High-temperature-resistant masking tape and preparation method thereof

Abstract

The invention provides a high-temperature-resistant masking tape and a preparation method thereof, and relates to the technical field of high polymer material engineering. The preparation method of the high-temperature-resistant masking tape comprises the following steps: S1, based on polyimide resin, forming a base material film by adopting an extrusion casting process, and generating an initial polyimide base material film through high-temperature imidization treatment; s2, performing low-temperature plasma activation treatment on the surface of one side of the substrate film to generate a surface activated polyimide substrate film; and S3, coating the activated surface with a silane coupling agent primer, and carrying out drying treatment to generate the interface modified polyimide substrate film. A stable film structure is formed through high-temperature imidization treatment of a polyimide base material, the heat resistance and mechanical strength of the base material are remarkably improved, the surface of the base material is activated by adopting low-temperature plasma, polar groups are introduced, and the interface chemical bonding force is enhanced by combining the directional bonding effect of a silane coupling agent primer, so that interlayer debonding in a high-temperature environment is avoided, and the heat resistance and mechanical strength of the base material are improved. And preparing the silicone rubber buffer layer.

Description

Technical Field

[0001] This invention relates to the field of polymer materials engineering technology, specifically to a high-temperature resistant masking tape and its preparation method. Background Technology

[0002] Polymer materials engineering is an interdisciplinary field that studies polymer molecular structure design, synthesis processes, physicochemical modification, processing and molding technologies, and performance characterization. It focuses on optimizing the mechanical properties (strength, toughness), thermal properties (glass transition temperature, thermal decomposition temperature), viscoelasticity, and durability of materials by controlling factors such as molecular chain configuration (e.g., linear, branched, cross-linked), molecular weight distribution, and copolymer sequence structure, combined with filler composites (nano / micro-scale reinforcement), blending compatibilization, and surface modification. It also develops efficient processing methods (e.g., extrusion, injection molding, coating, hot pressing) to achieve large-scale production. One such application is a high-temperature resistant masking tape and its preparation method. This involves developing a functional tape using high-temperature resistant polymers (e.g., polyimide, silicone) as the base material, through specific adhesive formulations (e.g., high-crosslink density silicone pressure-sensitive adhesive) and interlayer composite processes. This tape is used for temporary masking protection of untreated areas of electronic components, automotive parts, aerospace equipment, and other workpieces in high-temperature environments (≥200℃), preventing contamination or damage during painting, welding, and chemical treatment processes, and ensuring no residue and easy peeling after high-temperature treatment.

[0003] In traditional high-temperature masking tape manufacturing processes, the bonding between the substrate and adhesive layer relies primarily on physical adsorption, resulting in weak interfacial adhesion and a tendency for delamination under prolonged high temperatures. The lack of a buffer layer allows thermal stress to be directly transferred to the adhesive layer, accelerating high-temperature creep and causing deformation. The adhesive curing process employs a single-stage high-temperature treatment, and insufficient control of the cross-linking reaction rate leads to uneven curing, reducing the uniformity and durability of the adhesive layer. The simple laminated structure of the substrate and adhesive layer means that differences in thermal expansion coefficients generate shear stress during temperature changes, causing edge warping and masking failure. Furthermore, the selection of the release film and the lamination process do not adequately consider high-temperature compatibility, leading to release agent migration and contamination of the adhesive layer during storage, affecting initial adhesion performance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a high-temperature resistant masking tape and its preparation method. This invention solves the problems in the traditional high-temperature resistant masking tape preparation process, where the substrate and adhesive layer mainly rely on physical adsorption for bonding, resulting in weak interfacial bonding. Long-term high-temperature exposure can easily lead to interlayer separation, and the lack of a buffer layer causes thermal stress to be directly transferred to the adhesive layer, accelerating high-temperature creep and causing deformation.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-temperature resistant masking tape and its preparation method, comprising the following steps: S1: Based on polyimide resin, a substrate film is formed by extrusion casting process, and an initial polyimide substrate film is generated by high-temperature imidization treatment; S2: Low-temperature plasma activation treatment is performed on one side of the substrate film to generate a surface-activated polyimide substrate film; S3: A silane coupling agent primer is coated onto the activated surface and then dried to generate an interface-modified polyimide substrate film; S4: Based on silicone rubber material, a closed-cell structure layer is prepared by a foaming agent thermal decomposition process to generate a heat-resistant silicone rubber foam buffer layer. S5: The interface-modified substrate film and the buffer layer are combined by a hot-pressing composite process to generate a gradient composite substrate; S6: A high-temperature resistant silicone pressure-sensitive adhesive is coated on the surface of the buffer layer of the gradient composite substrate to form a pressure-sensitive adhesive coating layer; S7: Perform segmented thermosetting treatment on the coating layer, including pre-curing and deep curing, to generate a deep-cured adhesive layer; S8: Cover the surface of the cured adhesive layer with a high-temperature resistant release film, and then roll it up to produce a finished high-temperature resistant masking tape.

[0006] Preferably, step S1 includes the following steps; S101: Based on polyimide resin particles, a vacuum pre-drying process is used to remove the moisture absorbed by the raw materials and generate pre-dried polyimide resin. S102: Based on pre-dried polyimide resin, a twin-screw melt extrusion process is used to achieve complete plasticization and homogenization of the resin, generating a molten polyimide homogeneous body; S103: Based on molten polyimide homogeneous material, a continuous wet film is formed by using a precision casting die coating process to generate a primary polyimide casting film; S104: Based on a polyimide primary cast film, a programmed temperature imidization process is used to complete the closed-loop reaction and generate an initial polyimide substrate film.

[0007] Preferably, step S2 includes the following steps; S201: Based on the initial polyimide substrate film, an electrostatic dust removal process is used to remove free dust from the surface and generate a clean polyimide substrate film. S202: Based on a clean polyimide substrate film, an oxygen plasma treatment process is used to generate active free radicals on the surface, thus generating a plasma-activated substrate film. S203: Based on plasma-activated substrate film, in-situ contact angle detection process is used to verify surface energy enhancement and generate surface energy verification substrate film; S204: Based on surface energy verification substrate film, a nitrogen-protected transport process is used to prevent secondary contamination of the active surface and generate a surface-activated polyimide substrate film.

[0008] Preferably, step S3 includes the following steps; S301: Based on γ-aminopropyltriethoxysilane, a coupling agent solution is prepared using an ethanol solution preparation process to generate a silane coupling agent activation solution; S302: Based on surface-activated polyimide substrate film, a wet coupling agent coating substrate is generated by uniformly coating silane coupling agent activation liquid with micro-gravure roller coating process. S303: Based on a wet coupling agent coating substrate, a gradient temperature drying process is used to achieve complete solvent evaporation and generate a dry coupling agent coating substrate; S304: Based on a drying coupling agent coated substrate, an online infrared spectroscopy monitoring process is used to confirm the interfacial chemical bonding and generate an interfacial modified polyimide substrate film.

[0009] Preferably, step S4 includes the following steps; S401: Based on liquid silicone rubber and azodicarbonamide foaming agent, a high-speed dispersion process is used to achieve uniform dispersion of the foaming agent and generate a silicone rubber / foaming agent mixture; S402: Based on a silicone rubber / foaming agent mixture, an unfoamed precursor film is prepared by calendering film formation process to generate a silicone rubber precursor film; S403: Based on silicone rubber precursor film, a thermal decomposition foaming process is used to activate the foaming agent to generate a closed-cell structure and produce porous silicone rubber foam. S404: Based on porous silicone rubber foam, a heat-setting process is used to stabilize the cell structure and generate a heat-resistant silicone rubber foam buffer layer.

[0010] Preferably, step S5 includes the following steps; S501: Based on an interface-modified polyimide substrate film and a heat-resistant silicone rubber foam buffer layer, a preheated composite component is generated using an infrared preheating process. S502: Based on preheated composite components, a roller alignment bonding process is used to achieve precise interlayer lamination and generate aligned composite components. S503: Based on the para-composite component, a flat hot-pressing process is used to promote the diffusion of interfacial molecules and generate a hot-pressed composite substrate. S504: Based on hot-pressed composite substrate, a stepped cooling process is used to release internal stress and generate gradient composite substrate.

[0011] Preferably, step S6 includes the following steps; S601: Based on vinyl silicone rubber and hydrogen-containing silicone oil crosslinking agent, a defoaming adhesive liquid is prepared by planetary stirring defoaming process to generate a defoamed organosilicon pressure-sensitive adhesive. S602: Based on gradient composite substrate, a corona secondary treatment process is used to enhance the surface energy of the buffer layer and generate a surface-activated composite substrate; S603: Based on surface-activated composite substrate and defoamed silicone pressure-sensitive adhesive, a slit coating process is used to form a wet adhesive layer, thereby generating a wet adhesive coated composite substrate. S604: Based on wet adhesive coating composite substrate, using leveling control process to eliminate coating texture and generate pressure-sensitive adhesive coating layer.

[0012] Preferably, step S7 includes the following steps; S701: Based on a pressure-sensitive adhesive coating, an infrared pre-curing process is used to achieve surface gelation and generate a pre-cured adhesive layer; S702: Based on the pre-cured adhesive layer, a hot air circulation curing process is used to complete the main cross-linking reaction and generate a primary cured adhesive layer; S703: Based on the primary cured adhesive layer, a post-curing process is used to stabilize the cross-linking network and generate a deep cured adhesive layer.

[0013] Preferably, step S8 includes the following steps; S801: Based on polyester film treated with fluorosilicone release agent, a corona strengthening process is used to improve the surface stability of the release film and generate a modified release film; S802: Based on a deep-curing adhesive layer and a modified release film, a hot roller lamination process is used to achieve close interfacial adhesion and generate a laminated release film semi-finished product. S803: Based on the composite release film semi-finished product, a constant tension winding process is used to generate a winding tape blank; S804: Based on the preform of the wound tape, an aging and setting process is used to release internal stress and produce a finished high-temperature masking tape.

[0014] A high-temperature resistant masking tape, including a method for preparing the high-temperature resistant masking tape.

[0015] This invention provides a high-temperature resistant masking tape and its preparation method. It has the following beneficial effects: This invention utilizes high-temperature imidization of a polyimide substrate to form a stable thin film structure, significantly improving the substrate's heat resistance and mechanical strength. Low-temperature plasma activation of the substrate surface introduces polar groups, which, combined with the directional bonding of a silane coupling agent primer, enhances interfacial chemical bonding and prevents interlayer debonding under high-temperature conditions. In the preparation of the silicone rubber buffer layer, a uniform closed-cell structure is constructed through the thermal decomposition of the foaming agent, utilizing its low thermal conductivity to buffer thermal stress and reduce overall tape deformation. The interface-modified substrate and buffer layer are hot-pressed together to form a functionally graded structure, achieving a gradient transition in the material's thermal expansion coefficient and suppressing internal stress concentration caused by thermal cycling. In the segmented thermosetting process, the pre-curing stage stabilizes the adhesive layer morphology, while the deep curing stage forms a high-crosslink density network, ensuring the adhesive maintains its adhesion strength and anti-flow properties at high temperatures. A high-temperature release film is laminated, and the winding tension is controlled, protecting the integrity of the adhesive layer while improving the finished product's storage stability. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the main steps of the present invention; Figure 2 This is a detailed schematic diagram of S1 of the present invention; Figure 3 This is a detailed schematic diagram of S2 of the present invention; Figure 4 This is a detailed schematic diagram of S3 of the present invention; Figure 5 This is a detailed schematic diagram of S4 of the present invention; Figure 6 This is a detailed schematic diagram of S5 of the present invention; Figure 7 This is a detailed schematic diagram of S6 of the present invention; Figure 8 This is a detailed schematic diagram of S7 of the present invention; Figure 9 This is a detailed schematic diagram of S8 of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0018] Example: like Figure 1-9 As shown, this embodiment of the invention provides a high-temperature resistant masking tape and its preparation method, including the following steps: S1: Based on polyimide resin, a substrate film is formed by extrusion casting process, and an initial polyimide substrate film is generated by high-temperature imidization treatment; S2: Low-temperature plasma activation treatment is performed on one side of the substrate film to generate a surface-activated polyimide substrate film; S3: A silane coupling agent primer is coated onto the activated surface and then dried to generate an interface-modified polyimide substrate film; S4: Based on silicone rubber material, a closed-cell structure layer is prepared by a foaming agent thermal decomposition process to generate a heat-resistant silicone rubber foam buffer layer. S5: The interface-modified substrate film and the buffer layer are combined by a hot-pressing composite process to generate a gradient composite substrate; S6: A high-temperature resistant silicone pressure-sensitive adhesive is coated on the surface of the buffer layer of the gradient composite substrate to form a pressure-sensitive adhesive coating layer; S7: Perform segmented thermosetting treatment on the coating layer, including pre-curing and deep curing, to generate a deep-cured adhesive layer; S8: Cover the surface of the cured adhesive layer with a high-temperature resistant release film, and then roll it up to produce a finished high-temperature resistant masking tape.

[0019] S1 includes the following steps; S101: Based on polyimide resin particles, a vacuum pre-drying process is used to remove the moisture absorbed by the raw materials and generate pre-dried polyimide resin. Pre-dried polyimide resin particles are subjected to temperature-controlled treatment in a vacuum environment, with the vacuum level maintained within a specific negative pressure range and the temperature set to a safe range below the glass transition temperature of the material to avoid thermal degradation of the resin. The treatment time is adjusted according to the initial moisture content of the raw material. For example, when the moisture content exceeds the preset threshold, the treatment time is extended until the moisture evaporation reaches equilibrium. Finally, drying is terminated after the moisture content is determined to be within the standard by Karl Fischer method, resulting in pre-dried polyimide resin.

[0020] S102: Based on pre-dried polyimide resin, a twin-screw melt extrusion process is used to achieve complete plasticization and homogenization of the resin, generating a molten polyimide homogeneous body; Pre-dried polyimide resin is fed into the feed inlet of a twin-screw extruder. The barrel is temperature-controlled in zones, with a temperature gradient from the feed zone to the die zone. The temperature setpoints for each zone are determined based on the resin melt index and thermal stability data. The screw speed is dynamically adjusted according to the melt viscosity to maintain the shear rate below the critical value to prevent molecular chain breakage. The melt pressure sensor monitors in real time to ensure uniform plasticization. The extrusion die temperature is set above the lower limit of the resin decomposition temperature to generate a homogeneous molten polyimide.

[0021] S103: Based on molten polyimide homogeneous material, a continuous wet film is formed by using a precision casting die coating process to generate a primary polyimide casting film; Molten polyimide homogeneous material is transported to the casting die head by a metering pump. The die head gap is calculated and set according to the target film thickness and melt rheological properties. The melt temperature is controlled in the viscous flow range. The surface temperature of the cooling roller is set above the resin crystallization temperature. The roller speed is matched with the melt flow rate. The traction tension is maintained below the film yield strength. The temperature gradient is monitored by infrared thermography during the casting film cooling and curing process to generate a primary polyimide casting film.

[0022] S104: Based on a polyimide primary cast film, a programmed temperature imidization process is used to complete the closed-loop reaction and generate an initial polyimide substrate film.

[0023] The primary polyimide cast film is placed in an inert atmosphere high-temperature furnace. The heating rate is set according to the activation energy of the polyamic acid dehydration cyclization reaction. The holding temperature is determined with reference to the imidization reaction kinetic curve. The holding time is calculated based on the film thickness and thermal conductivity coefficient. The degree of imidization is monitored by Fourier transform infrared spectroscopy during the reaction process. The reaction is terminated when the intensity of the characteristic peak reaches the saturation value, thus generating the initial polyimide substrate film.

[0024] S2 includes the following steps; S201: Based on the initial polyimide substrate film, an electrostatic dust removal process is used to remove free dust from the surface and generate a clean polyimide substrate film. The initial polyimide substrate film is subjected to a high-voltage electrostatic field with a voltage between the material breakdown voltage and the corona discharge threshold. For example, when the film thickness is 25 micrometers, a voltage of 15 kV is used. The wind speed is adjusted to a value that can suspend dust but does not reach the critical value of the film yield strength. The dust coverage rate is analyzed by optical microscope image analysis. When the coverage rate of the detection area is lower than the preset threshold, the dust removal is terminated, resulting in a clean polyimide substrate film.

[0025] S202: Based on a clean polyimide substrate film, an oxygen plasma treatment process is used to generate active free radicals on the surface, thus generating a plasma-activated substrate film. A clean polyimide substrate film is placed in a plasma reaction chamber. The oxygen flow rate is set according to the chamber volume and reaction rate. The power density is controlled below the thermal damage threshold of the substrate. The processing time is calculated based on the activation energy. For example, when the initial contact angle of the substrate surface is 85 degrees, the contact angle drops to 35 degrees after 180 seconds of processing. The free radical density is semi-quantitatively analyzed by X-ray photoelectron spectroscopy to generate a plasma-activated substrate film.

[0026] S203: Based on plasma-activated substrate film, in-situ contact angle detection process is used to verify surface energy enhancement and generate surface energy verification substrate film; Deionized water droplets are dropped onto the surface of a plasma-activated substrate film with a constant droplet volume. The liquid-solid contact angle is recorded by a high-speed camera to show the interfacial tension equilibrium. The surface energy value is calculated using the Owens-Wendt formula. The hydrophilicity standard is based on the reduction in contact angle. For example, a contact angle of 85 degrees before treatment and 40 degrees after treatment is considered a significant improvement. This process generates a substrate film to verify the surface energy.

[0027] S204: Based on surface energy verification substrate film, a nitrogen-protected transport process is used to prevent secondary contamination of the active surface and generate a surface-activated polyimide substrate film.

[0028] The surface energy verification substrate film is placed in a closed transmission channel. The nitrogen purity is higher than the dew point requirement. The oxygen content is monitored in real time by a sensor. The transmission speed is set according to the activity decay half-life. For example, when the surface activity half-life is 30 minutes, the transmission time is controlled within 10 minutes. An air curtain is set at the end of the channel to isolate the air and generate a surface-activated polyimide substrate film.

[0029] S3 includes the following steps; S301: Based on γ-aminopropyltriethoxysilane, a coupling agent solution is prepared using an ethanol solution preparation process to generate a silane coupling agent activation solution; γ-aminopropyltriethoxysilane stock solution and anhydrous ethanol are mixed at a preset mass ratio, which is determined by solute solubility experiments and target concentration requirements. For example, if the target concentration is set to 2.0% by weight, 2.00 g of silane stock solution and 98.00 g of ethanol are weighed and placed in a sealed container made of polytetrafluoroethylene to avoid catalytic hydrolysis of silane. The magnetic stirrer is set to a speed of 300 revolutions per minute, and the stirring duration is adjusted according to the change in solution viscosity. Stirring is stopped when the transmittance of the solution is stable above the preset threshold and there are no visible suspended matter, thus generating a silane coupling agent activated solution.

[0030] S302: Based on surface-activated polyimide substrate film, a wet coupling agent coating substrate is generated by uniformly coating silane coupling agent activation liquid with micro-gravure roller coating process. The surface-activated polyimide substrate film is fixed on the coating platform. The screen count of the gravure roller is selected according to the target wet film thickness and solution rheology. For example, a 200-line-per-inch anilox roller is used. The silane coupling agent activation liquid is injected into the closed cavity formed by the doctor blade and the anilox roller. The coating speed is controlled in the range of 2 to 5 meters per minute. The surface tension of the substrate is confirmed to be higher than 36 millinewtons per meter by a dyne pen test. The wet film thickness after coating is monitored online by a laser thickness gauge. The thickness fluctuation range is controlled within ±5% of the target value, thus generating a wet coupling agent coated substrate. S303: Based on a wet coupling agent coating substrate, a gradient temperature drying process is used to achieve complete solvent evaporation and generate a dry coupling agent coating substrate; The wet coupling agent coated substrate is placed in a hot air circulating drying oven. The temperature of the first stage is set below the boiling point of the solvent, for example, 80 degrees Celsius for the ethanol system. The duration is calculated based on the solvent volatilization kinetic model. The temperature of the second stage is raised above the condensation initiation temperature of the silane coupling agent but below the glass transition temperature of the substrate, for example, set to 120 degrees Celsius. The duration of each stage is determined based on the plateau period of the weight loss curve determined by thermogravimetric analysis. The final product is tested by Karl Fischer method and the residual solvent content is less than 50 ppm, thus generating a dried coupling agent coated substrate.

[0031] S304: Based on a drying coupling agent coated substrate, an online infrared spectroscopy monitoring process is used to confirm the interfacial chemical bonding and generate an interfacial modified polyimide substrate film.

[0032] The drying coupling agent coating substrate was scanned using a Fourier transform infrared spectrometer in transmission mode, with the scanning range covering the characteristic absorption region of silicon-oxygen bonds. For example, the wavenumber range was set to 1300 to 1000 per centimeter, the resolution was 4 per centimeter, and the number of scans was 32. During data processing, the spectrum of the untreated polyimide film was used as background subtraction. The peak intensity was measured by the peak height after baseline correction. When the ratio of peak height to background noise at a specific wavenumber exceeded the set threshold, it was determined that interfacial chemical bonding had formed, and an interfacial modified polyimide substrate film was generated.

[0033] S4 includes the following steps; S401: Based on liquid silicone rubber and azodicarbonamide foaming agent, a high-speed dispersion process is used to achieve uniform dispersion of the foaming agent and generate a silicone rubber / foaming agent mixture; Liquid silicone rubber and azodicarbonamide foaming agent are added to a high-speed disperser in a preset ratio. This ratio is determined based on the target foaming density and cell structure requirements. For example, 100 parts by mass of liquid silicone rubber corresponds to 5 parts by mass of foaming agent. The linear velocity of the disperser blades is set between 5 and 10 meters per second, and the temperature is controlled below the initial vulcanization temperature of the silicone rubber. The dispersion time is adjusted in real time according to the viscosity change. The dispersion uniformity is observed by sampling and sectioning under a microscope. When the standard deviation of the foaming agent particle size distribution is less than the set threshold, the dispersion is terminated, and a silicone rubber / foaming agent mixture is generated.

[0034] S402: Based on a silicone rubber / foaming agent mixture, an unfoamed precursor film is prepared by calendering film formation process to generate a silicone rubber precursor film; The silicone rubber / foaming agent mixture is fed into a two-roll mill. The roller temperature is maintained within the silicone rubber plasticizing temperature range. The roller gap is adjusted according to the target precursor film thickness. For example, when the target thickness is 0.5 mm, the roller gap is set to 0.6 mm. The mixing time is set according to the rheological properties of the mixture. The flatness of the film edge is monitored by a laser rangefinder. After cutting, there are no visible bubbles or impurities on the film surface, thus generating a silicone rubber precursor film.

[0035] S403: Based on silicone rubber precursor film, a thermal decomposition foaming process is used to activate the foaming agent to generate a closed-cell structure and produce porous silicone rubber foam. The silicone rubber precursor film is placed in a hot air circulating foaming oven. The heating rate is set according to the decomposition kinetic curve of the foaming agent. For example, the decomposition temperature of azodicarbonamide is 195 degrees Celsius, so the oven temperature is set to 200 degrees Celsius. The holding time is calculated based on the film thickness and thermal conductivity. The foaming process is determined by real-time density monitoring. When the density drops to the preset value and the closed-cell rate exceeds 95%, the foaming is terminated, and a porous silicone rubber foam is generated.

[0036] S404: Based on porous silicone rubber foam, a heat-setting process is used to stabilize the cell structure and generate a heat-resistant silicone rubber foam buffer layer.

[0037] The porous silicone rubber foam is transferred to a heat setting device. The temperature is set above the secondary crosslinking temperature of silicone rubber but below the thermal decomposition temperature of the material, such as 180 degrees Celsius. The pressure applied is controlled below the critical collapse pressure of the cell structure. The setting time is adjusted according to the cell wall thickness. The cooling process adopts a stepped cooling mode to prevent stress cracking and generate a heat-resistant silicone rubber foam buffer layer.

[0038] S5 includes the following steps; S501: Based on an interface-modified polyimide substrate film and a heat-resistant silicone rubber foam buffer layer, a preheated composite component is generated using an infrared preheating process. The interface-modified polyimide substrate film and the heat-resistant silicone rubber foamed buffer layer are respectively placed in the radiation area of ​​the infrared heater. The radiation wavelength is selected based on the main absorption band of the material. For example, the absorption rate of polyimide in the 3 to 5 micrometer band exceeds 80%. The power density is set according to the heat distortion temperature of the substrate. The preheating temperature is controlled between the glass transition temperatures of the two materials. The time is calculated based on the thickness and thermal diffusivity. For example, when the substrate thickness is 50 micrometers and the buffer layer thickness is 500 micrometers, the preheating time is set to 30 seconds to generate a preheated composite component.

[0039] S502: Based on preheated composite components, a roller alignment bonding process is used to achieve precise interlayer lamination and generate aligned composite components. The preheated composite component is introduced into the alignment roller system. The synchronization error between the speed of the active roller and the driven roller is controlled within one-thousandth. The position of the substrate edge is captured in real time by the CCD vision system. The position offset is dynamically compensated by the servo motor. The bonding pressure is set within the elastic deformation range of the buffer layer pores. For example, when the critical pressure of the closed-cell structure is 1.5 MPa, the pressure is set to 0.3 MPa to generate the alignment composite component.

[0040] S503: Based on the para-composite component, a flat hot-pressing process is used to promote the diffusion of interfacial molecules and generate a hot-pressed composite substrate. The alignment composite component is moved into a flatbed hot press. The temperature of the hot plate is set above the activation temperature of the silicone rubber molecular chain segment movement, such as 170 degrees Celsius. The pressure value is set according to the material's compressive strength, and the holding time is calculated based on the interface diffusion depth. For example, when the molecular diffusion depth is proportional to the square root of time, it is set to 120 seconds to generate a hot-pressed composite substrate.

[0041] S504: Based on hot-pressed composite substrate, a stepped cooling process is used to release internal stress and generate gradient composite substrate.

[0042] The hot-pressed composite substrate is placed in a programmable temperature control box. The cooling rate in the first stage is set with reference to the material's thermal stress relaxation time. For example, the stress relaxation time of polyimide at 170 degrees Celsius is 300 seconds, and the cooling rate is set to 1 degree Celsius per minute. In the second stage, the cooling rate is increased to 3 degrees Celsius per minute. The duration of each stage is calculated based on the difference in thermal expansion coefficients to generate a gradient composite substrate.

[0043] S6 includes the following steps; S601: Based on vinyl silicone rubber and hydrogen-containing silicone oil crosslinking agent, a defoaming adhesive liquid is prepared by planetary stirring defoaming process to generate a defoamed organosilicon pressure-sensitive adhesive. Vinyl silicone rubber and hydrogen-containing silicone oil crosslinking agent are added to a planetary mixer at a preset hydrogen molar ratio. This ratio is determined based on the target crosslinking density and the adhesion requirements of the pressure-sensitive adhesive. For example, the ratio of vinyl to silane molars is 1:1.2. The revolution speed is set to 500 revolutions per minute, the rotation speed is 1500 revolutions per minute, the vacuum degree is maintained under negative pressure, and the degassing time is adjusted according to the bubble size distribution. When the bubble volume fraction is lower than the set threshold, the mixing is stopped, and a degassed silicone pressure-sensitive adhesive is generated.

[0044] S602: Based on gradient composite substrate, a corona secondary treatment process is used to enhance the surface energy of the buffer layer and generate a surface-activated composite substrate; The surface of the buffer layer of the gradient composite substrate is treated with a corona treatment device. The electrode spacing is set according to the dielectric strength of the material. The energy value per unit area of ​​the treatment intensity is calculated according to the surface energy improvement target. For example, when the initial surface energy is 35 millinewtons per meter, it needs to reach 55 millinewtons per meter. The treatment intensity is set to 50 watts per minute per square meter. The number of treatments is adjusted according to the surface activity decay curve to generate a surface-activated composite substrate.

[0045] S603: Based on surface-activated composite substrate and defoamed silicone pressure-sensitive adhesive, a slit coating process is used to form a wet adhesive layer, thereby generating a wet adhesive coated composite substrate. The surface-activated composite substrate is fixed to the unwinding system of the coating machine. The degassed silicone pressure-sensitive adhesive is injected into the adhesive storage tank of the slit coating head. The coating gap is set according to the target wet adhesive thickness and the rheological index of the adhesive. For example, when the adhesive viscosity is 5000 mPa·s, the gap is set to 200 micrometers. The coating speed is matched with the flow rate of the adhesive supply pump. The substrate tension is controlled within the elastic deformation range to generate a wet adhesive coated composite substrate.

[0046] S604: Based on wet adhesive coating composite substrate, using leveling control process to eliminate coating texture and generate pressure-sensitive adhesive coating layer.

[0047] The wet adhesive-coated composite substrate is horizontally transported to the leveling zone. The leveling time is calculated based on the thixotropic recovery of the adhesive and the coating thickness. The environmental cleanliness is controlled at a particle concentration of less than 100,000 particles per cubic meter, and the temperature is maintained below the gelation initiation temperature of the adhesive, such as 25 degrees Celsius. After leveling, the surface waviness is detected by a laser interferometer, and a pressure-sensitive adhesive coating layer is generated.

[0048] S7 includes the following steps; S701: Based on a pressure-sensitive adhesive coating, an infrared pre-curing process is used to achieve surface gelation and generate a pre-cured adhesive layer; The pressure-sensitive adhesive coating layer is irradiated with short-wavelength infrared radiation. The peak wavelength of the radiation is selected based on the main absorption band of the adhesive layer. For example, the absorption rate of silicone pressure-sensitive adhesive exceeds 70% in the 2 to 4 micrometer wavelength band. The power density is set to a specific proportion when the surface temperature of the adhesive layer reaches the lower limit of the thermal decomposition temperature, such as setting the surface temperature to 120 degrees Celsius. The radiation distance is adjusted according to the thickness of the adhesive layer. The pre-curing time is determined based on the gel point test. When the penetration test value of the adhesive layer surface is lower than the set threshold, the radiation is terminated, and a pre-cured adhesive layer is generated.

[0049] S702: Based on the pre-cured adhesive layer, a hot air circulation curing process is used to complete the main cross-linking reaction and generate a primary cured adhesive layer; The pre-cured adhesive layer is placed in a hot air circulating curing oven. The hot air temperature gradient is set according to the thickness of the adhesive layer and the exothermic curve of the cross-linking reaction. The inlet temperature is lower than the outlet temperature, for example, 100 degrees Celsius at the inlet and 150 degrees Celsius at the outlet. The wind speed is controlled in the range of 0.5 to 1.0 meters per second. The curing time is calculated according to the target value of the degree of cross-linking, for example, when the target degree of cross-linking is 85%, the time is set to 20 minutes to generate the primary cured adhesive layer.

[0050] S703: Based on the primary cured adhesive layer, a post-curing process is used to stabilize the cross-linking network and generate a deep cured adhesive layer.

[0051] The primary cured adhesive layer is transferred to a constant temperature curing chamber. The temperature is set below the glass transition temperature of the material, such as 40 degrees Celsius. The relative humidity is controlled below the critical value for hydrolysis of the crosslinking agent. The curing time is adjusted according to the rate of change of crosslinking density. For example, curing is terminated when the crosslinking density increase is less than 0.5% per hour, thus generating a deep cured adhesive layer.

[0052] S8 includes the following steps; S801: Based on polyester film treated with fluorosilicone release agent, a corona strengthening process is used to improve the surface stability of the release film and generate a modified release film; The polyester film treated with fluorosilicone release agent is subjected to corona treatment equipment. The treatment intensity is set according to the crosslinking density of the release agent and the thermal stability of the substrate. For example, if the curing degree of the release agent is less than 80%, it needs to be increased to 90%. The discharge energy per unit area is controlled in the range of 30 to 50 watts per square meter per minute. The number of treatments is adjusted according to the release force stability test. When the release force fluctuation amplitude is lower than the set threshold for three consecutive tests, the treatment is terminated, and a modified release film is generated.

[0053] S802: Based on a deep-curing adhesive layer and a modified release film, a hot roller lamination process is used to achieve close interfacial adhesion and generate a laminated release film semi-finished product. The deep-cured adhesive layer and the modified release film are simultaneously introduced into the hot lamination roller system. The temperature of the hot roller is set above the viscous flow temperature of the adhesive layer surface, for example, 100 degrees Celsius. The lamination pressure is set according to the compressive elastic modulus of the adhesive layer. The dynamic error of the linear speed matching system is controlled within one percent. After lamination, the interface is verified by peel strength test to generate a semi-finished laminated release film.

[0054] S803: Based on the composite release film semi-finished product, a constant tension winding process is used to generate a winding tape blank; The laminated release film semi-finished product enters the constant tension winding machine. The tension gradient decreases from the unwinding zone to the winding zone. The initial tension is set to a specific proportion of the material's yield strength. For example, when the yield strength of polyester film is 100 MPa, the tension is set to 3 Newtons per millimeter. Tension fluctuations are monitored by a real-time strain gauge. The winding speed is adjusted according to the material's stress relaxation characteristics to generate a winding tape preform.

[0055] S804: Based on the preform of the wound tape, an aging and setting process is used to release internal stress and produce a finished high-temperature masking tape.

[0056] The rolled-up tape blank is placed in a constant temperature and humidity aging chamber. The temperature is set below the glass transition temperature of the material, for example, 25 degrees Celsius. The relative humidity is controlled within the range where the crosslinking agent does not hydrolyze. The aging time is determined according to the internal stress relaxation curve. For example, the aging is terminated when the stress decays to 10% of the initial value, thus producing a high-temperature resistant masking tape product.

[0057] A high-temperature resistant masking tape, including a method for preparing the high-temperature resistant masking tape.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-temperature resistant masking tape, characterized in that, Includes the following steps: S1: Based on polyimide resin, a substrate film is formed by extrusion casting process, and an initial polyimide substrate film is generated by high-temperature imidization treatment; S2: Low-temperature plasma activation treatment is performed on one side of the substrate film to generate a surface-activated polyimide substrate film; S3: A silane coupling agent primer is coated onto the activated surface and then dried to generate an interface-modified polyimide substrate film; S4: Based on silicone rubber material, a closed-cell structure layer is prepared by a foaming agent thermal decomposition process to generate a heat-resistant silicone rubber foam buffer layer. S5: The interface-modified substrate film and the buffer layer are combined by a hot-pressing composite process to generate a gradient composite substrate; S6: A high-temperature resistant silicone pressure-sensitive adhesive is coated on the surface of the buffer layer of the gradient composite substrate to form a pressure-sensitive adhesive coating layer; S7: Perform segmented thermosetting treatment on the coating layer, including pre-curing and deep curing, to generate a deep-cured adhesive layer; S8: Cover the surface of the cured adhesive layer with a high-temperature resistant release film, and then roll it up to produce a finished high-temperature resistant masking tape.

2. The method for preparing a high-temperature resistant masking tape according to claim 1, characterized in that: S1 includes the following steps; S101: Based on polyimide resin particles, a vacuum pre-drying process is used to remove the moisture absorbed by the raw materials and generate pre-dried polyimide resin. S102: Based on pre-dried polyimide resin, a twin-screw melt extrusion process is used to achieve complete plasticization and homogenization of the resin, generating a molten polyimide homogeneous body; S103: Based on molten polyimide homogeneous material, a continuous wet film is formed by using a precision casting die coating process to generate a primary polyimide casting film; S104: Based on a polyimide primary cast film, a programmed temperature imidization process is used to complete the closed-loop reaction and generate an initial polyimide substrate film.

3. The method for preparing a high-temperature resistant masking tape according to claim 1, characterized in that: S2 includes the following steps; S201: Based on the initial polyimide substrate film, an electrostatic dust removal process is used to remove free dust from the surface and generate a clean polyimide substrate film. S202: Based on a clean polyimide substrate film, an oxygen plasma treatment process is used to generate active free radicals on the surface, thus generating a plasma-activated substrate film. S203: Based on plasma-activated substrate film, in-situ contact angle detection process is used to verify surface energy enhancement and generate surface energy verification substrate film; S204: Based on surface energy verification substrate film, a nitrogen-protected transport process is used to prevent secondary contamination of the active surface and generate a surface-activated polyimide substrate film.

4. The method for preparing a high-temperature resistant masking tape according to claim 1, characterized in that: S3 includes the following steps; S301: Based on γ-aminopropyltriethoxysilane, a coupling agent solution is prepared using an ethanol solution preparation process to generate a silane coupling agent activation solution; S302: Based on surface-activated polyimide substrate film, a wet coupling agent coating substrate is generated by uniformly coating silane coupling agent activation liquid with micro-gravure roller coating process. S303: Based on a wet coupling agent coating substrate, a gradient temperature drying process is used to achieve complete solvent evaporation and generate a dry coupling agent coating substrate; S304: Based on a drying coupling agent coated substrate, an online infrared spectroscopy monitoring process is used to confirm the interfacial chemical bonding and generate an interfacial modified polyimide substrate film.

5. The method for preparing a high-temperature resistant masking tape according to claim 1, characterized in that: S4 includes the following steps; S401: Based on liquid silicone rubber and azodicarbonamide foaming agent, a high-speed dispersion process is used to achieve uniform dispersion of the foaming agent and generate a silicone rubber / foaming agent mixture; S402: Based on a silicone rubber / foaming agent mixture, an unfoamed precursor film is prepared by calendering film formation process to generate a silicone rubber precursor film; S403: Based on silicone rubber precursor film, a thermal decomposition foaming process is used to activate the foaming agent to generate a closed-cell structure and produce porous silicone rubber foam. S404: Based on porous silicone rubber foam, a heat-setting process is used to stabilize the cell structure and generate a heat-resistant silicone rubber foam buffer layer.

6. The method for preparing a high-temperature resistant masking tape according to claim 1, characterized in that: S5 includes the following steps; S501: Based on an interface-modified polyimide substrate film and a heat-resistant silicone rubber foam buffer layer, a preheated composite component is generated using an infrared preheating process. S502: Based on preheated composite components, a roller alignment bonding process is used to achieve precise interlayer lamination and generate aligned composite components. S503: Based on the para-composite component, a flat hot-pressing process is used to promote the diffusion of interfacial molecules and generate a hot-pressed composite substrate. S504: Based on hot-pressed composite substrate, a stepped cooling process is used to release internal stress and generate gradient composite substrate.

7. The method for preparing a high-temperature resistant masking tape according to claim 1, characterized in that: S6 includes the following steps; S601: Based on vinyl silicone rubber and hydrogen-containing silicone oil crosslinking agent, a defoaming adhesive liquid is prepared by planetary stirring defoaming process to generate a defoamed organosilicon pressure-sensitive adhesive. S602: Based on gradient composite substrate, a corona secondary treatment process is used to enhance the surface energy of the buffer layer and generate a surface-activated composite substrate; S603: Based on surface-activated composite substrate and defoamed silicone pressure-sensitive adhesive, a slit coating process is used to form a wet adhesive layer, thereby generating a wet adhesive coated composite substrate. S604: Based on wet adhesive coating composite substrate, using leveling control process to eliminate coating texture and generate pressure-sensitive adhesive coating layer.

8. The method for preparing a high-temperature resistant masking tape according to claim 1, characterized in that: S7 includes the following steps; S701: Based on a pressure-sensitive adhesive coating, an infrared pre-curing process is used to achieve surface gelation and generate a pre-cured adhesive layer; S702: Based on the pre-cured adhesive layer, a hot air circulation curing process is used to complete the main cross-linking reaction and generate a primary cured adhesive layer; S703: Based on the primary cured adhesive layer, a post-curing process is used to stabilize the cross-linking network and generate a deep cured adhesive layer.

9. The method for preparing a high-temperature resistant masking tape according to claim 1, characterized in that: S8 includes the following steps; S801: Based on polyester film treated with fluorosilicone release agent, a corona strengthening process is used to improve the surface stability of the release film and generate a modified release film; S802: Based on a deep-curing adhesive layer and a modified release film, a hot roller lamination process is used to achieve close interfacial adhesion and generate a laminated release film semi-finished product. S803: Based on the composite release film semi-finished product, a constant tension winding process is used to generate a winding tape blank; S804: Based on the preform of the wound tape, an aging and setting process is used to release internal stress and produce a finished high-temperature masking tape.

10. A high-temperature resistant masking tape, characterized in that: The method for preparing high-temperature resistant masking tape according to any one of claims 1-9.

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