Lightweight high-temperature-resistant heat-insulating polyimide prepreg, resin-based composite material and preparation method of resin-based composite material

Abstract

The invention provides a light high-temperature-resistant heat-insulating polyimide prepreg, a resin-based composite material and a preparation method of the resin-based composite material. The preparation method comprises the following steps: S1, melting a polyimide resin solution; s2, mixing the molten polyimide resin solution with a light filler to obtain a polyimide resin glue solution; s3, pouring the polyimide resin glue solution into a glue solution tank to prepare a polyimide resin glue film, and controlling the surface density of the polyimide resin glue film by adjusting the gap between rollers and the coating speed; and S4, arranging a fiber reinforcement on the polyimide resin adhesive film, impregnating the polyimide resin adhesive film into the fiber reinforcement through a compression roller, compounding, and then drying to obtain the light high-temperature-resistant heat-insulating polyimide prepreg. The prepreg prepared through the preparation method is more uniform in resin content and lower in volatile matter content, and a composite material flat plate formed through compression has higher temperature resistance, better heat insulation performance and lower density.

Description

Technical Field

[0001] The present invention belongs to the field of composite material preparation, and in particular relates to a lightweight, high temperature resistant and heat insulating polyimide prepreg, a resin-based composite material and a preparation method thereof. Background Art

[0002] Polyimide is one of the organic polymer materials with the best comprehensive performance. Its heat resistance temperature can reach above 600℃, and its long-term use temperature range is 200-500℃. Polyimide resin can maintain relatively high physical and mechanical properties within the temperature range of 400℃. At the same time, its resin-based composite materials have good weather resistance, high temperature resistance, dielectric and wear resistance, and are used in a variety of aerospace material component products.

[0003] The preparation of polyimide resin-based composite materials usually involves first preparing a prepreg, then paving the prepreg into a mold, and curing it using different curing methods to obtain a composite material. The Chinese patent document with publication number CN117360009A discloses a polyimide composite material and a preparation method thereof, which solves the problems of poor electrical conductivity and high temperature resistance of existing polyimide composite materials. The polyimide composite material includes a skin layer and a core layer; the skin layer is wrapped around the outside of the core layer; the skin layer is composed of a carbon nanotube fiber cloth reinforced polyimide composite material; and the core layer is composed of a carbon fiber reinforced polyimide composite material. The preparation method includes: S1, preparing carbon nanotube fiber cloth / polyimide prepreg and carbon fiber / polyimide unidirectional prepreg; S2, designing and laying the carbon nanotube fiber cloth / polyimide prepreg as a skin layer, and then adding a carbon fiber reinforced polyimide prepreg as a core layer design layer, then removing the solvent and curing, and demolding after curing to obtain a polyimide composite material. The polyimide composite material prepared by this patent has high temperature resistance and conductivity, and the skin layer is not easy to fall off under high temperature conditions.

[0004] Polyimide resin-based prepreg is an important intermediate material in the preparation process of polyimide resin-based composite materials. At present, the solution impregnation method is mainly used to prepare prepreg, that is, the polyimide resin is prepared into a solution, and the reinforcing material is impregnated in the polyimide resin solution to obtain the prepreg. The solution method is simple to operate, but there are problems such as uneven prepreg resin content, high volatile content, and easy contamination and inclusion, which cause certain fluctuations and influences on the quality stability of batch products. In addition, polyimide resin-based composite materials still have problems such as insufficient thermal insulation performance, high material density, and high temperature resistance that still needs to be improved.

[0005] Therefore, it is necessary to provide a polyimide resin-based composite material with excellent thermal stability and low density. Summary of the invention

[0006] The technical problem solved by the present invention is to provide a lightweight, high temperature resistant and heat insulating polyimide prepreg, a resin-based composite material and a preparation method thereof, in order to solve the problems of poor thermal stability and high density of the current polyimide resin-based composite materials.

[0007] In order to solve the above problems, the first aspect of the present invention provides a method for preparing a lightweight, high temperature resistant and heat insulating polyimide prepreg, comprising the following steps:

[0008] S1: melting the polyimide resin solution;

[0009] S2: mixing the molten polyimide resin solution with the light filler to obtain a polyimide resin glue solution;

[0010] S3: pouring the polyimide resin adhesive into the adhesive tank to form a polyimide resin adhesive film, and controlling the surface density of the polyimide resin adhesive film by adjusting the roller gap and the coating speed;

[0011] S4: placing a fiber reinforcement on the polyimide resin film, impregnating the polyimide resin film into the fiber reinforcement by a pressing roller, compounding, and then drying to obtain a lightweight, high-temperature-resistant, heat-insulating polyimide prepreg.

[0012] Preferably, in the lightweight high temperature resistant heat insulating polyimide prepreg, the solid content of the polyimide resin is 50%-70% and the viscosity is 60-120mpa . s, the density of the polyimide resin is 1.0±0.2g / ml; the lightweight filler is hollow glass microspheres, the density of the lightweight filler is 0.125-0.60g / cc, and the particle size is 15-135μm; the fiber reinforcement is one of carbon fiber and quartz glass fiber, the warp tensile breaking strength of the fiber reinforcement is ≥1500N / m, the weft tensile breaking strength is ≥1500N / m, the silicon dioxide content is ≥99.9%, and the fiber reinforcement is a plain fabric.

[0013] Preferably, the weight proportions of the raw materials for preparation are: 40-60 parts of polyimide resin solution, 10-20 parts of lightweight filler, and 20-50 parts of fiber reinforcement.

[0014] Preferably, the step S1 specifically includes: drying the polyimide resin solution at 55-70°C for 30-60 minutes to melt it; in the step S2, when the molten polyimide resin solution is mixed with the lightweight filler, the stirring temperature is 50-70°C and the stirring time is 10-30 minutes; in the step S3, the coating temperature is 50-70°C and the coating speed is 3-6m / min; in the step S4, the pressure roller temperature is 60-80°C and the compounding speed is 3-6m / min; the drying temperature is 70-80°C and the drying speed is 2-3m / min.

[0015] The second aspect of the present invention provides a lightweight, high temperature resistant, heat insulating polyimide prepreg prepared by the above-mentioned preparation method.

[0016] The third aspect of the present invention provides a polyimide resin-based composite material, the raw materials for preparing the composite material include:

[0017] Multiple layers of lightweight, high temperature resistant, heat insulating polyimide prepreg as described above and a mixture of fiber fabric and polyimide resin;

[0018] The mixture of fiber fabric and polyimide resin is spread between the lightweight high-temperature-resistant and heat-insulating polyimide prepreg layers.

[0019] Preferably, in the mixture of the fiber fabric and the polyimide resin, the fiber fabric is a chopped fiber fabric; the chopped fiber fabric accounts for 20%-50% of the total mass of the mixture of the fiber fabric and the polyimide resin; the solid content of the polyimide resin is 20%-50%; in the mixture of the fiber fabric and the polyimide resin, the viscosity of the polyimide resin is 20-100mpa . s, and the resin density of the polyimide resin is 1.0±0.1 g / ml.

[0020] Preferably, the chopped fiber fabric is one of chopped carbon fiber and chopped quartz glass fiber, the length of the single fiber is 10-50 mm, the average diameter of the single fiber is 5-10 μm, and the silicon dioxide content is ≥99.9%.

[0021] Preferably, the ply quantity ratio of the lightweight high temperature resistant heat insulating polyimide prepreg layer to the mixture layer of the fiber fabric and the polyimide resin is 4:1-1:1.

[0022] A fourth aspect of the present invention provides a method for preparing the above-mentioned polyimide resin-based composite material, comprising the following steps:

[0023] According to the selected ply sequence and ply ratio, the lightweight, high-temperature resistant, thermally insulating polyimide prepreg is cut according to the mold size, and a mixture of fiber fabric and polyimide resin is laid on the lightweight, high-temperature resistant, thermally insulating polyimide prepreg according to the mold size to obtain an assembly; and then the assembly is placed on a press for gradient curing to obtain the polyimide resin-based composite material.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The method for preparing a lightweight, high-temperature-resistant, heat-insulating polyimide prepreg of the present invention uses a hot-melt method to prepare the prepreg, and the resin content of the polyimide prepreg is more uniform and the volatile content is lower than that of the polyimide prepreg prepared by a solution method, thereby realizing stable batch preparation of the polyimide prepreg; hollow glass microbeads as fillers are added to the polyimide resin solution, which can significantly improve the heat insulation performance of the composite material, reduce the density of the composite material, and have good high-temperature resistance; and the composite material is prepared by using a combination of prepreg, fiber fabric and resin to significantly reduce the mass and density of the composite material.

[0026] The lightweight high-temperature-resistant heat-insulating polyimide prepreg, resin-based composite material and preparation method thereof of the present invention have a quartz fiber fabric content of 60±5%, a resin content of 40±5%, a volatile content in the prepreg of no more than 8%, a more uniform resin content in the prepreg, and a lower volatile content. The pressed composite material flat plate has higher temperature resistance, better heat insulation performance and lower density. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] A first aspect of an embodiment of the present invention provides a method for preparing a lightweight, high temperature resistant, heat insulating polyimide prepreg, comprising the following steps:

[0029] S1: melting the polyimide resin solution;

[0030] S2: mixing the molten polyimide resin solution with the light filler to obtain a polyimide resin glue solution;

[0031] S3: pouring the polyimide resin adhesive into the adhesive tank to form a polyimide resin adhesive film, and controlling the surface density of the polyimide resin adhesive film by adjusting the roller gap and the coating speed;

[0032] S4: placing a fiber reinforcement on the polyimide resin film, impregnating the polyimide resin film into the fiber reinforcement by a pressing roller, compounding, and then drying to obtain a lightweight, high-temperature-resistant, heat-insulating polyimide prepreg.

[0033] The method for preparing a lightweight, high-temperature resistant, heat-insulating polyimide prepreg in an embodiment of the present invention uses a hot-melt method to prepare the prepreg, and the resin content of the polyimide prepreg prepared by the solution method is more uniform and the volatile content is lower, thereby realizing stable batch preparation of polyimide prepreg; adding hollow glass microbeads as filler to the polyimide resin solution can significantly improve the thermal insulation performance of the composite material, reduce the density of the composite material, and at the same time have good high-temperature resistance; by using a combination of prepreg, fiber fabric and resin to prepare the composite material, the mass and density of the composite material can be significantly reduced.

[0034] In some embodiments, the light-weight, high-temperature-resistant, heat-insulating polyimide prepreg has a solid content of 50%-70% and a viscosity of 60-120 mpa. . s, the density of the polyimide resin is 1.0±0.2g / ml; the lightweight filler is hollow glass microspheres, the density of the lightweight filler is 0.125-0.60g / cc, and the particle size is 15-135μm; the fiber reinforcement is one of carbon fiber and quartz glass fiber, the warp tensile breaking strength of the fiber reinforcement is ≥1500N / m, the weft tensile breaking strength is ≥1500N / m, the silicon dioxide content is ≥99.9%, and the fiber reinforcement is a plain weave fabric.

[0035] In some embodiments, the weight proportions of the raw materials for preparation are: 40-60 parts of polyimide resin solution, 10-20 parts of lightweight filler, and 20-50 parts of fiber reinforcement.

[0036] In some embodiments, the step S1 specifically includes: drying the polyimide resin solution at 55-70°C for 30-60 minutes to melt it; in the step S2, when the molten polyimide resin solution is mixed with the lightweight filler, the stirring temperature is 50-70°C and the stirring time is 10-30 minutes; in the step S3, the coating temperature is 50-70°C and the coating speed is 3-6m / min; in the step S4, the pressure roller temperature is 60-80°C and the compounding speed is 3-6m / min; the drying temperature is 70-80°C and the drying speed is 2-3m / min.

[0037] A second aspect of the embodiments of the present invention provides a lightweight, high temperature resistant, heat insulating polyimide prepreg prepared by the above-mentioned preparation method.

[0038] A third aspect of the embodiments of the present invention provides a polyimide resin-based composite material, the raw materials for preparing the composite material include:

[0039] Multiple layers of lightweight, high temperature resistant, heat insulating polyimide prepreg as described above and a mixture of fiber fabric and polyimide resin;

[0040] The mixture of fiber fabric and polyimide resin is spread between the lightweight high-temperature-resistant and heat-insulating polyimide prepreg layers.

[0041] In some embodiments, in the mixture of fiber fabric and polyimide resin, the fiber fabric is a chopped fiber fabric; the chopped fiber fabric accounts for 20%-50% of the total mass of the mixture of fiber fabric and polyimide resin; the solid content of the polyimide resin is 20%-50%; in the mixture of fiber fabric and polyimide resin, the viscosity of the polyimide resin is 20-100mpa . s, and the resin density of the polyimide resin is 1.0±0.1 g / ml.

[0042] In some embodiments, the chopped fiber fabric is one of chopped carbon fiber and chopped quartz glass fiber, the length of the single fiber is 10-50 mm, the average diameter of the single fiber is 5-10 μm, and the silicon dioxide content is ≥99.9%.

[0043] In some embodiments, the ply ratio of the lightweight high temperature resistant heat insulating polyimide prepreg layer to the mixture layer of the fiber fabric and the polyimide resin is 4:1-1:1.

[0044] A fourth aspect of the embodiments of the present invention provides a method for preparing the polyimide resin-based composite material as described above, comprising the following steps:

[0045] According to the selected ply sequence and ply ratio, the lightweight, high-temperature resistant, thermally insulating polyimide prepreg is cut according to the mold size, and a mixture of fiber fabric and polyimide resin is laid on the lightweight, high-temperature resistant, thermally insulating polyimide prepreg according to the mold size to obtain an assembly; and then the assembly is placed on a press for gradient curing to obtain the polyimide resin-based composite material.

[0046] Example 1

[0047] The preparation method of the polyimide resin-based composite material of this embodiment comprises the following steps:

[0048] S1: Pour a polyimide resin solution with a solid content of 60% into a tray container with a sufficiently large surface area, place it in an oven and dry it at 55°C for 30 minutes to melt the resin;

[0049] S2: Pour 60 parts of polyimide resin solution and 10 parts of hollow glass microspheres into a blender and mix them evenly to form a glue solution at a stirring temperature of 60° C. for 10 minutes;

[0050] S3: Pour the prepared polyimide resin glue into the glue tank to form a polyimide resin solution glue film on the release paper. The coating temperature is 55°C. The surface density of the glue film is controlled by adjusting the roller gap and the coating speed. The coating speed is 3m / min.

[0051] S4: 30 parts of quartz glass fiber cloth are pulled onto the polyimide resin film, and the polyimide resin film is impregnated into the quartz glass fiber fabric, the pressure roller temperature is 60°C, and the compounding speed is 3m / min; the prepared product is uniformly dried through a drying tunnel at a set travel speed, the temperature is 70°C, and the speed is 2m / min, and an isolation film is placed on the dried product, and the product is rolled up by a rolling device to obtain a prepreg.

[0052] 20 parts of a polyimide resin solution with a solid content of 20% are mixed with 10 parts of quartz glass chopped fibers, and the mixture is placed in an oven and dried at 60°C for 30 minutes to volatilize the solvent, thereby obtaining a composite material; 16 prepregs are cut according to the size of a mold, and 4 layers of the composition are neatly laid on the prepregs according to the size of the mold and evenly interspersed between the prepregs, with a ply ratio of 4:1; and then the combination of the prepreg and the composition is placed on a press and gradient cured according to a process system of RT-80°C / 1h-160°C / 2h-380°C / 2h to obtain a composite material.

[0053] Example 2

[0054] The preparation method of the polyimide resin-based composite material of this embodiment comprises the following steps:

[0055] S1: Pour a polyimide resin solution with a solid content of 60% into a tray container with a sufficiently large surface area, place it in an oven and dry it at 55°C for 30 minutes to melt the resin;

[0056] S2: Pour 50 parts of polyimide resin solution and 20 parts of hollow glass microspheres into a blender and mix them evenly to form a glue solution at a stirring temperature of 60° C. for 10 minutes;

[0057] S3: Pour the prepared polyimide resin glue into the glue tank to form a polyimide resin solution glue film on the release paper. The coating temperature is 55°C. The surface density of the glue film is controlled by adjusting the roller gap and the coating speed. The coating speed is 3m / min.

[0058] S4: 30 parts of quartz glass fiber cloth are pulled onto the polyimide resin film, and the polyimide resin film is impregnated into the quartz glass fiber fabric, the pressure roller temperature is 60°C, and the compounding speed is 3m / min; the prepared product is uniformly dried through a drying tunnel at a set travel speed, the temperature is 70°C, and the speed is 2m / min, and an isolation film is placed on the dried product, and the product is rolled up by a rolling device to obtain a prepreg.

[0059] 20 parts of a polyimide resin solution with a solid content of 20% are mixed with 10 parts of quartz glass chopped fibers, and the mixture is placed in an oven and dried at 60°C for 30 minutes to volatilize the solvent, thereby obtaining a composite material; 16 prepregs are cut according to the size of a mold, and 4 layers of the composition are neatly laid on the prepregs according to the size of the mold and evenly interspersed between the prepregs, with a ply ratio of 4:1; the combination of the prepreg and the composition is placed on a press and gradient cured according to a process system of RT-80°C / 1h-160°C / 2h-380°C / 2h to obtain a composite material.

[0060] Example 3

[0061] The preparation method of the polyimide resin-based composite material of this embodiment comprises the following steps:

[0062] S1: Pour a polyimide resin solution with a solid content of 60% into a tray container with a sufficiently large surface area, place it in an oven and dry it at 55°C for 30 minutes to melt the resin;

[0063] S2: Pour 55 parts of polyimide resin solution and 15 parts of hollow glass microspheres into a blender and mix them evenly to form a glue solution at a stirring temperature of 60° C. for 10 minutes;

[0064] S3: Pour the prepared polyimide resin glue into the glue tank to form a polyimide resin solution glue film on the release paper. The coating temperature is 55°C. The surface density of the glue film is controlled by adjusting the roller gap and the coating speed. The coating speed is 3m / min.

[0065] S4: 30 parts of quartz glass fiber cloth are pulled onto the polyimide resin film, and the polyimide resin film is impregnated into the quartz glass fiber fabric, the pressure roller temperature is 60°C, and the compounding speed is 3m / min; the prepared product is uniformly dried through a drying tunnel at a set travel speed, the temperature is 70°C, and the speed is 2m / min, and an isolation film is placed on the dried product, and the product is rolled up by a rolling device to obtain a prepreg.

[0066] 20 parts of a polyimide resin solution with a solid content of 20% are mixed with 10 parts of quartz glass chopped fibers, and the mixture is placed in an oven and dried at 60°C for 30 minutes to volatilize the solvent, thereby obtaining a composite material; 16 prepregs are cut according to the size of a mold, and 4 layers of the composition are neatly laid on the prepregs according to the size of the mold and evenly interspersed between the prepregs, with a ply ratio of 4:1; the combination of the prepreg and the composition is placed on a press and gradient cured according to a process system of RT-80°C / 1h-160°C / 2h-380°C / 2h to obtain a composite material.

[0067] Example 4

[0068] The preparation method of the polyimide resin-based composite material of this embodiment comprises the following steps:

[0069] S1: Pour a polyimide resin solution with a solid content of 60% into a tray container with a sufficiently large surface area, place it in an oven and dry it at 55°C for 30 minutes to melt the resin;

[0070] S2: Pour 45 parts of polyimide resin solution and 25 parts of hollow glass microspheres into a blender and mix them evenly to form a glue solution at a stirring temperature of 60° C. for 10 minutes;

[0071] S3: Pour the prepared polyimide resin glue into the glue tank to form a polyimide resin solution glue film on the release paper. The coating temperature is 55°C. The surface density of the glue film is controlled by adjusting the roller gap and the coating speed. The coating speed is 3m / min.

[0072] S4: 30 parts of quartz glass fiber cloth are pulled onto the polyimide resin film, and the polyimide resin film is impregnated into the quartz glass fiber fabric, the pressure roller temperature is 60°C, and the compounding speed is 3m / min; the prepared product is uniformly dried through a drying tunnel at a set travel speed, the temperature is 70°C, and the speed is 2m / min, and an isolation film is placed on the dried product, and the product is rolled up by a rolling device to obtain a prepreg.

[0073] 20 parts of a polyimide resin solution with a solid content of 20% are mixed with 10 parts of quartz glass chopped fibers, and the mixture is placed in an oven and dried at 60°C for 30 minutes to volatilize the solvent, thereby obtaining a composite material; 16 prepregs are cut according to the size of a mold, and 4 layers of the composition are neatly laid on the prepregs according to the size of the mold and evenly interspersed between the prepregs, with a ply ratio of 4:1; the combination of the prepreg and the composition is placed on a press and gradient cured according to a process system of RT-80°C / 1h-160°C / 2h-380°C / 2h to obtain a composite material.

[0074] Example 5

[0075] The preparation method of the polyimide resin-based composite material of this embodiment comprises the following steps:

[0076] S1: Pour a polyimide resin solution with a solid content of 60% into a tray container with a sufficiently large surface area, place it in an oven and dry it at 55°C for 30 minutes to melt the resin;

[0077] S2: Pour 60 parts of polyimide resin solution and 10 parts of hollow glass microspheres into a blender and mix them evenly to form a glue solution at a stirring temperature of 60° C. for 10 minutes;

[0078] S3: Pour the prepared polyimide resin glue into the glue tank to form a polyimide resin solution glue film on the release paper. The coating temperature is 55°C. The surface density of the glue film is controlled by adjusting the roller gap and the coating speed. The coating speed is 3m / min.

[0079] S4: 30 parts of quartz glass fiber cloth are pulled onto the polyimide resin film, and the polyimide resin film is impregnated into the quartz glass fiber fabric, the pressure roller temperature is 60°C, and the compounding speed is 3m / min; the prepared product is uniformly dried through a drying tunnel at a set travel speed, the temperature is 70°C, and the speed is 2m / min, and an isolation film is placed on the dried product, and the product is rolled up by a rolling device to obtain a prepreg.

[0080] 20 parts of a polyimide resin solution with a solid content of 20% are mixed with 10 parts of quartz glass chopped fibers, and the mixture is placed in an oven and dried at 60°C for 30 minutes to evaporate the solvent; 10 prepregs are cut according to the size of a mold, and 10 layers of the composition are neatly laid on the prepreg according to the size of the mold and evenly interspersed between the prepregs, with a ply ratio of 1:1; the combination of the prepreg and the composition is placed on a press and gradient cured according to a process system of RT-80°C / 1h-160°C / 2h-380°C / 2h to obtain a composite material.

[0081] Example 6

[0082] The preparation method of the polyimide resin-based composite material of this embodiment is different from that of Embodiment 1 in that the number of ply layers of the lightweight, high-temperature-resistant and heat-insulating polyimide prepreg layer and the mixture layer of the fiber fabric and the polyimide resin is different, that is, 3:2.

[0083] Example 7

[0084] The preparation method of the polyimide resin-based composite material of this embodiment is different from that of Embodiment 1 in that the number of ply layers of the lightweight, high-temperature-resistant, heat-insulating polyimide prepreg layer and the mixture layer of the fiber fabric and the polyimide resin is different, which is 9:1.

[0085] Example 8

[0086] The preparation method of the polyimide resin-based composite material of this embodiment is different from that of Embodiment 1 in that the number of ply layers of the lightweight, high-temperature-resistant and heat-insulating polyimide prepreg layer and the mixture layer of the fiber fabric and the polyimide resin is different, that is, 2:3.

[0087] Comparative Example 1

[0088] The difference between this comparative example and Example 1 is that the prepreg is prepared by solution impregnation method, and the composite material is prepared by the obtained prepreg and the composition.

[0089] Comparative Example 2

[0090] The difference between this comparative example and Example 1 is that no lightweight filler is added, and the obtained prepreg and the composition are used to prepare a composite material.

[0091] Table 1 Related performance tests of composite materials of various embodiments and comparative examples

[0092]

[0093]

[0094] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing a lightweight, high temperature resistant, heat insulating polyimide prepreg, characterized in that: The steps include: S1: melting the polyimide resin solution; S2: mixing the molten polyimide resin solution with the light filler to obtain a polyimide resin glue solution; S3: pouring the polyimide resin adhesive into the adhesive tank to form a polyimide resin adhesive film, and controlling the surface density of the polyimide resin adhesive film by adjusting the roller gap and the coating speed; S4: placing a fiber reinforcement on the polyimide resin film, impregnating the polyimide resin film into the fiber reinforcement by a pressing roller, compounding, and then drying to obtain a lightweight, high-temperature-resistant, heat-insulating polyimide prepreg.

2. The method for preparing a lightweight, high temperature resistant, heat insulating polyimide prepreg according to claim 1, characterized in that: In the lightweight high temperature resistant heat insulating polyimide prepreg, the solid content of the polyimide resin is 50%-70% and the viscosity is 60-120mpa . s, the density of the polyimide resin is 1.0±0.2 g / ml; The lightweight filler is hollow glass microspheres, the density of the lightweight filler is 0.125-0.60 g / cc, and the particle size is 15-135 μm; The fiber reinforcement is one of carbon fiber and quartz glass fiber, the fiber reinforcement has a warp tensile breaking strength of ≥1500N / m, a weft tensile breaking strength of ≥1500N / m, a silicon dioxide content of ≥99.9%, and is a plain weave fabric.

3. The method for preparing a lightweight, high temperature resistant, heat insulating polyimide prepreg according to claim 1, characterized in that: The mass fractions of the raw materials are as follows: 40-60 parts of polyimide resin solution, 10-20 parts of lightweight filler, and 20-50 parts of fiber reinforcement.

4. The method for preparing a lightweight, high temperature resistant, heat insulating polyimide prepreg according to claim 1, characterized in that: The step S1 specifically comprises: drying the polyimide resin solution at 55-70° C. for 30-60 min to melt it; In the step S2, when the molten polyimide resin solution is mixed with the lightweight filler, the stirring temperature is 50-70° C. and the stirring time is 10-30 min; In step S3, the coating temperature is 50-70°C and the coating speed is 3-6m / min; In step S4, the temperature of the pressing roller is 60-80° C., the compounding speed is 3-6 m / min; the drying temperature is 70-80° C., and the drying speed is 2-3 m / min.

5. A lightweight, high temperature resistant, heat insulating polyimide prepreg prepared by the preparation method according to any one of claims 1 to 4.

6. A polyimide resin-based composite material, characterized in that: The raw materials for its preparation include: A mixture of a multilayer lightweight, high temperature resistant, heat insulating polyimide prepreg as claimed in claim 5 and a fiber fabric and a polyimide resin; The mixture of fiber fabric and polyimide resin is spread between the lightweight high-temperature-resistant and heat-insulating polyimide prepreg layers.

7. The polyimide resin-based composite material according to claim 6, characterized in that: In the mixture of fiber fabric and polyimide resin, the fiber fabric is short-cut fiber fabric; The chopped fiber fabric accounts for 20%-50% of the total mass of the mixture of fiber fabric and polyimide resin; the solid content of the polyimide resin is 20%-50%; In the mixture of fiber fabric and polyimide resin, the viscosity of the polyimide resin is 20-100mpa . s, and the resin density of the polyimide resin is 1.0±0.1 g / ml.

8. The polyimide resin-based composite material according to claim 6, characterized in that: The chopped fiber fabric is one of chopped carbon fiber and chopped quartz glass fiber, the length of the single fiber is 10-50 mm, the average diameter of the single fiber is 5-10 μm, and the silicon dioxide content is ≥99.9%.

9. The polyimide resin-based composite material according to claim 6, characterized in that: The ply quantity ratio of the lightweight high temperature resistant heat insulating polyimide prepreg layer to the mixture layer of the fiber fabric and the polyimide resin is 4:1-1:

1.

10. A method for preparing a polyimide resin-based composite material as claimed in claim 6, characterized in that: The steps include: According to the selected ply sequence and ply ratio, the lightweight, high-temperature resistant, thermally insulating polyimide prepreg is cut according to the mold size, and a mixture of fiber fabric and polyimide resin is laid on the lightweight, high-temperature resistant, thermally insulating polyimide prepreg according to the mold size to obtain an assembly; and then the assembly is placed on a press for gradient curing to obtain the polyimide resin-based composite material.

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