A method for preparing a functional release film coated prepreg tape

Abstract

The application discloses a kind of functional release film coated prepreg preparation method, belong to composite material preparation technical field.The method includes: thermoplastic resin is mixed with solvent according to proportion and heated stirring to form resin solution, functional filler is added in the resin solution to prepare coating solution, coating solution is coated on the surface of prepreg, and the prepreg with functional release film is obtained by drying and winding.The functional filler is graphene, boron nitride or iron oxide and the like material, the release film prepared is not needed to peel off in the process of composite material forming, and can be integrally formed with prepreg.The application integrates the function of release film and prepreg, avoids the problem of filament extraction and fiber damage in the peeling process of traditional release film, and can also give the prepreg electrically conductive, thermal or electromagnetic functional characteristics, simplifies the production process, improves the automation production efficiency and product consistency.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, and in particular to a method for preparing a prepreg tape coated with a functional release film. Background Technology

[0002] Dry-process (hot-melt) prepreg tapes, as important intermediate materials for high-performance continuous fiber composites, have been widely used in aerospace structural components, wind turbine blades, and lightweight automotive parts. These prepreg tapes are typically prepared by compounding a resin film with reinforcing fibers under heating conditions, offering advantages such as no solvent residue, environmental friendliness, and stable product performance.

[0003] In existing technologies, to achieve effective resin transfer and surface protection during the prepreg tape preparation process, a release film or release paper is typically applied to the surface of the prepreg tape. The release film serves as an isolation and protection mechanism during the storage, transportation, and subsequent application of the prepreg tape, but it needs to be peeled off before the composite material is molded. This peeling process can easily cause resin to be carried out from the surface of the prepreg tape, leading to defects such as fraying and fiber damage, which affect the mechanical properties of the composite material and the quality of the finished product.

[0004] Meanwhile, existing release systems mostly rely on release agents or traditional release materials, whose release force is greatly affected by environmental conditions and storage time, easily leading to batch-to-batch instability. This makes it difficult to meet the consistency requirements of automated manufacturing processes such as automatic tape laying, winding, and high-speed molding. In addition, the process of peeling off the release film increases the complexity of the production process, reduces production efficiency, and causes some material waste.

[0005] To address the aforementioned issues, most technical solutions focus on improving release agent formulations or optimizing release film structures, such as by introducing modified siloxane systems to adjust release performance. However, these solutions have not fundamentally solved the problems of interface damage and process efficiency caused by the need to peel off the release film.

[0006] Therefore, how to avoid the adverse effects of the release film peeling process while ensuring the processing performance and interface quality of the prepreg tape, and at the same time improve the functional integration level and automated production adaptability of the prepreg tape, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a method for preparing a prepreg tape coated with a functional release film, so as to solve the problems of filament pulling, fiber damage and low production efficiency caused by the need to peel off the release film in the prior art, and to realize the integration of the release function and multifunctional characteristics of the prepreg tape.

[0008] To achieve the above objectives, the present invention provides the following technical solution: In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film includes the following steps: Step 1, mixing thermoplastic resin and solvent at a mass ratio of (5~15):(90~120) at room temperature, and then stirring at 25~100°C until uniformly mixed to obtain a resin solution; Step 2, adding functional filler to the resin solution and stirring evenly to obtain a coating solution; Step 3, coating the coating solution onto the surface of the prepreg tape; Step 4, drying the prepreg tape coated with the coating solution at 60~150°C and then winding it up to obtain an integrally formed prepreg tape with a functional release film.

[0009] Furthermore, the thermoplastic resin in step one is one of polyethersulfone resin, polysulfone resin, polyphenylene sulfide resin, high-temperature nylon, or polyimide resin.

[0010] Further, the solvent in step one is one of dichloromethane, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpyrrolidone, or tetrahydrofuran.

[0011] Furthermore, the functional filler in step two is one of graphene, boron nitride, or iron oxide.

[0012] Preferably, the mass fraction of the solute in the coating solution in step two is 5% to 25%.

[0013] Optionally, the coating method in step three can be one of spraying, wiping, or dipping.

[0014] Preferably, the drying temperature range in step four is 60~150℃.

[0015] Furthermore, the functional release film does not need to be peeled off during the subsequent composite material molding process and is integrally formed with the prepreg tape.

[0016] Optionally, the prepreg tape is a dry prepreg used for winding, weaving, or 3D printing processes.

[0017] In one embodiment of the present invention, a prepreg tape coated with a functional release film is prepared by the method described in any of the above embodiments.

[0018] Based on the above technical solution, the prepreg tape preparation method of the present invention for coating functional release film involves mixing thermoplastic resin and solvent in a certain proportion to form a uniform and stable resin solution, introducing functional filler into it to prepare a coating solution, uniformly coating the coating solution onto the surface of the prepreg tape, and drying it under controlled temperature conditions, so that the functional release film and the prepreg tape are integrally formed, which solves the problems of fraying, fiber damage and low production efficiency caused by the need to peel off the release film in the prior art.

[0019] Furthermore, by optimizing and controlling the type of thermoplastic resin, solvent system, and their ratio range, the rheological properties and film uniformity of the coating solution can be effectively adjusted, thereby achieving precise control over the release film thickness and film content, and improving product consistency.

[0020] Furthermore, by introducing functional fillers such as graphene, boron nitride, or iron oxide, the resulting release film not only possesses excellent release properties but also endows the prepreg tape with multifunctional properties such as electrical conductivity, thermal conductivity, wave absorption, and low magnetic loss, thus expanding the application scope of prepreg tape in the field of electromagnetic functional composite materials.

[0021] Furthermore, by adopting different coating methods such as spraying, wiping, or dipping, the coating uniformity and production cycle can be flexibly adjusted according to production needs, adapting to continuous and automated production processes and improving process stability.

[0022] Furthermore, by drying the film at a temperature range of 60~150℃, the solvent is fully evaporated and the film layer is densified, ensuring a stable bonding interface between the release film and the prepreg tape, thereby avoiding interface failure during subsequent use.

[0023] Furthermore, by eliminating the traditional release film peeling process, this invention allows the functional release film to directly participate in interface fusion during the composite material molding process. This not only significantly shortens the production process and reduces material loss, but also improves the efficiency and stability of automated tape laying, winding, and 3D printing processes.

[0024] In summary, this invention achieves the integrated development of release function and multifunctional performance while ensuring the mechanical properties of prepreg tape, significantly improving the process adaptability and overall performance of prepreg tape in automated composite material manufacturing. Detailed Implementation

[0025] To make the technical solution, technical features, and beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described are only for explaining the present invention and are not intended to limit the scope of protection of the present invention.

[0026] Furthermore, in the following embodiments, the description of each process step and parameter range is intended to illustrate the implementation of the present invention. Those skilled in the art can make appropriate adjustments or substitutions to the relevant parameters without departing from the technical concept of the present invention.

[0027] It should be noted that the raw materials, process conditions and equipment involved in the following embodiments are all technical means that are conventionally available in the art, and the parts not described in detail are all well-known technologies to those skilled in the art.

[0028] I. Overall Technical Solution Description In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film is provided, belonging to the technical field of dry continuous fiber composite material preparation. This method integrates the release function with the prepreg tape structure by constructing a release film with specific functions in situ on the surface of the prepreg tape, thereby replacing the traditional release film structure that needs to be laid separately and peeled off before use.

[0029] Specifically, the technical solution of the present invention uses thermoplastic resin as the matrix material. First, it is dissolved in a solvent to form a uniform and stable resin solution system. Then, functional fillers are introduced into the system, and a coating liquid with good fluidity and film-forming properties is obtained by full dispersion. Further, the coating liquid is uniformly applied to the surface of the prepreg tape by spraying, wiping or dipping, and dried under controlled temperature conditions to evaporate the solvent and promote the film layer to solidify, thereby forming a continuous, uniform and dense functional release film structure on the surface of the prepreg tape, and finally obtaining an integrally formed functional release film prepreg tape.

[0030] Furthermore, this invention rationally designs the types of thermoplastic resins, solvents, and their mixing ratios to ensure that the resulting resin solution possesses suitable viscosity and rheological properties, thereby guaranteeing the spreadability and uniformity of the coating solution during the coating process. Preferably, the resin-solvent ratio is controlled at (5~15):(90~120), and stirring is performed at 25~100°C to ensure that the system is fully dissolved and that phase separation does not occur.

[0031] Furthermore, by introducing functional fillers such as graphene, boron nitride, or iron oxide into the resin solution, not only can the basic release properties of the release film be maintained, but the prepreg tape can also be endowed with various functional properties such as electrical conductivity, thermal conductivity, electromagnetic shielding, or wave absorption. By controlling the type and content of fillers, the functional properties can be directionally regulated, while ensuring the stability and uniformity of the film structure.

[0032] Furthermore, regarding the coating process, this invention allows for the selection of spraying, wiping, or dipping coating methods according to different production needs, enabling the coating solution to adhere uniformly to the surface of the prepreg tape and form a continuous film structure with controllable thickness. This process is suitable for continuous production lines, which helps improve production efficiency and reduce human error.

[0033] Preferably, during the drying process, the coated prepreg tape is treated at a temperature range of 60~150℃ to allow the solvent to fully evaporate and promote film densification, thereby forming a stable interfacial bonding structure between the prepreg tape and the functional release film. This integrated structure can directly participate in interfacial fusion during subsequent composite material molding processes, eliminating the need for release film peeling.

[0034] Alternatively, the prepreg tape prepared by this invention is a dry prepreg, which can be widely used in various molding processes such as automatic tape laying, fiber winding, composite material weaving, and 3D printing. By eliminating the traditional release film peeling process, not only is material loss during production significantly reduced, but problems such as fraying and fiber damage caused by peeling are also effectively avoided, thereby improving the quality stability of composite material products.

[0035] In summary, by constructing an integrated structure of functional release film and prepreg tape, this invention achieves multifunctional integration and process optimization while ensuring release performance, providing an efficient, stable and scalable technical path for the automated manufacturing of composite materials.

[0036] II. Key Process Steps (I) Step 1: Preparation of resin solution In one embodiment of the present invention, the resin solution is first prepared. Specifically, a thermoplastic resin and a solvent are mixed in a certain proportion at room temperature, wherein the thermoplastic resin is one of polyethersulfone resin, polysulfone resin, polyphenylene sulfide resin, high-temperature nylon, or polyimide resin, and the solvent is one of dichloromethane, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpyrrolidone, or tetrahydrofuran.

[0037] Furthermore, the mass ratio of the thermoplastic resin to the solvent is controlled within the range of (5~15):(90~120) to ensure that the resin can be fully dissolved and form a solution system with suitable viscosity.

[0038] Preferably, the above-mentioned mixture is stirred at 25~100°C. The stirring time can be adjusted according to the viscosity and dissolution of the system to ensure that the resin is completely dissolved and forms a uniform and stable resin solution.

[0039] Furthermore, by controlling the above parameters, the resulting resin solution has good fluidity and stability, providing a basis for the uniform dispersion and coating of functional fillers in the subsequent process.

[0040] (II) Step Two: Preparation of Coating Solution In one embodiment of the present invention, a functional filler is added to the resin solution and stirred to disperse it evenly to obtain a coating solution.

[0041] Furthermore, the functional filler is one of graphene, boron nitride, or iron oxide, and different fillers respectively endow the film with electrical, thermal, or electromagnetic functional properties.

[0042] Preferably, the mass fraction of the solute in the coating solution is controlled within the range of 5% to 25% to ensure good film formation while achieving adjustable film thickness and functional performance.

[0043] Furthermore, during the addition of fillers, continuous stirring or other dispersion methods should be used to prevent filler agglomeration, so that the functional fillers are evenly distributed in the resin matrix, thereby improving the structural uniformity and performance stability of the film.

[0044] (III) Step 3: Coating process In one embodiment of the present invention, the prepared coating solution is coated onto the surface of the prepreg tape.

[0045] Optionally, the coating method can be one of spraying, wiping, or dipping, and the appropriate process method can be selected according to different production conditions and product requirements.

[0046] Furthermore, by controlling the coating speed, coating amount, and process parameters, the coating solution forms a continuous and uniformly distributed liquid film layer on the surface of the prepreg tape.

[0047] Furthermore, this coating process is suitable for continuous production lines, which is conducive to the large-scale and automated preparation of prepreg tapes, while ensuring the consistency of film thickness.

[0048] (iv) Step 4: Drying and Shaping In one embodiment of the present invention, the prepreg tape coated with the coating solution is dried.

[0049] Preferably, the drying temperature is controlled within the range of 60~150℃ to allow the solvent to fully evaporate, while promoting the curing or densification of the resin matrix to form a stable film structure.

[0050] Furthermore, during the drying process, the membrane material gradually changes from a liquid to a solid state and forms a good interfacial bond with the surface of the prepreg tape, thereby obtaining a continuous, uniform and firmly adhered functional release membrane.

[0051] Furthermore, the dried prepreg tape is wound up to obtain a prepreg tape product with an integrally formed functional release film.

[0052] (V) Key Control Points of the Process Furthermore, in the above steps, by synergistically controlling the viscosity of the resin solution, the dispersion state of the filler, the coating uniformity, and the drying temperature, it is possible to achieve uniform release film thickness, continuous structure, and stable performance.

[0053] Preferably, by matching the overall process parameters, the resulting functional release film does not need to be peeled off during the subsequent composite material molding process and can be fused with the interface of the prepreg tape, thereby improving the overall material performance and process efficiency.

[0054] To further illustrate the feasibility and technical effects of the present invention, the following detailed description of the prepreg tape preparation method for coating functional release film according to the present invention is provided in conjunction with several specific embodiments. It should be understood that the following embodiments are specific combinations and application examples of different thermoplastic resins, solvent systems, types of functional fillers, coating methods, and drying conditions, based on the aforementioned overall technical solution and key process steps. These embodiments are used to verify that the present invention can stably form a functional release film integrally molded with the prepreg tape under different parameter conditions, and achieve the corresponding release and functional characteristics. Those skilled in the art can make appropriate adjustments or equivalent substitutions to the specific parameters in the embodiments according to actual needs, but this does not depart from the technical concept and protection scope of the present invention.

[0055] Example 1

[0056] In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film is provided, specifically including the following steps: Step 1: At room temperature, thermoplastic polyethersulfone resin and dichloromethane are mixed at a mass ratio of 5:90, and then stirred at 25°C for 60 minutes to fully dissolve the thermoplastic polyethersulfone resin in the solvent, resulting in a uniform and stable resin solution.

[0057] Step 2: Graphene is added to the resin solution as a functional filler and stirred continuously to ensure that the graphene is evenly dispersed in the resin solution, thereby obtaining a coating solution with conductive function.

[0058] Step 3: The coating solution is uniformly coated onto the surface of the prepreg tape by spraying, so that the coating solution forms a continuous liquid film layer on the surface of the prepreg tape.

[0059] Step four: The prepreg tape coated with the coating solution is placed in an environment of 60°C for drying treatment to allow the solvent to evaporate and form a dense film layer. Then it is wound up to obtain a continuous and uniform prepreg tape with a functional release film.

[0060] Furthermore, the functional release film obtained above is introduced into the subsequent composite material molding process along with the prepreg tape, for example, by composite bonding using a hot press roller of an impregnation machine, so that the functional release film and the prepreg tape achieve interfacial fusion during the molding process, without the need for peeling operation, thereby obtaining a high-performance prepreg tape product with conductive properties.

[0061] Example 2

[0062] In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film is provided, specifically including the following steps: Step one: At room temperature, thermoplastic polyphenylene sulfide resin and N,N-dimethylformamide are mixed at a mass ratio of 6:100, and then stirred at 26°C for 90 minutes to ensure the thermoplastic resin is fully dissolved in the solvent, forming a homogeneous and stable resin solution. By controlling the resin-solvent ratio and stirring temperature, it is beneficial to obtain a solution system with suitable viscosity, thereby providing good flowability and a good film-forming basis for subsequent coating.

[0063] Step two: Boron nitride is added to the resin solution as a functional filler, and the mixture is continuously stirred to ensure uniform dispersion of the boron nitride in the resin matrix, thus obtaining the coating solution. The boron nitride possesses excellent thermal conductivity and electrical insulation properties, and its uniform distribution within the resin system helps improve the thermal management capability and structural stability of the film.

[0064] Preferably, the content of solute in the coating solution is controlled within a suitable range to balance the uniformity of film formation and the realization of functional performance.

[0065] Step 3: The coating solution is uniformly coated onto the surface of the prepreg tape by wiping. By adjusting the coating amount and operating speed during the wiping process, the coating solution forms a continuous liquid film layer with controllable thickness on the surface of the prepreg tape, thereby ensuring the quality of subsequent film formation.

[0066] Step four: The coated prepreg tape is dried at 70°C to allow the solvent to gradually evaporate and promote the densification of the film layer, forming a functional release film that is stably attached to the surface of the prepreg tape. Then, it is wound up to obtain a continuous and uniform functional release film prepreg tape.

[0067] Furthermore, when the prepreg tape prepared above is applied to the subsequent composite material molding process, the functional release film does not need to be peeled off and can directly participate in interface fusion. This not only reduces the problems of fraying and fiber damage caused by traditional release film peeling, but also improves the stability of automated tape laying and molding processes.

[0068] Example 3

[0069] In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film is provided, specifically including the following steps: Step one: At room temperature, thermoplastic polysulfone resin and tetrahydrofuran are mixed at a mass ratio of 7:110, and then stirred at 35°C for 120 minutes to fully dissolve the thermoplastic polysulfone resin in the tetrahydrofuran, obtaining a homogeneous and stable resin solution. By controlling the type of resin, solvent, and ratio, the resulting resin solution can have good flowability and film-forming properties, providing a foundation for the uniform dispersion and continuous coating of subsequent functional fillers.

[0070] Step two involves adding iron oxide as a functional filler to the resin solution and continuously stirring to ensure that the iron oxide particles are uniformly dispersed in the resin solution, thus obtaining a coating solution. The iron oxide can impart certain microwave absorption or magnetic functional properties to the formed film, thereby enabling the final prepreg tape to possess not only release properties but also potential for electromagnetic functional applications. Furthermore, controlling the uniformity of iron oxide dispersion in the system helps improve the consistency of the film's functional distribution and structural stability.

[0071] Preferably, the solute content in the coating solution is controlled within a suitable range to balance the coating performance, film quality, and structural continuity of the final functional release film.

[0072] Step three involves applying the coating solution to the surface of the prepreg tape via dip coating. During the dip coating process, the prepreg tape and the coating solution are in full contact, which facilitates the formation of a relatively complete liquid film layer on the surface of the prepreg tape. Furthermore, by controlling the pull-up speed, the amount of liquid applied, and the surface spreading state during the dip coating process, the thickness of the formed film layer can be made more uniform, thereby improving the quality of the film layer after subsequent drying and film formation.

[0073] Step four involves drying the prepreg tape coated with the coating solution at 80°C to allow the tetrahydrofuran in the system to gradually evaporate and promote film curing and densification. The tape is then wound up to obtain a continuous and uniform prepreg tape with a functional release film. This drying process ensures that the functional release film is stably attached to the surface of the prepreg tape, forming a relatively strong interfacial bond.

[0074] Furthermore, when the functional release film prepreg tape prepared above is applied to subsequent composite material molding processes, the functional release film does not need to be peeled off separately and can directly participate in the interface fusion during the molding process along with the prepreg tape. Compared with the traditional process using a separate release film, this embodiment can reduce peeling steps, reduce the risk of fraying, fiber damage, and material waste, while improving the continuity and stability of the automated production process.

[0075] Furthermore, this embodiment verifies the applicability of the technical solution of the present invention in the preparation of microwave-absorbing or magnetic functional release film prepreg tapes by combining polysulfone resin, tetrahydrofuran and iron oxide, and using dip coating and 80°C drying processes. It shows that the method can achieve the synergistic integration of the release function and electromagnetic functional characteristics of the prepreg tape.

[0076] Example 4

[0077] In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film is provided, specifically including the following steps: Step one: At room temperature, thermoplastic polyphenylene sulfide resin and N,N-dimethylpyrrolidone are mixed at a mass ratio of 7:110. The mixture is then stirred at 45°C for 150 minutes to ensure the polyphenylene sulfide resin is fully dissolved in the solvent, forming a homogeneous and stable resin solution. By selecting the polyphenylene sulfide resin and N,N-dimethylpyrrolidone system, it is beneficial to obtain a resin system with good heat resistance and processing stability. Simultaneously, by controlling the stirring temperature and time, the resin is fully dissolved, thereby ensuring the homogeneity of the system and its subsequent film-forming properties.

[0078] Step two: Graphene is added to the resin solution as a functional filler, and the mixture is continuously stirred to ensure that the graphene is uniformly dispersed in the resin solution, thus obtaining a coating solution. The graphene has excellent electrical and thermal conductivity, and its uniform distribution in the resin system can construct a conductive or thermally conductive network structure after the film layer is formed, thereby endowing the functional release film with good electrical and thermal properties.

[0079] Preferably, by controlling the solute content and graphene dispersion state in the coating solution, the continuity and functional uniformity of the film layer can be improved while ensuring coating performance.

[0080] Step 3: The coating solution is uniformly coated onto the surface of the prepreg tape by spraying. During the spraying process, the spraying pressure, nozzle parameters, and moving speed are adjusted to form a uniformly distributed liquid film layer on the surface of the prepreg tape, which is beneficial for obtaining a functional release film with uniform thickness.

[0081] Furthermore, spraying is suitable for continuous production processes, which can improve production efficiency and reduce the instability caused by manual operation.

[0082] Step four involves drying the prepreg tape coated with the coating solution at 90°C to allow the solvent to gradually evaporate and promote film curing and densification. The tape is then wound up to obtain a continuous and uniform prepreg tape with a functional release film. This temperature condition ensures sufficient solvent evaporation while preventing film cracking or uneven shrinkage.

[0083] Furthermore, when the functional release film prepreg tape prepared above is applied to the subsequent composite material molding process, the functional release film does not need to be peeled off and can directly participate in interface fusion, thereby reducing the interface damage problem caused by release film peeling in traditional processes and improving the efficiency of automated tape laying and molding processes.

[0084] Furthermore, this embodiment verifies the applicability of the present invention in the preparation of conductive / thermal conductive functional release film prepreg tape by combining polyphenylene sulfide resin, N,N-dimethylpyrrolidone and graphene, and using spraying and medium-temperature drying processes, indicating that the method can achieve synergistic integration of release function and conductive and thermal conductivity.

[0085] Example 5

[0086] In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film is provided, specifically including the following steps: Step one: At room temperature, thermoplastic high-temperature nylon resin and N,N-dimethylacetamide are mixed at a mass ratio of 6:90, and then stirred at 25°C for 180 minutes to ensure the high-temperature nylon resin is fully dissolved in the solvent, resulting in a homogeneous and stable resin solution. By selecting a high-temperature nylon resin, the toughness and heat resistance of the film can be improved, while N,N-dimethylacetamide has good solubility, which is beneficial for forming a stable resin system.

[0087] Furthermore, by controlling the stirring time and temperature, the resin solution can achieve better uniformity and a suitable viscosity range, thereby providing favorable conditions for the subsequent dispersion and coating processes of functional fillers.

[0088] Step two: Graphene is added to the resin solution as a functional filler, and the mixture is continuously stirred to ensure that the graphene is uniformly dispersed in the resin system, thus obtaining a coating solution. The graphene can form a conductive and thermally conductive network structure in the resin matrix, thereby endowing the film layer with good electrical and thermal properties.

[0089] Preferably, by controlling the dispersion state of graphene and the solute content in the coating solution, the coating solution can have good film-forming ability while ensuring fluidity, thereby improving the uniformity and functional stability of the film layer.

[0090] Step 3: The coating solution is uniformly coated onto the surface of the prepreg tape by wiping. During the wiping process, the coating pressure and coating speed are adjusted to form a continuous liquid film layer with controllable thickness on the surface of the prepreg tape.

[0091] Furthermore, the wiping method is simple to operate and highly adaptable, suitable for surface treatment of prepreg tapes of different specifications, and helps to ensure uniform film coverage.

[0092] Step four involves drying the prepreg tape coated with the coating solution at 100°C to allow the solvent to gradually evaporate and promote film densification and stabilization. The tape is then wound up to obtain a continuous, uniform prepreg tape with a functional release film. Appropriately increasing the drying temperature helps accelerate the solvent evaporation rate while ensuring the integrity of the film structure.

[0093] Furthermore, when the functional release film prepreg tape prepared above is applied to the subsequent composite material molding process, the functional release film does not need to be peeled off and can directly participate in interface fusion, thereby effectively avoiding the problems of fraying and fiber damage caused during the peeling process of traditional release films.

[0094] Furthermore, this embodiment verifies the applicability of the present invention in the preparation of high-toughness conductive functional release film prepreg tape by combining high-temperature nylon resin, N,N-dimethylacetamide and graphene, and using a wiping coating and high-temperature drying process. It shows that the method can achieve synergistic optimization of release function, mechanical properties and conductivity.

[0095] Example 6

[0096] In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film is provided, specifically including the following steps: Step one: At room temperature, thermoplastic polyethersulfone resin and N,N-dimethylpyrrolidone are mixed at a mass ratio of 10:120. The mixture is then stirred at 55°C for 210 minutes to ensure the polyethersulfone resin is fully dissolved in the solvent, forming a homogeneous and stable resin solution. Polyethersulfone resin possesses excellent heat resistance and mechanical properties, while N,N-dimethylpyrrolidone exhibits good solubility for it. Appropriately increasing the stirring temperature and extending the stirring time can improve the resin dissolution efficiency and enhance the system stability.

[0097] Furthermore, by controlling the above parameters, the resulting resin solution has suitable viscosity and good fluidity, providing a basis for the uniform dispersion and continuous coating of subsequent functional fillers.

[0098] Step two: Boron nitride is added to the resin solution as a functional filler, and the mixture is continuously stirred to ensure uniform dispersion of the boron nitride in the resin system, thus obtaining the coating solution. The boron nitride possesses excellent thermal conductivity and electrical insulation properties, forming thermally conductive channels within the film layer, thereby improving the thermal conductivity of the prepreg tape while maintaining stable electrical properties.

[0099] Preferably, by controlling the dispersion state of boron nitride and the solute content in the coating solution, the coating solution can obtain a uniform and continuous functional film structure while ensuring good coating performance.

[0100] Step 3: The coating solution is applied to the surface of the prepreg tape by dip coating. During the dip coating process, the prepreg tape is fully immersed in the coating solution, and the coating solution forms a uniform liquid film layer on the surface of the prepreg tape by controlling the lifting speed and the amount of liquid applied.

[0101] Furthermore, dip coating is beneficial for improving the integrity of the film coverage and is suitable for application scenarios where high uniformity of the film is required.

[0102] Step four involves drying the prepreg tape coated with the coating solution at 110°C to allow the solvent to gradually evaporate and promote film densification and structural stabilization. The tape is then wound up to obtain a continuous and uniform prepreg tape with a functional release film. The higher drying temperature accelerates the solvent evaporation rate and improves the interfacial bonding strength between the film and the prepreg tape.

[0103] Furthermore, when the functional release film prepreg tape prepared above is applied to the subsequent composite material molding process, the functional release film does not need to be peeled off and can directly participate in interface fusion, thereby avoiding the interface damage problem caused by the traditional release film peeling process and improving the continuity and stability of the automated molding process.

[0104] Furthermore, this embodiment verifies the applicability of the present invention in the preparation of high thermal conductivity insulating functional release film prepreg tape by combining polyethersulfone resin, N,N-dimethylpyrrolidone and boron nitride, and using dip coating and high-temperature drying processes, indicating that the method can effectively integrate release performance and thermal management performance.

[0105] Example 7

[0106] In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film is provided, specifically including the following steps: Step one: At room temperature, mix thermoplastic polyimide resin and tetrahydrofuran at a mass ratio of 7:110, then stir at 75°C for 240 minutes to ensure the polyimide resin is fully dissolved in the tetrahydrofuran, forming a homogeneous and stable resin solution. Polyimide resin has excellent high-temperature resistance and mechanical strength. Increasing the stirring temperature and extending the stirring time facilitates its complete dissolution in the solvent, thereby obtaining a stable resin system suitable for subsequent processing.

[0107] Furthermore, by controlling the dissolution temperature and time, the resin solution can be made to have good homogeneity and suitable rheological properties, thereby providing a reliable basis for the uniform dispersion of functional fillers and subsequent coating.

[0108] Step two: Iron oxide is added to the resin solution as a functional filler, and the mixture is continuously stirred to ensure uniform dispersion of the iron oxide in the resin system, thus obtaining the coating solution. The iron oxide has excellent electromagnetic absorption and magnetic response characteristics, and its uniform distribution in the film layer helps to construct a microwave absorbing structure, thereby endowing the prepreg tape with excellent electromagnetic functional properties.

[0109] Preferably, by controlling the dispersion state of iron oxide and the solute content in the coating solution, the coating solution can improve the functional uniformity and structural stability of the film layer while ensuring the film-forming performance.

[0110] Step 3: The coating solution is uniformly coated onto the surface of the prepreg tape by wiping. During the wiping process, the coating pressure and speed are adjusted to form a continuous liquid film with controllable thickness on the surface of the prepreg tape, thereby improving the consistency of the film.

[0111] Furthermore, the wiping method is suitable for applications where the film thickness needs to be precisely controlled, which is beneficial for obtaining a uniform and stable coating structure.

[0112] Step four involves drying the prepreg tape coated with the coating solution at 120°C to allow the solvent to fully evaporate and promote film curing and densification. The tape is then wound up to obtain a continuous and uniform prepreg tape with a functional release film. This high-temperature drying process further enhances the interfacial bonding strength between the film and the prepreg tape, improving overall structural stability.

[0113] Furthermore, when the functional release film prepreg tape prepared above is applied to the subsequent composite material molding process, the functional release film does not need to be peeled off and can directly participate in interface fusion, thereby avoiding the interface damage problem caused by the traditional release film peeling process and improving the efficiency and stability of the automated molding process.

[0114] Furthermore, this embodiment verifies the applicability of the present invention in the preparation of electromagnetic absorption type functional release film prepreg tape in high temperature environment by combining polyimide resin, tetrahydrofuran and iron oxide, and using a wiping and high temperature drying process. It shows that the method can effectively integrate release performance and electromagnetic functional characteristics, and is particularly suitable for composite material application scenarios with high requirements for high temperature resistance and electromagnetic performance.

[0115] Example 8

[0116] In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film is provided, specifically including the following steps: Step one: At room temperature, thermoplastic polyethersulfone resin and dichloromethane are mixed at a mass ratio of 11:120. The mixture is then stirred at 65°C for 300 minutes to ensure the polyethersulfone resin is fully dissolved in the dichloromethane, forming a homogeneous and stable resin solution. Increasing the resin content and solvent ratio, along with higher temperature and longer stirring time, improves the solubility and stability of the system, thereby obtaining a resin solution suitable for continuous coating processes.

[0117] Furthermore, by combining the above parameters, the resulting resin solution has good fluidity and film-forming ability, while ensuring that the system still has good homogeneity under high concentration conditions.

[0118] Step two: Boron nitride is added to the resin solution as a functional filler, and the mixture is continuously stirred to ensure uniform dispersion of the boron nitride in the resin system, thus obtaining the coating solution. The boron nitride possesses excellent thermal conductivity and electrical insulation properties, and its uniform distribution within the film layer helps to form stable thermal conduction channels, thereby improving the thermal management capability of the prepreg tape.

[0119] Preferably, by controlling the dispersion degree of boron nitride and the solute content in the coating solution, the coating solution can maintain good coating performance while ensuring a high solid content, thereby achieving effective control over the film thickness and functional performance.

[0120] Step 3: The coating solution is uniformly coated onto the surface of the prepreg tape by spraying. During the spraying process, the spraying pressure, nozzle structure, and spraying path are adjusted to form a uniform and continuous liquid film layer on the surface of the prepreg tape.

[0121] Furthermore, spraying is suitable for high-speed continuous production lines, which can improve production efficiency and reduce process fluctuations while ensuring coating uniformity.

[0122] Step four involves drying the prepreg tape coated with the coating solution at 130°C to rapidly evaporate the solvent and promote film densification and structural stabilization. The tape is then wound up to obtain a continuous and uniform prepreg tape with a functional release film. This high-temperature drying process improves film density and interfacial bonding strength, thereby enhancing the overall stability of the product.

[0123] Furthermore, when the functional release film prepreg tape prepared above is applied to the subsequent composite material molding process, the functional release film does not need to be peeled off and can directly participate in interface fusion, thereby avoiding the interface damage problem caused by the traditional release film peeling process and significantly improving the efficiency of automated production.

[0124] Furthermore, this embodiment, through the combination of high resin content, long stirring time, and high drying temperature, along with boron nitride filler and spraying process, verifies the process stability and applicability of the present invention under high parameter conditions, indicating that the method has good application prospects in scenarios requiring high-efficiency continuous production and high thermal conductivity.

[0125] Example 9

[0126] In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film is provided, specifically including the following steps: Step 1: At room temperature, thermoplastic high-temperature nylon resin and N,N-dimethylformamide are mixed at a mass ratio of 5:100. The mixture is then stirred at 90°C for 180 minutes to ensure the high-temperature nylon resin is fully dissolved in the solvent, forming a homogeneous and stable resin solution. Increasing the stirring temperature helps to accelerate the resin dissolution rate while ensuring good homogeneity and suitable flowability of the system.

[0127] Furthermore, high-temperature nylon resin has good toughness and heat resistance. Its combination with the N,N-dimethylformamide system is beneficial to obtaining a resin matrix that has both processing performance and mechanical properties.

[0128] Step two: Graphene is added to the resin solution as a functional filler, and the mixture is continuously stirred to ensure uniform dispersion of the graphene in the resin system, thus obtaining the coating solution. The graphene possesses excellent thermal and electrical conductivity, and it can form a continuous or semi-continuous thermally conductive network structure in the film layer, thereby significantly improving the thermal conductivity of the prepreg tape.

[0129] Preferably, by controlling the dispersion state of graphene and the solute content in the coating solution, the coating solution can maintain good stability and film-forming performance even under high-temperature processing conditions.

[0130] Step 3: The coating solution is applied to the surface of the prepreg tape by dip coating. During the dip coating process, the prepreg tape is fully immersed in the coating solution, and the coating solution forms a uniform and continuous liquid film layer on the surface of the prepreg tape by controlling the lifting speed and the amount of liquid applied.

[0131] Furthermore, dip coating is advantageous for obtaining a stable coating structure under higher temperatures and higher fluidity systems, thereby improving the integrity of the film coverage.

[0132] Step four involves drying the prepreg tape coated with the coating solution at 140°C to rapidly evaporate the solvent and promote film densification and structural stabilization. The tape is then wound up to obtain a continuous and uniform prepreg tape with a functional release film. This high-temperature drying process further enhances the interfacial bonding strength between the film and the prepreg tape, while also improving production efficiency.

[0133] Furthermore, when the functional release film prepreg tape prepared above is applied to the subsequent composite material molding process, the functional release film does not need to be peeled off and can directly participate in interface fusion, thereby avoiding the interface damage problem caused by the traditional release film peeling process and improving the continuity of the automated molding process.

[0134] Furthermore, this embodiment verifies the applicability of the present invention in the preparation of high-temperature thermally conductive functional release film prepreg tape by combining high-temperature nylon resin, N,N-dimethylformamide and graphene, and using dip coating and high-temperature drying processes. It shows that the method can achieve stable integration of release function and thermal conductivity under high process temperature conditions.

[0135] Example 10

[0136] In one embodiment of the present invention, a method for preparing a prepreg tape coated with a functional release film is provided, specifically including the following steps: Step one: At room temperature, thermoplastic polysulfone resin and N,N-dimethylacetamide are mixed at a mass ratio of 15:120. The mixture is then stirred at 100°C for 300 minutes to ensure the polysulfone resin is fully dissolved in the solvent, forming a homogeneous and stable resin solution. Using a higher resin content and solvent ratio, combined with a higher stirring temperature and a longer stirring time, improves the solubility and stability of the system, thereby obtaining a resin solution suitable for high solids content conditions.

[0137] Furthermore, by combining the above high parameters, the resulting resin solution can have a high film-forming ability while ensuring fluidity, which is beneficial for forming a functional film layer with controllable thickness and dense structure.

[0138] Step two: Iron oxide is added to the resin solution as a functional filler, and the mixture is continuously stirred to ensure uniform dispersion of the iron oxide in the resin system, thus obtaining the coating solution. The iron oxide has excellent electromagnetic absorption properties and can form a stable absorbing structure in the film layer, thereby endowing the prepreg tape with excellent electromagnetic functional characteristics.

[0139] Preferably, by controlling the dispersion state of iron oxide and the solute content in the coating solution, the coating solution can still maintain good stability and coating performance under high solid content conditions, thereby ensuring the continuity of the film structure and the uniformity of function.

[0140] Step 3: The coating solution is applied to the surface of the prepreg tape by dip coating. During the dip coating process, the dip coating time, pull-up speed, and liquid volume are controlled to ensure that the coating solution forms a uniform and continuous liquid film layer on the surface of the prepreg tape.

[0141] Furthermore, dip coating is suitable for high-viscosity systems, which helps improve the integrity of the film coverage and enhances the controllability of the film thickness.

[0142] Step four involves drying the prepreg tape coated with the coating solution at 150°C to rapidly evaporate the solvent and promote thorough densification and structural stabilization of the film layer. The tape is then wound up to obtain a continuous and uniform prepreg tape with a functional release film. This high-temperature drying process further enhances the interfacial bonding strength between the film layer and the prepreg tape, improving the overall stability of the product.

[0143] Furthermore, when the functional release film prepreg tape prepared above is applied to the subsequent composite material molding process, the functional release film does not need to be peeled off and can directly participate in interface fusion, thereby avoiding the interface damage problem caused by the traditional release film peeling process and significantly improving the efficiency of automated production.

[0144] Furthermore, this embodiment verifies the applicability of the present invention under the upper limit of process parameters by combining polysulfone resin, N,N-dimethylacetamide and iron oxide, and using dip coating and drying at the highest temperature. It shows that the method can still stably prepare functional release film prepreg tape with a continuous and uniform structure under conditions of high solid content, high temperature processing and high functional requirements, thus fully supporting the rationality and feasibility of the parameter ranges in the claims.

[0145] Comparative Example To verify the effectiveness of the technical solution of this invention, a comparative experiment was conducted using the traditional prepreg tape preparation process.

[0146] Comparative Example 1: Using the existing dry prepreg tape preparation method, an independent release film (such as polyester release film or release paper) is laid on the surface of the prepreg tape. The release film is peeled off before the subsequent composite material molding. The remaining process conditions are basically the same as in Example 1.

[0147] In this comparative example, the release film exists only as an auxiliary material and does not participate in the final product structure.

[0148] Performance comparison and effect analysis The functional release film prepreg tape prepared in Example 1 was compared with the conventional prepreg tape prepared in Comparative Example 1. The results are as follows: (1) Interface quality comparison In Comparative Example 1, during the process of peeling off the release film, resin was easily carried out and fibers were pulled out on the surface of the prepreg tape, and there were problems of loose or damaged fibers in some areas. However, in the embodiment of the present invention, since the functional release film and the prepreg tape are integrally formed, there is no need for peeling operation, which effectively avoids interface disturbance and thus significantly improves the surface integrity of the prepreg tape.

[0149] (2) Comparison of process efficiency Comparative Example 1 requires the addition of a release film laying and peeling process, which makes the process more complex and difficult to automate stably. In contrast, the present invention eliminates the release film peeling step, simplifies the production process, and is more suitable for automatic tape laying, winding and continuous molding processes, thereby significantly improving production efficiency.

[0150] (3) Comparison of material utilization rates In Comparative Example 1, the release film needs to be discarded after use, which results in material waste. In this invention, the functional release film participates in the final molding as part of the prepreg tape structure, without generating additional waste materials, thereby improving material utilization.

[0151] (4) Functional performance comparison The traditional release film in Comparative Example 1 is not functional and only serves as a barrier; however, the present invention introduces functional fillers such as graphene, boron nitride or iron oxide to enable the release film to have functions such as electrical conductivity, thermal conductivity or electromagnetic absorption, thereby realizing the multi-functional integration of the prepreg tape.

[0152] (5) Product consistency comparison In Comparative Example 1, the release film peeling force is greatly affected by the environment and time, which can easily cause performance fluctuations between batches. In this invention, the release film and the prepreg tape are integrally formed, resulting in high interface stability and improving product consistency.

[0153] in conclusion As can be seen from the above comparison, the present invention, by constructing a functional release film on the surface of the prepreg tape and achieving integral molding, not only effectively solves the problems of fraying and fiber damage caused by the peeling of traditional release films, but also significantly simplifies the process and improves production efficiency. At the same time, it endows the prepreg tape with multifunctional characteristics and has good prospects for industrial application.

[0154] In summary, this invention, by coating the surface of the prepreg tape with a functional release film and achieving integral molding of the release film with the prepreg tape, changes the traditional process of prepreg tape preparation that relies on a separate release film. This not only effectively avoids the problems of fraying and fiber damage during the release film peeling process, but also significantly simplifies the production process and improves production efficiency. Furthermore, by introducing functional fillers, the resulting prepreg tape possesses multiple functional properties such as electrical conductivity, thermal conductivity, and electromagnetic absorption, thereby expanding its application range in the field of composite materials and demonstrating good engineering application value and promising prospects for widespread adoption.

[0155] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0156] Furthermore, those skilled in the art can adjust or combine specific embodiments according to actual needs without departing from the concept of the present invention, and such changes or substitutions should be considered to fall within the protection scope of the present invention.

Claims

1. A method for preparing a prepreg tape coated with a functional release film, characterized in that, Includes the following steps: Step 1: Mix the thermoplastic resin and solvent at a mass ratio of (5~15):(90~120) at room temperature, and then stir at 25~100℃ until the mixture is homogeneous to obtain a resin solution; Step 2: Add functional fillers to the resin solution and stir until homogeneous to obtain the coating solution; Step 3: Apply the coating solution to the surface of the prepreg tape; Step 4: After drying the prepreg tape coated with the coating solution at 60~150℃, roll it up to obtain a prepreg tape with an integrally formed functional release film.

2. The method for preparing a prepreg tape coated with a functional release film according to claim 1, characterized in that: The thermoplastic resin in step one is one of polyethersulfone resin, polysulfone resin, polyphenylene sulfide resin, high-temperature nylon, or polyimide resin.

3. The method for preparing a prepreg tape coated with a functional release film according to claim 1, characterized in that: The solvent in step one is one of dichloromethane, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpyrrolidone, or tetrahydrofuran.

4. The method for preparing a prepreg tape coated with a functional release film according to claim 1, characterized in that: The functional filler in step two is one of graphene, boron nitride, or iron oxide.

5. The method for preparing a prepreg tape coated with a functional release film according to claim 1, characterized in that: In step two, the mass fraction of the solute in the coating solution is 5% to 25%.

6. The method for preparing a prepreg tape coated with a functional release film according to claim 1, characterized in that: The coating method in step three is one of spraying, wiping, or dipping.

7. The method for preparing a prepreg tape coated with a functional release film according to claim 1, characterized in that: The drying temperature range in step four is 60~150℃.

8. The method for preparing a prepreg tape coated with a functional release film according to claim 1, characterized in that: The functional release film does not need to be peeled off during the subsequent composite material molding process and is integrally formed with the prepreg tape.

9. The method for preparing a prepreg tape coated with a functional release film according to claim 1, characterized in that: The prepreg tape is a dry prepreg material used for winding, weaving, or 3D printing molding processes.

10. A prepreg tape coated with a functional release film, characterized in that, It is prepared by the method described in any one of claims 1 to 9.