.

8. The method for producing PEEK film according to claim 7, characterized in that, The air gap L can be adjusted from 5 to 100 mm, and the traction angle α can be adjusted from 10 to 90°.

9. The method for producing PEEK film according to claim 7, characterized in that, The spacing of the shaping rollers can be adjusted from 50 to 150 mm. Different functions are performed according to different ranges. The temperature of the first shaping roller (9) is 230 to 255°C, the temperature of the second shaping roller (10) is 180 to 205°C, and the temperature of the third shaping roller (11) is 50 to 185°C.

10. The method for producing PEEK film according to claim 7, characterized in that, Based on the real-time data from the thickness measuring device, the central controller synchronously controls the rotation speed (flow rate adjustment) of the host and melt pump (6), the die lip opening of the coat hanger extrusion die (8), and the rotation speed of the servo motor of the shaping roller according to the film thickness, so as to dynamically control the thickness tolerance within ±0.01mm.

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