A polyimide-based composite thermal insulation film laminate material structure and preparation method thereof

Abstract

The present invention relates to a polyimide-based composite thermal insulation film laminate material structure and a preparation method thereof, comprising a cross-linked and bonded polyimide thermal insulation base film and a polyimide thermal insulation fiber film, wherein a metal reflective layer is deposited on the side of the polyimide thermal insulation base film facing away from the polyimide thermal insulation fiber film. Although the polyimide thermal insulation fiber film of the present invention has a good thermal insulation effect, it has poor mechanical properties and contains a large number of pores. The polyimide thermal insulation base film is designed into the laminate structure so that it serves as the mechanical support layer and airtight layer of the laminate structure, which can effectively solve the problems of poor mechanical properties and poor thermal convection protection existing in the polyimide thermal insulation fiber film. The polyimide thermal insulation fiber film with a rich pore structure is designed into the laminate structure to significantly reduce the thermal conductivity of the composite film laminate material. In addition, by designing a metal reflective layer into the laminate structure, it can provide good radiant heat protection.

Description

Technical Field

[0001] The present invention relates to the technical field of polyimide composite film preparation, and in particular to a polyimide-based composite thermal insulation film laminate material structure and a preparation method thereof. Background Art

[0002] Polyimide (PI) refers to a class of polymers containing imide rings in the main chain. Due to the presence of highly rigid structures and strong intermolecular association forces in the molecular chain, it has excellent thermal stability, mechanical properties, dielectric properties, chemical stability, etc. It is widely used in aerospace, microelectronics, optoelectronic engineering, high-temperature insulation materials, gas separation and other fields.

[0003] Traditional thermal insulation materials have limited application scope due to their own defects, while polyimide has excellent comprehensive performance. When used as a thermal insulation material, it can break through the application limitations of traditional thermal insulation materials by virtue of its own performance and synthetic advantages. At present, polyimide-based thermal insulation materials mainly include polyimide foam, polyimide fiber, polyimide aerogel and polyimide-based thermal insulation composite materials. Polyimide-based composite diaphragm film materials used in small spaces have broad application prospects. The intrinsic thermal conductivity of polyimide film is about 0.2-0.3W·m -1 ·K -1 It is difficult to use it directly as a heat dissipation material. Adding thermal insulation materials such as nano-silica aerogel into the polyimide matrix is ​​a common composite method, but its thermal conductivity is generally 0.1W·m -1 ·K -1 Its thermal insulation performance is not outstanding. Although the polyimide fiber membrane layer has good thermal insulation effect, its mechanical properties are poor and there are a large number of pores, which are not conducive to thermal convection protection. In summary, it is urgent to propose a polyimide-based composite thermal insulation film laminate material structure and its preparation method. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a polyimide-based composite thermal insulation film laminate material structure and a preparation method thereof in view of the deficiencies of the above-mentioned prior art.

[0005] The present invention provides a preparation method of a polyimide-based composite thermal insulation film laminate material structure, comprising the following steps: surface-treating a first thermal insulation filler with a first coupling agent, mixing the first thermal insulation filler with a first polyamic acid adhesive, coating the first thermal insulation filler with a pore-forming agent and a second polyamic acid adhesive, electrospinning the second thermal insulation filler and drying the second thermal insulation filler to obtain a nanofiber membrane; laminating the composite adhesive film and the nanofiber membrane with a cross-linking agent solution and imidizing the composite adhesive film to obtain a polyimide composite membrane; and depositing a metal reflective layer on the side of the polyimide composite membrane facing away from the nanofiber membrane to obtain a polyimide-based composite thermal insulation film.

[0006] Preferably, the first coupling agent and the second coupling agent are independently at least one of a phthalate coupling agent and an amino-functional silane coupling agent, wherein the phthalate coupling agent is at least one of PN-130, PN-101, and PN-102; and the amino-functional silane coupling agent is at least one of KH-540, KH-550, and KH-602.

[0007] Preferably, a first polyamic acid glue and a second polyamic acid glue are prepared independently of each other by solution polycondensation in a polar aprotic solvent using dibasic acid anhydride and diamine monomers as raw materials; the dibasic acid anhydride is any one or a combination of pyromellitic dianhydride, 3,3',4,4'-dibenzophenone tetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 3,3,4,4-diphenylsulfone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 2,3,3',4'-biphenyltetracarboxylic dianhydride; the diamine is 4,4'-diaminodiphenyl ether, p-phenylenediamine, 4 ,4-diaminobiphenyl, 3,4'-diaminodiphenyl ether, m-phenylenediamine, 4,4'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, any one or a combination thereof; the molar ratio of the dibasic acid anhydride and the diamine is (1-1.01):1; the polar aprotic solvent is any one or a combination of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; the solid content of the first polyamic acid glue and the second polyamic acid glue is independently 5-25%.

[0008] Preferably, the amount of the first coupling agent is 0.5-2% of the mass of the first thermal insulation filler; the amount of the second coupling agent is 0.5-2% of the mass of the second thermal insulation filler.

[0009] Preferably, the crosslinking agent is any one of trimesoyl chloride, triisocyanate, polymaleic anhydride, 1,3,5-tris(4-aminophenoxy)benzene, and melamine, or a combination thereof, and the amount of the crosslinking agent is 10-50 μL / cm 2 .

[0010] Preferably, the metal reflective layer is any one of aluminum, copper, silver and gold, and the metal reflective layer is prepared by any one of vacuum evaporation and vacuum sputtering.

[0011] The present invention also provides a polyimide-based composite thermal insulation film laminate material structure prepared by any of the above-mentioned preparation methods, comprising a cross-linked composite adhesive film and a nanofiber membrane, wherein the composite adhesive film and the nanofiber membrane are stacked and imidized using a cross-linking agent solution to obtain a polyimide composite membrane, and a metal reflective layer is deposited on the side of the polyimide composite membrane facing away from the nanofiber membrane to obtain a polyimide-based composite thermal insulation film; wherein the polyimide thermal insulation base film (composite adhesive film) comprises a polyimide base film and a first thermal insulation filler dispersed in the polyimide base film, and the polyimide thermal insulation fiber membrane (nanofiber membrane) comprises a polyimide fiber membrane formed by electrospinning and a second thermal insulation filler embedded in the polyimide fiber membrane.

[0012] Preferably, the first thermal insulation filler and the second thermal insulation filler independently include any one or a combination of silica aerogel and white carbon black; the average particle size of the first thermal insulation filler and the second thermal insulation filler independently is 5-100nm; the thickness of the polyimide thermal insulation base film is 15-120μm; the thickness of the polyimide thermal insulation fiber film is 50-200μm; the thickness of the metal reflective layer is 0.5-2μm.

[0013] Preferably, the polyimide fiber filaments in the polyimide fiber membrane have a plurality of holes in an open or closed state; the specific surface area of ​​the polyimide fiber membrane is greater than or equal to 500m 2 / g; the average diameter of the polyimide fiber filaments in the polyimide fiber membrane is 50-900nm.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. Although polyimide thermal insulation fiber membrane has good thermal insulation effect, its mechanical properties are poor and there are a lot of pores. Designing the polyimide thermal insulation base membrane into the laminate structure, so that it serves as the mechanical support layer and airtight layer of the laminate structure, can effectively solve the problems of poor mechanical properties and poor thermal convection protection of polyimide thermal insulation fiber membrane;

[0016] The thermal conductivity of polyimide insulation base film is generally 0.1W·m -1 ·K -1 The thermal insulation performance is not outstanding. The design of polyimide thermal insulation fiber membrane with rich pore structure in the laminated structure can greatly reduce the thermal conductivity of the composite film laminated material;

[0017] 2. By designing a metal reflective layer in the laminated structure, it can provide good radiation heat protection;

[0018] 3. The application of cross-linking agent at the interface between polyimide thermal insulation base film and polyimide thermal insulation fiber membrane enables the linear polyimide molecular chain to be transformed into a three-dimensional cross-linked network structure during interface penetration, further strengthening the interface bonding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the polyimide-based composite thermal insulation film laminate material of the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of polyimide composite nanofiber filaments in the polyimide thermal insulation fiber membrane of the polyimide-based composite thermal insulation film laminate material of the present invention.

[0021] Figure 3 This is the stress-strain curve of the polyimide-based composite thermal insulation film laminate material of Example 1 of the present invention.

[0022] Figure 4 This is an infrared thermal imaging image of the polyimide-based composite thermal insulation film laminate material of Example 1 of the present invention.

[0023] Illustration:

[0024] 100, polyimide thermal insulation base film; 200, polyimide thermal insulation fiber film; 300, metal reflective layer;

[0025] 101. Polyimide matrix; 102. First thermal insulation filler; 201. Polyimide fiber membrane; 202. Second thermal insulation filler; 203. Holes. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] It should be noted that when an element is referred to as being “fixed to” another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or there may be an intermediate element.

[0028] The present invention provides a preparation method of a polyimide-based composite thermal insulation film laminate material structure, comprising the following steps: surface-treating a first thermal insulation filler with a first coupling agent, mixing the first thermal insulation filler with a first polyamic acid adhesive, coating the first thermal insulation filler with a pore-forming agent and a second polyamic acid adhesive, electrospinning the second thermal insulation filler and drying the nanofiber membrane; laminating the composite adhesive film and the nanofiber membrane with a cross-linking agent solution and imidizing the composite adhesive film to obtain a polyimide composite film (a two-layer material of a polyimide thermal insulation base film / polyimide thermal insulation fiber membrane); and depositing a metal reflective layer on the side of the polyimide composite membrane facing away from the nanofiber membrane to obtain a polyimide-based composite thermal insulation film.

[0029] In the implementation, the first thermal insulation filler is infiltrated, modified, dispersed, filtered, and dried in an alcohol aqueous solution containing a first coupling agent to obtain a surface-modified first thermal insulation filler, wherein the alcohol aqueous solution is a mixture of water and a low-molecular alcohol, and the mass ratio of water to the low-molecular alcohol is (0.5-2): (9.5-8), and the low-molecular alcohol is any one or a combination of methanol, ethanol, and isopropanol; the second thermal insulation filler is infiltrated, modified, dispersed, filtered, and dried in an alcohol aqueous solution containing a second coupling agent to obtain a surface-modified second thermal insulation filler, wherein the alcohol aqueous solution is a mixture of water and a low-molecular alcohol, and the mass ratio of water to the low-molecular alcohol is (0.5-2): (9.5-8), and the low-molecular alcohol is any one or a combination of methanol, ethanol, and isopropanol;

[0030] Furthermore, a first polyamic acid glue solution and a second polyamic acid glue solution are independently prepared by solution condensation polymerization in a polar aprotic solvent using dibasic acid anhydride and diamine monomers as raw materials; the dibasic acid anhydride is any one or a combination of pyromellitic dianhydride, 3,3',4,4'-dibenzophenone tetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 3,3,4,4-diphenylsulfone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 2,3,3',4'-biphenyltetracarboxylic dianhydride; the diamine is 4,4'-diaminodiphenyl ether, p-phenylenediamine, 4 ,4-diaminobiphenyl, 3,4'-diaminodiphenyl ether, m-phenylenediamine, 4,4'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, any one or a combination thereof; the molar ratio of the dibasic acid anhydride to the diamine is (1-1.01):1; the polar aprotic solvent is any one or a combination of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; the solid content of the first polyamic acid glue and the second polyamic acid glue is independently 5-25%;

[0031] In practice, the surface-treated and modified first thermal insulation filler is added to the polyamic acid second glue at a ratio of 5-50% by mass; the pore-forming agent that promotes the formation of pores is any one of polyvinyl pyrrolidone, polystyrene, and polymethyl methacrylate, or a combination thereof; the mass fraction ratio of the surface-treated and modified second thermal insulation filler, the pore-forming agent, and the polyamic acid second glue is (5-35%): (2-20%): (45-93%);

[0032] Furthermore, the first coupling agent and the second coupling agent are independently at least one of a phthalate coupling agent and an amino-functional silane coupling agent, wherein the phthalate coupling agent is at least one of PN-130, PN-101, and PN-102; and the amino-functional silane coupling agent is at least one of KH-540, KH-550, and KH-602.

[0033] Furthermore, the amount of the first coupling agent is 0.5-2% of the mass of the first thermal insulation filler; the amount of the second coupling agent is 0.5-2% of the mass of the second thermal insulation filler.

[0034] Furthermore, the cross-linking agent is any one of trimesoyl chloride, triisocyanate, polymaleic anhydride, 1,3,5-tris(4-aminophenoxy)benzene, and melamine, or a combination thereof, and the amount of the cross-linking agent is 10-50 μL / cm 2 .

[0035] Furthermore, the metal reflective layer is any one of aluminum, copper, silver and gold, and the metal reflective layer is prepared by any one of vacuum evaporation and vacuum sputtering.

[0036] The present invention also provides a polyimide-based composite thermal insulation film laminate material structure prepared by any of the above-mentioned preparation methods, comprising a cross-linked composite adhesive film and a nanofiber membrane, wherein the composite adhesive film and the nanofiber membrane are stacked and imidized using a cross-linking agent solution to obtain a polyimide composite membrane, and a metal reflective layer is deposited on the side of the polyimide composite membrane facing away from the nanofiber membrane to obtain a polyimide-based composite thermal insulation film; wherein the polyimide thermal insulation base membrane comprises a polyimide base membrane and a first thermal insulation filler dispersed in the polyimide base membrane, and the polyimide thermal insulation fiber membrane comprises a polyimide fiber membrane formed by electrospinning and a second thermal insulation filler embedded in the polyimide fiber membrane.

[0037] Furthermore, the first thermal insulation filler and the second thermal insulation filler independently include any one or a combination of silica aerogel and white carbon black; the average particle size of the first thermal insulation filler and the second thermal insulation filler independently is 5-100nm; the thickness of the polyimide thermal insulation base film is 15-120μm; the thickness of the polyimide thermal insulation fiber film is 50-200μm; the thickness of the metal reflective layer is 0.5-2μm.

[0038] Furthermore, the polyimide fiber filaments in the polyimide fiber membrane have holes in an open or closed state; the specific surface area of ​​the polyimide fiber membrane is greater than or equal to 500m 2 / g; the average diameter of the polyimide fiber filaments in the polyimide fiber membrane is 50-900nm.

[0039] Example 1

[0040] This embodiment 1 provides a method for preparing a polyimide-based composite thermal insulation film laminate material, comprising the following steps:

[0041] (1) The silica aerogel thermal insulation filler is infiltrated, modified, dispersed, filtered, and dried in an alcohol aqueous solution containing a KH550 surface modifier (the mass ratio of water to ethanol is 1:9) to obtain a surface-modified silica aerogel thermal insulation filler.

[0042] (2) Using pyromellitic dianhydride and 4,4'-diaminodiphenyl ether as raw materials (molar ratio of 1.01:1), a polyamic acid adhesive with a solid content of 25% was synthesized by solution polycondensation in a polar aprotic solvent N,N-dimethylacetamide.

[0043] (3) adding 30% by mass of the surface-modified silica aerogel thermal insulation filler obtained in step (1) to the polyamic acid adhesive solution obtained in step (2), stirring and dispersing, filtering, and vacuum degassing to obtain a polyamic acid composite adhesive solution containing the surface-modified silica aerogel thermal insulation filler; then coating the composite adhesive solution on a smooth clean glass plate to form a film, placing the film in a blast drying oven at 100° C. for 1 hour, and removing the smooth clean glass plate after cooling to obtain a polyamic acid composite adhesive film having a residual solvent content of 23%.

[0044] (4) The polyvinyl pyrrolidone pore-forming agent, the surface-modified silica aerogel thermal insulation filler obtained in step (1), and the polyamic acid glue obtained in step (2) are mixed in a mass fraction of 5%:15%:80%, and the mixture is dispersed by stirring, filtered, and vacuum degassed to obtain a polyamic acid composite glue containing the surface-modified thermal insulation filler and the pore-forming agent; then, at a temperature of 25°C and a humidity of 50RH%, a polyamic acid nanofiber membrane containing the surface-modified thermal insulation filler and the pore-forming agent is obtained by electrospinning; and the mixture is treated in a blast drying oven at 80°C for 1 hour to obtain a polyamic acid nanofiber membrane with a solvent residue of 20%.

[0045] (5) The materials are stacked from bottom to top as follows: a smooth clean glass plate with a thickness of 15 mm, a polyamic acid composite adhesive film with a solvent residue of 23% obtained in step (3) (and a 20 μL / cm 2 The four layers are heated in a forced imidization furnace to a temperature of 420°C for thermal imidization. After the furnace cools, the smooth, clean glass plates on both sides of the four layers are removed to produce a polyimide thermal insulation base membrane / polyimide thermal insulation fiber membrane two-layer material.

[0046] (6) The polyimide insulation base film / polyimide insulation fiber film two-layer material obtained in step (5) is transferred to a magnetron sputtering coating apparatus, with the polyimide insulation base film surface facing upward, and pre-sputtered for 320s and then sputtered for 1500s at a rotation speed of 12r / min and a power of 200W to deposit an aluminum metal reflective layer to obtain a polyimide-based composite insulation film laminate material.

[0047] The polyimide-based composite thermal insulation film laminate consists of a polyimide thermal insulation base film, a polyimide thermal insulation fiber film, and a metal reflective layer. The thickness of the polyimide thermal insulation base film is 62 μm; the thickness of the polyimide thermal insulation fiber film is 150 μm, and the specific surface area is 840 m 2 / g, the average diameter of the polyimide fiber is 570nm; the thickness of the metal aluminum reflective layer is 1.4μm.

[0048] Example 2

[0049] This embodiment 2 provides a method for preparing a polyimide-based composite thermal insulation film laminate material, which differs from embodiment 1 in that:

[0050] (4) The polymethyl methacrylate pore-forming agent, the surface-modified silica aerogel thermal insulation filler obtained in step (1), and the polyamic acid glue obtained in step (2) are mixed in a mass fraction of 10%:20%:70%, and the mixture is dispersed by stirring, filtered, and vacuum degassed to obtain a polyamic acid composite glue containing the surface-modified thermal insulation filler and the pore-forming agent; then, at a temperature of 25°C and a humidity of 50RH%, a polyamic acid nanofiber membrane containing the surface-modified thermal insulation filler and the pore-forming agent is obtained by electrospinning; and the mixture is treated in a blast drying oven at 80°C for 1 hour to obtain a polyamic acid nanofiber membrane with a solvent residue of 20%.

[0051] The polyimide-based composite thermal insulation film laminate consists of a polyimide thermal insulation base film, a polyimide thermal insulation fiber film, and a metal reflective layer. The thickness of the polyimide thermal insulation base film is 62 μm; the thickness of the polyimide thermal insulation fiber film is 150 μm, and the specific surface area is 1040 m 2 / g, the average diameter of the polyimide fiber is 640nm; the thickness of the metal aluminum reflective layer is 1.4μm.

[0052] Example 3

[0053] This embodiment 3 provides a method for preparing a polyimide-based composite thermal insulation film laminate material, which differs from embodiment 1 in that:

[0054] (3) adding 25% by mass of the surface-modified silica aerogel thermal insulation filler obtained in step (1) to the polyamic acid adhesive solution obtained in step (2), stirring and dispersing, filtering, and vacuum degassing to obtain a polyamic acid composite adhesive solution containing the surface-modified silica aerogel thermal insulation filler; then coating the composite adhesive solution on a smooth clean glass plate to form a film, placing the film in a blast drying oven at 110° C. for 50 minutes, and removing the smooth clean glass plate after cooling to obtain a polyamic acid composite adhesive film having a residual solvent content of 18%.

[0055] The polyimide-based composite thermal insulation film laminate consists of a polyimide thermal insulation base film, a polyimide thermal insulation fiber film, and a metal reflective layer. The thickness of the polyimide thermal insulation base film is 55 μm; the thickness of the polyimide thermal insulation fiber film is 150 μm, and the specific surface area is 1040 m 2 / g, the average diameter of the polyimide fiber is 640nm; the thickness of the metal aluminum reflective layer is 1.4μm.

[0056] Example 4

[0057] This embodiment 4 provides a method for preparing a polyimide-based composite thermal insulation film laminate material, which differs from embodiment 1 in that:

[0058] (5) The materials are stacked from bottom to top as follows: a smooth clean glass plate with a thickness of 15 mm, a polyamic acid composite adhesive film with a solvent residue of 23% obtained in step (3) (and a 25 μL / cm 2 The four layers are heated to 420°C in a forced imidization furnace for thermal imidization. After the furnace cools, the smooth, clean glass plates on both sides of the four layers are removed to produce a two-layer polyimide thermal insulation base film / polyimide thermal insulation fiber film material.

[0059] The polyimide-based composite thermal insulation film laminate consists of a polyimide thermal insulation base film, a polyimide thermal insulation fiber film, and a metal reflective layer. The thickness of the polyimide thermal insulation base film is 62 μm; the thickness of the polyimide thermal insulation fiber film is 150 μm, and the specific surface area is 840 m 2 / g, the average diameter of the polyimide fiber is 570nm; the thickness of the metal aluminum reflective layer is 1.4μm.

[0060] Comparative Example 1

[0061] This comparative example 1 provides a preparation method of a polyimide thermal insulation base film / polyimide thermal insulation fiber film two-layer material, which is different from Example 1 in that:

[0062] Step (6) is not performed, and after completing step (5), a two-layer material of polyimide thermal insulation base film / polyimide thermal insulation fiber film is obtained.

[0063] The polyimide two-layer material consists of a polyimide insulation base film and a polyimide insulation fiber film. The thickness of the polyimide insulation base film is 62μm; the thickness of the polyimide insulation fiber film is 150μm, and the specific surface area is 840m 2 / g, and the average diameter of the polyimide fiber is 570nm.

[0064] Comparative Example 2

[0065] Comparative Example 2 provides a method for preparing a polyimide-based composite thermal insulation film base layer, which differs from Example 1 in that:

[0066] After completing steps (1), (2), and (3), the polyamic acid composite adhesive film obtained in step (3) is gradually heated to 420° C. in a forced imidization furnace for thermal imidization treatment. After the furnace temperature is cooled, a polyimide thermal insulation base film material is obtained.

[0067] The thickness of the polyimide thermal insulation base film material is 62 μm.

[0068] Comparative Example 3

[0069] Comparative Example 3 provides a method for preparing a polyimide thermal insulation fiber membrane material, which differs from Example 1 in that:

[0070] After completing steps (1), (2), and (4), the polyamic acid nanofiber membrane obtained in step (4) is subjected to thermal imidization treatment by gradually increasing the temperature to 420° C. in a forced imidization furnace. After the furnace temperature is cooled, a polyimide thermal insulation fiber membrane material is obtained.

[0071] The thickness of the polyimide thermal insulation fiber membrane material is 150μm and the specific surface area is 840m 2 / g, and the average diameter of the polyimide fiber is 570nm.

[0072] Comparative Example 4

[0073] Comparative Example 4 provides a method for preparing a polyimide thermal insulation base film / metal reflective layer two-layer material, which differs from Example 1 in that:

[0074] After completing steps (1), (2), and (3), the polyamic acid composite adhesive film obtained in step (3) is gradually heated to 420°C in a forced imidization furnace for thermal imidization. After the furnace temperature is cooled, a polyimide thermal insulation base film material is obtained. Subsequently, step (6) is performed to obtain a polyimide thermal insulation base film / metal reflective layer two-layer material.

[0075] The polyimide two-layer material consists of a polyimide thermal insulation base film with a thickness of 62μm and a metal reflective layer with a thickness of 1.4μm.

[0076] Comparative Example 5

[0077] Comparative Example 5 provides a method for preparing a composite thermal insulation film laminate material having a polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure, which differs from Example 1 in that:

[0078] In step (5), the polyamic acid composite film is not coated with 20 μL / cm 2 Application of trimesoyl chloride solution.

[0079] The polyimide-based composite thermal insulation film laminate consists of a polyimide thermal insulation base film, a polyimide thermal insulation fiber film, and a metal reflective layer. The thickness of the polyimide thermal insulation base film is 62 μm; the thickness of the polyimide thermal insulation fiber film is 150 μm, and the specific surface area is 840 m 2 / g, the average diameter of the polyimide fiber is 570nm; the thickness of the metal aluminum reflective layer is 1.4μm.

[0080] Performance testing

[0081] Mechanical properties:

[0082] The thermal insulation polyimide composite films prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were subjected to a tensile strength test in accordance with ASTM D882 standard.

[0083] Thermal insulation performance:

[0084] The thermal conductivity of the polyimide composite thermal insulation film materials obtained in Examples 1-4 and Comparative Examples 5-9 was measured using a Hot Disk 2500S thermal constant analyzer.

[0085] Infrared imaging analysis was performed on the polyimide composite thermal insulation film materials obtained in Examples 1-4 and Comparative Examples 1-5. A sample of the polyimide composite thermal insulation film material was placed in the center of a 150mm x 150mm heating platform at 100°C. An infrared thermal imager was used to measure the surface temperature of the polyimide composite thermal insulation film material directly above the sample after stabilization for 3 minutes.

[0086] Table 1

[0087]

[0088] Comparative Example 1 is a two-layer material of polyimide thermal insulation base film / polyimide thermal insulation fiber film; Comparative Example 2 is a polyimide thermal insulation base film material; Comparative Example 3 is a polyimide thermal insulation fiber film material; Comparative Example 4 is a two-layer material of polyimide thermal insulation base film / metal reflective layer; Comparative Example 5 is a composite thermal insulation film laminate material of polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure without the application of a cross-linking agent.

[0089] As can be seen from Table 1, the polyimide-based composite thermal insulation film laminated materials of the polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure prepared in Examples 1 to 4 provided in this application have a tensile strength similar to that of the polyimide thermal insulation base film material (Comparative Example 2) and significantly higher than that of the polyimide thermal insulation fiber film material (Comparative Example 3) due to the high-temperature resistant mechanical support of the polyimide thermal insulation base film. During the mechanical stretching process, the polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure of the polyimide-based composite thermal insulation film laminated materials prepared in Examples 1 to 4, the polyimide thermal insulation base film and the polyimide thermal insulation fiber film interpenetrate at the interface, and the three-dimensional cross-linked network structure of the polyimide molecular chains is interspersed and anchored, thus forming a strong interface bond. During the mechanical stretching process, there is no obvious separation between the two layers of the polyimide thermal insulation base film and the polyimide thermal insulation fiber film.

[0090] In the composite thermal insulation film laminate material (Comparative Example 5) composed of a polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure, which does not use a crosslinking agent, interpenetration occurs at the interface between the polyimide thermal insulation base film and the polyimide thermal insulation fiber film due to the interpenetration of polyimide molecular chains. However, in the absence of a crosslinking agent, a three-dimensional crosslinked network structure cannot be formed, and only linear molecular chains are connected, resulting in a relatively weak interfacial bond. During mechanical stretching, the polyimide thermal insulation base film and the polyimide thermal insulation fiber film separated prematurely, and the fiber film layer fell off.

[0091] As can be seen from Table 1, compared with the polyimide insulation base film / polyimide insulation fiber film two-layer material (Comparative Example 1), polyimide insulation base film material (Comparative Example 2), polyimide insulation fiber film material (Comparative Example 3), and polyimide insulation base film / metal reflective layer two-layer material (Comparative Example 4), the polyimide-based composite insulation film laminate material with a polyimide insulation base film / polyimide insulation fiber film / metal reflective layer structure prepared in Examples 1 to 4 provided in this application, the polyimide insulation base film is a heat convection protection layer, the polyimide insulation fiber film is a heat conduction barrier layer, and the metal reflective layer is a heat radiation protection layer, showing a relatively excellent insulation effect.

[0092] The polyimide-based composite thermal insulation film laminate material of the polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure prepared in Examples 1 to 4 provided in the present application has the same laminate structure design as the composite thermal insulation film laminate material of the polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure without the application of a cross-linking agent (Comparative Example 5), and the thermal insulation performance of the two is similar.

[0093] Please refer to Figure 1-Figure 4 In summary, the present invention prepares a polyimide-based composite thermal insulation film laminate material through a polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer laminate structure design. The polyimide thermal insulation base film serves as a high-temperature resistant support layer and a heat convection protection layer, the polyimide thermal insulation fiber film serves as a heat conduction barrier layer, and the metal reflective layer serves as a heat radiation protection layer. The polyimide thermal insulation base film and the polyimide thermal insulation fiber film interpenetrate each other at the interface, and the three-dimensional cross-linked network structure intersperses and anchors the polyimide molecular chains, thereby achieving the polyimide-based composite thermal insulation film laminate material of the polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure provided in the present application, which has the excellent effects of high mechanical strength, high film layer bonding strength, and high thermal insulation performance.

[0094] It should be noted that, in this document, if there are relational terms such as first and second, etc., they are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0095] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

[0096] While the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations of these embodiments are possible. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the claims. Furthermore, the invention described herein is susceptible to other embodiments and may be practiced or implemented in a variety of ways.

Claims

1. A method for preparing a polyimide-based composite thermal insulation film laminate structure, characterized in that: A first thermal insulation filler is surface-treated with a first coupling agent, mixed with a first polyamic acid glue, coated to form a film, and dried to obtain a composite adhesive film; a second thermal insulation filler is surface-treated with a second coupling agent, mixed with a pore-forming agent and a second polyamic acid glue, electrospun, and then dried to obtain a nanofiber membrane; the composite adhesive film and the nanofiber membrane are superimposed and imidized with a cross-linking agent solution to obtain a polyimide composite membrane; a metal reflective layer is deposited on the side of the polyimide composite membrane facing away from the nanofiber membrane to obtain a polyimide-based composite thermal insulation film; the cross-linking agent is any one or a combination of trimesoyl chloride, triisocyanate, polymaleic anhydride, 1,3,5-tris(4-aminophenoxy)benzene, and melamine.

2. The method for preparing a polyimide-based composite thermal insulation film laminate material structure according to claim 1, characterized in that: The first coupling agent and the second coupling agent are independently at least one of a phthalate coupling agent and an amino-functional silane coupling agent, wherein the phthalate coupling agent is at least one of PN-130, PN-101, and PN-102; and the amino-functional silane coupling agent is at least one of KH-540, KH-550, and KH-602.

3. The method for preparing a polyimide-based composite thermal insulation film laminate material structure according to claim 1, characterized in that: The first polyamic acid glue and the second polyamic acid glue are prepared by solution polycondensation in a polar aprotic solvent independently of each other using dibasic acid anhydride and diamine monomers as raw materials; the dibasic acid anhydride is any one of pyromellitic dianhydride, 3,3',4,4'-dibenzophenone tetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 3,3,4,4-diphenylsulfone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 2,3,3',4'-biphenyltetracarboxylic dianhydride or a combination thereof; the diamine is 4,4'-diaminodiphenyl ether, p-phenylenediamine, 4,4 -diaminobiphenyl, 3,4'-diaminodiphenyl ether, m-phenylenediamine, 4,4'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, or a combination thereof; the molar ratio of the dibasic acid anhydride to the diamine is (1-1.01):1; the polar aprotic solvent is any one or a combination of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; the solid contents of the first polyamic acid glue and the second polyamic acid glue are independently 5-25%.

4. The method for preparing a polyimide-based composite thermal insulation film laminate material structure according to claim 1, characterized in that: The amount of the first coupling agent is 0.5-2% of the mass of the first thermal insulation filler; the amount of the second coupling agent is 0.5-2% of the mass of the second thermal insulation filler.

5. The method for preparing a polyimide-based composite thermal insulation film laminate material structure according to claim 1, characterized in that: The amount of the cross-linking agent is 10-50 μL / cm 2 .

6. The method for preparing a polyimide-based composite thermal insulation film laminate material structure according to claim 1, characterized in that: The metal reflective layer is any one of aluminum, copper, silver and gold, and the metal reflective layer is prepared by any one of vacuum evaporation and vacuum sputtering.

7. The method for preparing a polyimide-based composite thermal insulation film laminate material structure according to claim 1, characterized in that: The first thermal insulation filler and the second thermal insulation filler independently include any one of silica aerogel and white carbon black or a combination thereof; the average particle size of the first thermal insulation filler and the second thermal insulation filler independently ranges from 5 to 100 nm.

8. A polyimide-based composite thermal insulation film laminate material structure prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The invention comprises a cross-linked composite adhesive film and a nanofiber membrane. The composite adhesive film and the nanofiber membrane are stacked and imidized with a cross-linking agent solution to obtain a polyimide composite membrane. A metal reflective layer is deposited on the side of the polyimide composite membrane facing away from the nanofiber membrane to obtain a polyimide-based composite thermal insulation film.

9. The polyimide-based composite thermal insulation film laminate material structure according to claim 8, characterized in that: The thickness of the composite adhesive film is 15-120 μm; the thickness of the nanofiber membrane is 50-200 μm; and the thickness of the metal reflective layer is 0.5-2 μm.

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