A method for preparing a peelable polyimide laminated film

Abstract

The present application relates to a kind of preparation methods of peelable polyimide laminated film, which is made of multiple polyimide composite films by hot pressing forming, wherein the polyimide composite film is composed of polyimide film and adhesive, by controlling the thickness of adhesive layer, forming temperature, forming pressure and holding time, the peel strength of laminated film is controlled, and the peel strength controllable polyimide laminated film is obtained.Compared with the prior art, the present application effectively controls the peel strength of laminated film, and obtains a peelable polyimide laminated film with controllable peel strength.The method can control the peel strength of laminated film according to the use requirement, is easy to process and use, has low requirement for equipment, is easy to implement, and can be used for preparing peelable gasket.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a method for manufacturing a peelable polyimide laminate for making peelable gaskets. Background Technology

[0002] In high-end manufacturing fields such as aerospace and precision electronics, high-temperature assembly and temporary protection processes place extremely stringent requirements on functional gaskets. An ideal gasket not only needs to withstand temperatures of hundreds of degrees Celsius while maintaining dimensional and mechanical strength stability, but more importantly, it must be completely and cleanly peeled off after the process is completed, leaving no residue or damaging the precision workpiece. While there are reports of applications for aluminum foil-based peelable gaskets in the prior art (such as those used in engine testing and helicopter tail rotor experiments in patents CN 205538222 U and CN 104215458 A), their peeling behavior is difficult to predict and control, prone to breakage or residue, and their mechanical protection performance is limited, failing to fully meet the needs of high-reliability scenarios.

[0003] To replace traditional materials, the industry has explored peelable coatings or gaskets based on polymer adhesives. For example, a patent (CN 112358849 A) ​​uses POSS-modified epoxy resin to prepare an adhesive layer. While achieving film-forming properties and a certain degree of peelability, its formulation relies on organic solvents, leading to volatile organic compound (VOC) emissions, posing challenges to the environment and production safety. Subsequent water-based systems (such as CN 105860889 A) have solved the VOC problem, but face new technical bottlenecks: their preparation processes are complex, and their water resistance (e.g., failing to meet AMS-DTL-22499B standards) and high-temperature resistance are often poor. More importantly, existing technologies generally lack the ability to precisely control the core performance indicator—peel strength. This results in unstable product performance, unable to provide gradient, predictable peel forces according to different application scenarios (such as from precision chip packaging to the adjustment of large aircraft door hinges), thus severely restricting its large-scale application in automated, high-standard industrial processes.

[0004] Therefore, the industry urgently needs a brand-new solution that can effectively design and precisely control the peel strength of the gasket according to the usage requirements, and on this basis, simultaneously achieve excellent high temperature resistance, good water resistance and processing characteristics that are friendly to industrial production equipment, so as to fill the multiple gaps left by the existing technology. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a peelable polyimide laminate with controllable adhesion to overcome the defects of the prior art.

[0006] The objective of this invention can be achieved through the following technical solution: a method for preparing a peelable polyimide laminate, wherein the polyimide laminate is obtained by hot pressing multiple polyimide composite films, wherein the polyimide composite film is composed of a polyimide film and a thermoplastic adhesive, and the peel strength of the laminate is controlled by adjusting the adhesive layer thickness, molding temperature, molding pressure and molding heat and pressure holding time, thereby obtaining a polyimide laminate with controllable peel strength.

[0007] Furthermore, the specific process of controlling the peel strength of the laminate by adjusting the adhesive layer thickness, molding temperature, molding pressure, and molding holding and pressure time is as follows: S1. Determine the peel strength requirements of the polyimide laminate to be used; S2. Based on the selected thermoplastic adhesive, adhesive layer thickness, molding temperature T, molding pressure P, and molding heat and pressure holding time t, a series of gasket samples are made according to the DOE matrix, and all samples are subjected to standard 90° or 180° peel strength tests. S3. Using Minitab software, analyze the experimental data from step S2 and establish a model formula relating the peel strength S of the polyimide laminate to the molding temperature T, molding pressure P, and molding holding time t: Where S is the lamination strength, K is the control factor, and T This refers to the edge temperature of the molding insulation. τ P is a temperature characteristic parameter. For molding edge pressure, p t is a pressure characteristic parameter. Insulation and pressure retention margin time θ These are the characteristic parameters for heat preservation and pressure retention; S4. Based on the process window determined in step S3, a peelable polyimide laminate that meets the peel strength requirement of step S1 is obtained.

[0008] Furthermore, the thermoplastic adhesive is one of polyamide-imide, polyether-imide, perfluoroethylene propylene, polyvinylidene fluoride, polyether ether ketone, and polyphenylene sulfide.

[0009] Furthermore, the thermoplastic adhesive is perfluoroethylene propylene; the model formula for the peel strength S of the polyimide laminate with respect to the molding temperature T, molding pressure P, and molding holding time t is as follows: .

[0010] Furthermore, the thermoplastic adhesive is polyamide-imide, and the model formula for the peel strength S of the polyimide laminate with respect to the molding temperature T, molding pressure P, and molding holding time t is as follows: .

[0011] The thermoplastic adhesive is polyetherimide. The model formula for the peel strength S of the polyimide laminate with respect to the molding temperature T, molding pressure P, and molding holding time t is as follows: .

[0012] Step S2, according to the DOE matrix, involves fabricating a series of gasket samples as follows: A thermoplastic adhesive is selected and hot-pressed with a polyimide film to obtain a polyimide composite film. Multiple polyimide composite films are then hot-pressed to obtain a polyimide laminate. The thickness of the polyimide film is 0.010–0.075 mm, and the thickness of the thermoplastic adhesive layer is 0.010–0.040 mm. The heating rate during hot pressing is 2–6 °C / min, the holding temperature is 30–260 °C higher than the glass transition temperature of the thermoplastic adhesive, and the holding pressure is 30–100 kg / cm². 2 The heat preservation and pressure holding time is 5~50 minutes, and the cooling process is pressure preservation and cooling, with a pressure holding pressure of 30~100 kg / cm². 2 Demolding should be done when the temperature is below 40℃.

[0013] The thickness ratio of the polyimide film to the thermoplastic adhesive layer is 2:1 to 4:1; Furthermore, the polyimide composite film comprises 2 to 200 sheets.

[0014] Furthermore, the polyimide laminate has a size of (50×10)~(1000×1000) mm.

[0015] Furthermore, the hot pressing process employs a programmable multilayer press. The specific hot pressing process is as follows: the polyimide composite film is neatly stacked, covered with polyimide films of the same size on both the top and bottom surfaces, placed on a flat mold steel plate, and covered with a mold steel plate on top of the stacked polyimide composite film. Asbestos cloth is then placed on the upper mold steel plate and placed in a programmable multilayer press, heated to the specified temperature, and kept warm and under pressure.

[0016] Furthermore, the polyimide laminate has a peel strength of 0.0550–0.7130 N / mm and does not delaminate after being bathed in a water bath at 50°C for 48 hours.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. Existing gaskets lack precise control over their peel strength, posing significant challenges in application: excessive peel force can lead to residue or breakage during removal, contaminating workpiece surfaces and potentially damaging precision components; insufficient peel force can cause accidental detachment during processing or transportation, resulting in positioning failure. This unpredictable peeling behavior drastically reduces process stability, forcing manufacturers to rely on operator experience for risk control, increasing the difficulty of product consistency control and directly hindering the advancement of automated production lines in high-end manufacturing. This invention addresses this issue by using polyimide composite film as raw material and laminating ordered stacked polyimide composite films under high-temperature molding to produce gaskets with controllable peel strength. The unique aromatic heterocyclic molecular structure of these polyimide peelable gaskets endows the material with the ability to withstand temperatures above 400°C, fundamentally overcoming the positioning drift problem caused by high-temperature deformation. Controllable release properties achieved through molecular chain segment orientation design allow the gasket to be cleanly peeled off after fulfilling its protective function, completely eliminating residual adhesive contamination. This makes it particularly suitable for scenarios with extremely high cleanliness requirements, such as wafer grinding and multilayer PCB lamination. The material's near-zero coefficient of thermal expansion and mechanical strength work synergistically to ensure millimeter-level control over part gaps in precision assembly while maintaining structural integrity during repeated disassembly and assembly. This significantly reduces the scrap rate of workpieces due to gasket failure, providing a standardized temporary support solution for high-end manufacturing that combines protective effectiveness with process controllability.

[0018] 2. This invention uses polyimide composite film as raw material, and laminates ordered stacked polyimide composite films through high-temperature molding. The composite films are bonded together by van der Waals forces. The high-temperature molecular motion mode of the thermoplastic adhesive is controlled by adjusting the molding temperature and molding pressure. Temperature provides energy to the molecular chains, causing them to transform from a glassy state to a highly elastic state or a viscous flow state, thereby enabling them to wet the opposing surface and undergo mutual diffusion and entanglement, forming an interface layer that determines the adhesive strength. Pressure, on the other hand, forcibly removes interfacial gases, promotes close molecular-level contact, creates ideal conditions for molecular diffusion, and controls the structure of the interface layer. Therefore, by using a model relationship between specific parameters and peelable strength, the macroscopic adhesive strength can be controllably adjusted by regulating the depth of molecular diffusion and entanglement density at the interface, thus preparing a peelable polyimide laminate with controllable adhesive strength. The peelable polyimide laminate prepared by this method can have its peel strength adjusted according to the application requirements. It is water-resistant, high-temperature resistant, solvent-free, easy to process and use, has low equipment requirements, is easy to implement industrially, and can be used to prepare peelable gaskets.

[0019] 3. This invention uses polyimide film and one of polyamide-imide, polyether-imide, perfluoroethylene propylene, polyvinylidene fluoride, polyether ether ketone, and polyphenylene sulfide as an adhesive. It does not require organic solvents, is environmentally friendly and safe, and can be prepared using a laminator. It has low equipment requirements and is easy to implement industrially. The resulting product has good water resistance and high temperature resistance. Attached Figure Description

[0020] Figure 1 This is an appearance diagram of the peelable polyimide laminate of Example 1.

[0021] Figure 2 This is an optical microscope image of the cross-section of the peelable polyimide laminate in Example 1.

[0022] Figure 3 This is a cross-sectional optical microscope image of the peelable polyimide laminate of Example 1 after being bathed in a water bath at 50°C for 48 hours. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0024] All raw materials used in this invention are commercially available in the field, and the equipment used is commonly used in the field, such as film scraping machines and CNC multilayer presses. The polyimide film used in the following examples is a commonly used commercially available Kapton polyimide film. The adhesives used are all commercially available products from Shanghai Plastics Research Institute Co., Ltd., such as YS30 and YS40.

[0025] The following model formulas are used to determine the relationship between the adhesive layer thickness, molding temperature, molding pressure, and molding holding time and the glass strength of the polyimide laminate: Polyamide-imide, polyether-imide, perfluoroethylene propylene, polyvinylidene fluoride, polyether ether ketone, and polyphenylene sulfide were selected as thermoplastic adhesives, respectively. Molding temperature T, molding pressure P, molding holding time t, and adhesive layer thickness were set as influencing factors. A Design of Effect (DOE) matrix design experiment was conducted. The experimental process window was as follows: polyimide film thickness 0.010–0.075 mm, thermoplastic adhesive layer thickness 0.010–0.040 mm, polyimide film to thermoplastic adhesive layer thickness ratio 2:1–4:1; hot pressing heating rate 2–6 °C / min, holding temperature 30–260 °C above the glass transition temperature of the thermoplastic adhesive, and holding pressure 30–100 kg / cm². 2The heat preservation and pressure holding time is 5~50 minutes, and the cooling process is pressure preservation and cooling, with a pressure holding pressure of 30~100 kg / cm². 2 Demolding is performed below 40℃; the polyimide composite film consists of 2 to 200 sheets; Based on the experimental design in step 2, a thermoplastic adhesive was coated onto a polyimide film and hot-pressed to obtain a polyimide composite film. Multiple polyimide composite films were hot-pressed to obtain a polyimide laminate film. A series of gasket samples were made, and all samples were subjected to standard 90° or 180° peel strength tests. 4. The experimental data from step 3 were analyzed using Minitab software. Since the adhesive layer thickness had little impact, a model formula was established to determine the relationship between the peel strength S of the polyimide laminate and the molding temperature T, molding pressure P, and molding holding time t: Where S is the lamination strength, K is the control factor, and T This refers to the edge temperature of the molding insulation. τ P is a temperature characteristic parameter. For molding edge pressure, p t is a pressure characteristic parameter. Insulation and pressure retention margin time θ These are the characteristic parameters for heat preservation and pressure retention; 5. Based on the model determined in step 4, a peelable polyimide laminate that meets the peel strength requirements is prepared.

[0026] Example 1 The peelable polyimide laminate prepared in this embodiment is specifically prepared by the following steps: S1. Determine the peel strength requirement of the polyimide laminate to be used: In this embodiment, the peel strength requirement is 0.0550~0.7130 N / mm; S2. Using perfluoroethylene propylene (glass transition temperature 80℃) as the adhesive, based on the relationship between the peel strength S of the polyimide laminate to be used and the molding temperature T, molding pressure P, and molding holding time t: Set the peel strength range to S = 0.0550~0.7130 N / mm, input the preferred molding temperature to be 150~300℃, and the preferred molding pressure to be 30~80 kg / cm². 2 The optimal heat preservation and pressure holding time is 10~40min; use Matlab to create a three-dimensional mesh, generate three-dimensional mesh points and calculate the S value of all mesh points; create a logical mask, mark the points that meet the peel strength condition in step S1, extract the coordinates of the points that meet the condition, combine them into a data point set, and verify whether all data points meet the S range requirement; after verification, draw a three-dimensional scatter plot.

[0027] S2. Based on the three-dimensional scatter plot generated in step S2, process combination points are selected. In this embodiment, the number of polyimide composite film layers is set to 16, the hot pressing temperature is 270℃, and the holding pressure is 50 kg / cm². 2 The heat preservation and pressure holding time is 25 minutes.

[0028] S3. As can be seen from the formula in step S2, the calculated peel strength is 0.172 N / mm, which meets the peel strength requirement of S1 in this embodiment.

[0029] Based on this, a peelable polyimide laminate was prepared using the following method. Preparation of S4 polyimide composite film A polytetrafluoroethylene propylene layer with a thickness of 0.015 mm (glass transition temperature 80℃) is coated on the surface of a polyimide film with a thickness of 0.035 mm to obtain a polyimide composite film. Preparation of S5 polyimide laminate Cut the polyimide composite film obtained in step S4 to 200×200 mm and prepare 16 sheets.

[0030] Stack the following materials in the following order from top to bottom: asbestos cloth, mold steel plate, 1 sheet of polyimide film, 16 sheets of polyimide composite film, 1 polyimide film, and mold steel plate; place the resulting stack in a programmable multilayer press, heat it to 270°C at a heating rate of 5°C / min, and maintain a pressure of 50 kg / cm². 2 Heat preservation and pressure holding time: 25 minutes; pressure holding time after heating is turned off: 30 kg / cm² 2 Cool down to 40℃ and remove from the mold.

[0031] The resulting laminate was subjected to a peel strength test according to ASTM D 903, and the peel strength was 0.212 N / mm. The thickness of the interlayer adhesive was tested using an optical microscope and was found to be 0.01503 mm. No delamination was observed after a 48-hour water bath at 50°C.

[0032] like Figure 1 The image shown is an appearance diagram of the peelable polyimide laminate obtained in Example 1. As can be seen from the image, the surface of the polyimide laminate is smooth and clean, without defects such as bubbles or flow lines.

[0033] Figure 2 The image shows a cross-sectional optical microscope image of the peelable polyimide laminate obtained in Example 1. The light-colored layer is the adhesive layer, and the dark-colored layer is the polyimide layer. The layers are tightly bonded, have uniform thickness, and are free of defects. Figure 3This is a cross-sectional optical microscope image of a peelable polyimide laminate after being bathed in a water bath at 50°C for 48 hours. The interlayer thickness remains uniform after the water bath, and no defects are generated.

[0034] Example 2 The peelable polyimide laminate prepared in this embodiment is specifically prepared by the following steps: S1. Determine the peel strength requirement of the polyimide laminate to be used: In this embodiment, the peel strength requirement is 0.0550~0.7130 N / mm; S2. The peel strength S of the polyimide laminate to be used, which uses polyamide-imide (glass transition temperature 270℃) as an adhesive, is related to the molding temperature T, molding pressure P, and molding holding time t by the following formula: The polyimide composite film is set to have 10 layers, a hot-pressing temperature of 360℃, and a holding pressure of 90 kg / cm². 2 The heat preservation and pressure holding time is 50 minutes. As can be seen from the above formula, the calculated peel strength value is 0.394 N / mm, which meets the peel strength requirement of S1 in this embodiment.

[0035] Based on this, a peelable polyimide laminate was prepared using the following method. Preparation of S3 and polyimide composite film A polyamide-imide layer with a thickness of 0.030 mm (glass transition temperature 270℃) is coated on the surface of a polyimide film with a thickness of 0.060 mm to obtain a polyimide composite film. Preparation of S4 polyimide laminate Cut the polyimide composite film obtained in step S4 to 300×300 mm and prepare 10 sheets.

[0036] Stack the following materials in the following order from top to bottom: asbestos cloth, mold steel plate, 1 sheet of polyimide film, 10 sheets of polyimide composite film, 1 polyimide film, and mold steel plate; place the resulting stack in a programmable multilayer press, heat to 360°C at a heating rate of 3°C / min, and maintain a pressure of 90 kg / cm². 2 Heat and pressure hold time: 50 minutes. Pressure hold at 50 kg / cm² after heating is turned off. 2 Cool down to 40℃ and remove from the mold.

[0037] The resulting laminate was subjected to a peel strength test according to ASTM D 903, and the peel strength was 0.445 N / mm. The thickness of the interlayer adhesive was tested using an optical microscope and was found to be 0.01503 mm. No delamination was observed after bathing in a 50°C water bath for 48 h.

[0038] Example 3 The peelable polyimide laminate prepared in this embodiment is specifically prepared by the following steps: S1. Determine the peel strength requirement of the polyimide laminate to be used: In this embodiment, the peel strength requirement is 0.0550~0.7130 N / mm; S2. The peel strength S of the polyimide laminate to be used, which uses polyetherimide (glass transition temperature 180℃) as an adhesive, is related to the molding temperature T, molding pressure P, and molding holding time t by the following formula: The polyimide composite film is set to have 18 layers, a hot-pressing temperature of 245℃, and a holding pressure of 30 kg / cm². 2 The heat preservation and pressure holding time is 35 minutes. As can be seen from the above formula, the calculated peel strength value is 0.153 N / mm, which meets the peel strength requirement of S1 in this embodiment.

[0039] Based on this, a peelable polyimide laminate was prepared using the following method. Preparation of S3 and polyimide composite film A polyetherimide (glass transition temperature 180℃) layer with a thickness of 0.010 mm is coated on the surface of a polyimide film with a thickness of 0.040 mm to obtain a polyimide composite film. Preparation of S4 polyimide laminate Cut the polyimide composite film obtained in step S4 to 250×250 mm and prepare 18 sheets.

[0040] Stack the following materials in the following order from top to bottom: asbestos cloth, mold steel plate, 1 sheet of polyimide film, 18 sheets of polyimide composite film, 1 polyimide film, and mold steel plate; place the resulting stack in a programmable multilayer press, heat it to 245°C at a heating rate of 4°C / min, and maintain a pressure of 30 kg / cm². 2 The heat preservation and pressure holding time is 35 minutes. After heating is turned off, the pressure holding time is 30 kg / cm². 2 Cool down to 40℃ and remove from the mold.

[0041] The resulting laminate was subjected to a peel strength test according to ASTM D 903, and the peel strength was 0.132 N / mm. The thickness of the interlayer adhesive was tested using an optical microscope and was found to be 0.01010 mm. No delamination was observed after bathing in a 50°C water bath for 48 h.

[0042] Example 4 The peelable polyimide laminate prepared in this embodiment is specifically prepared by the following steps: S1. Determine the peel strength requirement of the polyimide laminate to be used: In this embodiment, the peel strength requirement is 0.0550~0.7130 N / mm; S2. The peel strength S of the polyimide laminate to be used (glass transition temperature 180℃) is related to the molding temperature T, molding pressure P, and molding holding time t by the following formula: The polyimide composite film is set to have 18 layers, a hot-pressing temperature of 280℃, and a holding pressure of 65 kg / cm². 2 The heat preservation and pressure holding time is 50 minutes. As can be seen from the above formula, the calculated peel strength value is 0.386 N / mm, which meets the peel strength requirement of S1 in this embodiment.

[0043] Based on this, a peelable polyimide laminate was prepared using the following method. Preparation of S3 and polyimide composite film A polyetherimide (glass transition temperature 180℃) layer with a thickness of 0.010 mm is coated on the surface of a polyimide film with a thickness of 0.040 mm to obtain a polyimide composite film. Preparation of S4 polyimide laminate Cut the polyimide composite film obtained in step S4 to 250×250 mm and prepare 18 sheets.

[0044] Stack the following materials in the following order from top to bottom: asbestos cloth, mold steel plate, 1 sheet of polyimide film, 18 sheets of polyimide composite film, 1 polyimide film, and mold steel plate; place the resulting stack in a programmable multilayer press, heat it to 280°C at a heating rate of 4°C / min, and maintain a pressure of 65 kg / cm². 2 Heat and pressure hold time: 50 minutes. Pressure hold at 50 kg / cm² after heating is turned off. 2 Cool down to 40℃ and remove from the mold.

[0045] The resulting laminate was subjected to a peel strength test according to ASTM D 903, and the peel strength was 0.415 N / mm. The thickness of the interlayer adhesive was tested using an optical microscope and was found to be 0.00912 mm. No delamination was observed after bathing in a 50°C water bath for 48 h.

[0046] Example 5 The peelable polyimide laminate prepared in this embodiment is specifically prepared by the following steps: S1. Determine the peel strength requirement of the polyimide laminate to be used: In this embodiment, the peel strength requirement is 0.0550~0.7130 N / mm; S2. The peel strength S of the polyimide laminate to be used (glass transition temperature 180℃) is related to the molding temperature T, molding pressure P, and molding holding time t by the following formula: The polyimide composite film is set to have 18 layers, a hot-pressing temperature of 280℃, and a holding pressure of 100 kg / cm². 2 The heat preservation and pressure holding time is 50 minutes. As can be seen from the above formula, the calculated peel strength value is 0.463 N / mm, which meets the peel strength requirement of S1 in this embodiment.

[0047] Based on this, a peelable polyimide laminate was prepared using the following method. Preparation of S3 and polyimide composite film A polyetherimide (glass transition temperature 180℃) layer with a thickness of 0.010 mm is coated on the surface of a polyimide film with a thickness of 0.040 mm to obtain a polyimide composite film. Preparation of S4 polyimide laminate Cut the polyimide composite film obtained in step S4 to 250×250 mm and prepare 18 sheets.

[0048] Stack the following materials in the following order from top to bottom: asbestos cloth, mold steel plate, 1 sheet of polyimide film, 18 sheets of polyimide composite film, 1 polyimide film, and mold steel plate; place the resulting stack in a programmable multilayer press, heat it to 280°C at a heating rate of 4°C / min, and maintain a pressure of 100 kg / cm². 2 Heat and pressure hold time: 50 minutes. Pressure hold at 50 kg / cm² after heating is turned off. 2 Cool down to 40℃ and remove from the mold.

[0049] The resulting laminate was subjected to a peel strength test according to ASTM D 903, and the peel strength was 0.504 N / mm. The thickness of the interlayer adhesive was tested using an optical microscope and was found to be 0.00953 mm. No delamination was observed after bathing in a 50°C water bath for 48 h.

Claims

1. A method for preparing a peelable polyimide laminate, characterized in that, The polyimide laminate is made by hot pressing multiple polyimide composite films. The polyimide composite film is composed of polyimide film and thermoplastic adhesive. By adjusting the adhesive layer thickness, molding temperature, molding pressure and molding heat and pressure holding time, the peel strength of the laminate can be controlled, resulting in a polyimide laminate with controllable peel strength. The specific process of controlling the peel strength of the laminate by adjusting the adhesive layer thickness, molding temperature, molding pressure, and molding heat and pressure holding time is as follows: S1. Determine the peel strength requirements of the polyimide laminate to be used; S2. Based on the selected thermoplastic adhesive, adhesive layer thickness, molding temperature T, molding pressure P, and molding heat and pressure holding time t, a series of gasket samples are made according to the DOE matrix, and all samples are subjected to standard 90° or 180° peel strength tests. S3. Using Minitab software, analyze the experimental data from step S2 and establish a model formula relating the peel strength S of the polyimide laminate to the molding temperature T, molding pressure P, and molding holding time t: ； Where S is the lamination strength, K is the control factor, and T This refers to the edge temperature of the molding insulation. τ P is a temperature characteristic parameter. For molding edge pressure, p t is a pressure characteristic parameter. Insulation and pressure retention margin time θ These are the characteristic parameters for heat preservation and pressure retention; S4. Based on the process window determined in step S3, a peelable polyimide laminate that meets the peel strength requirement of step S1 is obtained.

2. The method for preparing a peelable polyimide laminate according to claim 1, characterized in that, The thermoplastic adhesive is one of polyamide-imide, polyether-imide, perfluoroethylene propylene, polyvinylidene fluoride, polyether ether ketone, and polyphenylene sulfide.

3. The method for preparing a peelable polyimide laminate according to claim 2, characterized in that, The thermoplastic adhesive is perfluoroethylene propylene; the model formula for the peel strength S of the polyimide laminate with respect to molding temperature T, molding pressure P, and molding holding time t is as follows: 。 4. The method for preparing a peelable polyimide laminate according to claim 2, characterized in that, The thermoplastic adhesive is polyamide-imide. The model formula for the peel strength S of the polyimide laminate with respect to the molding temperature T, molding pressure P, and molding holding time t is as follows: 。 5. The method for preparing a peelable polyimide laminate according to claim 2, characterized in that, The thermoplastic adhesive is polyetherimide. The model formula for the peel strength S of the polyimide laminate with respect to the molding temperature T, molding pressure P, and molding holding time t is as follows: 。 6. The method for preparing a peelable polyimide laminate according to claim 1, characterized in that, Step S2, according to the DOE matrix, involves fabricating a series of gasket samples as follows: A thermoplastic adhesive is selected and hot-pressed with a polyimide film to obtain a polyimide composite film. Multiple polyimide composite films are then hot-pressed to obtain a polyimide laminate. The thickness of the polyimide film is 0.010–0.075 mm, and the thickness of the thermoplastic adhesive layer is 0.010–0.040 mm. The heating rate during hot pressing is 2–6 °C / min, the holding temperature is 30–260 °C higher than the glass transition temperature of the thermoplastic adhesive, and the holding pressure is 30–100 kg / cm². 2 The heat preservation and pressure holding time is 5~50 minutes, and the cooling process is pressure preservation and cooling, with a pressure holding pressure of 30~100 kg / cm². 2 Demolding should be done when the temperature is below 40℃.

7. The method for preparing a peelable polyimide laminate according to claim 6, characterized in that, The thickness ratio of the polyimide film to the thermoplastic adhesive layer is 2:1 to 4:1; The polyimide composite film comprises 2 to 200 sheets.

8. The method for preparing a peelable polyimide laminate according to claim 1, characterized in that, The hot pressing process uses a programmable multilayer press. The specific hot pressing process is as follows: the polyimide composite film is neatly stacked, and the top and bottom surfaces are covered with polyimide films of the same size. The film is placed on a flat mold steel plate, and the stacked polyimide composite film is covered with a mold steel plate. Asbestos cloth is then placed on the upper mold steel plate and placed in the programmable multilayer press. The temperature is raised to the specified temperature and maintained under heat and pressure.

9. The method for preparing a peelable polyimide laminate according to claim 1, characterized in that, The polyimide laminate has a peel strength of 0.0550 to 0.7130 N / mm and does not delaminate after being bathed in a water bath at 50°C for 48 hours.

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